i/jl \#k&L&\ No. eZ 5" 0 0 ^ .x i; ^_ «** :»^«<, /•<•.. / '••'>• %£ 1)/t<, 0 / f if'f 7 J <*\ ^"^ THE "^ ANATOMY AND PHYSIOLOGY "3 OP smeb hhml&s? ©. III. Artkrieb of the Stomach, Liver and Spleen - 170 Arteria Coeliaca - fa 1. Arteria Coronaria Ventriculi - 171 Its Branches - fa 2. Arteria Hepatica ... 172 Its Branches - - - 173 3. Arteria Splenica - - - 175 Its Branches - - 176 Arteries of the Intestines - - ib. Mesenteric Arteries - - ib. 1. Mesenterica Superior - - - 177 Colica Media - - - 178 -----Dextra - ib. Ileo-Colica - - . - 179 2. Mesenterica Inferior - - - 180 Arteria Colica Sinistra - - #, Arteria HrsmorrhoidaJes - \%[ CONTENTS. XI Page Arteries of the fixed Viscera op the Abdomen 181 1. Arteria? Capsulares - - ib. 2. ------Renales - - - 182 3. Arteria Spermatica - - ib. 4. Arteria? Adiposa? - - - 183 5. ------Ureterica? ... fa 6.------Lirnbares - - 184 Arteries of the Pelvis ... fa Arteria Sacra Media - - - 185 Arteria Iliaca Interna ... fa Order First, of Arteries which keep within the Pelvis 186 1. Arteria Ileo-Iumbalis - - ib. 2.------ Sacra? Laterales - - 187 3. ------Hypogastrica - - - ib. 4.------Vesicales - - - 188 5. ------Haemorrhoidales - - ib. 6. ------Ha?morrhoidea Media - ib. 7. ------Uterina - - - 189 Order Second, of Arteries which go out from the Pelvis ib. 1. Arteria Gluta?a - - 190 2. ------Ischiadica - - - ib. 3. ------Pudica Communis - - 192 4.------Obturatoria - - 194 CHAP. IV. ARTERIES OF THE LOWER EXTREMITY. Iliaca Externa - - - - - 196 General Description of this Artery. Arteria Epigastrica - - - ib. Arteria Circumflexa Ilii - - - 197 The Femoral Artery. Surgery of the Femoral Artery - - 198 Branches of the Femoral Artery - - 203 1. Arteria Profunda Femoris - - 204 2. ------Circumflexa Externa - ib. 3.----------------Interna - - 205 4. ------Perforantes - - 206 1. Arteria Perforans Prima - 207 2.----------------Secunda Magna ib. 3. Arteria Perforans Tertia - 208 4.------------■ Quart a - ib. 5. Arteria Femoralis ... 209 6. Popliteal Artery - - - 211 1. Arteria Articularis Superior Externa 212 2.----------------------Interna ib. 3.--------.--------Media------ ib. 4.----------------Inferior Externa 213 5. ---•-.--------1-------Interna ib. Xll CONTENTS. Arteries or the Leg and Foot 1. Arteria Tibialis Antica Arteria Recurrens ------Malleolaris Interna -----------------Externa Tareea Metatarsea Dorsalis Externa Halucis 2. Arteria Tibialis Postica ------Plantaris Interna ---------------Externa 3. Arteria Peronea Anterior Posterior CHAP. V. General Character of the Veins Sect. 1. Of the Veins, Branches of the Superior Vena Cava Of the Veins of the Head and Neck External Jugular Veins Posterior External Jugular Veins Thyroid Veins Internal Jugular Veins Vertebral Veins Sect. 2. Veins of the Arm Vena Cephalica Vena Basilica Vena Mediana Axillary Vein Subclavian Veins The Superior Vena Cava, the Vena Azygos and Lesser Veins of the Thorax CHAP. II. Of the Veins which unite to form the Inferior Vena Cava Of the Veins of the Leg and Thigh Saphena Major Saphena Minor . Anterior Tibial Veins Sect. 3. Pag« 214 ib. 215 216 ib. ib. 217 ib. 218 219 220 222 223 ib. Op the Structure of Arteries . . 224 Op the Motion of the Blood through the Arteries 225 BOOK III. OF THE VEINS. CHAP. I. 229 235 ib. 236 ib. ib. 237 238 ib. 239 ib. 240 ib. ib. 241 242 243 ib. 244 ib. CONTENTS. X1U Posterior Tibial Veins Venae Peronea? Popliteal Vein External Iliac Veins Vena Cava Abdominalis Renal Veins Spermatic Veins Page 244 ib. ib. 245 ib. ib. ib. BOOK IV. OF THE LYMPHATIC AND LACTEAL SYSTEMS OF VESSELS. CHAP. I. Introductory Views .... Sect. 1. Of the Capillary Vessels 2. Of the Lymphatic System in particular 3. Of the Glands of the Lymphatic System 4. Origin of the Lymphatics, and of the Doctrines of Absorption .... Of the Absorption of Solids .... Examination of some Opinions of Mr. Hunter on the Sub- ject of" Absorption of Solids CHAP. II. Op the Course of the Lymphatics Of the Foot, Leg, and Thigh Of the Lymphatics of the Arm Lymphatics of the Head and Neck Of the Trunks of the Absorbent System The Trunk of the Absorbents of the Right Side Of the Lymphatics and Lacteals of the Intestinal Canal Origin of the Lacteals .... Of the remaining Absorbents of the Solid Viscera ANATOMY OF THE BRAIN AND NERVES. CHAP. I. Structure of Verves .... CHAP. II. Introductory View op the Anatomy of the Brain CHAP. III. Of the Membranes of the Brain, and of the Substance and Texture of the Brain itself Of the Dura Mater .... Of the Septa which intersect the Brain 247 ib. 250 252 254 258 259 263 ib. 267 268 270 271 ib. 273 276 280 288 294 ib. 299 XIV CONTENTS. Page Of the Sphenoidal Folds . . .300 Of the Tunica Arachnoidea . . . 302 Of the Pia Mater . . . .303 Of the Substance of the Brain . . 305 Of the Observations made upon the minute Struc- ture of the Brain . . . .307 Of the Sensibility of the Substance of the Brain 311 CHAP. IV. Of the Veins and Sinuses of the Brain . . 312 Of the Veins which are seen upon the Surface of the Brain ..... 314 Of the Internal Veins of the Brain, and of the Cho- roid Plexus . . . . .317 Of the particular Sinuses . . . 320 Superior Longitudinal Sinus . . . ib. Lateral Sinuses, or the first and second of the An- cients ..... 321 Of the Inferior Longitudinal Sinus . . 323 Of the Internal, Straight, or Fourth Sinus . ib. Posterior Occipital Sinuses . . . 324 The Inferior Lateral Sinuses . . . ib. Of the Lesser Sinuses in the Basis of the Skull . 325 The Sphenoidal Sinuses . . . fa The Cavernous Sinus .... 326 Emissaria Santorini .... 328 CHAP. V. Brain, and principally of the Internal Parts 332 Of the Cavities of the Brain in general , 333 Of the Corpus Callosum and Centrum Ovale of Vieussens 335 Of the Septum Lucidum 336 Lateral Ventricles 337 Of the parts of the Lateral Ventricles 338 Of the Hippocampi, or Cornua Ammonis, and of the Tenia Hippocampi 339 Of the third Ventricle 344 Of the Infundibulum . 345 Infundibulum and Pituitary Gland 346 The Tubercula Quadrigemina 347 The Pineal Gland 348 Posterior Commissure 349 Cerebellum 350 Of the Fourth Ventricle ib. Of the Base of the Brain and Origin of the Nerv BS 352 Cr.e intestines e the /tear t t'f its conical vesicular Lunys — [n the Mettt a a the Liver b the Stomach, r. the Intestines & (',■,( in the Ovaria or Evy beds e the Heart ff Z'hin vesicular Lunys which are tcna like intestines K transparent like the swimming bladder of a fiih a the Bay of the Jaws liy which the kings are blown up OF RESPIRATION. 1! as if intending some particular motion j then gradually the bag swells out under the lower jaw to a great size; then the air contained in it is puffed down into the lungs with a sudden flap of the bag; and in proportion as the jaws are emptied the long sides of the creature are heaved up. The Toad, the Cameleon, the Green Lizard, breathe ex- actly in the same way. The Cameleon has the flat broad jaws of the Frog; they lock into each other, and it does not open its mouth in respiration; it swallows its air in mouthfuls, dnves it downwards into its lungs; its lungs are of a vast extent, stretching from the jaws all along the abdomen : it is the vast size of its lungs, almost concealing the abdominal viscera, that makes Gesner say, " that of the entrails of a Cameleon the lungs only are visible." The air it swallows in greater or smaller quantity as its needs or fears prompt it. When you alarm this timorous animal, it fills it sides just as a Frog swells out its back: and either in this greater respiration, or in its or- dinary breathing, we see it pressing the air onwards from cell to cell; and we see the motion proceeding from its jaws to its breast, and all along its sides, till its lank form is quite puffed up ulmost to bursting. All these creatures have, in addition to their peculiar respira- tion, a peculiar kind of lungs, thin, membranous, and extremely delicate : the lungs even of so great an animal as the Croco- dile, are, when inflated, very delicate and transparent, of a rose colour or slight red, consisting of delicate vesicles, and exactly like the Frog's lungs. The lungs of the Frog are in shape like a fir-cone, with the stalk of the cone on each side fixed to the side of tho heart. But these conical lungs of each side are delicate silvery, perfectly transparent, divided within into innumerable cells like a honeycomb; and these also are so extremely deli- cate, that though the outside membrane is as transparent as a soap-bubble, the divisions can hardly be seen, except by in- flating and drying the lungs and then cutting them. The lungs of the Ask are still more beautiftd, as a specimen of what are called membranous lungs; for the creature is very long in the body, its lungs run down along all its sides; they are about the size of a common earth-worm or writing quill; they end like a blind gut; they are of a bluish white, exquisitely transparent, like the swimming bladder of a fish. It is the nature of membranous lungs to oxygenate but a very small quantity of blood ; they are membranous, only be- cause there is not that vast profusion of arteries, veins, and strong vesicles, which there is in the human lungs. The pul- monic artery and vein are always, in the membranous lungs, extremely small in proportion to the vast system which they 12 OF RESPIRATION serve. There cannot be better examples of this fact than these two drawings of a Frog and of a Newt: in the Frog is seen the small artery and vein spreading more suddenly over the lungs ; in the Newt is seen the same artery and vein, run- ning down more directly, and for a greater length along its lungs: in both we see the artery to be little bigger than- the ranular arteries of the Frog's tongue at the head of the chap- ter. The manner of its coming off from the aorta is seen in the first plan in the book, where figure 2. represents truly the Frog's heart; and there we may observe how small a propor- tion the pulmonic artery bears to the rest of the arterial system. From these peculiarities of the membranous lungs, it is plain that the oxydation of the blood is a process of small import- ance in their system; that this process being of little value with them, they are the better enabled to go into the water, t and to want breath for a time. But chiefly it appears, that the meaning of this peculiarity is not so much to give them the privilege of Amphibia?, in allowing them to go into the water; for many creatures, as the Camelion, all the tribe of Lizards, Newts, Toads, Serpents, he. have these lungs, and yet never approach the water: but that the chief use of it is to establish in this class of animals a peculiar constitution, a permanent, almost inexhaustible irritability, and a tenaciousness of life ; which, I believe, no creature, whether of the land or the wa- ter, wants, which has membranous lungs. And when we are told that these creatures can be kept two days under water, as a proof of their being Amphibia?, I cannot but consider it as a very childish proof; for, in the first place, we see them breath- ing with wonderful regularity when out of the water; when plunged into the water, we see them very soon struggling for breath, and if they can live for two days without air, it is only because they could bear any other kind of injury with equal ease, and could live two days without their heart or head. ♦ FOURTH SPECIES OP RESPIRATION, VIZ. THAT OF FISHES. In this species of respiration the creature breathes neither water nor air, but water mixed with air, and this office is per- formed by gills in place of lungs. The reason why I have called this a species of respiration, needs be very fully explained ; for, though little observed, it is a certain fact, that a creature, without any apparent change upon its system, can do well, having its blood oxygenated at OF RESPIRATION IS one time by gills, at another time by lungs. The Frog, for example, lives long in the water; while it does so, it maybe considered as a foetus which cannot breathe : the young Frog which has not yet acquired its proper and natural respiration, breathes like a fish. For the first fourteen days after hatching from the egg, and while the tadpole is very small, it has gills, which are two long, projecting, fimbriated appendages like fins; by the thirty-sixth day these appendages are taken into the jaws, and form four rows of gills on each side, regular, and like those of a fish; but at the same time, this fetus has its lungs within the body, not to be used till it come out into the air, when the lungs assume their function and the gills shrink. The same system in this instance, which was at first served by gills, is in the end oxygenated by lungs. The motion of gills in fishes is a true and perfect respira- tion : for, in the first place, if there be no air in the water, or not enough of air, they cannot breathe; distilled water is to a fish what the vacuum of an air-pump is to a breathing creature : if you exhaust water with an air-pump, if you boil it, if you distil it, if any way you deprive it of its air, fishes cannot breathe in it, but come up to the surface and gasp for air. If you take a fish out into the air, it is the same with plunging any breathing creature into water, it gasps and dies. Fishes cannot breathe in air wanting water, for that element is not accommodated to their species of lungs ; nor in water wanting air, for then there is no oxygene ; and we find, upon extracting the air from water which fishes have breathed, that it is con- taminated, exactly in the same way with air which had been breathed by any breathing animal, and that it differs very little from that in which a candle has burnt out. This is the reason that when many small fishes are inclosed in a narrow glassy they all struggle for the uppermost place, and that when in winter a fish-pond is entirely frozen over, you must break holes for the fishes, not that they may come and feed, but that they may come and breathe; without this, if the pond be small, they must die. In the respiretion of fishes, there are two curious points to be considered : first, the manner in which their respiration is performed ; and, secondly, the manner in which their blood, when thus oxydated, is distributed over the body. The red part of the gills, which serve as lungs, lie under a broad scale, which defends them from all extraneous bodies, or hurt, or pressure of any kind, for they are exquisitely deli- cate. Their respiration is like the Frog's in this respect, that they swallow the water with their mouths; and in this it is 14 OF RESPIRATION. like the fowl's, that they drive it through among their gills, which lie perfectly passive like the true lungs of a fowl. A fish's gills are ranged in semicircles under the great flap which covers them, four or five semicircles on each side ; the fish opens its mouth wide, fills it with water, shuts the mouth, then drives the water backwards, so that it lifts the great flap and makes its way out behind, and rushes with a sort of stream through among the red gills, raising each semicircle from ano- ther, and making the water play freely round each feathery- like process. It seems to me, that where- ever this mixture of water and air is used* there must be some force to give impres- sion to the air up- on the blood. The depth to which fishes go, and the pressure of the water, must give some effect in impressing the air upon the lungs. The gill must play more or less strongly according to various depths, just as the fish must swim more strongly against a ruder stream. Some fishes, as the Trout, Perch, Salmon, Herring, have more open gills, yet they do not want this power of impressing the air more or less strongly against the gills. The Eel and the flat fishes, as the Skate, have their gills more concealed. They swallow the air by the mouth,* and breathe it out by holes in their side. The shell-fishes give the most curious example (and none more singular than the oyster) of very .regular and beautiful gills ; and therefore I have given two slight marginal drawings ; the first of which shows the heart and lungs; at (a) the heart, which may be seen beating about 40 in a minute ; at (£,) the whole of the gills as they lie out upon the side of the Oyster, and bear a very large proportion to its body. The canal is partly opened, in which the water passes to the gills from the mouth (d;)—and at (e,) figure 2., is seen, separated from the body, a long canal opened; before it was laid open, it was OF RESPIRATION. 15 somewhat of a triangular figure within; it constitutes the basis of all the circles of gills; it contains the most beautiful ranges of holes that can be seen in nature, by which, as is very plain, the water is admitted to each feather of each gill. The fish swallows the water by its mouth, which is at (rf,) figure 1.—drives it down into this great canal, and so out again. It is by this, I am persuaded, that merely the soak- ing of a fish's gills in water would not do, for they might have lain abroad, as indeed they do, and soaked very securely in a shell-fish j but the water must be applied with a degree of force proportioned to the condition of the lungs, or the needs of the system ; and every fish, whatever be the mechanism of its respiration, has this power. Having explained this first point, viz. the mechanism of their gills, I proceed next to explain the circulation of their blood, how their blood is oxydated, and how it is distributed over the body. A fish and an amphibious animal have both of them the simple heart, consisting of one auricle and ventricle, but with this singular variety, that the Frog, for example, wants the heart belonging to the lungs, a small artery only from the common system performing the office; while the fish again wants the heart, which should circulate the blood through the 16 OF RESPIRATION. body, and has that heart only which belongs to the lungs. The whole blood of the fish passes through this single heart, and therefore the whole mass circulates, parcel by parcel, through the gills, for every time that it circulates through the body. We shall begin its circulation, then, at the heart. First, The whole blood of the body is returned into the heart of a Skate, by two great veins. These two great veins deliver it into a vast auricle, or reservoir rather, which lies over the heart. The auricle delivers it into a strong ventricle, whose action is further strengthened by the action of its aorta, which from the heart up to where the valves are, is very muscular and powerful, and constitutes, in a manner, a part of the heart. But this great vessel must in this species of circulation change its name, for it really is not an aorta, has nothing to do with the body : both the heart of a fish, and this its only vessel, belong entirely to the lungs or gills, and as these are called bronchiae, this is the bronchial artery. The gills of this fish are five in number on each side, and on each side the bronchial artery gives out two branches which serve the five gills; the lower branch is large, and serves the three lower gills; the higher branch, which goes off like one of the arms of a cross, serves the two upper gills. Secondly, These arteries being distributed along the gills, divide into exquisitely small branches producing that feathery appearance which is so beautiful. Those minute subdivisions of the bronchial vessels expose the blood to the air. This may explain to us how in the human lungs the exposing of the blood, even with the interposition of membranes and of the arterial coats, may be sufficient for the oxydation of the blood. All the blood thus oxygenated is returned by veins, corres- ponding exactly in number and arrangement with their arte- ries : and the heart being turned aside, and all the other viscera taken out, the veins are seen accompanying their arte- ries and emerging from the gills to form the aorta. Thirdly, The aorta is formed by the veins of the gills, and the veins of the gills lie close upon the skull of the fish, and the aorta upon the back-bone ; and this vessel is in one sense a vein, since it is a continuation of those veins which return the blood of the gills; but both in office and form it is a true aorta; in office, because it distributes blood to the whole body; and in form, because it no sooner swells out into the shape of an aorta than its coats grow hard, strong, muscular, fit for its office, while those of the veins from which it is formed are pellucid, delicate, and very tender. The aorta is full of the oxydated blood of the gills; and although, bv the delicate circulation of the gills, it has lost all communi- cation with the heart, it circulates this oxydated blood through OF RESPIRATION. 17 the body to all the muscles, glands, viscera, &c. without the intervention of a new heart. The veins which return the blood of this aorta are the or- dinary veins; they arrive in two great branches at the heart, and need not be further explained. I will not be at the trouble to repeat the tedious calculations of authors concerning the immense surface which the gills ex- pose : let the student look to the gills, and he will presently, with the help of this short sketch, understand how the whole function goes on. JV.°1 FIFTH SPECIES OF RESPIRATION, VIZ. THAT OF INSECTS. There is in this kind of respiration no breathing organ like the lungs, but tracheas or air tubes by which air enters into all parts of their body. What is most perplexing in this species of respiration is the prodigious quantity of air which these creatures receive; the little connection betwixt the air tubes and the heart; the im- possibility of tracing blood vessels from the heart to the various parts to nourish them ; and the clearness with which we see their air tubes branching over all parts of their body. The stomach, bowels, and other viscera, the legs and wings, even the^very scales of insects, have branches of the air tubes dividing over their surfaces like the delicate vessels of leaves and flowers. In short, the magnitude of these air- tubes is quite surprising; and their branchings are so minute, delicate, universal over all the body, that it looks almost as if the air tube had exchanged functions with the heart and arteries. It is plain by these expressions of admiration that I do not mean to attempt so difficult a subject as this at present: I only mention diffiulties which it is surprising that others have not declared and investigated, for nothing can be more inte- resting. The little that we do know shall be simply and plainly told. VOL. II. C 18 OF RESPIRATION. The forms of insects are often very strange, their lives very irregular, sometimes in water, sometimes in air; many of them begin in worms, and end their lives as Flies and Moths; and according to these varieties of their form, or life, or gene- ration, their air tubes are various. Sometimes, as in the common Bee, they have nearly the form of lungs ; they begin like two bags, resembling those of the Alga Marina or sea-weed, in shape ; and these bags dis- tribute pulmonary tubes, with occasional bag-like dilatations in the course of the tubes, through all the body. More com- monly the air tubes of insects are direct tubes, mere tracheas, of a very singular construction; they, have rings like the tra- cheas of animals; they have a delicate membrane covering these rings and forming them into a tube : the tube continues always rigid like a flexible catheter, or other tube of twisted wire not liable to collapse : they begin by many open mouths opening along the sides of the insect, and they terminate in myriads of vessels, which in their forms and progress over the various parts of the body, resemble blood vessels more than it is easy to conceive. These air tubes being thus rigid, are always full of air, and by their refractions through the transparent parts of the insect's body they give it in the micros- cope a great degree of brilliancy; as for example in the Louse, whose air tubes make the brilliant lines and points which are contrasted like a silvery colour with the dark and opaque parts; or in the Mite, which is as beautiful in the micros- cope as the Louse ; and when the larger insects are prepared by drying and varnishing, and preserved in turpentine, the air tubes are beautiful. Of these curious particulars, the openings of the air tubes are best seen in the Worm from which the common Butterfly is produced; we count these holes down the sides, we name them puncta respiratoria, spi- racula, or most commonly stigmata. (Vide figure 1.) Their transparency and brilliancy is well understood from the view of the microscope Louscf, (figure 2.—That particular form in which they resemble more the lungs of animals is seen in the pulmonic bags (aa)—and the tracheas or air tubes (bb)—of the common Bee, (figure 3.)—Their exquisite branchings through the various parts are well seen in the drawing of the air tubes which (run along the wings of a Bee, • figure 4.) or those which twist OF RESPIRATION. 19 and ramify round the intestines and stomach of a Worm ; and it is not to be forgotten, that though the beginnings of these tubes in their great tracheas and near the puncta respiratoria are quite transparent, their extreme branches are beautifully white like vessels filled with chyle, or rather one might be apt to mistake them for nerves. Of the way in which this function is performed, there must be more varieties than we can know or comprehend : this we may safely conclude from the little that we do know, finding the variety so very great. * Almost all insects have their puncta like those of the Cater- pillar, ranged along the side, and inosculating like those of the Louse from branch to branch : often the puncta open along the sides; but in place of inosculating from branch to branch, *#1 round one side, they inosculate across the belly, the one side communicating with the other. This is best ob- served in the small Worm from which the Bee proceeds, (vide fig. 6. which is a magnified drawing of the Bee-worm.) And here it must be observed, that, as in other insects, al- ways the stigmata or breathing points correspond neatly with the folds or rings while it continues a Worm, and with the scales or divisions of the body when it becomes a Fly; in the Bee-worm also the inosculations answer to the flexures or joints of the body. Often when the insect lives in water, it has only two puncta 20 OF RESPIRATION. respiratoria: these puncta begin either in the snout or in the tail; they are the openings of two great air tubes which run down each side of the insect like two aortas, and the insect has means of rising to the surface, takes down a bubble of air along with it, and discharges a bubble of air before it rises again : of this nature are the air tubes of that Worm from which the Ephemeris proceeds. The sketch of the Ephe- meris and its air tubes is given in figure 7 —This Fly has but two spiracula; they are so small towards the neck, where their commencement is, that their mouths cannot be easily found. The two great air tubes (act) are seen like two aortas running all along the body, and their minuter branches (bb) are seen'ramifying beautifully upon the abdominal muscles and other parts. Many insects are aquatic when first they are hatched from the egg. They have little gills which serve them while they continue in the water, as, for example, the Ephe- meris Fly; but along with these gills they have the ordinary structure of air tubes, and the day on which they emerge from the water, the gills shrink, and the air tubes begin their func- tion ; and these changes succeed each other very rapidly in all insects, but most especially in the Ephemeris, which is destined to live but one day. It is most of all singular, that in some insects the number of respiratory points, or puncta, changes according to the various conditions or stages of their existence. For example, a Worm which crawls among the dust, since it must breathe less easily, has more puncta than when it has changed its state to thai of a Fly, and has its puncta very freely exposed to the air: in the Rhinoceros Beetle the Worm has more puncta respirato- ria, and closer, because it crawls on the ground amidst mud or dust: they are less numerous in the Fly, as its air holes are always more freely exposed ; and when the Beetle is ac- tually flying, those puncta which were closed by the cases of the wings are fully opened ; so that the insect breathes more freely, and perhaps its body is lightened, so that it flies more easily : it is also particular, that in the full-gro^ Beetle, though the puncta be less in number, the lungs are enlarged, they both change their form and become more capacious; for the tubes are mere tracheas or straight lines, with direct branches in the Worm, but in the Beetle they are dilated from point to point into air bags. Insects in general are bred in eggs, transformed into worms, assume then the form of an aurelia, that is, of a Fly, small but full formed, with its legs drawn up, its wings plaited and folded, ready at all points to burst from the covering which surrounds it; for both in posture and in the membranes which OP RESPIRATION. 21 surround it, it resembles a foetus. In these three stages it still is nourished by air tubes : they open by puncta respira- toria while it remains a Worm; the same puncta still serve it while it is wrapped up an aurelia or concealed Fly; when the Fly bursts out, the same puncta, the same tubes, which have served in its former stages, serve it still; only this is most curious, that when from a Worm it proceeds a Fly, the skin which it rids itself of (crawling out of it and pushing with its feet) carries off along with it many of the internal parts; the mouth, the anus, and especially all the respiratory tubes, lose an internal skin, at the same time that the old skin or slough is pushed off from the outward surface of the body; and when the puncta are thus changed, they are left more open than before, and often their number is changed. For the drawing of this slough or skin (a)—from which the Worm has just disengaged itself, and the old air tubes (b)—inverted, and adhering to the cast skin, see figure 8. which is the figure of the Cossus, an affected name by which Mouffet and others have chosen to distinguish the Worm from which the Horned Beetle proceeds. These are the various ways by which insects are supplied with air; and nothing can be more interesting than to observe the vast proportion of air which they draw in, which is cer- tainly a provision for their living in places where oxygene can- not be plentifully supplied. And the fact is well known, that insects can live on air much less pure than what is necessary 22 OF RESPIRATION. to breathing creatures, and that they exhaust the oxygene of the atmosphere much more completely than any other living creature. The variety in the manner of conducting the air to the system of insects is changed, and suited, as I have ob- served, to their various ways of life, and to the various con- ditions and stages of their life ; while they are Worms, when they are involved foetuses, and when they have burst their shell and are full grown. In short, Worms, Aurelia?, Flies, Beetles, Bees and all forms of insects, have all of them their tracheas by which they breathe a wonderfully large proportion of air. There can be no mistake concerning the function of their air tubes and of their heart; it is ignorance or inattention only that can cause confusion; the heart of a Caterpillar, of a Snail, of the Worms from which various Flies are produced, are seen distinctly through their transparent body, running down their back in form of a tube, sometimes slightly oval, sometimes having frequent dilations, and throbbing, though with less equable and distinct pulses than in the more perfect animals. Nor can there be any mistake that it is air they breathe; for before we dissect an insect, we must kill it; the contortions of a live Caterpillar prevent all deliberate dissection, or even a view of the parts; we may poison the insect, as with turpen- tine or spirits: we commonly drown it: this is done by im- mersing it in a little tepid water. Nay, we find a thing which is at first inconceivable to be really true, that notwithstanding the inosculations of the air tubes with each other, which seems to provide against all such effects, when we close up the stigmata of an insect one by one, the parts become in the same proportion paralytic; if we varnish over the stigmata of one side, that side becomes paralytic ; if we varnish over the stig- mata of both sides up to the last holes, the insect lives, but in a very languid condition, it survives in a kind of lethargic state for two days, without any pulsation in its heart; if we also stop the two highest holes, it dies. Of all the examples of respiration, that which is "Imported by Spallanzani is what I most wonder at, and cannot but doubt. In acescent liquors, or the juices of animal bodies, animal- cules are seen plainly with simple glasses, moving sometimes rapidly, sometimes slowly: but never hitherto has any author N?&±--.-.-.^ pretended to see their lungs or heart. Mr. Spallanzani says, " that these ani- malcules are elliptic bodies; that in the centre of each ellipsis he sees two stars, which are in constant al- ternate and regular motion, whether • i * ^/iiiiJ if //tr (/ fft/t/tiftyt/t XV Sfiewmf th\ Mac >md fcrru of I/a- iMnphrayt. P. li-fi ■ OF RESPIRATION. 23 the creature rests or moves. Each star-like body has in its centre a small globe, and every three or four seconds the glo- bules are blown up slowly to three or four times their natural size, and as slowly compressed again ; and every time that the radii are inflated the central globule subsides. On one side of these star-like bodies there is an oval part, which is continually agitated with a trembling motion ; he calls the star-like bodies lungs, and the oval body he thinks is the heart." Spallanzani surely has forgotten that he is speaking of lungs in an aquatic insect: if these star-like bodies have any such use, they must be gills. These are the animalcules which Buffon called organic germs, and from which, as materials and pieces, he built up the animal body. But if all this be true, the day is come which he little expected, when the organic particles, on the faith of which he built all his system of generation, are proved to be living and moving animalcules, voracious of food, de- vouring each other, breathing air, and having a visible pulsating heart; animalcules deposited from the atmosphere, and gene- rating like other insects of their kind. Thus we are convinced of the importance of respiration, and the absorption of air in all living creatures, from Man even to the meanest reptile ; and not least needful in the last^and lower order, which receive in proportion a fuller supply of air ""han fishes, amphibia?, or Man, CHAP. IV. OF THE PECULIARITIES IN THE CIRCULATION OF THE FffiTUS. J. HE peculiarities of the foetus all relate to the oxydation of the blood, and are such chiefly as fulfil the circulation of the blood without any need of its passing through the lungs, ena- bling the foetus to live without that function in its mother's womb. 1. We are assured that the blood which comes to the foetus thrbugh the umbilical vein is pure, or of greater value than that which the foetus returns to the mother's system. Either this blood is restored to all its properties merely by passing through the mother's system, and what is thus drained off from the extremeties of the mother's system is more than sufficient for the life of the child ; or, without such direct communica- 24 CIRCULATION OF tion, the placenta performs to the foetus a function equivalent to that of the kings. Then this blood, whose value and pro- perties must be lost, if pushed through the circulation of the liver, passes only in' part through the liver, while a chief share of it goes by a side passage, which is called the ductus* or canalis venosus, under the liver, directly to the heart.* £. This blood does not pass through the circulation of the lungs ; perhaps it ought not to pass ; for there being no respi- ration, no air admitted to the lungs, the blood might rather be contaminated ; perhaps it cannot pass, the lungs never having been expanded with air : but, however that be, there is a side passage for conveying it from the right to the left side Of the heart clear of the lungs. For this use is the foramen ovale, which is an apening of no inconsiderable size betwixt the right and left auricle of the heart; its area is as large as that of the vena cava; and it is sufficient, without the help of the ductus arteriosus, to convey the blood freely from right to left. 3. The ductus arteriosus serves quite another purpose; for though the circulation of» the aorta is well maintained in the adult body by the force of one ventricle only, yet in the foetus one ventricle will not suffice. In the foetus the heart must push its blood not only through that system of vessels which is within the body, but also it must push it onwards through a second circle of vessels, viz. those of the placenta ; for the iliac arteries do not descend into the thigh and pelvis of the foetus, Ijut the iliac artery itself, with little diminution, (very small branches only being given downwards into the pel- vis and thigh,) turns upwards along the side of the bladder; and these two arteries going out from the navel, form the um- bilical cord; and the heart of the foetus has to give life and action not only to its internal system, but to these two arteries comprehending the chief bulk of the aorta, which run out to the distance of three feet along the umbilical cord, and which make wonderful "convolutions in the placenta, and terminate with extreme minuteness upon its surface. It is this which occasions the necessity of the ductus arteriosus, which is mere- ly a union or inosculation of the pulmonic artery with the aorta. This union is formed by a great branch of the pulmo- nic artery in the foetus, joining the aorta below its curve. This great branch (for it is greater than the two branches which go to the lungs) is named the ductus arteriosus, and rhay be defined an inosculation betwixt the pulmonic artery and the aorta, so very large, that it gives the aorta of the foetus twice its natural size and proportion, and enables the blood of that * N. B. The canalis venosus is marked in the plan, THE FfETUS. 25 artery to have the full force of both ventricles; of the left ven- tricle through the aorta, and of the right ventricle through the ductus arteriosus by one synchronous stroke. 4. The contaminated blood of the foetus must be returned to the mother, or at least to the placenta; for which purpose the two iliac arteries are reflected along the side of the bladder as I have just explained. I say the iliac arteries without reserve, because the hypogastric and femoral arteries, that is, the arte- ries of the pelvis and and thigh, though they are the largest branches of all the body in the adult, are in the foetus ex- tremely small; and thence that smallness of the lower extre- mities compared with the largeness of the head, which charac- terizes the child, and which it takes years to redress. ductus venosus. Thus have I defined these parts and their uses, in order that their strict anatomy may be the more easily explained; and the part first mentioned, viz. the ductus venosus, is the part the most difficult to be understood, and never without the help of a plan. In my plan I have endeavoured to elucidate these points. First, The mere anatomy, connections, and inosculations of the vessels; showing how the umbilical vein brings in the blood of the mother; how that vein spreads in the liver, and feed all its left side with blood; and how the ductus venosus carries part of that blood away from the circulation of the liver, con- ducting it directly onwards to the right side of the heart. Secondly,'I have endeavoured to explain what parts of the liver each branch supplies, and how these vessels lie in the liver of a new-born child. Thirdly, I have contrasted with this the change of form in these same vessels, when, as happens in the ayiult, the form of the liver is changed, and the ductus venosus a*d the umbilical vein are obliterated, and gone, or converted into ligaments of very trivial use or size. Th# blood from the maternal system transmitted through the placenta, and oxydated, or having undergone some change equivalent to oxydation, conies down along the umbilical vein: —the vein enters by the navel, adheres to the inner surface of the abdomen, enters into the liver at the top of that great transverse cleft which divides the liver into two lobes; and after entering the liver, it begins, as if it were the regular and peculiar vessel of the liver, to distribute branches through its substance from right to left. ^ VOL. 11- D 2Q CIRCULATION Oi In figure 1.—(aa) shows the umbilical vein,— (b) the pom* at which it enters the liver,—(c. d, e,f,) branches given to the substance of the liver, till at last it gives off (g) a very great branch, which is indeed the chief trunk for the leftside of the liver; it branches out in the liver like the opposite trunk, ('»•) ---But I cut it off short, lest it should confuse the plan. Next comes (h,) the ductus venosus, whose office is important, but whose size is not quite what we should suppose. It comes off direct from the umbilical vein ; its course is short and a little curved; it joins at (i) the largest of the hepatic veins, (i. e.) of those great veins which return the blood from the liver, and along with "it goes directly into the right auricle of the heart, which is marked (*.)—This, perhaps, might suffice as a descrip- tion of the ductus venosus; but it is convenient, and will make a clear subject, to finish that circulation of which this ductus venosus is one of the chief difficulties. This I consider as the end of the umbilical vein, for here its circulation ends; or, if it sends blood into the right branch of the vena portae, its proportion is but small. But the vena port."£, (which is just the collection of all the abdominal veins into one trunk,—of the splenic vein (1)—of the mesentric vein (2)—of the hemorrhoidal vein, (i. e.) the vein from the pel- vis (3);)—the vena port£e, I say, composed of all these veins,, is the true vein of the liver. The branches of the vena portae are gathered into a trunk at (A)—that trunk enters the liver at (/)—it divides into two great transverse branches at (m) and (n)—the one serving the right side of the liver and the other the left; but in the foetus this left branch (n) is not known as the limb or left branch of of the vena portae, but looks rather like the right branch of the umbilical vein; indeed, it is named so by Mr. Bertin. But that I may not convey vague uncertain notions of ves- sels apart from the organ which they are to supply, I have in figure 2. laid these vessels upon an outline of the liver; by which I am sure to explain correctly, 1. How the umbilical vein (a) enters at (b) into that great longitudinal cleft which parts the liver into two lobes. 2. How it begins, as if it were the peculiar vessel of the liver, to distribute its branches (c, d, e,f,) from right to left. 3. How the last great branch (g) of the umbilical vein is the left trunk for supplying the left side of the liver with blood. 4. How the ductus venosus (/») goes off in the most direct manner from the umbilical vein, and the fairest for receiving its full proportion of blood; and how it carries that blood directly onwards to the back of the liver, •>. 7f.% P, w S&etl Vena Cava allele \ol.H /?« y/nrr/ Vf/n. (>/'///<• -Jitv-f \\ is the Vena Cm a. Abdoinuu/lis o is the, place, wlitrt, ttit Cava, enters t/u, Might Auricle p is the Diuphraym up en winch, tJu Riyht-ixiricU lus arid, the, heart ■„ and a.rtcri,-.? arc seen above tlu Dlaphrayrn. <^ bevng th^. apejc if the heart THE FCETL'S. 27 •wr (hat part which touches the diaphragm, and there the ductus venosus enters the heart.r But my third plan explains the adult liver as if these branches had never existed. The two first plans show what are its veins in the foetus. This third plan shows what are its proper and permanent veins; for those peculiar veins which we find in the child are accommodations for the foetus, are ranked among the peculiarities of the foetus, and are, when the child is born, obliterated by anew circulation; and what is very curious, by a circulation which goes through the same vessels in a retro- gade course. In this third plan I represent the liver of the adult; I con- sider only the vena portae, which is its proper vein, and I give the vein and the liver itself in a_new form. This plan is drawn from an adult liver, most of its substance being dissected away .—(a) Marks the right lobe—(b) the left—(c) the lobulus Spigelii. These are sufficient to mark the more important points, and I have not spared the substance of the liver in other parts where vessels were to be shown.—(of) Is the shape of the vena porta? tied after injection, and cut short and twisted a little, so as to make it stand almost perpen- dicularly;—(e) and (/) are the two great lateral branches going to the right and left sides of the liver; and this cylin- drical part of this very great vein is called the sinus of the vena porta). It is so formal, lies so fairly at right angles with the vena portae, goes so regularly into two equal limbs, the branches too, even "when spreading in the liver, are so formal, that it looks more like a piece of human mechanism than any thing belonging to the living body: it appears so here, not from the stiff and awkward forms which a plan must have, but because it is thus in nature. The right branch (g) is distributed very formally to the right side of the liver;—(h) the opposite branch is distributed as formajjfe-fojh^'-jeft; and there is no mark or note by which it can bWChown that this left branch had ever proceeded from the umbilical vein, or been filled by it, or been any thing but what it now appears, the left branch of the vena porta corresponding most regularly with the right. And in the same way it may be observed, that the middle veins of the liver (i, k, /, m,) are now plainly known to be legitimate branches of the vena portas, though they appeared in the foetus to be proper branches of the umbilical vein; they are named * The lohes of the liver in figure "flfcare marked thus:—(1) The great right lobe—(2) The «reat left lobe—(3) The little lobe, or lobulus Spigelii, lying betwixt them: and it should be renictneuibered with regard to the position of the liver in this drawing, that it stands up- right, as if pulled up by pulling at the umbilical vein («)—or at the round li 'anient, which is the same thing, (for the vein is converted into this ligament,) so as to brii^ it into a per- pendicular posture, and show the back line of the liver (i, 4)—where it touches the spine and diaphragm. n CIRCULATION OF so by Bertin and others, the best anatomists ; but that they are* plainly not so, because the umbilical vein (since these branches go off at an angle) filled them only by a backward course, while here in the adult they are filled by their natural trunk, the vena porta?, in a more natural way. Now, by glancing the eye from the circulation of the foetus to that of the adult, we observe these changes: First, The liver of the foetus has blood circulating in two directions ; the right side of the liver is filled from the veila portae, the left side by the Umbilical vein. The liver of the foetus having two veins, has a large quantity of blood, a growth larger than that of any of the viscera; and indeed the liver alone seems to fill all the upper region of the abdomen. This is changed when the child is born ; the umbilical circulation is cut off and the liver of the child ceases to grow but in proportion to the other parts.* Next, we observe in the foetus how the umbilical vein runs into the left branch of the vena portae, insomuch that the left branch of the portae has not any determined form; nor has the sinus vena porta?, or the horizontal shaft of this vein, that peculiar and formal shape which I have already ob- served. This shape, then, of the sinus vena portae, is not to be looked for in the child, and is not found in these plans. Again, we find in the adult those blood vessels obliterated which served such peculiar uses in the foetus; the blood which flowed formerly into all the left side of the liver by the um- bilical vein, now comes along the vena portae; these veins are now working their blood in a retrograde course; the blood which flowed once in the direction (r) No. 2. runs now in the direction (k) No. 3. In this plan are seen also the hepatic veins, or branches of the vena cava, in the liver. These three great veins marked (III)—are the returning veins, which carry back to the heart that blood which the vena ports (assuming the office of an artery) circulates in the liver; and it is with one of these that the ductus venosus joins before it enters the heart. * One is forced to speak this unphilosophic language, though the size of the liver in the f > lus is as just and welt proportioned to the fetus as that of an adult body is to an adult body. 1 THE F05TUS. 29 FORAMEN OVALE. The foramen ovale, the second peculiarity of the foetus., is a hole of no inconsiderable size, transmitting the blood freely from the right to the left side of the heart. Its use is obvious, even from a general view of the system; and when we look more closely into its mechanism, its uses are com- pletely explained. Its valve being placed on the side of the left auricle, perfectly settles (and that by the only authentic- proof) the course of its blood; and, satisfied with the des- cription which I am now to give, I decline all disputes about the nature of this opening or valve. This is a subject which disputes may perplex, but not explain. Another reason which I have for declining such controversies, is this : It is an easv matter to impose upon a whole academy, easier by far than upon one ingenious man ; and thus it came to pass that in the French Academy each theorist brought dissections of the heart and foramen ovale suited to his own doctrines ; each, when convenient, changed his ground a little, and brought new dissections; and thus valves and auricles, foetal and adult hearts, double Cats and human monsters, made their annual exhibitions in the halls of the French Academy : the Society never sickened nor tired, and the raree-show lasted exactly one hundred years. What kind of doctrines were current at such a time it is almost superfluous to explain; yet I think it not amiss to re- mark two examples, of obduracy on the one hand, and of in- "V Explanation of the Plan of the Foramen Ovale. V (a) Tlie ascending cava, with its hepatic branches (bb,)~(c) the descending cava,—(tf) the right auricle, where it lies against the roots of the aorta and of the pulmonic artery,— (t) the isthmus Vcusscnii, as it is called, or circle which surrounds the oval hole,—(m) the valve of the foramen ovale,—(n) a small opening, which we always find towards iU upper part,—(o) the opening towards the ventricle.—This plan is intended chiefly for shew- ing the true place of the foramen ovale; its anatomy and jast form is better represented iu the true diawing which end*? tliis subject. 30 CIRCULATION OF enuity on the other, in two of the greatest men. Mr. Mery ad conceived notions about the circulation of the blood in the foetus, which can hardly be explained ; * but it was one point essential to his doctrine, that the blood in the foetus moved directly from the left auricle to the right. He was forced to deny that the foramen ovale had a valve; and this doctrine he continued, with many quirks and tricks, to main- tain to his dying day. Mr. Winslow agreed with Mer"y ; he said, that the foramen ovale had no valve; that though it had a membrane, that membrane performed nothing of the office of a valve ; that the blood passed freely from right to left, or from left to right, as occasion required; that thus the two auricles were as one. He forgot for a time that there is but little circulation in the foetal lungs; that the right auricle is filled with all the blood of the body, while the left is filled very sparingly by the pulmonic veins. From these data it is plain, that the balance must always be in favour of the right auricle; that it always must be more full of blood ; that without some valve the blood must rush with a continual pres- sure from right to left; while, again, the place of the valve is itself a demonstration that the blood.cannot pass from left to right. Winslow, when he some years after perceived that lie had spoken idly upon this snbject, left Mr. Mery among his foolish arguments and dissection, and retracted all that he had written, with a manliness of spirit which deserves to be recorded. The foramen ovale is not strictly oval, but is rather round. In the plan it appears oval, because there I have endeavoured to represent the condition of the vessels when the heart is dilated and the vessels full; but when we lay it out for demonstration or for drawing, it appears, as in the drawing, of a rounded shape. The oval hole is in the partition betwixt the two auricles at its very backmost point; for, in fact, the auricles touch each other only behind; at their forepart they are separated by the roots of the aorta and pulmonic artery, as may be seen in any of the plans. We look, then, for the foramen ovale at the very backmost part of the right auricle ; or rather it is placed so high in the auricle as to seem to belong rather to the root of the cava descendens.—A ring rises round the borders of the hole, very prominent, and exactly like the ring of the meatus auditorius internus in a child—This was named * All that can be done towards the explaining it in one word is this: He " fancied that the right cavity of the heart was so large and the left so small, that always the left side was obliged to disgorge again upon the right side; and this was the meaning of the blood lushing through the foramen ovale from the left side to the right." THE F02TUS. *3l isthmus veussenii ; but this conceited name of isthmus, which Veussens gave it, is quite unintelligible, and it must be changed for that of the circulus foraminis ovalis, the ring or circle of the oval hole.—This circle is thick at its edges; very strongly muscular, like the musculi pectinati of the auricle; in so much that authors of some character have thought this a sphincter for the oval hole. There is no doubt a kind of decussation of the fibres at each end of the oval hole ; so that these fibres, forming a sort of pillar on each side or edge of the foramen, the name of Pillars of the Ring, or cqllmnje foraminis ovalis, is less exceptionable ; though these pillars, or any thing deserving such a name, will not be easily found by one beginning anatomy. The valve of the oval hole lies entirely on the left side, as the round edges of the right side may demonstrate. By taking the blunt probe, we find we can lift it towards the left side • but being pushed towards the right side, it rises into a sort of bag, and opposes the probe. The valve is perfectly transpa- rent ; it seems delicate, like all the other membranous valves but is really strong. There is often left, after the closing of the valve, a small opening at its upper part. The valve closes soon after birth: the hole is so large, that this membrane forms a very large share of the partition betwixt the auricles • its transparency is such, compared with the rest of the walls that it is as distinct in a boy, or in an adult, as in a foetus. This is the anatomy of the oval hole, and of its valve : and this proves, and any one who examines it will entirely be con- vinced, that the blood of the foetus passes through it from right to left.* * This heart of a foetus had all its parts cut away, except the ventricles (a a) -the vena cava, with a blow- pipe in it (b)—and the wall or partition betwixt the au- ricles (c c)—which is here unfolded, to shew the fora- men ovale. The musculi pectinati, or muscular film-, of the auricle, are well seen at (k k -,)—(d) is the annu- lus foraminis ovalis,—(e) U the valve itself,— (i) is the small opening in the upper part of the valve, where the valve falls slack, and ready to open. 32 circulation of DUCTUS ARTERIOSUS. The ductus arteriosus I have defined a great inosculation be- twixt the pulmonic artery and the aorta; not for the purpose of conveying away that blood which should pass through the lungs, but for giving to the blood of the aorta the propelling power of both ventricles; and how well it is able to per- form this office, will be easily seen from the drawing on my margin.* The pulmonic "artery of the adult divides, as has been marked in all my for- mer plans, into two great arteries, one going to the right side, another to the left; but in the foetus there arises a middle branch be- twixt these two. It is larger than both put together; it is in the middle, and so comes most directly from the heart; it goes in a straight line towards the aorta, and joins with it im- mediately below the arch. This is the ductus arterio- sus, the centre branch of the three branches into which the pulmonic artery of the foetus is divided. It is bigger than the aorta in the foetus; it gives the full force of the right ventricle *lo the blood of the aorta, in addition to that of the left. In the adult itisso thoroughly obliterated, that by the most care- ful dissection we can show no other vestige of it than a cord- like adhesion of the aorta and pulmonic artery. These, then, are the chief peculiarities of the foetus :f but the conclusions which have been drawn from this mechanism are, as I suspect, very far wrong. But this I can in no shape * This sketch is taken from a little preparation made on purpose, where a ouill wasthr-mt in so strongly betwixt the ductus arteriosus and aorta, as to separate them Lnah JSL ! leave a space (a betwixt them.-(ft 6) Marks the two veE^-^AT^f U^» faml which the two auricles were cut away to make every thin" ctea7_^K™*e &* fT known by (e«) its carotids.-^) is the root of th7Pu\mo£a terylS1ftlt LT& the left pulmonic arter.es,- m the ductus arteriosus, or middle mWl, ™„«E£ • ."^ aortarrfn) the place where they join,-(0 o) the aorta increased'i„^ L T nin* \"t0 "*e NB-Vhis heart is but a very little uWr the natural^^e n a ne^£n ?'f"M diUon - The umbilical arte™* mnrt be explained in another place. THE FOETUS. 33 prove, till I shall have first represented the real condition of the foetal heart. First, then, let it be observed, that every drop of blood which comes into the system is, either by the powers of the placenta, or by communion with the mother's system, oxydated blood.-«*-One part of this blood, indeed, passes through the circulation of the liver before it reaches the heart, while another passes more directly through the ductus venosus; but both are mixed, and the blood is all of one quality when it arrives at the auricle, in order to fill the heart, and to begin its course round the body. Now since, the blood is all of one quality, Nature could have no cause for dividing such blood into two portions; one to pass through the lungs, the other to pass over the body. She could have no motive for employing, as in the adult, two hearts. The de- sign of Nature plainly is, to prepare a double heart and keep it in reserve for the circulation of the adult, but to use it in a single heart in the foetus. And see how simply this is accom- plished. The two auricles communicate so freely by the foramen ovale, that they are as one : the two ventricles both deliver their blood into one vessel, the aorta; and they are also as one. The blood arrives by the cavas, fills the right auricle, and in the same moment fills, through the foramen ovale, the left auricle; so that the auricles are as one, and filled by one stroke : the two auricles act at once, and so the ventricles also are filled by one stroke; the aorta receives the blood of both ventricles at one stroke. So that, in the strictest sense of the word, the foetus has but one single heart, the heart of the body (the function of the lungs being performed by the placenta, far from its proper system;) and when the function of its own lungs begins, then Nature by the simplest of all mechanisms, divides the two hearts, that they may per- form each its peculiar function. First, the flow of blood into the lungs deprives the ductus arteriosus of blood; and, se- condly, this flow of blood coming round to the left auricle of the heart restores the balance, presses down the valve of the foramen ovale, and makes the partition betwixt the auricles entire. In short, while the oval hole and ductus arteriosus are open, it is a single heart; and when they close, as they do the moment the child is born, it becomes the double or perfect heart. Now the mistake which all physiologists have fallen into is this, They have not observed thai no creature can live with a single heart, which has the oxydation of its blood performed by lungs. A fish lives by a single heart, because its blood is oxydated by VOL. II. E 34 CIRCULATION OF gills, not by lungs : insects live with a single heart, as their lungs, or the branches of their lungs, are distributed like arte- ries over all their body : the foetus can live with a single heart, because its blood is oxydated by the placenta. And that this idea may make a more determined impression, it will be good to prove, that the function of the placenta actually is equiva- lent to the function of the lungs; and that it is the placenta it- self that produces this change upon the blood, I am the rather inclined to believe, because we see the veins and arteries of the Chick spreading over the membranes of the egg, and we can observe the artery sending dark-coloured blood into these membranes, while the vein brings back florid or oxydated blood. If, during child-labour, the umbilical cord falls down be- fore the head of the child, at first it is not pressed but beats strongly, and the foetus is felt struggling in the womb; but when, after a few pains, the head descends into the pelvis, the cord is pressed betwixt the head and pelvis, the pulse falters, ceases; the child ceases to stir in the womb ; and if not born in a few minutes is irrecoverably dead, and is black in the face like one strangled or drowned. When a child comes with its feet or other parts of the body first, the bead being last delivered, is difficultly delivered ; the accoucheur struggles long in bringing out the head; the umbilical cord is compressed all the while, and the child dies. The ductus arteriosus, nor the oval hole, cannot save the child, for it dies because it is deprived of the function of the placenta, which is the foetal lungs; and this is- the cause why it appears like one suffocated or drowned. When the child is born, lay it upon your knee, the cord being uncut, and you will observe that the one function declines ex- actly as the other strengthens. That if the child do not breathe freely, the cord will continue to beat steadily, the placenta still continuing to perform the function of the lungs: that when the child begins to cry freely the pulse of the cord and the function of the placenta cease at once. If the child breathe freely, but yet do not cry, and you tie the cord, it is instantly forced to cry for a fuller breath; and if a rash person tie the cord prematurely, when the child neither cries nor- breathes, he cuts off the function of the placenta before the function of the lungs is established, and often the child is lost: this, in the hurry and officiousness of ignorant women, hap- pens every day. If even after two days the child's breathin" be much interrupted by coughing, crying, or any spasmodic affec- tion of the lungs, Nature seeks again the function of the placen- ta, and the pulse returns into the cord so as to raise it from the belly of the child. These things prove what the best physi- THE FCETUS. 35 ologists have forgotten or have not known, that the foetus has, in the placenta, something equivalent to the function of the lungs. One great mistake then runs through the whole of physi- ology. It has been universally believed that the free and easy transmission of the blood was the chief use of the lungs, as* if they had acted like fanners to flap on the blood from the right to the left side of the heart. They affirmed, that either continued distention, or continued collapse, hindered the pro- gress of the blood; and they also believed universally, that if but the ductus arteriosus or foramen ovale, or any thing, in short, were left open to let the blood pass, that person might live in spite of hanging, drowning, or suffocation of any kind. This will be found to be the most perfect of all absurdities; and to allege such a thing against all authors requires some kind of proof; it will suffice, if I prove it against a few of the most eminent. So much were the older authors wedded to this misapprehension of the dilatation of the lungs being use- ful only by driving forwards the blood, that, in the Parisian dissections, we find the following experiment made on purpose to prove the fact. " We have also made another experiment (says the Parisian dissectors*) to know more distinctly the ne- cessity of the motion of the lungs for the entire circulation of the blood. An injection being made by the right ventricle of the heart into the artery of the lungs of a dead Dog, it hap- pens, that if one continue to make the lungs rise and sink al- ternately by means of bellows put into his trachea ihe liquor pushed into the artery does easily pass and go through the vein into the left auricle; but when one ceases to blow, it passes not but with a great deal of difficulty," (page 262)—Which doctrine is dilated into its full absurdity in the next paragraph. " Having viewed the difference of structure in a Tortoise and in a Dog, it is easy to give some probable reason of the phe- nomena of these experiments; and the reason is, that it is ne- cessary that these vessels shall be dilated for the receiving of the blood of the right ventricle of the heart, and that they may be afterwards compressed in expiration to press out the blood, and make it pass into the left ventricle." Swammer- dam indeed says, concerning the Frog's lungs, that an artery goes over them, which has no other purpose but to nourish the lungs; and that it is of the nature of those called bronchial arteries in Man. But the College of Dissectors have plunged still deeper into this remarkable blunder; for they say, (page * A". B. This was a wheelJwithin a wheel; it was a committee of the great academv, who were separated into a smaller society for investigating the organization of all strange aminahs; and a very pretty account they gave of them, as shali be seen presently. 36 CIRCULATION OF 261.) in speaking of the lungs of Newts, Frogs, and other creatures which I have represented as having a pulmonic ar- tery extremely small in proportion to their system, " that in such creatures the lungs have merely that quantity of blood passing through their substance which is necessary for their own particular nourishment;" which is saying in the plainest terms, that they have lungs (only, I suppose, that they may be like other creatures;) but their lungs are of no manner of use, except to nourish themselves. One should have thought that the folly of this opinion would have appeared more striking in proportion to the earnestness of these arguments, and that no subsequent author would have deigned to honour such an opinion so far even as to notice it: but behold the celebrated Haller not only adopts this notion very fully, but enriches it with further explanations, saying, " that the vessels are all, during the contraction of the lungs, forced into numerous angles and joint-like folds; that the angles are made even, and the passages of the blood more direct upon the expansion of the lungs." As if, forsooth, the lungs, (which as I shall presently demonstrate, scarcely move in respiration,) folded and closed upon each other like the wings of a Butterfly or Beetle.* Santorini also represents the vessels of the lungs as thus collapsed, plaited, and folded a thousand various ways, " assaisse et replie de mille manieres differents, Sic."—" One effect of expiration (says Haller) is so to compress all the arteries of the lungs, that they cannot re- ceive the blood from the ventricle of the heart so freely as they are wont to do.f " It must seem very strange for me, after saying that inflating the lungs restores an animal after apparent death, and recovers the drowned, to affirm that long continued respiration is fatal :J and yet we need not look long for the cause of this; for du- ring this long continued inspiration, much blood must be gathered in th.e lungs, but none can get out."Cj Nothing is at- * " Pra-terea, in vivo animali, cujus cor contrahitur et in arterias pulmonale* sanguinem data vi emittit, omnino nunc sanguis in eas arterias facilius, atque adeo celerius irrumpit, post- quam deletus retardatricibus phcis, recta nunc sunt." f " Veruin alter effcctus expirationis est utique pulmonis arterias ita coraprimere, utne pari facilitate sanguinem a suo cordis ventriculo redipiant.'-' t " Paradoxum videri possit, ab iuspiratione sanguinis in pulmonem commeatum expediri: inflato etiam aere, quod genus est magna; inspirationis, animalia moribunda reviviscere et sanguinis per pulmones iter revocari: et tamcn banc eandem, adeo faventem sanguinis per pulmonem motui inspirationem, sola paulo diuturniori continuatione, anxietatem primo in- credibilem facere, deinde, si vel voluntatis violento imperio tamen aer in pulmone retineatur vel ab alia causa intra pulmonem copiosior servetur, denique sanissimum et fortissimum hominem subito interire." 5 " Hujusnunc anxietatis et suffocation'*, et denique mortis causam non est arduum inve- nire. Adparet enim, ab inspiratione diutius continuata, sanguinem in pulmonem quidem ad venire, et congeri, exitum rero ex pulmone non invenire." THE FffiTUS. 37 tributed, in his explanation, to the want of air, but all is attri- buted to the obstruction of the blood: yet if this were all, Amphibiae would need no lungs, fishes would need no gills, in- sects could need*no air tubes; for none of these assist the mo- tions of the heart. Monro, who puts Haller to rights in every thing else, follows him in this. "In all amphibious animals, therefore," says Monro, " every part of the body may receive a considerable portion of blood, although the respiration and free passage of the blood through their lungs be interrupted," he. (p. 21.) And the celebrated Blumenbach, the man most admired on the continent for his Physiology, says, at p. 80., " Post extremam respirationem redeunti per venas cavas san- guini via sueta in pulmones nunc collapsos praecludatur."^ Thus I have proved, that it has been the opinion down to the present day, that the collapse or over distention of the lungs are both equally opposite to the easy passage of the blood: but instead of going round' about the matter slyly, as some authors have done, I like rather the manner of the Reve- rend Dr. Hales, who says plumply, " that suffocation consists in the falling flat of the lungs," (p. 271.) He talks in this way, because like Buffon, Derham, Des Cartes, and some others, he was a philosopher by inclination, and by force a sort of an anatomist. Now the condition o£ the human lungs is quite opposite to all this ; and also (in respect of the distention) is less different from the lungs of reptiles than it is easy for any one bred up in the old doctrines to conceive. In expiration the lungs do not even collapse in any sensible degree. Let us take for our data the common calculations concerning the quantity of air in the lungs, and let us see what they will do towards proving this opinion. The lungs are sup- posed to contain at the time of their utmost fulness about 220 cubic inches of air. When we continue breathing in a natural and easy way, we draw in and expel alternately about 40 cubic- inches of air; but when we choose to force respiration, we find that we can expel without danger or harm 70 inches more ; we can expel 110 inches of air, leaving only 110 inches re- maining in the lungs. Now let us, for a moment, observe how little danger or distress it occasions when a forced respi- ration is made—such as is used in coughing, laughing, speak- ing, crying, expelling the child, urine, or faeces, bracing up the body for the lifting of heavy weights, or other violent occa- * Mr. Keate, one of the latest writers on the recovery of drowned persons, has the same notion. " We inflate and empty the lungs, (says he,) in order by their expansion and con- traction to fop.ce the bloody across from the right to the left side of the heart."—And he ex- presses hirmelfas perf< > tly indifferent what kind of air be used, foul or pure is all one. 38 CIRCULATION OF sions, for which such forced respirations are by nature reserv- ed. Let us notice how much forced respiration exceeds the ordinary respiration, and how small a proportion the quantity of an ordinary breathing, viz. 40, bears to 220, the whole quantity of air within the lungs. Reflecting thus what large inspirations of air we may take, and how very little we do take, we begin to perceive how gentle the motion of the lungs must be. There remains always within the lungs a great mass of air, which I will call the permanent dilatation of the lungs, which, from the first movements of the child, from the hour of birth till death, and even after death, must remain in the lungs. This^ mass, equal tq 220, cannot be entirely breathed out; even the utmost force of respiration expels but the half: this is never done but on extraordinary and most urgent occa- sions, which do indeed disturb the circulation; as coughing, laughing, crying, or running do. But this great mass is seldom , so moved ; it is regularly and gently agitated by the change of 40 parts of the 220 which we expire and draw in again at each breath : we do not empty and fill the lungs at each breath; there is, on the contrary, a permanent expansion of the lungs, and a mass of air always in them ; there is along with this a gentle and regular agitation; and there is changed at each respiration a small proportion of the mass of air. Our lungs are little different (in respect of distention) from those of Am- phibia? : for their lungs also, as I have described in the Frog, are permanently expanded, and at each respiration a little di- lated and contracted ; the air a little changed, a little moved, a little renewed; the change is in both cases placid and gen- tle, and hardly to be perceived. With these opinions concerning the state of our lungs, nothing can appear to me more coarse than the notion of their being entirely filled and emptied at e^,ch breath ; nothing more ig- norant than the supposing them to fall flat, as Hales expresses it, so as to hinder the motion of the blood: and the grossness of this opinion appears in its true light when I put down this last proof, viz. that for each act of respiration there are four pulses of the artery, or four strokes of the heart. Is it not plain, then, to the meanest apprehension, that if the blood moves twice through the lungs in expiration, and twice during inspiration ; or, in other words, if there be four strokes of the artery for each respiration, and if each of the four pulses be equally strong, that the blood passes through the lungs in all states and conditions with equal ease ?* * Their old and favourite experiment, so often repeated by Hooke, Croone and other* % before our Royal Soeiety, viz. of blowmg up the lungs of a Dog, and then'compressing THE F(ETUS. 39 It is also universally believed, and it is indeed a most legiti- mate conclusion, from this doctrine of the collapse of the lungs hindering the passage of the blood, that if but the fora- men ovale or any passage be reft open to let through the blood, that person will live without breathing. It has been affirmed, that the Seal, the Beaver, the Otter, have the foramen ovale open. In the Seal, the Parisian dis- sectors found the ovale open as in a child; but when they came to the foramen ovale of the Beaver and Otter, they found them, and sore against their will, quite close. In their disappointment they could have said any thing; but all that they thought prudent to say was, that the Beaver had not been in the water for a long while, not even to refresh himself,-%and the Otter had been close penned*up in his hut at Versailles; , and so the foramen ovale had closed in these poor beasts quite close; and behold they were no longer Otters and Beavers, but little better than dogs.f Although HallerJ declares that he had found the foramen ovale open in a man who was hang- . ed ; though Roederer, Ghesselden, and many creditable wit- nesses, have testified the same ; still there has gone along "." with thqse confused doctrines about the foramen ovale a kind of dream (like that concerning the transfusion of the blood,)^ that if but the foramen ovale could be preserved open, Man even might be made an amphibious creature. At fi"gst this no- tion began to peep through the mists of this .doctrine; and* you might find an author, when he had dissected a person; with the foramen ovale open, insinuating by oblique noUonjTwhat a vast pity it was that the man htd not known, duringfftis life, how kind Nature had been to him, and \vhat a perfect diver he was ! while another says plainly, on a like occasion, " what a pity it was that this child did hot nVe !" we should have seen almost an amphibious human animal, at least a most notable diver.^ On this slender ground they told the most wonderful them, is good for nothing*: for there the thorax is cut clean away; the permanent disten- tion of the lungs is entirely lost; and then, no doubt, there is such a collapse of the lung*, as may, or rather must, hinder respiration; for the lungs are alternately distended to the greatest degree, and then emptied as completely. * Ths Beaver sits in his hut just up to the hips in the water, and builds his hut so that he may sit just up to the bins. f Cette ouverture, qu'on appelle le trou ovalaire dans le foetus, fait l'anastomose par le moyen de laquelle le sang va de la veine cave dans l'aorte sans passer au travers du poumon ; et c'est apparemiiient pour une meme usage que ce passage se trouve dans le veau marin que dans le foetus, a cause du besoin que l'un et l'autre ont de se passer de la respiration, sc»- voir le veau marin p-ndant qu'il est plong6 dans l'eau, et le foetus pendant quu est dans In ventre de sa mere, ou ■ il est certain que les anastomoses servent a ddcharger le poumon d< Pabondance du sang qui le suffoqueroit."—Vid. Acad, da Sciences, Anno 1699, page 110. i Vol. II. Part 2. p. 11. • $ Mr. Chemiueau says, "On auroit vuc avec etonnement »n Hjuirac presque ampliiuie comure la Tortue." rage 38. 40 CIRCULATION OF tales, among which Pecblinus's story of the Tronningholm gardener is one of the prettiest. " The ice having broken, the gardener, in trying to help out some others, as frequently happens, slipt in himself into a place full eighteen yards deep. There he no sooner touched the bottom, than Be felt as if you had clapt a plaster, over his mouth; his feet stuck fast, his body became rigid, and he stood there as stiff as a stake, with no one of his senses about him, except only that he thought he heard all the while the Stockholm bells ringing most pleasantly; and there he stood for sixteen hours, the folks seeking him up and down, and wondering where he could be : at last having found him, they hooked him out with a pole; and after much warm- ing, and rubbing, and working, and giving him hot drinks, they got his blood to circulate, an_d brought him to life again. He had sense enough, however, he said, to feel their hook ; and indeed they had angled so ill, that his head was all bruised, and he had terrible headaches : but, however, the Queen-Mo- ther gave" him a good pension, and he was sixty-five years of age when Pechlinus wrote."* This is one of the many stories o£ men preserved by the foramen ovale not having been shut. At first, 1 say, this opinion began to peep out in hints and re- flections ; then it strengthened into wonderful tales of people ^being recovered who had been under the water six days ; till at last a great genius undertoook to make water-whelps upon a new principle, viz. with the foramen '"Wale open. This great genius was the Count de Buffon. Indeed even this very year a very celebrated author Dr. Beddoes, forgetting, perhaps, how successful Buffon is, tells us, f^page 41.) that " by frequent im- mersion in water, the association betwixt the heart and lungs might perhaps be dissolved, and an animal be inured to live commodiously under water "for anytime." Let us move just a step backwards in this new trade of ma- king amphibious animals, and observe how the celebrated Buf- * • * Hortulanus Tronniogholmensis etiamnum vivens, annos nalus 65, pro ilia setate sati* adliuc valens et vegetus, cum ante 18 annos alii in aquas delapso opem ferre vellet, forte fortuna et ipse per glaciem incnutius procedons, aquas incidit 18 uluas profundas: ubi ille, corpore ercclo qriasi ad perpcndiculum, pedibus fundo adhcesit. Constitit sic per 16 horas, antequam producereturin auras. Dixit autem, simul ac infra aquarum superficiem fuit de- mersus, slatim obriguisst totum, et, si quern turn habuit motum et sensum^ amisisae nisi quod sonantes Stockholmii campanns etiam sub aquis obscurius percipere sibi sit visus. Sensit r.tiam, statim sese velul vesiculam ori applicasse, adeo ut aqua nulla-os penetraverit, in aures vero tramilum, etiam sentiente illo, habuerit; atque inde auditum suum debilitatum ali- quandiu esse. Hoc statum dum 16 horas peimansit frustra quaesitus, tandem repertum, i-onto in capite infixo, cuius etiam sensum se habuisse dixit, fundo extraxerunt, sperantes ex more aut persuaeione gentis revicturum esse. Itaque pannis linleisque productum obvolvunt, ne aer admitte possit pernido.-us futurus subito il lapsu ! Custoditum sic satis ab aere seusini sensimque tepidiore loco adinovent mox calidis adoriuntur fasciis, ft icant, radunt et sufflami- natura tot horis sanguinis corporisque motmn negotiosa ilia opera reducunt: denique antapo- plecticis et genialibus liquoribus vitae reddunt et pristinte mobilitati. Retuiit is atque osteti- dit se etiamnuin in capite circuraferre vestigia violentiae a conto illatae et cephalalgiis vexari ^ravissimis. Et propter hunc ipsum casum, religiose a popularibus, et hujusce rei testibus « probation, Serenissimae Regina; Matris munificentia et annuo stipendio est donatus." THE FCETL'S. 41 Ion succeeded. " I procured a pregnant bitch (says Buffon) of the large greyhound kind: and when just about to litter, I fixed her so in a bucket full of warm water that her hinder parts were entirely covered. In this situation she brought forth three puppies; which, after being disengaged from their membranes, were immersed in a fluid nearly of an equal tem- perature with that of the amnios. After assisting the mother, and washing the puppies in this water, I suddenly removed them into a pail of warm milk, without allowing them time to respire. I put them into the milk in preference to the water, that they might have an opportunity of taking some food, if they found a desire for it. I kept them immersed in the milk for more than half an hour; and when taken out of it, all the three were alive. They began to breathe, and they discharged a quantity of fluid matter by the mouth. I allowed them to respire about half an hour, and again immersed them in the warm milk, where they remained another half hour. I then took them out; two of them were still vigorous, but the third seemed to languish: I therefore ordered it to be carried to the mother; which, besides the three brought forth in the wa- ter, had littered other six in the natural manner. The puppy which was born in the water and had continued one half hour in warm milk before it was allowed to breathe, and another half hour after it had respired, seemed to be very little incom- moded ; for it soon recovered, and was as active and lively as those which had received no injury. Of the six that were brought forth in the air, I threw away four; so that there re- mained only two with the mother, beside the one that had been littered in the water. I continued my experiments upon the other two which had been twice immersed in the milk : after allowing them to breathe about half an hour, I plunged them a third time into the milk, where they remained another half hour. Whether they swallowed any of the milk I could not determine; but when removed, they appeared to be nearly as vigorous as before their immersion." " I pushed these trials no farther : but I learned enough to convince me, that respiration is not so indispensably necessary to the existence of a new-born animal as to an adult; and that by employing certain precautions, it is, perhaps, possible to keep the foramen ovale open: and by this means, produce excellent divers, or a species of amphibious animals, which would be able to live equally in air or in water." I am sorry to say that I cannot pay Mr. Buffon the com- » pliment of thinking that he was deceived in so simple an affair as this; yet he certainly could not succeed. I leave it with my reader to judge what shall be said of Mr. Buffon; for it was VOL. II. F 42 MALC0NF0RMAT10N OF not the foramen ovale that he was to keep open, if he wanted to make Amphibiae : but, since the function of the placenta was just cut off in these whelps, and since he did not allow them the office of the lungs, he was to seek for some other third function, which could stand in place of the functions of the placenta and lungs; and since no such function has yet been observed, I judge from all the principles which I have laid down, that Mr. Buffon was telling a vain-glorious idle tale; that he was conscious that he had succeeded in no degree ; and that he could no more have converted them into amphibious animals, than he could have made them what they were, viz. plain whelps. " Sed quis fallat omnisciam, ut sic loquar, natu- ram ? Ilia non colludit nostris erroribus, et quod ignorantia celaverat suo detegit tempore." CHAP. V. OF MALCONFORMATIONS OF THE HEART, AND OTHER CAUSES, PREVENTING THE DUE OXYDATION OF THE BLOOD. W E are at no period of life, from the cradle to the grave, exempted from those diseases which prevent the due oxydation of the blood. They often are born with us; they often over- take us when advanced in life ; they cause an anxiety and misery, which exceeds all other distress: pain and suffering of every other kind humanity can bear, but the feeling of instant dissolution is what the noblest mind sinks under. We f know by the pale and subsiding countenance how awful the in- ward feelings are, and woe be to him who has not feeling enough to sympathize with this distress, and an anxious desire to understand the cause, and to alleviate the misery of inward diseases which he cannot cure ! These are seducing motives, and might of themselves have . drawn me on to give this slight sketch of the malconforma- tiofts^nd diseases of the heart; but I feel also the stronger motives of duty and necessity; for truly, without some know- ledge of the ill organized, irregular, and diseased heart",* the structure and functions of the heart in its sounder state would be but poorly understood. This sketch, then, is the last part of this anatomy of the heart. • While the following history serves to correct our notions of the mechanism of the heart, we must also observe how it ex- THE HEART. 43 plains and illustrates up to a much higher point, the combined functions of the heart and lungs, viz. the oxydation of the blood. Perhaps nothing can better explain the effects of a full and healthy oxydation, than a sparing oxydation of the blood, such as produces disease. The foetus alone can live with its single heart; it lives in the womb by its having a heart different from that of an adult. A foetus, then, being born, cannot live with that heart which served it in the womb; and Nature, as I have explained al- ready, divides the single heart, and there is then a heart for the lungs and a heart for the body. But if any fault in the organization prevent this separation of the heart; if the fora- men ovale be preserved open ; or if there should be any hole in the septum betwixt the ventricles of the heart; if the pul- monic artery do not admit the idood, now that the child is born, and should breathe the air; if the aorta arise from the right ventricle, so as to carry off all the blood from the lungs; or if the aorta be so displaced, that its mouth stands in part over both ventricles, so as to receive the blood of both—then the organization, movements, functions of the heart are all wrong; no blood passes into the lungs, the child cannot live ; it either dies immediately in convulsive struggles, or lives in misery but a few years. It is not in this rapid enumeration that these varieties of malconformation can be understood, nor yet do they deserve to be minutely detailed. I shall keep the middle path; and those of my readers will easily follow me who have studied the mechanism of the heart; concerning which this subject will recall to their memory all the important facts. The most usual of all these disorders of the heart is some fault in the pulmonic artery; and that disorder again is fruitful of others: for if the pulmonic artery cannot receive its blood, the foramen ovale cannot close : then the blood cannot circu- late nor pass into the lungs when they first expand ; then the office of the right heart is taken away, it has no power but to drive the blood with struggles through the foramen ovale into the left heart; the left heart then drives this blood, unoxy- dated as it is, into the aorta : the heart is now a single heart; it is the left heart alone that receives or circulates the blood : either it labours but for a few pulses, and then the child, after a convulsive struggle, expires; or there is some degree of opening in the pulmonic artery, a little blood passes through it into the lungs; the child is by that enabled to struggle with its convulsive pangs for eight or ten days, and then expires. Such a scene the celebrated Dr. Hunter once witnessed ; and there was, I perceive, in that heart a peculiarity very 44 MALCONFORMATION OF much to be admired. The chief fault was in the pulmonic ar- tery, which was contracted into a solid substance or cord ab- solutely and completely impervious, so that the lungs had never received one drop of blood by the pulmonic artery. And here I must stop to notice one thing which 1 have always suspected, and which this dissection proves, viz. that though it is natural to believe, and the best physiologists suppose it, that some blood, as much at least as to support the form of the pulmonic vessels, passes through the fcetul lungs; yet here is direct proof that a well-nourished child may be born capable of breathing, and in which the pulmonic vessels are all free ex- cept at the heart, in which not one drop of blood ever has passed into the lungs. But chiefly it is to be observed, that this child, with its pulmonic artery quite impervious, could not have struggled a single day, far less ten days, without some proportion of oxydated blood ! and accordingly we find that it had a small portion, just such as supported life for a few days; which small proportion is obtained thus: The blood went to be oxydated, not from the right ventricle into the pul- monic artery, but from the left ventricle into the aorta; from thence into the ductus arteriosus; and then, by a retrograde course, backwards through the lungs; and then by the pul- monic veins it was returned oxydated into the left side of the heart, from whence it came. This child accordingly lived a few days, and could not live longer; because this difficult cir- culation was continually accumulating a quantity of black blood in the right side of the heart. This child, then, had a heart resembling that of the Newt or Frog; for the pulmonic artery was closed, and the right heart of no value; the left heart pushed its blood into the aorta, and the aorta, as we may express it, sent a side branch into the lungs. . In this first instance, then, of malconformation, the child could not live, because it wanted the pulmonary artery, and of course the office of the right ventricle ; it had but a single heart. Next to this disorder of the pulmonic artery, viz. being ob- literated or being closed, is this: That the aorta, in place of arising distinctly either from the right or from the left ventri- cle, is so placed, that its root stands directly over the septum ventriculorum, or partition of the ventricles; that the parti- tion is perforated with a large hole, opening a very free pas- sage from side to side ; and that the heart being cut up, we find, upon thrusting down the finger into the aorta, that it passes with equal ease into the right or into the left side of the heart: All which we are the less surprised at, when we remember that in * the Chick in ovo, the parts of the heart are all separate pieces, • ' which are joined one to another; and that in the foetus of THE HEART. 4.5 other creatures, in the Frog for example, the auricle, ventricle, and artery, are first seen at a distance from each other and then joined.* In this conformation of the heart, the single heart appears again in a new form, and the office of the right or pulmonic side of the heart is well nigh annihilated. First, The pulmo- nic artery is small, sometimes almost close : Secondly, The aorta, arising as well from the right as from the left ventricle, carries off one half of that blood which should be circulated through the lungs: And, lastly, That blood, small as it is in quantity, which has passed through the lungs, is brought round to the left side of the heart; but the left side is not as it should be, close, to keep this purer blood for the circulation of the body, but it is mixed with the blood of the right side, through the perforated septum, so that its virtues, as oxydated blood, are diluted or almost lost. If the pulmonic artery were unaffected, and the aorta placed equally over both ventricles, then the one half exactly of that blood which should be oxydated would undergo the change. But in all these malconformations, the root of the pulmonic artery also is in fault; it is narrow; it is so small, that at first opening such a body it alone attracts the eye ; its mouth is sometimes so beset with a sort of fleshy granulous papilla?, that there is hardly left opening enough to pass a silver probe. The degree of contraction in the pulmonic artery is the true mea- sure of all the oxydated blood which that system can receive ; but in such a system the quantity is still farther reduced by. va- rious accidents of the organization. Thus, for example,— The pulmonic artery, is, we shall suppose, but one third of its natural size, and the original quantity of oxydated blood is proportionably small;—next, the foramen ovale, being open, carries off much blood towards the left auricle; the aorta, planted over the right ventricle, carries off also much blood.— But let us suppose, that still as much remains as to fill the pul- monic artery to its full: when the pure blood comes round tc the left side, it is mixed through the foramen ovale, and through the breach of the septum, with a quantity of black blood, which is continually accumulating upon it; and the small quantity of oxydated blood is, if I may use the expres- sion, drowned in the general mass. That I may explain the point of its accumulating a little * I do not mean to argue, that when we first see them, they are so little connected, that oue could be awkwardly joined to the other, nor that they have no real connection, because it appears as if they had not; but merely this, that as they scan like the parts of the eye, fo be organized iu leparate pieces, 1 should sooner -\;ect an unnatural displacement of the i l'.-m-1s ot" tlw heart than in the middle of the femoral alter}'. 46 MALCONFORMATION OF farther, let me repeat, that even in a child which has died on the tenth day of such a disorder, the heart is crammed with dark-coloured blood : That in those children which have lived two or three years under such a distress, the heart has been greatly enlarged: That in a boy dissected by Sandifort, who died at fifteen, the thing that was first seen upon opening the body was, not the lungs covering the heart and lapping over it, but a large mass, lying betwixt the lungs, oppressing them and pushing them aside in every direction. This was the pericar- dium covering a heart of enormous size, filling the thorax, and reaching almost to the first rib; very little of the right lobe of the lungs, and none almost of the left, was to be seen; the veins in the upper part of the thorax, viz. the subclavian and jugulars, were ,choaked by the pressure, and much distended; the heart itself was full of blood, and the coronary veins so turgid, that it resembled a most minute and beautiful injection of the heart. But it is most of all singular, that this heart was so enlarged, that the great veins, (which are indeed as reservoirs for the right side of the heart,) and especially the upper cava, dilated along with it in such a degree that there was felt distinctly a pulsation in the neck by a sort of back stroke every time the heart beat. Still a child, even with a heart so ill organized, may strug- gle through all the weakness and all the diseases of childhood* for a few years, but they are years of complete misery; and still, as is proved by much sad experience, the boy cannot live, but must die. Another conformation, the strangest of all, is that in which new parts are added to the circulating system, as if with design to make it resemble the heart of an amphibious creature ; for it happens, sometimes, that there is, as it were, a third heart interposed. For example, the two vena cavas end in the right auricle, the pulmonic veins enter into the left auricle, and the right and left ventricles receive their blood from their auricles in the usual way; yet the right ventricle sends out no pulmo- nary artery, the left ventricle sends out no aorta; but both of them pour their blood into a middle ventricle, and the arteries go out from it: and here, as the blood is fairly delivered by both ventricles into this third ventricle, and as the pulmonic ar- tery and aorta both arise from it, there is, of course, a fair di- vision of the blood ; and of the quantity which should be oxy- dated, exactly one half undergoes that change. This is some- * Sandifort attended a puer cceruleus, who, in addition to his chief disease, passed throuMi the small pox and measles safely, and attained the age of fifteen. THE HEART. 47 what like the heart of the Turtle; it is plainly the structure of an amphibious heart, a single heart; for though there be three cavities, yet they are single in their function; it is a single heart with half oxydated blood. Such a heart is sufficient for Amphibiae, or for the foetus, but not for a child, which must * breathe and have a double heart. These are a few of the varieties of the imperfect heart; but the sufferings of children who are born with these imperfec- tions, the marks of imperfect oxydation, and the manner of their life and death, was a chief motive for entering on this subject. When the heart is so imperfect that the child lives but a few days, its sufferings are slight, and not lingering, so that we cannot mark tbem : They are not explained to us by any account of its inward feelings : They are all accumu- lated into one terrible struggle, in which we see the worst marks of ill oxydated blood. The child is born well and healthy, it cries and draws its breath, it is removed from the mother ; the function of the placenta ceases, but there is no other to succeed it; the child turns black in the face, struggles for breath, and is convulsed ; and without any apparent cause it seems in the agonies of death : but yet it lives, it becomes black all over the body; the blackness never goes off except when it changes some- times into a deadly ash colour. The child continues for a few days labouring under almost unceasing convulsions, which growing gradually weaker, it at last expires; and while it lives, the heart palpitates, sometimes it throbs so that it can be distinguished at a distance by the eye. Dr. Hunter, in the child which I have already mentioned, laid his hand upon the breast, and the throbbing which he felt there was terrible to him. When the child has the heart so formed as to admit into the lungs even a very small proportion of blood, it struggles through the first years of life, and its protracted sufferings can be more easily observed. Then no mark of ill oxydated blood is wanting ; every thing is the reverse of health, or the natural appearance flushed and florid of a growing child ; its colour is always dark, its motions languid and powerless ; it is cold, so that the parents must keep it carefully wrapped in flannels and furs to preserve any thing of vital heat; its breath- ing is difficult and distressed; fits come upon it at times; and if the child has begun to walk, the least hurry, or fear, or quick step, even walking across the room, bring a return of the fit: in which the extremities are deadly cold, the face black, the breathing one continued struggle, and the end of the fit is 48 MALC0NF0RMAT10N OF the obtaining of a degree of relief, which happens in a most singular way. The coldness, the livor, the langour, the fainting, the strug- gle for free breathing, are all marks of ill oxydated blood. The convulsive paroxysm is a sure consequence of the want Of stimulus and force, and of blood accumulating on the right side of the heart. If, then, the child fall down in this pa- roxysm, it is the very surest proof that ordinary respiration will not save him from the struggle; if during the fit he breathe so that he recovers, and that presently his strength, colour, spirits, every thing, is in a degree restored ; then is it plain that the respiration during the fit, imperfect as it appears to us, is really more effectual than ordinary respiration. When we observe which is the most natural way of obtain- ing relief, and notice the very peculiar manner in which these children breathe, we shall understand why they are breathing best when we believe they are hardly getting breath, and how they are recovering slowly when we think them labouring in the greatest danger. The child feeling the growing oppres- sion at its breast, if it be young, signifies a desire to be turned upon its face ; if not indulged, it contrives to turn itself that way before its hard struggle begins. When the child begins to breathe hard, it drives out the air with a sudden exertion, and apparent pain; he remains longer without respiration than an adult could do; his expirations are attended with a sort of scream. What can this way of breathing mean ? To my apprehension it implies that kind of breathing which I have called forced respiration, and no other plainly can serve. The ordinary respiration, by which we draw in 40 cubic inches of air, has failed; the fit is approaching, because that quantity of air will not suffice. However rapidly the child breathes, however rapidly the heart palpitates, it will not do, because there are but 40 inches of pure air mixed with the whole of that great mass which remains always in the lungs. Then the child, driven by instinct, provides for the fullest respiration : it turns upon its face, that the weight may help to compress the thorax ; it forces with all its power and seems to cease from breathing, and refrains a long while in that state because it is emptying and compressing the lungs. Then its purpose is accomplished ; the lungs are more emptied than in ordinary respiraion ; it draws in the largest draught of air, utters a sort of scream, seems quiet again ; and again, by pressing its breast, and by contortions (convulsive like) of its body, it empties its lungs at a distant interval, and receives again the fullest draught of air. It is this forced respiration THE HEART. 49 that brings into the lungs 70 cubic inches of air more than the usual respiration does. This, then, is three times more ef- fectual than ordinary breathing : and when a boy grown up to those years in which he knows the warnings of his disorder, and has found out this relief: when such a boy by pressing upon the corner of a table, or by throwing himself upon the ground, prevents or alleviates his paroxysms, in what way can it be but by practising for a time this deeper respiration ? pressing the chest, forcing and compressing the lungs be- yond their usual degree of collapse, and so obtaining a fuller draught of 110 inches of air, to be mixed with the 110 inches which must always remain in the lungs ? After half an hour of a kind of breathing, most awful to be- hold, but much more effectual than common breathing, the child recovers slowly. The boy, when advanced a few years, knows how to prevent the fit; but the child of two or three years old knows only how to* struggle with it: yet this strug- gle being a more effectual breathing, the child is relieved at once from an anxiety, and oppression, and throbbing, which precedes the fit for many days; the languor goes off, the heat in some degree returns, and the lips acquire a vermilion colour, and the skin a higher tint, which last for many hours after the fit is gone. In those children, again, which have the heart so formed • that they may live not two or three years only, but to the age of 15 years, it naturally happens that the symptoms fol- low each other in their course very slowly; and the ill oxy- dation of the blood in this its slower progress it is very curious to observe. There is one thing in the economy of the foetus very sin- gular, viz. that while it is receiving much oxydated blood from the mother, but a small portion goes through the ductus venosus directly to the heart, much of it circulates through the liver, and is spoiled (we must suppose.) What then can this mean ? Surely the child, the chick, the foetus of every kind, needs less of this principle of oxygene : the foetus lives (if this be so) like an amphibious creature ; perhaps it has little oxydated blood ; yet being totally deprived of that little it soon dies. Perhaps the foetus, living the life of an amphibi- ous creature, does not want also that peculiar tenacity of life which characterizes that class ; for the struggles and sufferings which a weakly infant endures, before it parts with life, are matter of observation even among the vulgar. For this rea- son I believe it is that children, having a heart so ill arranged that absolutely they cannot live beyond the years of puberty, jet during the first year feel no complaint, and seem thriving vol. n. G 60 MALCONFORMATION pT and healtfiy; the vegetating life of a sucking child saves ii from all dangers of hurried respiration and rapid pulse.—But when it leaves the breast; when it begins to stir and move ; when its blood moving languidly, begins slowly to accumulate at its heart; when the properties of its living fibres changes so as to require a fuller supply of oxygene from the blood—then the ill colour, languor, palpitations, slighter fits, and all the marks of its disease, begin ; and often its colour gradually changes, and it becomes the puer coeruleus, or livid child, be- fore we can perceive by any other marks how dangerous a condition it is in. In one child* the first year had elapsed before the very slightest of those complaints came on, which ended in death at a very distant period of 15 years. At first its finger nails were observed to be livid, yet not continually; the colour varied, but still the "nails were unnaturally livid, so as to alarm and surprise the parents: but there was as yet no reason to de- sire advice. The child seemed healthy, began to use its legs, and in the second year it walked alone.—Next it happened, that one day after being forced to take a medicine, not with- out some resistance, his face was on the following day freckled with red spots, which soon changed to a lived hue. Now the lassitude and chilliness came on ; motion or exercise were more and more oppressive to the boy; till at last when he fatigued or hurried himself, the hands and feet became livid, the mouth and tongue became almost black, and last of all those fits came on in which the whole body becomes livid or black. This is the progress of this darker colour of the body; but his other complaints also advanced with a very slow and regular pace. He increased in stature, his appetite was good, he com- plained of great lassitude, of head-ach, with a sort of gravi- tating pain, of anxieties, especially during the winter months, and of such extreme coldness, that neither fire in winter nor summer's sun could warm him; he never felt heat except when just wrapped up and newly laid in bed. Now the blood began to accumulate; the struggles of the heart began; and so terrible were the throbbings of his heart at times, that they might be seen or even heard. Actual faint- ings succeeded; the poor boy, now eleven years of age, knew that he was to die; he said, that " no one could know or cure his illness, and that no one could imagine what feelings he had here at his heart." Motion was now quite impossible; upon the slightest effort ■'♦ Vide Santfifort. THE LUNGS. 31 saliva flowed from his mouth, a fainting fit ensued, and he con- tinued for a little while blind. All that he was wont to delight in was now indifferent to him; he could not move; his face was turgid, his eyes prominent, his feet were swelled with an oedema, his eyes dead and heavy, expressive of some inward distress: when he was put to bed his anxieties were very great, and thus he died a slow and miserable death. Sometimes a child wants spirit or strength to strive against the lassitude of this disease. A girl under Vasalva's care lived to her fifteenth year; but from her infancy, from her very birth, she had lain in bed, partly on account of sickness, but chiefly on account of extreme weakness. She had a short and diffi- cult breathing, and her skin was tinged all over with a livid colour; her quiet state saved her from the suffocating pa- roxysms ; but her heart was just like all the others, the fora- men ovale open, and the pulmonic artery closed. These, then, are the marks of ill 0x3 iated blood : a livid colour, coldness which nothing can remove, oppression and anxiety of the breast, palpitations and difficult breathing; and when the blood is by passion or motion hurried too fast to- wards the right side of the heart, then come fits, which last a longer or shorter time in proportion as they have been long delayed, and which end in death. And last of all I would rank among these consequences an imperfect nourishment, for all the boys have been small, most of them particularly slender; and one boy especially, of fifteen years of age, is mentioned by Hunter, who, in respect of tallness, was just what you should expect at his years, but slender to a wonderful degree; not as if wasted by consumption, but as if by natural habit. His form was quite surprising, so that Hunter could give no idea of his shape, otherwise than by comparing his body with that of a Grey-hound ; and his legs, he says, put him in mind of those of a Crane, or some tall water-fowl. The consequences must be alike, whether it be that the heart sends no blood towards the lungs, or that the lungs cannot receive that blood; and the malconformations of the heart are hardly more frequent than those of the lungs; and both, we may be well assured, are infinitely more frequent than we suppose; especially when we observe how many children die suddenly, discoloured, and in convulsions; and how many of ol those advanced in years have lived very miserable with com- plaints in the breast. A young man of -twenty-four years of age, by birth a Pole, and at the time of his death a soldier in the German service, had been continually oppressed from his cradle upwards with difficult breathing and anxieties at his breast. He had been 52 RIALCONFORMATION OF three or four times relieved from slighter complaints of the breast; but at last the bleedings and demulcent medicines failed: he lay ill in the military hospital two months, where of course his complaints were correctly known. He had none but the slighter degrees of difficult breathing; when one day sitting up in bed he suddenly expired. Being opened, the right side of the lungs was found to be totally wanting; not destroyed by disease, as we have often seen, not oppressed by water nor eroded by pus, but entirely wanting; a peculiarity which he had from his mother's womb, for it was attended with a pecu- liar arrangement of the vessels. On the right side there was no vestige of the lungs, not even the smallest button to mark where they might have been; there was no branch of the trachea for the right lobe intended by Nature, but both the legs of the trachea plunged into the left lung, which was large: there was no forking of the pulmonary artery to give a branch to the right side, but the whole trunk of the pulmonic artery plunged into the left lung. But if one should suspect that there might have been once a right branch, the lungs destroyed, and the mouths curiously united by that mucus which the membranes of the viscera, and the pleura especially, throw out when inflamed; there are still other cases which must remove all our doubts, especially that of a young man,* who died in a very lingering way, and in whom before his death there was plainly perceived, along with his slighc anxieties, a pulsation in the right side of the breast. Upon opening his body, there was found in the left side neither Jungs nor heart; nor, upon the most careful ex- amination (seeking for the wasted lungs) could there be found the smallest remains of lungs, bronchia?, pulmonic arteries, or the slightest evidence that any such parts had ever been. But the surest proof of this remains behind, for the heart stood in the right side of the chest; it stood perpendicularly, quite up- right like a dog's; it gave out aright pulmonic artery, but there was not even the smallest vestige of any artery having been appointed for the left lobe. We must not say, yet his chest may have been full enough of lungs and heart, and he may have had a well oxydated blood; in which case it was no very dangerous derangement that his lungs were all on the right side, more than if his liver had been on the left. But let us notice that the aorta was extremely small; the diame- ter of the aorta is the true measure of the blood which is re- ceived from the lungs. Where the aorta is small, surely the lungs are not good, nor the system fully supplied with oxyda- ted blood. * Under the care of Dr. Heberden. Vid. Acta Vendobonensu. THE LUNGS. 53 We also know that though the vessels of the lungs them- selves may be natural and well arranged, the lungs may still be amiss; they may want the proper structure of cells in which the blood should be exposed ; they may be encumbered with tumours arising out of their substance, by which they will be prevented from dilating One is pleased to find in old authors good descriptions of diseases which have remained for ages unknown; and among these I reckon that of the celebrated Spindler; whose description I admire as much as that of any succeeding author. The child of a certain prince having died after a few days of great suffering, Spindler opened the body, and found all sound and right, except that there were seated upon the two lungs two tubercles of a variegated red colour, as were the lungs themselves; which tumours, no doubt, hindered the passage of the blood, which he expresses with a correctness in respect of physiology quite unknown in those times. " Quae vomicae procul dubio hujus asphyxia; causae extitere denegata circulatione ex dextro in sinistrum cordis ventriculum." His description of the disease so long before it was properly un- derstood is curious: " During the eight days in which the child lived, it had never cried strongly nor clearly, had never sucked, had never been regular in its bowels, breatbed as if its sides had been blown up; it was suddenly seized with a fit, which seemed epileptic, soon went off, but soon returned ; the whole face and body became first red, then of a copper colour; the breathing was interrupted, the eyes immoveable, the feet and hands lay almost lifeless; it suffered at least a hundred of these fits before it expired." To enumerate those cases where a defect of the lungs were the consequence, not of malconformation, but of disease, were a business quite inconsistent with my design ; yet I wish to record these two. First, it has been long observed, that by long continued suppuration, the lungs are often so wasted that not a bud or particle of them remains : sometimes these pa- tients survive, dragging on a languid and miserable existence, enjoying no freedom, life, nor spirits; and the cause of their frequent ailments is discovered at. their death. The lungs also may be thus compressed even by the mere pressure of water within the chest, which has caused such a subsiding, or rather absorption, of the lungs, without any ulcer of their surface, that one lung has been oppressed till it became no more than three lines in thickness; and indeed it was not easily found : so t ^ Haller says in his commentary upon Boerhaave. But of all * the strange things which Haller, or any man has ever related, what he tells in the following words is the most incredible ; at 54 DISEASES Of least it is so improbable as to be incredible : " A man having- died of a lingering disease occasioned by a fall, the left lobe of the lungs was not to be found ; that side of the chest was full of a coagulable serum; but the asperia arteria and large arteries and veins (a thing which I never could have believed, had I not seen it myself,) opened with gaping orifices into the eavity of the thorax, as if they had been cut across; so that it was very hard to conceive what had prevented the blood from pouring out." Haller, p. 34. Secondly, In the peripneumonia notha there is not merely an inflammation of the pleura, as the name expresses, but of the lungs themselves; and it is not from inflammation, pais, fever, or acute suffering, that they die ; but because the lungs are entirely crammed with blood; the heart can no longer move : they are not sensible of their dangerous state, but are suffocated in a moment, and die without a groan. It seems more frequent in other countries than in this, though no country is exempted. When this disease comes upon a place, it comes with all the frequency and destruction of an epidemic disease; and the sudden unexpected deaths are terrible. Vasalva found an old gentleman going abroad in the morning, and prevented him, questioning him about his complaints, which he himself thought very slight: but Vasalva gave notice privately to the servants to expect nothing better than their master's death; and notwithstanding all assistance, he was that very evening dead. The pulse is weak, the cough slight, the difficulty of breath- ing more anxious than painful; the face sunk in the features and flushed, or rather of a lurid colour, except when it is cadaverous, pale, and sallow ; the suffocation is sudden ; the lungs have, as Morgagni expresses it, a liver-like, solid con- sistence ; they have no longer the cellular appearance of lungs, for their bronchiae are crammed with blood ; their common cellular texture is also full of exuded blood ; they are dense, solid, very heavy, and black, and they sink in water like the lungs of a foetus. The heart is so curbed in its actions, that it gives but a small, feeble, and trembling pulse ; and even in a few days (as in the foetus having an imperfect organization) the heart is wonderfully dilated and enlarged, and filled with fluid and grumous blood. Haller laments the death of friends by this terrible disease, and especially of his own son, " whose body he gave to be opened by those skilled in dissections." Perhaps the heart maybe too small forthe system to which it belongs; and this, I doubt not, had been the case with that # boy in whom Kerkringius found it so small, that though the' hoy was nine years old, the heart (i. e. the ventricles) was n» THE LUNGS. 65 bigger than that of a foetus; and the whole heart, auricles, ven- tricles, and all, was no bigger than that of a child born at the full time. But in proportion as the heart was small the vessels were large, not at all aneurismal, but of such a size, and scarcely of such a size, as might suit the heart of a boy of nine years old. This boy had for five years been hectic, that is to say, he had been troubled with no formed disease, but with continual distress, anxiety, weakness, and quick pulse. This heart was plainly inadequate to the functions of any system ; but the case is too slightly sketched for us to find any decided marks of ill oxydated blood. But that the heart may be too big for its system, is a melan- choly fact; for when it becomes relaxed, it enlarges, and as it grows in bulk loses in power. That the heart is enlarged merely by weakness, by submitting to dilatation, by wanting sufficient power to free itself of accumulating blood, is very plain; for in the plague, in low and pestilential fevers, even in nervous affections, it sometimes enlarges, and this enlarge- ment from a temporary becomes a mechanical and fixed dis- ease. How often do we read in the preface to such dissections of enlarged heart, " he was of a melancholy temperament, of a slow and sedentary life, oppressed by misfortunes, and struggling with vexations and grief." In the angina pectoris, which is in its first attack no organic disease, we often find the dilated heart pale and tender, so that the fingers may be pushed through its flesh. While the heart gradually enlarges, the system changes, and accommodates itself to its powers. There is little distress; often we find a heart enlarged to a degree such as we never could have suspected before death. But slowly there is formed such an accumulation of ill oxydated blood as oppresses the vital powers, and chokes the motions of the heart, and draws after it those other disorders which are already in part explained. Of the mechanical consequences which follow the enlarged heart, those chiefly attract our attention which prevent the due oxydation of the blood. First, the dilatation of the heart draws after it a dilatation of the great veins, so that they become reservoirs as it were ; and the auricle and veins both enlarge so, that the office of the auricular valves is quite lost; the veins feel, or rather the column of blood in the veins feels the back stroke from the heart, and it is perceived even in the neck by a strong pulsa- tion.—Secondly, These veins, and this monstrous heart, so fill the chest, prevent the blood of the neck descending, and so push aside the lungs, as to compress them te the last de- 56 DISEASES OF gree that is consistent with life.—Thirdly, The enlarged heart accumulates much blood in the system which before did not exist, and that blood dark coloured and unfit for the purposes of life. The proportion betwixt the great mass of ill oxydated blood lingering in the veins and about the heart, is increased •so very greatly, in opposition to the very small quantity which can now be oxydated in the lungs, that such persons are ex- posed every moment to the 'greatest dangers ; and the least accident which draws out more black blood from the veins, and hurries it towards the heart, quite overcomes them. Then there is an agonizing and fearful struggle; the heart often struggles, and often frees itself; but in most cases those who live in this condition do, after many escapes, fall down sud- denly dead. " A very learned man having this enlargement of the heart while he was still walking about in his ordinary health, his heart would often stop for three or four pulsations, as if struggling with its load, velutque expulsionem mo- liretur."**—Fourthly, In this enlargement of the heart, al- though sometimes there is a perfect and equal pulse, though sometimes also the disease scarcely shows itself till very far advanced, and after many years of slow increase; yet the heart being continually loaded, and often struggling, cannot free itself at one stroke of all its blood ; then, stroke suc- ceeding stroke in a confused irregular way, there is a weak, irregular, intermitting, fluttering pulse.—Fifthly, But nature, wonderful in her ways, sometimes finds relief from this in the regular constitution of these parts; for while the heart dilates, and becomes more powerless as it dilates, the aorta (being but poorly filled) contracts in proportion as the heart dilates, and accommodates itself to the small quantity of blood which such a heart can give out; and thence the wonder sometimes expressed at finding an aorta extremely slender joined often to an enormous heart. " In opening the body of a shoemaker," says Morgagni, "• whose heart was wonderfully enlarged, seeming as if you had joined two hearts, what chiefly struck us was the smallness of the aorta, more suitable to a delicate woman than to a man of good stature as this was. The aorta, from its passing under •"he diphragm to its great division in the pelvis, was very small." This Morgagni first of all believed was owing to some stricture at the diaphragm; for the aorta did not pass as usual under the legs of the diaphragm, it passed through a peculiar hole ; but he found this tendinous hole quite large and free. Still he believed that all the disorder of the heart arose from the con- traction of the aorta, and that again from the crooked posture * Vesalii, lib. i. cap. v. THE HEART. 04 in which those sit who are of this trade. But that often the artery is contracted in favour of the enlarged ventricle, I am able to prove better than by this case of Morgagni's. In the first place, the distorted posture of his shoemaker can have no effect; for we must not forget how limber, flexible, and free from disease, the aorta is in those who have the unhappiness to be deformed, and in whom the aorta follows the spine so closely, that often the bones almost meet in their distortions, and hide it. I have cut out these aortas sometimes and laid them on boards, to show the strange angles which they make with such perfect safety. Next I have to observe, that where the auricles and ventricles dilate in old people, the aorta also dilates: for there the aorta is old, partly ossified ; its muscular coat stiff and incapable of action ; it is, in short, as weak as the heart itself, and yields along with it to the accumulating blood. But in younger men, the aorta being muscular and strongly contractile, this phenomenon ensues: that as the heart increases jn size and weakness every day, it struggles with less effect against the accumulation ; its pulses are imperfect; it delivers less blood into the aorta; the aorta, less perfectly filled, is not excited by the same power which formerly filled it and kept it full: therefere it contracts gradually and slowly ; it preserves still its healthy constitution ; it is limber, pliant, and sound, in its muscular coat. In short, this doctrine .of Mor- gagni's implies only a stationary condition of the aorta; this other theory implies an active contraction. Now Morgagni's shoemaker was a portly man, but his aorta was smaller than a woman's. Even this case of his own implies an actual con- traction ; since, had this man's aorta continued stationary, it must have been still the aorta of a man of good stature, joined to a large heart. But a perfect proof is this : I have a heart which it would not be easy to describe; it is not only as big as two hearts joined, but I may say, with Bartholine, " ut saepe in Bobus non magis sit aut ponderosior." The heart is bigger actually than an ox's; it is bigger, I think, by the whole size of its two great auricles ; it is injected with wax; it weighs more than four pounds, and is two feet in circumference ; but the aorta is no bigger than the femoral artery at the groin, very straight and even in its diameter, very slender, and with coats which plainly have been very thin and suitable to such an ar- tery. Here the artery is equably and fairly contracted to one fourth of its natural size, which supposes a natural and sound condition of its coats; and one of two things must have hap- pened, either the artery must have contracted first, opposing the heart and causing it to enlarge; but then its violent con- traction, like the urethra contracting in opposition to the blad- VOT,. II. H Jo DISEASES OF der, would have thickened it into a strong muscular tube : or. secondly, the artery must have contracted gently and gradually in favour of the dilation and weakness of the heart; and then it would remain (as this artery really was) very soft, delicate, and limber. I suspect also, that where the aorta is enlarged, there ii required a strong, small, and muscular heart; because I have an aorta enlarged to a very great degree, the heart be- ing extremely small. These accidents will be noticed chiefly where, in young people, there happens such disproportion of muscular power betwixt the heart and its vessels; but in the aged, all the parts are but too much disposed to disease, and the whole will enlarge. These, then, are the chief consequences of that enlargement of the heart which often so fills the thorax and loads the dia- phragm, that it falls down under the weight of the heart: then the heart is felt lower than natural; and the disorder is named by most authors the prolapsus cordis. In a young man of twenty years of age, the most miserable creature I ever saw, I have felt a prodigious heart beating as if quite in the abdo- men: at the pit of the stomach the pulsation was particularly strong; it must have been mistaken for an aneurism of the coeliac artery, had not the heart been felt beating from the na- vel almost to the collar-bone. Whether we are to allow, that the blood sometimes does coagulate and form polypi in those enlarged hearts, I believe no man in the present state of our knowledge will venture to decide. That the blood should coagulate thus firmly, while within the body, and that not in a corner of the circulating system, but in the heart itself, where always there must be some motion, it is not easy to believe ; nor that such coagula- tions should remain there, be washed pure by the current of blood, so as to have a leathery colour, and to be firm and strong; that such coagula should entangle the valves and co- lumn* carna?, shoot up into the great vessels, and hinder the movements, and close, in some degree, the openings of the heart, is quite unlikely : yet if there be such a thing, this must stand as the description of a polypus of the heart. I incline then rather to the opinion of the able and diligent Kerkringius, who calls them pseudo-polypi, bastard polypi, mere clots of blood; of which he produces drawings from the pulmonic veins, the liver, the heart, the brain, &c. wherever great veins are. That when the heart is monstrously dilated, clots may be formed in it, very large, filhng all its cavity, but still bappen- ,ng chiefly in the moment of death, or during its slow ap- proaches, I believe from what Vesalius relates f who « in the THE HEART. 59 heart of a nobleman, found two pounds of a dark coloured flesh ; upon which lump, the heart, of monstrous size, was ex- tended like a gravid uterus." But this black flesh, since it was unconnected with the walls of the heart, was a mere clot; which, had it come really from the womb, Vesalius would have called a false pregnancy, an ovum deforme, or what the vul- gar call a mole. This, and all the lesser polypi, those strings of coagulum which entangle the columnae, and stretch upwards into the vessels, are really formed in the moment of death. But it is not to be forgotten, that many of the most eminent men have thought quite the reverse of all this. Polypi, when first noticed, seemed a strange and awful and frequent cause of death. Having once believed and wondered at such a thing, people did not even like to be disabused ; and when Kerkringius called them pseudo- polypi, the whole physicians, like a hive of bees, swarmed out upon him at once. Tulpius, Malpighi, Pechlinus, ridiculed this opinion. Pechlinus was so offended, that he could not re- frain himself from low and mean language. " True polypi there certainly are," says he, " but these polypi of Kerkringius are indeed pseudo-polypi, and every blind shaver knows them abundantly well;" (tam est vulgaris etlippis tonsoribus notus.) " The shop-boys," says Pechlinus, " make such polypi, by pouring vitriolic acid into the veins." Yet with all his bitter- ness, Pechlinus has not proved, to my satisfaction, either by his arguments, or by his cases, that polypi exist; but he made many believe him, for the ignorance of that time is very sin- gular. Dr. Petrus Russe tells us, that he had once found a polypus in the longitudinal sinus of the dura mater, of a quarter of a yard long: " Let this be put down," says he, " as one proof at least that polypi are sometimes found higher than the nose." What must have been the confusion of their notions, who could thus jumble the ideas of a polypus of the blood- vessels and a polypus of the nose ? They even mistook such clots for living animals. Dr. Ed- ward May sent from England to the celebrated Severinus, a description of an Eel which he had found in the cavity of the heart. He entitles it with some propriety, " Historia rai- rabilis anguis bifidi." It is, indeed, a wonderful story; they describe head and tail, and all fairly, as if it had been bona fide a living creature; and tell us how its head was sticking to the inside of the heart, (where you may suppose it was biting,) and how its body was very white and very strong, and its arms or tails, I do not know what to call them, red. But what amuses one most of all is the important air of these communi- cations betwixt Severinus and Dr. May: and then Severinus. 60 DISEASES OF warning his pupils against incredulity, and telling them, " that though wounds of the heart are really mortal, yet ulcers of the heart certainly are not mortal; by which he means, that while the Eel was alive it was continually biting the heart.* In short, from these things, we perceive that we need not look into books for any satisfaction on this delicate point; that v\e must depend upon ourselves, and make a better use of all future oc- casions; for unhappily there are no good histories attached to those dissections in which the coagula have been more like those of a long formed disease.f The heart, which is so often dilated by weakness, is some- times reduced in size by an increase of strength and action. It becomes dense, firm, thick in substance, but small in its cavity; it appears to be dilated without, but is, in fact, con- tracted within. This thickening of the walls of the ventricles is what I cannot understand, though I have cut many such hearts with the utmost care. There is no ossification of the valves, no straitening of the aorta, nor any other ob-truction to excite the heart. There is no enlargement of the auricles, no dilatations of the veins, no disease of the arteries, nothing appears but a thickening, and enlargement, and condensation of the walls of the ventricles, a proportionate enlargement of the columniae carneae, and a proportionate narrowing of the cavity of the heart itself. Upon opening such a hean, one would almost pronounce it natural. If one should speculate upon its peculiarities, he would (finding the heart strengthen- ed, and its valves and vessels all sound,) pronounce that it would cause rather a vigorous circulation and strong health: yet I shall never forget the miseries I have seen patients en- dure from having such a heart. They have often a lull and bloated habit of body, (at least so I have chanced to observe,) a pulse weak at all times, but trembling, and hardly sensible, when a fit of difficult circulation approaches; then the pulse vanishes, the patient sometimes faints; the anxieties, oppress- ed breathing, languid pulse, actual faintings, and all the inter- mediate conditions less than fainting, but like it, and infinitely more miserable, make their chief sufferings. After struggling long under this disease, the patients grow languid for a few days, often become dropsical, and then die. The variety of symptoms which those suffer who have this aorta^I^SoMn^^ Jut in the Worn, in the heart, producing St. Vitus'* dance iu *^A$^^j£&^ t A ease more like this disease than almostany other, is a verr mrlanrhnlt,, „„.i *• ^ - THE HEART. 61 simplest Of all the diseases of the heart is very surprising, and puts to nought all our conjectures about certain signs indicating particular diseases of the heart. We cannot be surprised that in great enlargements of the auricle, or vast aneurisms of the aorta, or in those enlargements in which something like polypi are found, and where, as Mr. Holder often said of himself, the circulation seems to go on for a time in one corner, as it were, of the heart; in all such cases, we cannot wonder at there being heard noises like the rushing of water. But how such should be heard in this thickening of the heart, I cannot conceive : yet it is certain that one gentleman, whose disease came upon him all at once, and while perfectly at rest, with the sudden sense of something bursting within; who had, moreover, for several years a palpitation which could be felt outwardly, and a plunging noise, which at times the by-standers could hear very loud; who died in the end in great distress,—had yet none of these ossified valves, enlarged aorta, nor other organic affec- tions, which there was so much reason to suppose, but merely this thickening of the substance of the heart. Among the diseases of the heart we may reckon the dilata- tion of the aorta, a disease more frequent than all the others, and more dreadful. It is a disease more frequent in the de- cline of life ; it is then a disease of weakness; it arises from a cause quite different from that which is commonly laid down. The celebrated Dr. Hunter believes that it arises from that predisposition or weakness which naturally belongs to the form of this part, viz. a sudden angle of the artery, exposed in the most direct manner to the whole force of the heart. Dr. Hun- ter also believed, that no sooner is Nature sensible of this dan- ger, than she seeks to prop up the artery; and for this end thickens its walls till it ossifies by slow degrees. Haller's theo- ry is different from this, and comes nearer to the truth; for he makes these scales of ossification not the consequence, but the cause of the disease. He says, the artery becoming scaly, and partly ossified, no longer yields to the force of the heart; and the heart thus excited to a higher action is itself dilated, and at last forces also the oarta. In truth neither of these is the true theory; but the aorta in aged persons beginning to ossify, has its middle or muscular coat annihilated, and its outer and inner coats thickened, by the same process. Its muscular pow- er is lost; it is no longer capable of withstanding, much less of seconding, the stroke of the heart by a second stroke; it ceases to act, suffers itself to be dilated, and in a few years grows into a dreadful disease. I never saw an old aorta with- out some specks of ossification, or rather of calcareous concre- tion, nor an aorta so affected which was not dilated in propor- 62 DISEASES OF tion, pretty nearly to the degree of this thickening and ossifica- tion ; at which we need not wonder, since we find not a bone, (as it> is usually called ossified aorta,) but a vile calcareous con- cretion substituted to its muscular coat. Nature is not at this time, as Hunter supposed, building up and strengthening the walls of the aorta against this disease ; but taking down slowly that fabric which has lasted its appointed time. However produced, it is an awful disease ; for every organ, when once deranged, especially if it be one as active as this is, never stops in its course ; and this especially ends early or late in some terrible kind of death. Sometimes, increasing in size, it destroys all the surrounding parts, and bursts within. Sometimes it bursts into the chest, and then the patient drops suddenly down; sometimes into the trachea, and then the cause of the sudden death is known; for the patient, after violent coughingsand ejections of blood by the mouth", expires. Sometimes it beats its way through the ribs, destroys the vertebras, affects the spinal marrow ; and thus the patient dies a less violent or sudden death. Most frequently, the tumours rise toward the root of the neck, is felt beating there, destroys the sternum, bursts up the ribs, dislocates and throws aside the clavicles, appears at last in the form of a great tu- mour upon the breast, beating awfully.—A dreadful state! and with nothing to keep in the blood but a thin covering of livid skin, which grows continually thinner, till, bursting at last, the patient expires in one gush of blood. But Nature can seldom bear all this distress; the patient dies before this awful scene commences; for the aorta often so fills the chest, so oppresses the lungs, chokes the trachea, and curbs the course of the descending blood, that the system with a poor circulation of ill oxydated blood, is quite exhaust- ed ! And thus, though the patient is saved from the most ter- rible scene of all, he suffers great miseries : he feels sharp pains passing across his chest, which he compares with the stabbing of knives and swords ; terrible palpitations; often an awful sense of sinking within him ; the sound within his breast as if of rushing waters; a continual sense of his condition; sudden startings during the night, and fearful dreams, and dangers of suffocation; until with sleepless nights, miserable thoughts by day, and the gradual failing of an ill supported system, he grows weak, dropsical, and ex- pires. How, except by attributing them to some peculiar weak- ness, to some inward predisposing cause, shall we account for all these terrible diseases of the heart? Albertine ascribed them so entirely to the passions of the mind, that he gives this THE HEART. 63 as the chief reason why in the lower animals* such accidents are not found. This is strange philosophy; for who does not know that the human passions are remarked only because they should be under continual restraint and controul; while those of animals pass thus unnoticed by Rammazini, only be- cause they are wild and furious, and we do not expect that they should be restrained. The wild and ungovernable spirits of animals would produce such diseases surely, if such causes could ; but whether they do produce them, neither Ramma- zini nor any of us know; we are too careless of this kind of dissection. Often, as I have explained, these complaints lie dormant for years, till on some violent exertion the patient begins to feel them ; and when questioned by his physicians, being himself also extremely anxious to recollect the cause, and always willing to satisfy his physician, he remembers some violent exertion, some paroxysm of passion, some fit of cough- ing, or something even less important than all this; and tells how from that day he does not think he has enjoyed an hour of health. That these disorders will arise from too violent exertions, independent of all predisposition, we have every reason to believe. Sometimes from blows, more frequently from shocks or falls (for I have formerly noticed how little there is; except its vessels, to support the heart, or hang it within the chest); but most frequently of all have we reason to suspect those kind of exertions which are* accompanied with a rapid pulse and hurried respiration. Of this kind I must surely reckon all exertions disproportioned to the strength, and most of all in the time of weakness and convalescence. Do we not observe how in scurvy, upon the smallest exertion, the men drop down dead ? how when a ship is in danger, and they are pumping day and night with a weakly crew, these also fall down dead? Do we not often remember, that after fevers, young men, having made rash exertions during their state of weakness, have brought upon themselves this dreadful disease .? Do we not see that boxers, horse-jockeys, and all the tribe of athletics, cannot make these exertions unprepared ? And what is their course of training, but a spare diet of generous food, with regular exercise and gradual exer- tions ; till, at last, the two great functions of respiration and circulation accompanying each other, are brought to the high- est pitch ; and the man become capable of exertions, before impossible or dangerous; now familiar and easy to him ? For * Had Rammazini never seen a Dog eDra^ed, nor a wild Bull, nor untamed Horsp, a Cat witli iti back up.'' b'4 DISEASES OF examples of this danger, let these suffice : A delicate man, little accustomed to fatigue, having alighted from his horse and tied it carelessly, it escaped ; and all day long he chased it, till, quite exhausted, he was forced in the evening to give over, breathless and palpitating, a hundred times during this vain pursuit. From that day he never had one moment's comfort. In about a year after two throbbing tumours ap- peared upon his breast; and, in the course of the second year when he came to me, these tumours covered all the breast, throbbing in a most alarming degree, each of them bigger than two fists. At this time he had walked with tolerable ease three miles to see me ; but in less than four months he was dead, having lived in the greatest misery. When I cut out the heart, I took also the sternum along with it. I found an aneurism of the aorta filling all the chest, two fair round holes betwixt the cartilages on each side of the sternum, by which the two tumours were filled ; the ribs and sternum were not eroded, but the intervals betwixt the carti- lages dilated ; the two tumours were, when the sternum was cut away, like two great flat cups, cymbal-shaped, one a little larger than the other, and each capable of containing about a pound of blood. It has been known to happen, that a young man, travelling on foot too far, has died in a few days of a prodigious enlarge- ment, with pulsation of the heart. But the case which comes nearest to that which I have just related, is that of a man about 47 years of age, who had fallen into the hands of robbers. These men, unwilling to commit direct murder, carried him into an unfrequented place in the forest, and there tied him to a tree. Sensible that no human ear could hear his cries, he made the most violent struggles but without success. At the distance of six hours he was found by a hunter accidentally passing that way, and saved ; but not long, for his struggles had produced an aneurism of the aorta, of which he died. Upon opening his body there were found two aneurisms; one in the arch of the aorta, and one in the left subclavian artery. The many cases in which aneurisms seem to proceed less directly from strains, blows, falls, and other mischances, I will not stop to explain; for a thousand such examples cannot prove that there did not exist an absolute predisposition in each individual case. But as I began with representing the marks of ill oxydated blood in a child, I shall conclude with representing the condition of a man, which, even by a regular history, could not be represented more faithfully than in this single case. THE HEART. 65 I attended, says Morgagni, the most excellent Marquis AI- loysis Pallucci, commander of the Pontifical forces at Rome; a man who deserved a longer and a happier life. His disease was an aneurism in the breast: he could neither lie down nor go to stool, nor take nourishment, but almost instantly a pa- roxysm was brought on, which threatened instant suffocation, and sometimes seemed like death itself. He never went to bed; he continually rested on a chair to avoid all motion; but instantly upon the attack of difficult circulation, he would leap from his seat, and run to the open window, in hopes of breathing there more freely: yet even there he was used to draw his breath with astertor, his face was quite livid, he pass- ed his urine and faeces without consciousness ; often the breath- ing was so very difficult, so interrupted, that even the snoring ceased, and he seemed dead, and fell forwards, apparently life- less, into the arms of the two servants who continually sup- ported him on either hand. This was the degree of his dis- tress. But after all these dreadful reports of diseased heart, must it not be a comfort for us all to know, that often the most sim- ple affections, such as we call nervous, from peculiarity of con- stitution, or from ill health, resemble these organic diseases, so that all the physicians on earth could not pronounce upon the case ? In short, often those which appear to be at first the most awful diseases, turn out in truth the most trivial and tem- porary. Palpitations and quick breathing are the most usual signs. Palpitations, says Sckenkius, may arise from tubercles, abscesses, or congestions of blood : from worms, from stones in the heart, from poisons. But why distress us with the cata- logue of these and many other horrible things, till first he have explained palpitation to us as a common but merely ner- vous disease, which many feel, but few complain of? Were a man to study only these examples of organic disease, he must of course believe that there were no other, and think that every palpitation portended death ; while palpitation is, in truth, the nervous disease of boys and girls, of women, or of weakly men: it alarms the young and the robust; while, in fact, organic disease belongs rather to advanced life, and comes seriously upon us at a time when all fears about palpitations are past and over. I like what Galen says (Lib. de Loc. Affect, cap. ii.) " Pal- pitatio visceris hujus, pluribus integra valetudine degentibus, cum adolescentibus turn adultis, subito, sine ullo alio mani- festo accidente, evenire visa est." I think it dangerous to add what follows; " atque omnes eos sanguinis detractio juvit;" for I know such bleeding to be but a temporary relief, more VOL. II. I 66 DISEASES OF than counterbalanced by a permanent loss. This text I shall explain a very little, and then conclude : for palpitation is, in- deed, the disease of boys and of young men, as I have just ex- plained, but not of the aged, in whom chiefly we find organic disease. Palpitation is like that fluttering which fear brings on; the heart rises in its action till it throbs, and beats against the ribs; it is strongly felt, it is even audible to the by-standers, and still it is but a nervous disease. Its intermissions usually distinguish it from any organic disease ; its paroxysms last for many days or weeks; and for weeks or months again it goes quite away. We see it relieved by a jaunt, by living from home and in company, by leaving all business and thoughts of business quite behind: we see the causes which bring it on as plainly as we know the cause of marsh fever, or the plague. The confine- ment even of a boil will cause it; the confinement of severe study is sure to cause it; and severe study, with an anxious mind, in a young man unused to study ; neglected where he is, and at a distance from all his friends, are sure to produce this distress. "My son," says Wierius, "while at Bologna pur- suing his studies, had this afflicting palpitation, accompanied with a capricious, frequent, and intermitting pulse; but by bleeding (which the older physicians never neglected) and care, and relaxation from his studies, he got quite well." This is the palpitation which the older authors distinguished by the name of palpitatio cardiaca, marking it as proceeding from the stomach; equivalent, in the language of the present time, to the calling it a nervous disease. These, then, are the habits in which it occurs, and this its cause : and there remains but two things to be shortly observed, or rather to be proved, viz. that it is sometimes as alarming as an organic disease is ; and that bleeding is dangerous in an ex- treme degree, or at least that it does not, as Galen affirms, " always bring relief." " Sanctius Velasco, son of the Count Velasco, had a palpi- tation of the heart so terrible, that I and many by-standers often heard it distinctly, as if a stone had been plumped into a jug half full of water."* Yet this boy got entirely well, and his physicians made themselves very happy in the thought that they had cured him, by a sacculus of aromatic herbs steeped in wine applied to the region of his heart; and by the same aromatics, or cardiacs as they called them, given along with his food. I proved the second point, viz. the danger of bleeding, by a * Christoph. a Vegas Ars M-'hndi, lib. iii. sect 6. cap. 8. THE HEART. 67 most alarming case, delivered by Morgagni, which I fear might (if it had so pleased the writers) have had in the records of medicine many precedents ; it wholly destroys the authority of Galen's rule, and plainly instructs us never to bleed. " A boarding-mistress, having a slighter palpitation of the heart, was bled with some appearance of relief: but after two days her palpitations returned with such violence, that the breast seemed at every stroke to be lifted up; she had withal pain, fever, and difficult breathing. They continued bleeding her first in the arm, which did no good; then in the foot, which was absolutely fatal; for in an hour after she died, the pulse becoming quicker instantly, and falling gradually lower and lower, and giving less resistance to the finger till she expired." fn her viscera both of the belly and of the thorax, every thing was entire, sound, and natural; and it had been well for the physicians who attended her, had they remembered that the very name of palpitatio cardiaca implies a course of pro- ceeding quite the reverse of this. Thus the simple disease of nervous palpitation is often ill understood, and the patient's health abused, and his miseries and agony of mind, and his real disease, all increased, by the serious looks of his physicians, when perhaps, it is but a very simple case. The French physicians, in a very formal consultation, made a very public mistake of this kind, in the disease of Marinus de Caballis, ambassador at Paris from the Venetian state. He complained to them of his palpitation and of his intermitting pulse, and they concealing nothing of their opinion from him, prognosticated the very worst; advised him to demand his au- dience of leave, to go off for his native country, and there to make his will, settle all the affairs of his family, and then com- pose himself for his last hour. Having obeyed them in all things, he arrived in Italy very disconsolate and dejected, and their prognostic was well nigh fulfilled. But, like a man who would have another throw for one precious stake, he called a consultation of the college ; among whom, happily, was Victor Trincavelli, then professor in the university of Pavia; who, perceiving that such tremors of his pulse proceeded entirely from the great charge of important matters which lay heavy upon his mind, assured him of recovering his health. He or- dered frequent bleedings, which the peculiar fulness of his habit seemed to require; and by cordial medicines he was en- tirely restored, and lived long; a man of great science, and skilful in many languages. After this sad journey, he perform- ed with much honour to the state two splendid embassies to the Emperor and to the Turks. 68 DISEASES OF THE HEART. Let no one in future pronounce so rashly; it is time alone, and various modes of living, that can explain to us whether there be in any individual case a fixed disease. Nor would I dare to speak of the organic diseases of the heart, without explaining more fully an idea which Albertine has shortly and simply, expressed. " Formerly, in diseased respiration, any vitiated structure of the heart and precordia were unheard of; but after observations being several times repeated in dead bodies, the same names are too much heard of and too much dreaded in the living." \ BOOK II. OF THE ARTERIES. :■»< GENERAL PLAN OF THE ARTERIES. AORTA. J. HE arteries of all the body (excepting only those of the lungs employed merely in oxydating the blood) arise from one trunk, the aorta; which we must describe as of great size, since we compare it with other arteries, but which is wonder- fully small considering that it is of its branches only that the whole body is composed. Those will have the truest notion of the distorted form of the aorta who have studied the anatomy of the heart. Its root is deep buried in the flesh of the heart. In the Tortoise we see the flesh of the heart rising round the root of the aorta, and endowing it with the power of a second ventricle : in the Frog we find its internal surface beset with a triple row of valves, and its coats are like those of a ventricle, they are so exceedingly strong: in Man We find it plainly muscular, surrounded in circles with great fibres, and having much mus- cular power. The beginning of the aorta, then, lies deep in the flesh of the heart; it is there that it gives off its coronary arteries; it bulges at its root into three great knobs, which mark the place of its three valves, and are called the lesser sinuses of the aorta; it is large at the root, it grows smallar as it rises, it mounts upwards and backwards from the heart, till it begins to form its arch or curvature'; its direction is first towards the right side of the thorax ; looking backwards, it turns in a very distorted manner, where it forms the arch ; it strides over the root of the lungs, going now to the left side and backwards, till 70 GENERAL PLAN OF it touches the spine ; its arch lies so upon the forking of the trachea, that its aneurisms often burst into the lungs : it then applies itself close to the spine, so that in aneurisms the pres- sure of the aorta often destroys the vertebrae; and now lying along the left side of the spine, and with the oesophagus run- ning close by it, it passes down through the thorax, and from that to the belly under the legs of the diaphragm. This, then, may serve as a short description of the aorta, which is the root of all those arteries which we proceed now to explain. Its structure is strong, muscular, and continually active, performing the office of a second heart. When in old age it begins to lose this muscular power, to have its fibres em- barrassed with chalky, or as they are called bony concretions, it is no longer able to resist the force of the blood; it is not dilated into aneurisms, because of the acute angle which it makes, and the direct impetus of the blood, for many other arteries turn backwards with very acute angles; the arteries tied in aneurisms, amputations, and on other occasions, do not dilate ; the inosculations which save a limb after the ope- rations for aneurism, receive the blood in a retrograde course, and the angles are often very acute, yet they do not dilate too much. The arteries under joints are oftener bent than straight; the aorta of deformed people follows closely the de- formity of the spine, and makes such singular angles, that after once seeing them no one will talk of angles occasioning dilatation. The aorta, when dilated, in nine of ten cases is covered with white spots ; it is diseased; they are aged peo- ple, and almost always the dilatation begins from the heart. The aorta, then, is the trunk from which the general tree of the arteries is to be explained. From the arch of the aorta go off three great arteries, which rise to the head, or bend sidewise towards the arms, and so nourish all the upper parts of the body. Of these three arteries, the first is a great one, which contains, if I may so express it, the right carotid and the right subclavian, and divides so as to form those two arteries, about one inch after it arises from the arch; the next thing is the left carotid artery going to the head; the third is the left subclavian, going to the left arm. These three branches oc- cupy all the arch of the aorta. RIGHT^ SUBCLAVIAN. 4. The right subclavian goes off from the aorta in a more di- rect course than the left.; it is thought to receive the blood THE ARTERIES. 71 more fully; perhaps, also, it is rather larger than the left subclavian; but, at all events, there is something peculiar in the mechanism of the right arm ; most probably it is the pecu- liar form or direction of this artery that gives to the right arm a superior dexterity and strength. When Horses are to be broken, we find the chief difficulty to consist in teaching them to move equally with both feet, for they prefer the right; when a Dog trots, or when he digs the ground, he goes with his right side foremost, and digs chiefly with his right foot; and in these creatures we find the same arrangement of these arteries as in ourselves. But in Birds, where an equal balance of strength is required for the wings, both subclavian arteries are distinct branches of the aorta. When we lose our arm, the left hand acquires by use all the strength and dexterity of the right. Since, then, either arm can require this dexterity, and since the right leg is stronger by its dependence upon the motions of the right hand, we have every reason to believe, that the preference given to the right hand has some physical cause, and that it is the peculiar form of this artery, viz. going off more directly on the right side, and that those who are ambidexter must have the right as well as the left subcla- vian going off as one independent branch. There is another peculiarity which has occurred. The arch sometimes gives out four branches, and the left subclavian, arising first from the arch, has passed behind the trachea, be- twixt the trachea and the oesophagus. The subject dying of difficult deglutition, which has subsisted from childhood, it has been attributed to the pressure of this preternatural artery, an effect which I cannot easily believe ; and it has been proposed to rank it as a new and certainly incurable species' of the dis- ease, under the title of dysphagia lusoria, as arising from a lu- sus naturae of this artery. CAROTIDS. The next branch of the arch is the left carotid. The two carotids mount along the sides of the neck, are felt beating strongly, and seem much exposed. They retire for protec- tion behind the prominency of the thyroid cartilage. They divide into external and internal carotids under the angle of the jaw. The external carotid supplies the neck, the face, the inside of the throat; aj"id the reader will have chiefly to observe its course all along the neck, its branching at the an- gle of the jaw, and the operations and wounds about the throat, neck, face, and especially about the root of the ear. s7£ GENERAL PLAN OF ^7 He *' P LEFT SUBCLAVIAN. The left subclavian is the third branch of the aorta. Each subclavian artery varies its name according to the parts through which its goes. This great artery of the arm is named sub- clavian under the clavicle, where it gives branches to the neck; axillary in the arm-pit, where it gives branches on the one hand to the scapula, on the other to the breast. It is named brachial where it runs down the arm, and where there are few important branches; and, finally, its branches, into which it divides at the bend of the arm, are named radial, ulnar, and interosseous, because they respectively run along these parts, the radius, the ulna, and the interosseous membrane. THORACIC AND ABDOMINAL AORTA. The aorta, after completing its arch, passes through the tho- rax, giving but few branches, and those very slender. But the abdominal aorta, as soon as it has emerged from under the legs of the diaphragm, gives three great abdominal arteries : first, the celiac, going in three branches to the liver, the stomach, and the spleen; secondly, the superior mesenteric, which furnishes all the small intestines ; and thirdly, the lower mesenteric, which supplies most of the great intestines down to the rectum. The arteries of the kidneys and of the tes- ticles follow these, and then the aorta divides into two great branches for the pelvis and legs. The iliac arteries are the two great branches into which ihe aorta divides within the abdomen, and these again are each subdivided into two great arteries; the internal iliacs to supply the pelvis, the external iliacs to go to the thigh. INTERNAL ILIACS. The internal iliac supplies the bladder, the rectum, the womb, with lesser arteries; but its great arteries go out by the openings of the pelvis to supply the very large muscles of the hip and thigh. Thus the gluteal, a very great artery, turns round the bone, goes out by the sciatic notch, and goes to the glutaeal muscles. The sciatic, almost equally large, turns down along the hip opposite to the glutaeal, which turns up. The pudic, of great size, also turns out of the pelvis, turns in- THE ARTERIES. *13 wards again towards the root of the penis, and belongs entirely to the private parts, as its name implies. EXTERNAL ILIACS. The external iliac, when it passes out of the abdomen, takes the name of femoral artery : it divides into two vast arteries a little bellow the ligament of the thigh : the one goes deep, belongs to the muscles, is called the profunda; it fur- nishes all the thigh, and it might with the strictest propriety be named the femoral artery. The femoral artery, as we call it, is the other great branch, which continues superficial, runs obliquely down the forepart of the thigh, gives Yew and but trivial branches to the thigh, and is really destined for the leg. When the artery turns inwards towards the ham, it is named popliteal arterv ; and, like the artery at the bend of the arm, this one at the bending of the knee di- vides into three great branches, which, like those of the arm, take their names from the bones along which they run; the anterior tibial artery lies on the forepart of the tibia : the posterior tibial artery runs along the back part of the ti- bia; the fibular artery runs along the fibula; and these great arteries terminate by making arches with each other in the sole of the foot, in the same manner that the radial and tjlnar arteries join in great arches in the palm of the* hand. This slight plan I have chosen to throw out before my read- er, that the succeeding parts may seem more methodical, and that he may have at a slight glance the chief parts of his task before him; and knowing all his duty, he cannot be inatten- tive to that on which the lives of his fellow-creatures must *t> often depend. '•"OL, II. K ( 74) CHAP. I. OF THE ARTERIES OF THE HEAI*. SECT. I. or the carotid arteries in general. JL HE carotid arteries are also named the Arterias Cerebri, as if they were the sole arteries of the brain; and the ancients either ignorant or forgetful of their being any other arteries for the brain, or not observing that the vertebral arteries might convey blood enough for the functions of the brain, did ac- tually name the carotids the Arteria? Soporiferae; believing that, if they were tied, the person must fall asleep.* How a person might die from having the great arteries of the head tied, I can most readily conceive; but how he should rather fall asleep, and not die, is quite beyond my comprehension ; and yet many of the best anatomists, in the best age of anato- my, have abused their time repeating these experiments. Va- salva, Van Swieten, Pechlinus, Lower, and especially Drelin- curtius in his Experimenta Canicidia, and many others, spent days and weeks in tying up the carotids of Dogs. What does all this imply ? Surely a strong belief in tales which would dis- grace the Arabian Nights; tales concerning a manner of tying a cord round the neck of a She-goat, or even of a young Man, so that, without hurting them, they should be made to sleep or wake according to the bidding of the spectators. Costaeus first tells this tale : " Circumforaneous mounte- banks (says hef) often perform this miracle. They tie a liga- ture round the jugular veins of a She-goat; and they tighten it and relax it from time to time, so that at their pleasure the animal falls down motionless and stupid, and at their bidding leaps up again with great vigour." The most incredible tales "" * The name which we use, via. that of carotids, is synonymous in Greek with Arterte Soporales. f Disquisitions Pathologies, lib. 6. cap. 6. « OF THE CAROTID ARTERIES. 75 r-oon followed, and soon crept into otherwise good and useful books. Even Hoffman seems not unwilling to believe that the Assyrians had been in use of tying up the jugular veins in their young men before circumcision, that they might feel less pain. A serious operation, God-wot! for so slight a cause. Even Morgagni talks more seriously of the She-goat, and of this snibbing of the young men of Assyria, than one could wish in res- pect to the character of one so truly great as Morgagni.f But the person the most celebrated in this affair was Reaidus Columbus; and the wildest and most barefaced tale that ever was told, is that delivered by his pupil Valverdus in his Anato- my of the Human Body. u The carotid arteries (says Valverdus) being tied up, or any how obstructed, the person grows stupid, and falls pre- sently into a profound sleep. This experiment I saw at Pisa in the year 1554. It was performed upon a young man by the celebrated Columbus in the presence of a great many gentlemen and strangers, with no less misery to them than amusement to us (the pupils), who, though we knew the cause, ascribed it altogether to the black art." But if any one word of this were true, Valverdus would have told us, and been proud to tell us, by what particular ope- ration, ligature, or pressure, this strange thing was per- formed ; and Columbus himself, the author of this new amusement, would surely have dropped some hints a- bout it in some place or other of his works. But from the modest silence of the master and the secrecy of the pupil, we have reason to believe it is untrue ; and if Colum- bus did ever venture to exhibit such a mean piece of leger- demain, he put himself quite upon the level with the quack and his She-goat. The quack, indeed, was much beyond him in point of merit, since it must have been far easier to teach a clever young man to fall down or start up than to teach all this to a She-goat. Galen has explained it well, saying, " that physicians and philosophers, tying the carotid arteries, tie in along with them the recurrent nerves which serve for the voice; and if they will have silence to be sleep, no doubt the creature is mute after their awkward operation ; but no other function is hurt neither then nor afterwards." t The celebrated Cant not only believes this most powerfully, but reasons upon it in the following manner : " Ruffus Ephesius, lib. 1. cap. 34. hanc soporem adferre negat, hiuc aliud nomen permitteret; sed Reaidus Columbus puhlice in theatro demonstravit nunc effertum praestari hac arteria; itaquc nomen retinebimui utpote rei conghukns. Sic eniin quotidie experimur post prandium roiunolentiam, quam facile deducere possumus ab ( efleclu hujus arteriae; nam ventriculo extenso premitur aorta desccndens, quo sanguis copia majoi i ruit in carotides j quae hinc eitensje comprimunt cerebrum quodainmodo, quo motus, animales non ita expedite absolvuntur, verum vitales augentur motus, quae anibo fiunt in »omno." Tab. Cant impetus faciens, p. 6. 76 OF THE CAROTID ARTERIES. This is the truth, and the whole truth nearly ; for if but one Dog lives after both carotids are tied, nothing can be more certain than that those which die must have suffered by some awkwardness or disease. Is it wonderful that, after such a cruel tedious operation as this is, the Dog should be exhausted, should be weakened by loss of blood, should feel sore, and hang his head and droop, and let the slaver fall from his jaws? that he should skulk in corners, look side-long, be jealous, and not easily moved from his hole ? These are what they have thought fit to call drowsiness and signs of sleep; but it is such drowsiness and such sleep as would have fol- lowed such a cutting up of the creature's neck, whether the experiment-maker had touched the carotids or not. The creature lolls its tongue, hangs its head, closes its watery and heavy eyes, is drowsy, or, in other words, feverish for many days : it eats with all the voracity of a Dog, but with difficul- ty, and slowly, owing to the swelling of its throat; and if it dies, it dies from the same cause. Nothing is more certain than that these are the only particuar effects, and that the carotids of a Dog may be tie,d without any other danger than that of the wound. There is nothing new under the sun. We are continually tantalised with old tales in new forms. Who would expect to find at this very day a practical application of the She-goat and the Assyrian young -Men ? One author has published to to the world, " that a young Lady, of a nervous and de- licate constitution, subject to nervous distresses in a wonder ful variety of forms, but more especially in the head, sometimes affected with head-aches, sometimes with de- lirium, sometimes with convulsions, was relieved by com- pressing the carotid arteries." Often by compressing the the carotid arteries, this gentleman prevented the delirium; " for all these complaints proceeded from a violent palpita- tion of the heart, with the stream of blood rushing violently towards the head." He has seen this compression bring on a stupor; he has seen it bring on a profound sleep. Is it not a pity that he had not attended more to the history of this busi- ness, and joined to these facts the story of the She-goat and the young Men of Assyria ? If what Dr. Parry says be true, that in lean people, in wo- men at least, we can, by reclining the head backwards, com- press the carotids entirely against the forepart of the neck, with the finger and thumb; why, then, we need have no fear of hemorrhagies of the nose, wounds about the jaw, cutting the parotid gland, or operations about the tonsils or tongue ! But there is a dangerous mistake here ; for there is (as I know OF THE CAROTID ARTERIES. 77 by much experience) a wide difference betwixt preventing the pulse of an artery and suppressing the flow of blood through it. In the case of a Man fainting during any great ope- ration, if you are holding in the blood with the point of your finger upon some great artery, you feel the pulse there, while the face is deadly pale, the extremities cold, and the pulse of the wrist and of all but the largest arteries gone. In fainting, even the heart itself is not felt to move ; and yet it moves, and the blood circulates: how else could a person lie in a hysterical faint for hours, I had almost said days ? I have tried, in great operations near the trunk of the body, to stop the blood with my hands ; but though I could suppress the pulse of the femoral artery with my fore finger, I could not command its blood with the whole strength of my body, but have seen it with horror rush as freely as if my hand had not been there. In short, I suspect Dr. Parry's belief of his stop- ping the carotids with his finger and thumb is as vain as Dr. Monro's expectations of compressing the abdominal aorta by pushing with his fist against the belly. The carotid artery, having emerged from the chest, runs up along the neck by the side of the trachea, a sin- rugle undivided artery, without twig or branch, till it is oppo- site the jaw. The length of this artery gives us a fair oppor- tunity of observing, of proving, if we choose, that arteries are cylinders, and not as they once were supposed, of a conical form. But the cylindrical form of this artery should not occu- py our attention so much, as that peculiarity of direction, which, though apparently exposed, keeps it safe; or those important connections which make it so dangerous either to cut or to tie this artery. First, The carotid artery, from the place where it emerges frcm the chest up to the angle of the jaw, is continually re- ceding from the forepart of the throat, is getting deeper and deeper by the side of the trachea, at last the strong projection of the larynx or cartilaginous part of the tube defends it ; and when it has got to the angle of the jaw, it lies there so deep under the ear, betwixt the ear and the jaw, in a sort of axilla, as we may call it, filled with fat and glands, that it is almost out of reach of danger unless it be sometimes of the surgeon's knife, but rarely of wounds. This continual retreating of the carotid artery, deeper and deeper as it rises along the neck, saves it from the attempts of suicides : it is rarely cut. or when cut, it bleeds so that no ig- 78 OF THE CAROTID ARTERIES. norant person can command it, and the surgeon is too late. But although tumours and aneurisms are rare, and through unwil- lingness and a well grounded fear such patients are usually lelt to take their fate; yet there may happen cases in which it may be necessary to do so bold a thing as to tie this artery.* Secondly, The connections of the carotid, as it rises along the neck, must determine our judgment, if ever any such case should occur. To stop the growth of an aneurism, to allow the extirpation of other tumours about the jaw, to save a pa- tient from dreadful bleedings of the throat, or from the he- morrhagies of deep wounds, when, for example, a patient is stabbed in the neck, or a ball passes through the mouth and under the angle of the jaw; these may, in some unlucky mo- ment, present themselves as motives for tying the trunk of this artery, when all its great branches are torn. But always the observation of Galen is to be remembered, that the nerves ac- companying these arteries are liable to be tied together with them. Let us recollect how the carotid artery, jugular vein, and eighth pair of nerves, come out from the skull, for it is almost at one single point. The carotid artery enters by a hole in the petrous bone ; the jugular vein comes out by a larger hole in the same bone, the foramen lacerum ; immediately behind it the eighth pair of nerves, or the par vagum, goes out through a division of the same foramen lacerum, separated from the vein only by a little cross slip of the dura mater; and so the carotid artery, jugular vein, and eighth pair, touch each other at the basis of the skull. Through the whole length of the neck they continue the connection which is thus early begun. They are, indeed, inclosed in one sheath of cellular mem- brane ; so that what touches the one almost inevitably affects the other. The par vagum being the great nerve of the vis- cera, at least of the stomach, strictures upon it, or wounds are certainly fatal. A surgeon might easily, if it were possible for him to be called in time, take up the gaping mouth of the artery safely when it were cut across; yet in most of such cases the nerve being also cut, the operation would be fruitless. But as for a deliberate dissection of the skin, the artery beating furiously, and the parts embarrassed with any tumour, and the operator alarmed with a deluge of blood from the veins; that, I think, would be a bold step. In short, the necessity of any such operation is reduced to the accident of tumours or wounds * I leave this as it was expressed in the first edition. The carotid artery has been often (led since this was written, and even by the author himself. It was with great pleasure that I lately witnessed the cure of a soldier by the tying of the carotid. He had received a .'operate wound with a sword, which entering in the neck came out at his mouth. C. B. OF THE EXTERNAL CAROTID. 79 about the angle of the jaw; in which cases, the sponge thrust down into the wound will almost always check the blood. When the common carotid has risen to the angle of the jaw, it divides into two great arteries, one going to the outside of the head, the other to the brain; the one of course named the external, the other the internal carotid. Some of the most eminent anatomists are incorrect when they say, that the carotid artery gives no branches till it arrives at the larynx. They say so because the first branch goes to the larynx; but, in fact, the carotid passes much beyond the place to which it is to give its first branch, for instead of branching at the larynx, it does not do so till it arrives at the corner of the jaw; there, as I have observed, it can, as in an axilla, lie deep and safe; and the laryngeal artery, which is the first branch of the caro- tid, turns downwards again to touch the larynx. The first division, then, of the carotid artery is into the ex- ternal and internal carotids; and the external carotid gives branches so interesting to the surgeon, yet so numerous, that it is at once very desirable and very difficult to get a knowledge of each : arrangement is here of more importance than in any order of arteries, though extremely useful in all. ARRANGEMENT OF THE BRANCHES OJf THE EXTERNAL CAROTID ARTERY. The external carotid gives three sets of arteries; each of which, having a plain and distinct character, cannot be forgot- ten, nor their direction, nor their uses, nor their relative impor- tance, misconceived; for if we consider but the parts along which the carotid artery passes, as 1. The thyriod gland ; 2. The tongue ; 3. The face; 4. The pharynx; 5. The occi- put; 6. The ear; 7. The inside of the jaws; 8. The tem- ple :—if we remember thus the order of these parts, we shall not forget the order in which the branches go off. But it will be further very useful to observe, that these many branches divide themselves most naturally into three sets. 1. The branches which go off from the carotid forwards are peculiarly important; one of them goes to the thyroid gland, another to the tongue, and a third to the face ; parts which, to say no more, are peculiarly exposed; but they are, besides, the subject of many particular operations. 80 OF THE EXTERNAL CAROTID. 2. Those branches which go backwards and inwards, as the pharyngeal, the auricular, and the occipital arteries going to the ear, the pharynx and the occiput are both extremely small, and also run so deep, that wounds of them are rare and of less importance, and fortunately those branches are the only ones which it is difficult to remember. 3. The great artery which passes behind the lower jaw, named maxillary artery, and the temporal artery which lies behind the jaw, imbedded in the parotid gland, must be stu- died with particular care; the difficulty of cutting tumours here, the course of the temporal artery in which we bleed, and which, lying imbedded in the parotid gland, demonstrates the absurdity of talking about cutting out the parotid gland, since plainly it cannot be done ; and, lastly, the terrible he- morrhagies which often happen from the throat, nose, tonsils, &c. give an importance to these two branches above almost any other. They should be very familiarly known to the sur- geon. These, then, are the three divisions of the external carotid artery which are to be described. FIRST ORDER, including the arteries which go forward to the thyroid gland, tongue, and face. 1. arteria thyroidea. The thyriod artery, often also named the upper laryngeal artery, comes off from the external carotid almost in the very moment in which it separates from the internal carotid. Its place is behind the angle of the jaw; it goes downwards and forwards in a very tortuous form, till it arrives at the thyroid gland, upon which it is almost entirely expended; but yet it gives some branches, or rather twigs, of which the following are the chief: 1. One superficial branch goes upwards to the os hyoides,. and sends its twigs sometimes under, sometimes over, the os hyoides : it belongs chiefly to that muscle and to that piece of membrane which join the os hyoides with the thyroid carti- lage, named musculus hyothyroideus. This branch is both long and beautiful ; it meets its fellow of the opposite side with free inosculations; it supplies cutaneous twigs, and twigs to the platisma myoides. OF THE EXTERNAL CAROTID. JJI 2. A second superficial twig goes downwards to the lower part of the thyroid cartilage, where it meets the cricoid, and there gives little arteries to the mastoid muscle, jugular vein, and skin. 3. There is another branch which proceeds frequently enough from this second one: it belongs entirely to - the larynx, for which reason the thyroid is often named the supe- rior laryngeal artery : it dives immediately betwixt the carti- lages of the larynx ; it enters betwixt the thyroid and cricoid cartilages, carries in along with it a twig from the eighth pair of nerves; it gives its twigs to the epiglottis, and to all the small muscles which lie under cover of the thyroid cartilage, and which move the little arytenoid cartilages; and then passes outward emerging from the larynx, and appears again supplying the cricothyroideus muscle. 4. The fourth branch of the thyroid is properly the main arlery, or continuation of this branch into the substance of the thyroid gland; it applies itself to the side of the gland, nourishes its substance by a great many small branches into which it is divided. These branches are all oblique, tending downwards and forwards. Their course is upon the side of the gland, .because, indeed, the gland consists chiefly of two lateral lobes, and hardly any of the gland, or only a small portion crosses the trachea; consequently this artery does not inosculate so much with its fellow of the opposite side as with the lower thyroid, which comes from the subclavian artery, and whose branches, mounting upon the lower part of the gland, have pretty nearly the same degree of obliquity with those of the upper thyroid. 2. ARTERIA LINGUALIS. The lingual artery is one of which the four branches are nearly of an equal size, and which of course require all of them to be equally well remembered. It is next to the thy- roid, comes off immediately above it, goes forwards towards the os hyoides, and at the same time upwards towards the tongue; but all along it lies flat upon the side of the tongue upon its flesh or muscles, and gives the following branches : 1. Upon passing the horn of the os hyoides, it gives first one twig of less note backwards to the constrictor pharyngis, at the place where that constrictor arises from the horn of the os hyoides (viz. the constrictor medius;) and it gives another branch forwards round the basis of the on-hyoides, where it meets its fellow: and to those who are acquainted with the vol. n. L 82 OF THE EXTERNAL CAROTID. muscles which arise from the os hyoides, it is needless to say what muscles it supplies.* This, which is named the ramus hyoideu^, seems to be very necessary, because it is a very constant branch ; and when it does not come from the lingual, it infallibly arises from some other, commonly from the facial artery. 2. Dorsalis lingua is a branch which goes off from the lingual at the insertion of the stylo-glossus muscle into the tongue : it turns first outwards a little, and then inwards over the root of the tongue, where the arteries of the opposite sides meet, and form a sort of net-work. Its chief branches are directed backwards towards the epiglottis and mouth of the pharynx, amygdala?, &c. About the middle of the tongue, or about half way to the chin, measuring along the jaw, the lingual artery forks into two branches; the one below the tongue, the sublingualis, be- longs to the sublingual gland and surrounding parts ; the other remaining at the root of the tongue, belongs to the tongue itself. 3. Sublingualis then arises next ; it comes from the side of the artery next the tongue; it runs under the sublingual gland, covered like it by the genio-hyoideus muscle and emerges only when it arrives at the chin, where it terminates in the skin. Its branches are chiefly to the sublingual gland, which lies over it, and to the genio-hyoidei and mylo-hyoidei muscles and skin, for these are the parts which immediately cover it. 4. The arteria ranina is the larger branch of these two : it runs along the root of the tongue quite to the tip of it. In this course it is accompanied by its vein, which appears on the inside- of the mouth when we turn up the tip of the tongue. This is the vein which the older physicians were so fond of having opened in sore throats; the artery is that which we are so apt to cut in dividing the frenulum linguae ; an awkward- ness from which a great many children have died. 3. ARTERIA LABIALI5. The labial artery is named occasionally the external max- illary artery, to distinguish it from one which goes off at a higher point, and goes to the inside of the jaw; or angu- laris, because it goes to the corner of the mouth and there * Viz. the hyo-glossus, digastricus, roylo-hyoideus, the coraco-hyoideus, sterno-hyoideui. and hyo-thyroideus. OF THE EXTERNAL CAROTID. 83 divides; or facialis, implying, that it supplies the face, as indeed it does as far as the angle of the eye and forehead, where there are other small arteries. Haller adheres to this name of labialis. and in compliment to him we adhere to it. This artery is still carefully kept down in the deep angle; al- though it is to come out upon the jaw, yet it is not exposed till it actually makes its turn : it lies under the stylo-hyoideus and the tendon of the digastric muscle: it is very tortuous^ that it may move along with the jaw, and lies still so deep, even when it approaches the jaw-bone, that it is forced to make a very violent and sudden angle when turning over it.. This sudden turn, which is sometimes almost a circle, is made, as it were, in the heart of the great sub-maxillary gland, the artery being buried under it. The labialis is a very large artery, very tortuous; sometimes one great trunk gives off two important arteries at once, the lingual and the fascial; in which case they separate just at the angle of the jaw, where the artery, dividing the substance of the gland, is quite im- bedded in fat. When we consider how deep this artery lies according to this general description, and the parts which it passes along, it becomes easy to foresee what branches it will give, and to trace them in imagination. 1. Where it lies the deepest upon the side of the pharynx, it sends a branch directly upwards, which goes straight to the arch of the palate, spreading its small twigs upon the arch of the palate, upon the velum palati, and upon the uvula: it usually has two small branches for supplying these parts, one superficial and one deep; and thus the labial gives a particular artery to the palate, named arteria palatina inferior. 2. It gives a particular artery to the tonsil, which arises at that point where the stylo-glossus begins to mix with the other muscles of the tongue. This little artery penetrates the walls of the pharynx upon which it lies, and spreads its many twigs upon the tonsil and tongue. 3. While passing through the sub-maxillary gland, dividing it, as it were, into two parts, the labial artery gives a great many small twigs into the substance of the gland itself; and after these it gives many twigs to the tongue, the skin, the muscles, he. Of these, two chiefly are remarkable; one, which goes to the pterygoid muscle chiefly, though it also gives branches to the constrictors of the fauces and palate, and to the root of the tongue; and another artery, more con- stant and regular, which breaks off at the place where the labial artery curls and bends to turn upwards; it runs super- vicially, and goes straight forwards to the root of the chin, 84 OF THE EXTERNAL CAROTID. where it is named arteria submentalis : it turns upward** over the chin to the face at the middle of the chin, and often inosculates with some of the arteries of the face: it some- times comes from the sublingual artery. But the artery having emerged from betwixt the lobes of the sub-maxillary gland, (for this artery in a manner divides it into lobes,) and from among the fat with which it is surround- ed, makes a sudden turn over the angle of the jaw at that point where we feel it beating strongly ; and then mounting upon the face, begins to give a new set of arteries. 1. A branch to the masseter muscle; for the labial artery passes over the jaw, and up the face, just at the fore edge of the masseter muscle; and this branch inosculates with a twig descending over the surface of the masseter from the temporal artery. 2. The labial artery ascending in the hollowest part of the cheek, and lying flat upon the buccinator muscle, gives out small branches to it, which inosculate chiefly with the trans- versalis faciei, another branch, and a considerable one, coming from the temporal artery across the face. Here also the main artery has still a very serpentine line, on account of the con- tinual motions of the part. 3. Before the artery comes to that.point where it is to give off the coronary artery of the lower lip, it gives a branch named labialis inferior ; which artery belongs to the lower part of the lower lip: its branches go to the triangularis and quadratus muscles, which lie on the chin and on the side of the chin, and also to the lower part of the orbicularis oris. This branch inosculates particularly'with a twig, which comes from within the lower jaw through the mental hole, and with its fellow, and of course with the coronary arteries which run immediately above it, viz. in the red part of the lip. The artery now divides into two branches, one for each lip, named the coronary arteries, because they always surround the lips entirely, though their manner of going off is not per- fectly regular. The lower coronary artery is usually smaller, and is to be named the branch, while the upper one not only surrounds the lip, but mounts along side of the nose ; it is larger; and is therefore to be considered as the continued trunk. We frequently observe the upper coronary larger on one side of the face, and the lower coronary larger on the other. 4. The lower coronary comes off about an inch or more from the angle of the mouth, at that point where the triangu- laris oris and many other muscles meet. It goes directly for- wards io the angle of the mouth, enters into the lower part of the lip, and runs along the red pulpy part of it, where with the OF THE EXTERNAL CAROTID. 85 finger and thumb it can be felt beating. It inosculates with all the arteries formerly mentioned; as the sub-mental, the twig which comes through the hole near the chin, the inferior labial artery, and with its fellow. With all these it inosculates so freely, that it signifies little from which side your injection is driven : it goes freely all round the lips, and the arteries are every where equally filled. 5. The upper coronary artery we are to consider as the continued trunk. The labial artery is still rising, and still tor- tuous, when it arrives at the angle of the mouth; runs into the border or fleshy part of the upper lip, and runs along it till at the middle of the lip it meets its fellow of the opposite side with a very free inosculation : yet the two arteries do not ter- minate here, but usually two very delicate arteries ascend towards the point of the nose, along that little ridge from the nose to the lip which we call the filtrum ; and almost always a considerable artery runs up from the superior labial artery by the side of the nose. From this is given off a branch to the nose, viz. the nasalis lateralis, and now the artery still ascend- ing, (under the name of angularis,) gives off branches to the cheek and eyelids, and growing gradually smaller, it arrives at last near the angle of the eye, and inosculates pretty freely with that artery, which is named ophthalmic, because it first nou- rishes the parts of the eye with many branches, and then comes out of the orbit at the corner of the eye, where, though small, it may be felt beating distinctly. SECOND ORDER. The second set of arteries, which go backwards from the external carotid, comprehend the pharyngeal, the occipital, the auricular. 4. pharyngea inferior. The lower pharyngeal* is a small slender artery, which gives no branches deserving to be numbered; it stands alone, and should be described as one simple artery, whose small branches spread all about the throat in the following manner. This artery is smaller than any other branch of the carotid yet enumerated. It arises opposite to the lingual artery; and as it ansesfrom the inner side, it comes out in a manner from pharyngeal, to distinguish it from one which comes downwards frouj 86 Of THE EXTERNAL CAROTID. the fork betwixt the external and internal carotid arteries; it rises upwards very slender and delicate : it lies deep in the neck, upon the forepart of the flat vertebrae, or rather lies upon the flat face of the longus colli muscle."* After rising in one slender artery, single, without branches or connections, it be- gins all at once to give twigs. First, It gives branches inwards to the throat; for one twig surrounds the lower part of the pharynx about the root of the tongue, and sometimes goes forwards along with the glosso- pharyngeal nerve into the tongue. Another twig goes to the middle of the pharynx, and wanders towards the velum palati, giving branches to the amygdalae. And still another goes higher towards the basis of the skull; it also gives twigs to the velum palati, to the back of the nostrils, to the upper part of the pharynx where the upper constrictor lies, (viz. that which comes from the basis of the skull,) and it gives small arteries to nourish the basis of the skull; as, to the os spbenoides, to the cuneiform process of the occiput, to the point of the tem- poral bone, and to the cartilage of the Eustachian tube. Secondly, It sends branches outwards to the mastoid mus- cle, to the jugular vein, to the ganglion of the intercostal nerve, and to the dura mater of the eighth pair ; and one particular branch, very small and delicate, goes along conducted by the great jugular vein, enters together with it into the skull, and makes one of the arteries of the dura mater, but it is a very delicate twig. In general one artery only of the dura mater is known or mentioned; but here we have seen, besides the great artery of the dura mater, lesser arteries.entering to it by all the per- forations at the basis of the skull. The pharyngeal actually terminates in the dura mater, passing through the foramen lacerum posterius, and sending also a branch in together with the jugular vein. The occipital artery also sends one with the jugular vein, one by the foramen mastoideum, and one by a small hole in the occiput. The temporal often sends one through by the hole in the back part of the parietal bone, 5. ARTERIA OCCIPITALIS. The occipital artery is also a simple artery, distributing its twigs about the ear, over the occiput, and down the back of the neck, and having no branches of sufficient importance to be particularly marked. * When dissected, it must lie taken out in a manner from behind the oesophagus. Thr .•■wtfidx must be raised outwards before it can be seen j for it lies under them, betwix' ■ bem and the throat. OF THE EXTERNAL CAROTID. 87 It arises next to the pharyngeal from the back part of the carotid ; and lying particularly deep, it not only is covered at its root by the other branches of the carotid, but is covered in all its course by the thick muscles of the neck, except just where it is passing round the mastoid process. At first the occipital artery lies close in among the bones, passing over the transverse process of the atlas, crossing the root of the great jugular vein, and passing under the root of the mastoid process so as to lie at this place under the belly of the digastric muscle. Still as it encircles the occiput, it passes along very deep under the bellies, first of the trachelo- matoideus, and then of the splenius and complexus, and emerges only when it arrives at or near the middle ridge of the occiput; and lastly, it rises with many beautiful branches over the back of the head, to meet the branches of the temporal artery. In this course the occipital artery sends out the following branches: 1. Branches to the biventer, which lies over it, and to the stylo-hyoideus muscle; and there is one longer artery which attaches itself to the root of the mastoid muscle, and passes along that muscle, to inosculate with the thyroid arteries or with the lower cervical arteries which mount upwards as this descends. 2. Next it gives like the pharyngeal, a small artery, which goes backwards along the jugular vein; and having entered by the foramen lacerum, attaches itself within the skull to that part of the dura mater which lies under the lobes of the cere- bellum. 3. The occipital artery, as it passes under the ear, sends out to it a small posterior artery, which goes to the little lobe of the ear, and creeps up along its posterior border. 4. At this point the occipital often gives another artery, which passes upwards behind the ear, and is named the pos- terior temporal arteky. 5. The occipital artery, as it passes under the trachelo-mas- toideus and splenius, gives branches to these two muscles ; and it sends out from betwixt the trachelo-mastoideus and complexus, a long branch, which descends along the neck a considerable way; and after having further supplied the sple- nius, complexus, and also the deeper muscles of the neck, it terminates by inosculating with a branch from the axillary ar- tery, which, as it crosses the neck, is named transversalis colli. - This descending branch of the occipital inosculates also, with the vertebral arteries through the interstices of the vertebra1. Having pierced the belly of the complexus, the artery now 88 OF THE EXTERNAL CAROTID. rises over the occiput in small and beautiful arteries; the chief of which belong to the occipital belly of the occipito- frontalis muscle and to the skin : it finally ends in inosculations with the backmost branches of the temporal artery. But of these extreme twigs of the occipital, two are remarkable, because they pass through the skull to the dura mater; one through a small hole in the occipital spine, and one through that small hole, which is behind the mastoid process. Some- times the hole is in the temporal bone, but more frequently in the suture which surrounds the back part of the temporal bone* 6. ARTERIA POSTERIOR AURIS. The posterior arterv of the ear is the smallest and least constant of all the arteries which go off from the carotid ; for it is often wanting, or often comes from some branch, and not from the carotid itself; often from the occipital, some- times from the pharyngeal artery; it can scarcely be reckoned as a regular branch of the carotid. This artery, also, like the pharyngeal and occipital, gives out no distinguished branches which we need to mark; it chiefly belongs to the ear, it gives branches to the cartilage of the external ear, it sends a larger branch through the stylo-mastoid hole to the internal ear, and the rest of its twigs go to the integuments, or to the bones. The posterior aitris arises much higher than any of those arteries which have been just described ; it does not come off from the external carotid till it reaches the parotid gland ; or rather it arises where the carotid is plunged into the substance of that gland; it passes directly across under the styloid pro- cess, and over the belly of the digastric muscle, and then goes up behind the ear: in this passage it gives branches to the parotid gland, and to the biventer muscle, the parts on which it lies; next it gives a twig, which furnishes the root of the cartilage of the ear, and perforates the lowest part of the cartilage, so as to spread itself upon the drum of the ear; this branch is named arteria tvmpani. Jts next branch, the arteria stvlo-mastoidea, is the most remarkable, for it is of considerable size, enters the mastoid hole, while the portio dura, or great nerve of the face, comes out: it is a chief artery of the internal ear; for it °-ives branches, 1. to the tympanum, one of which beautifullv&sur- * Viz. the additamentura sutunr squamosae. OF THE EXTERNAL CAROTID. 89 rounds the bony circle, and then spreads upon the membrane itself; 2. to the muscle of the stapes, to the semicircular canals, to the cells of the mastoid process and its delicate vessels; which arteries, when well injected with size, paint the walls of the cavity of the tympanum, and of the semicir- cular canals. The main artery having given off the arteria tympani and this stylo-mastoid artery, and having passed the stylo-mastoid hole becomes properly the arteria posterior auris, rising be- hind the ear, and giving its branches to the skin and mastoid muscle, and to the muscle behind the ear (posterior auris,) and to the bone and periosteum, chiefly about the mastoid process; then its small branches play round the back part of the concha or shell of the ear; and, lastly, the artery, still mounting behind the ear, ends in small twigs, which go to the fascia of the temporal muscle, and which of course inos- culate above the ear with the temporal artery : THIRD ORDER. The third order of arteries includes the termination of the external carotid artery in the temporal and maxillary arteries, which is after the following manner : The artery having entered into the parotid gland, lies there absolutely imbedded in its substance ; and of the two arteries in which it terminates, one passes directly through the sub- stance of the parotid gland,/emerges before the ear, mounts upon the temple, and is named of course the temporal ar- tery ; it performs here in the temple the same office which the occipital does behind, viz. it supplies the pericranium, mus- cles, and skin: all this is very simple. But the other branch, in which (since it is exceedingly large) one would say the carotid terminates, goes off from the temporal with a sudden bend, sinks very deep under the articulation of the lower jaw, terminates in a lash of branches at the back of the antrum Highmorianum, and there gives branches to the lower jaw, the upper jaw, the inside of the cheeks, to the temple, (deep arteries which lie under the temporal muscle,) to the upper part of the pharynx, to the nostrils, and to various other parts : it is this artery too which gives off the chief artery of the dura mater. The description of so great an artery, so widely distributed, becomes both difficult and important. VOL. II. M 90 OF THE EXTERNAL CAROTlB*. 7. ARTERIA MAXILLARIS INTERNA. The internal maxillary artery turns off from the tempo- ral artery while imbedded in the substance of the parotid gland, and about the middle of the upright branch or process of the lower jaw-bone. It passes betwixt the lower jaw-bone and the outer pterygoid muscle ; it then goes forwards till it touches the back part of the antrum maxillare, and termi- nates in a lash of vessels betwixt the back of the antrum and the pterygoid process; and, finally, it ends at the spheno- maxillary fissure, or, in other terms, at the bottom of the socket of the eye, where it gives the infra-orbitary artery, and a branch to the back of the nostrils In all this course the internal maxillary artery is extremely tortuous: first, it rises with a high and round turn at that point where it goes off from the temporal artery ; then it bends sud- denly downwards, where it passes betwixt the pterygoid mus- cle and the jaw-bone; then, as it approaches the back of the antrum, it rises with a third bending, and continues rising with very great contortions, till it ends in a lash of small vessels at the back of the eye and nostrils. Before this artery gives out its greater branches, which re- quire to be marked with numbers, it very generally gives some small twigs, nameless, and of less note ; as a small twig to the ear, and the glands around it, another which gets into the tym- panum to the muscle of the malleus, and a branch of it some- times goes into the skull by that hole named foramen ovale, by which the fifth pair of nerves come out, and goes to that part of the dura mater which covers the sides of the sella turcica. 1. Of the larger branches which the internal maxillary gives out, the first is the arteria meningea, the great or middle artehy of the dura mater. It goes off from the maxillary just where it leaves the temporal artery. Sometimes before entering the skull it gives small branches to the pterygoid mus- cle, to the mouth of the Eustachian tube, to the os sphenoides, and sometimes through that bone to the dura mater; but the main artery passes through what is called the spinous hole, which is in the very extreme point or spine of the sphenoid bone : it is this artery of which the surgeon should be particu- larly aware, and which touches the parietal bone at its lowest corner in the temple, and spreads from that point all over the dura mater like the branches of a tree. But besides these, its chief branches, which spread thus upon the parietal bone, on its inner surface, it gives smaller ones, which go into the sub- OF THE EXTERNAL CAROTID. 91 stance of the bone, or into the ear, and sometimes through the orbit into the eye. Thus first several smaller twigs go into the substance of the os petrosnm to nourish it; the holes may be seen about the rough part, where the os squamosum and os petrosum are united; next two twigs enter into the aqueduct by the small hole on the forepart of the petrous bone, one keeping to the canal itself, the other going to the cavity of the tympanum, and to the inner muscle of the malleus; and, last- ly, one or two small twigs pass through the outer end of the foramen lacerum into the orbit, and go to the lachrymal gland.* 2. The lower maxillary artery is a slender and curious artery, which belongs chiefly to the teeth of the lower jaw, and which runs all along in a canal within the jaw-bone. The in- ternal maxillary proceeds nearly an inch before it gives off this branch; and then, while lying under the pterygoid muscle, it gives off a long and slender artery, which enters the jaw-bone at that great hole which is betwixt the condyloid and coronary processes; then runs all along within the jaw-bone, surround- ing each of the teeth with arteries at the bottom of each sock- et. About the middle of the jaw-bone it divides into twa branches, which proceed together in the bony canal, till one of them emerges upon the chin at the mental hole, inosculat- ing there with the arteries of the face, viz. the labial and sub- mental arteries, while the other goes onwards to supply the roots of the fore-teeth also, and to meet its fellow within the jaw-bone at the chin. The nerve for the lower jaw enters along with this artery ; the vein of this artery accompanies it, but lies under it in a separate canal, though still in the same line. The artery itself, before it enters into the hole of the lower jaw, commonly gives twigs to the inner pterygoid mus- cle which covers the hole. Considering the size of this ar- tery, we cannot wonder at profuse bleedings from the teeth, or rather from their sockets. 3. The pterygoid arteries.—While the artery is thus crossing betwixt the jaw and the pterygoid muscle, it gives branches to the external pterygoid muscle, both into its sub- stance and over its surfaces. The number of these pterygoid arteries is variable and unimportant. Next, while the maxillary artery is passing in a contorted form under the zygoma, where the temporal muscle is lodged, it gives off two arteries, which are called the deep temporal artekies to distinguish them from the proper temporal artery, the only one which we feel outwardly, and which is superficial. * Sometimes the gre.it and proper artery of the lachrymal gland, instead of arising front the opthalmic or proper artery of the eye, arises thus from the artery of the dura mater. 92 OF THE EXTERNAL CAROTID. Of these two deep temporal arteries, one runs more outwards, viz. towards the ear, the other runs more inwards, viz. closer upon the bone; whence the one is-called the deep external, the other the deep internal, temporal artery. 4. The deep external temporal artery, arises where the maxillary is passing under or near the jugum ; it is of course near the coronary process of the jaw-bone. This branch then passes along the tendon of the temporal muscle, and ends in that muscle, giving branches also to the external pterygoid muscle; it is a short artery, and not very important by its size. 5. The deep internal temporal artery arises farther forwards, viz. where the artery is close upon the back of the antrum ; from which point, mounting directly upwards, it passes in the very deepest part of the temporal arch, viz. that which is formed by the cheek-bone. It is longer and more important than the outward branch, supplies the deepest and thickest part of the temporal muscle, mounts pretty high upon the temple betwixt the muscle and the bone, and often, where it lies be- hind the cheek-bone,, it sends a branch through that bone into the orbit which supplies the fat and periosteum of the socket, and in some degree also the lachrymal gland. 6. The artery of the cheek is a very regular artery, in so far as regards its destination, viz. for the cheek; but in its- origin it is extremely irregular. It has not often the impor- tance of coming off as a distinct branch from the maxillary; but comes off rather more frequently from some of its branches, as from the deep temporal artery just described, or from the alveolar, or infra-orbital arteries, which are presently to be described. This artery perforates the buccinator muscle, and is spent upon it, and upon the other muscles of the cheek, as the zygomaticus and levator labii; it ends, of course, by in- osculations with the arteries of the face. 7. The artery of the upper jaw serves much the same office with that of the lower jaw, viz. supplying chiefly the sockets of the teeth ; whence it is named arteria alveolaris. It is an artery full as large as that of the lower jaw; it begins upon the back of the antrum Highmorianum, and runs round that tuberosity towards the face and cheek with very tortuous branches. Its branches are distributed first to the buccinator and fat, which fills up the great hollow under the cheek-bone, and also to the cheek-bone itself, where it is connected with the jaw-bone. Secondly, Other branches perforate into the antrum Highmorianum by small holes, which are easily seen upon its back part, and some of these branches go into the sockets of the backmost teeth. Thirdly, A more important OF THE EXTERNAL CAROTID. 93 branch than any of these, the branch indeed from which it hag its name of alveolar artery, enters by a hole into the substance of the jaw-bone, and goes round in the canal of the teeth just as the artery of the lower jaw does, giving branches to each socket. The curlings of this artery upon the back of the an- trum are very curious ; and while its deeper artery furnishes the teeth, some of the superficial branches go to the gums. 8. The infra-orbital is so named from the hole or groove by which it passes all along under the eye from the back of the nostril till it emerges upon the face. The infra-orbital, and the branch last described, viz. the alveolar artery, gene- rally come off from the maxillary by one common trunk; the alveolar goes forwards and downwards by the back of the an- trum : the infra-orbital mounts upwards, and enters the sphe- no-maxillary hole, or rather it comes off just at the spheno- maxillary hole, which is the great slit at the bottom of the eye. As the artery enters its proper canal at the bottom of the eye, it gives some twigs to the periosteum and to the fat of the socket; as it passes along its canal in the bone, one branch dives down into the antrum through the bone ; for this plate of bone in which its groove runs, is at once the floor of the eye and the roof the antrum ; within the socket it gives twigs also to the deprimens occuli, and to the lower oblique muscle, to the lachrymal sac, or even to the nostrils ; when it emerges from the socket by the infra-orbitary hole, it termi- nates in the levator labii and levator anguli oris, and in inos- culations with the arteria buccalis, labialis, and especially with the nasal branch of the occular artery. This infra-orbitary artery is accompanied through the canal, and out upon the face, with a small nerve of the same name, viz. the infra-orbit- ary nerve. After this the maxillary, though nearly exhausted, still sends out three small arteries, in which it terminates irregularly, sometimes one sometimes another twig being larger. Of these three, one goes to the palate, one to the pharynx, one to the nostrils. 9. The upper palatine artery arises near the infra or- bital ; and from that point, viz. the spheno-maxillary slit, if descends along the groove, which is formed betwixt the pterygoid process and the palate-bone; and when it has got down to the palate, one lesser branch turns backwards through the posterior palatine hole, and expands upon the velum palati ; the other larger branch is the great palatine ar- tery, for it comes through the anterior or larger palatine hole : the artery itself is large, it runs all along the roof of the jnouth betwixt the pulpy substance of the palate and the 94 OF THE EXTERNAL CAROTID, bone ; in this progress it gives little arteries to the sockets of the teeth, and it frequently terminates, not merely in the palate itself, but in a small artery which runs up through the foramen incisivum or hole under the fore-teeth, into the cavi- ty of the nose. This artery is also accompanied with a cor- responding palatine nerve. 10. The upper pharyngeal artery is the highest of all the branches of the internal maxillary; it goes off at the back of the orbit, opposite the spheno-maxillary fissure ; it ascends along the sphenoid bone to the place of the sphenoi- dal sinus, and along the upper part or arch of the pharynx, where that bag adheres to the basis of the skull; it also goes along the sides of the pharynx: its twigs are of very dimi- nutive size ; some go into the substance of the sphenoid bone to nourish it by small holes both over the cells and in the alae: a branch goes towards the pterygoidean or vidian hole,* where it inosculates usually with a branch from the internal carotid artery, sometimes with the lower pharyngeal, or with the meningeal arteries. This artery ends in small branches which play round the mouth of the Eustachian tube. 11. The nasal artery is the last branch of the internal max- illary. It passes through the spheno-palatine hole ;t by this opening it comes into the nostril at its upper and back part; the twigs go, one shorter to the backmost of the aethmoid cells, another to the cells of the sphenoid bone ; one longer branch goes to the back part of the septum narium ; and one branch, the longest of all, often passes both the upper and lower spongy bones, (along the lining membrane of the nose, giving twigs to the antrum as it passes,) till'it inosculates with that twig of the palatine artery which rises through the fora- men incisivum into the nose. This nasal artery often has two branches. 8. ARTERIA TEMPORALIS. The temporal artery, if we consider its straight direc- tion, may be regarded as the termination of the external caro- tid artery. When the maxillary artery bends away from it to go under the jaw, this goes directly forwards through the sub- stance of the parotid gland, mounts before the ear ; and as it * This is the hole by which the recurrent of the 5th pair goes backwards from the nose into the scull. ■"• Observe, this is not the spheno-inaxillary BHt so often mention^, which is a slit-like opening lying between the wing of the sphenoid bone and the upper jaw bone; and, as it is at the bottom of the socket, whatever parts enter it go to the eye. The spheno-palatine hole is betwixt the sphenoid and palate bones; it is at the back of the nostrils, and the branch which enters it belongs to the nostril. OF THE EXTERNAL CAROTID. 95 passes alternately the parotid gland, the face, the ear, it gives its three chief branches to these parts and ends in that tempo- ral artery which runs along the side of the head under the skin, which we feel, and even see distinctly, beating, and which we open when bleeding in the temples is required. The temporal artery is named superficial, because of its lying under the skin only, above the fascia of the temporal mus- cle, while the deep branches from the maxillary artery lie under the muscle.—The temporal artery passes just before the meatus auditorius, and behind the branch of the jaw-bone ; it pushes its way through the substance of the parotid gland, and there it gives its fiFst branches, commonly seven or eight in num- ber, but quite irregular, into the substance of the gland itself; next it gives off to the face an artery of very considerable size ; which arises from the same part of the artery with these paro- tideal branches, viz. under the zygoma and within the gland-: like them it goes off almost at a right angle, and is like one of them, but larger, nearly of the size of a crow-quill; it pushes sidewise through the substance of the parotid, emerges from it upon the face just below the cheek-bone ; runs across the cheek in the same direction with the parotid duct; k is named from this direction transversalis faciei. Its branches go to the joint of the jaw-bone, the masseter, buc- cinator, parotid gland, &c. and terminate in inosculations with all the arteries of the face. Next the temporal artery, as it rises towards the zygoma, and of course approaches the angle of the jaw, gives an artery which is proper to the articulation of the jaw. This artery belonging to the joint of the jaw is often named arteria artkularis. After having sent its two branches to the arti- culation of the jaw, it sends -mother artery to the ear which divides into two twigs ; one of them going round the back part of the ear, assists the branch of the stylo-mastoid artery in forming the little circular artery of the tympanum ; while another branch, penetrating through the slit which is in the articulation of the lower jaw, goes to the muscle of the malleus. But before it reaches the zygoma, the temporal artery gives another branch, which is named the middle temporal arte- ry, to distinguish it from the deep temporal arteries which lie under the whole thickness of the temporal muscles, and the superficial temporal, which lies above the fascia ; for this mid- dle temporal artery lies under the fascia : but on the outside of the muscle it arises from the main artery just under the zygoma, rises over the zygoma, and then pierces its way un- der the fascia of the temporal muscle, and under that cover- ing gives branches to the temporal muscle, the artery itself 36 OF THE EXTERNAL CAROTID. still rising and passing obliquely forwards towards the outer corner of the eye, where one of its twigs often goes to the orbicularis oculi, and inosculates with the ophthalmic artery. About this point, or rather above the zygoma, the temporal gives off those small arteries, irregular in number, which are named anteriores auris, the anterior arteries of the ear, and which play all round the forepart of the ear. The temporal artery having now emerged from the parotid gland, and from the thick fascia which covers it, makes a sud- den serpentine turn before the ear; and then rising about half an inch perpendicularly, it forks with a pretty wide angle into two arteries, which are named the anterior and posterior tem- poral arteries. • These lie quite superficial under the skin, above the fascia, and are distributed in this manner : First, the anterior temporal artery goes directly forwards to the naked part of the temple, runs up the side of the forehead with a very serpentine course ; it is here that in old. men we see its contortions and pulsation very distinctly; it goes round arch- ing forwards and upwards, from the temple towards the top of the head. It belongs chiefly to the skin and frontal muscle, and that tendinous kind of sheath which covers the cranium; it gives some branches to the orbicular and corrugator mus- cles ; it forms often a superciliary arch with the proper frontal artery; it often sends off a branch very early towards the outer corner of the eye, which is entirely destined for the orbicula- ris oculi. The posterior temporal artery is the last branch of all. It arches backwards over the top of the ear; it turns thus back- wards till it meets the branches of the occipital artery; it deals its branches from either side upwards and downwards, (i. e.) towards the ear, and towards the top of the head in great pro- fu/ion, till it is quite exhausted. These branches belong to the skin chiefly and to the pericranium ; and the smaller twigs pierce the outer tables of the skull, and go into the bone in great profusion for its nourishment. CONCLUSION. It would surely be wrong to conclude the description of a system of arteries so important as this, without attempting to interest my reader in this piece of anatomy, by observing a few anatomical and surgical facts. That arteries are not tortuous to favour the extension of parts, but rather 1 .cause they have been extended and long pushed by the current of blood, is a fact very manifest to any OF THE EXTERNAL CAROT1L-. 97 one who considers the condition of many of these arteries which I have just described. When we first observe the thy- roid, lingual, and labial arteries; when we consider that the tongue, the throat, the lips, are moveable and dilatable parts— we are apt to say that such arteries are tortuous to favour those motions. But when we remark the curling form of the alveolar artery, where it lies against the back of the antrum ; of the occipital artery, where it lies firm against the bone; of the temporal, where it rises along the side of the head—we perceive clearly that this curling has nothing to do with dila- tation. And Dr. Hunter's observation of the arteries of the womb being tortuous, to allow of extension, is not like the ob- servation of so great an anatomist, but of one who had not considered many of the chief arteries in the body: for the womb itself has its arteries more tortuous at the end of preg- nancy than at its commencement; and the stomach, the bow- els, the bladder, although they suffer greater and more sudden distention than the womb, have arteries which are very straight in their course. Are there any curling arteries in the muscles which contract to one half their diameter? are there any in the joints which twist and bend so freely ? are there any curling arteries in the whole system of a child ? are there any arteries in the whole system of an aged person which want this tortuous form ? In short, this tortuous form has no relation to the dila- tation of the parts: it is merely a consequence of the long continued pressure of the blood: it is this only that can ac- count for the slowly increasing tortuosity in the temples or hands of an old man, or the sudden tortuosity which the newly dilated artery assumes after the operation for aneurism. Next it is natural to observe, as a thing which may prevent confusion in the student's mind, how irregular (after all our at- tempts at arrangement) the smaller arteries unavoidably must be; how natural it is that each particular part should draw its blood from all the arteries which are near or round it. The ear has its posterior artery peculiar to itself; but it has also an anterior artery from the temporal, where it lies under the pa- rotid gland ; and it has even a superior auris from that branch of the temporal artery, which bends round towards the occi- put, and arches oyer the ear. The dura mater has its great middle artery appropriated to itself, a peculiar branch, the first of the maxillary artery; but it has besides small assisting arte- ries, entering by almost every point at the basis of the skull; and especially it has arteries fro hi the maxillary, by the mouth of the Eustachian tube, from the pharyngeal, running in by the hole for the great jugular vein; and from the occipital both by the hole of the jugular vein in the basis of the skull, vol. n.. N 98 OF THE EXTERNAL CAROTID. and also by the small occipital hole in the back part of the skull, close by the temporal bone. The throat also, though it has many peculiar arteries, derives its branches from a great many sources; as from the lingual artery by twigs, which cross the root of the tongue; from the labial artery by branches, which go to the tonsil, tongue, and palate; from the pharyn- geal artery, many branches not confining themselves to the pharynx, stretch forwards to the palate, tongue, and tonsils; and, lastly, the maxillary artery gives a profusion of branches to all parts of the throat. These may serve as hints by which the student, if he wishes to become a correct anatomist, may trace the inosculations; or for the surgeon, if he wishes to separate the study of this minute anatomy from that of the greater arteries. The surgeon's interest in understanding these arteries is, in- deed, very strong. It were impossible to enumerate all the various occasions on which this piece of anatomy may be use- ful ; but, surely, one may easily say enough on this subject to attach the young surgeon to the diligent study of these ar- teries. Among the various motives for diligence, I would mention these; the tetrible hemorrhagies which he is daily called to stop, when suicides, though they have not cut the carotids, have cut the great arteries of the thyroid gland ; the necessity of thinking about the tumours of the gland itself, for I have had the unhappiness to see a person perish by suffocation while consulting physicians forbade any operation; and I had no other than the melancholy privilege of watching, for many hours, the last struggles of a person, who had the day before been walking through all the rooms in tolerable ease and health. Could nothing have been resolved on .? Must we al- ways submit to this ? Might not an incision in the forepart (where few arteries are) have at least uncovered the trachea, given a temporary relief, and made the tumour suppurate more freely ? The extirpation of the tongue, which is mentioned with horror, would be a less terrible operation to one acquaint- ed with these arteries; the extirpation of all tumours under the jaws is dangerous; the cutting out completely the parotid gland is a thing quite impossible, since the.greatest of all the arteries, viz. the temporal and the maxillary, lie absolutely im- bedded in the gland. What shall we think, then, of those sur- geons who talk in such familiar terms of cutting out the parotid gland ? Bleedings from the nose have been so often fatal, that Petit is celebrated to this day for a discovery which he never made, viz. the way of plugging the nose so as to stop this bleeding. Have not the French Society been busy renewing OF THE ARTERIES OF THE BRAIN. 99 inventions for securing even so small an artery as that of the dura mater? In the hair-lip operation, in cutting cancers, in dissecting tumours from all parts of the face, the surgeon com- mands the blood only by knowing these arteries. Cowper, the celebrated surgeon and anatomist, had his head so full of this project, that instead of waiting for haemorrhage during his operation, he cut off two days before, the chief source of the blood. He was going to cut out the parotid gland ; and two days before, he placed a small button of caustic on each side of the labial artery, where it lies upon the cheek, passed a liga- ture under it, tied it firm, and then proceeded to his operation next day. But this gftat anatomist made at one stroke two grievous blunders: he missed, for want of knowledge, the chief arteries of the parotid gland, for they come from the temporal artery; and, if I mistake not, he had tied the vein, for most assuredly it is the fascial vein which he is describing in his twelfth table from Bidloo. How terrible the extir- pation of tumours from the gums, throat, tonsils, &c. I need not say; where the surgeon always uses burning irons instead of needles, where not unfrequently the patient dies. SECT. II. OF THE ARTERIES OF THE BRAIN, SPINAL MARROW, AND EVE. 5} 1. OF THE ARTERIES OF THE BRAIN. J. HE internal carotid arteries are named the arteria cerebri, as being the chief arteries of the brain; while, in truth, the brain is also supplied by two other arteries nearly equal in size, viz. the vertebral arteries, which though they do indeed arise from a different trunk, viz. the subclavian artery, yet are so entirely destined for the brain, give so few branches before they reach the skull, are so important when they ar- rive there, and above all, make so large a communication with the carotid arteries, that without a description of the vertebral arteries, any description of the carotids must be defective ; they unite so with the carotids as to form but one great system of vessels for supplying the brain. 100 OF THE ARTERIES The two great functions of the animal body, those of the womb and of the brain, the one for the life of the individual, the other for the continuation of the species, are the most liberally supplied with blood. The womb has on each side two arteries; it has two spermatic?, and two hypogastrics, and the inosculations of these vessels are very large and free. The brain has two great arteries on each side; it has two carotids, and two vertebral arteries ; they are infinitely larger than those of the womb; their inosculations are so particular, that there are no others like them in all the body ; the injection of any one artery easily fills the whole ; the preservation of but one artery saves the life of the creature, when the others are stopped. These four arteries alone convey to the head the fifth part of the whole mass of blood. This is the calculation of the older authors; and even those who would settle it at the lowest point, still acknowledge, that the carotids and vertebral arteries receive at least the tenth part of all the blood of the body. The brain then which weighs not a fortieth part of the whole body, receives one tenth of all the blood; a proportion which must occasion surprise. Besides the profusion of blood which thus rushes into the brain, the impetus with which it forces its way seems dangerous; and Nature also seems to have provided against the danger. We cannot be but sensible of this danger; for the slightest in- crease of velocity occasions strange feelings, if not absolute pain. We cannot run for any length of way, nor ascend a stair rapidly, nor suffer a paroxysm of fever, nor in short have the circulation quickened by violent exertions, by emotions of the mind, or by disease, without feeling an alarming beating within the head ; we feel it particularly in the carotid canal where the artery passes through the bone. If it continue from disease, or if we persist in our exertions, giddiness, blindness, ringing of the ears, come on. Haller remembers, that while he was lying in a bad fever, he suffered so much from the pul- sations of the carotid artery within the skull, that his head was lifted from his pillow at every stroke. I wish he had said "seemed to be lifted from his pillow at every stroke;" for it was rather a sickly feeling than what could actually happen. Did this vast column of blood rush directly into the brain, we do not know what might be its effects; but surely they could not be harmless, since Nature has provided against it in man, and in the lower animals whicii hang their heads, with a peculiar care. In Man, this blood is retarded chiefly by the tortuous course Wiieh the artery is obliged to follow, and by that long bony canal whicii, by holding the carotid as in a OF THE BRAIN. 101 sheath, must suppress its violent action, and at least prevent its being dilated by force of the blood, when, as often happens, the lower part of the artery is more full and tense. Perhaps also it may have some effect, that the carotid as it lies by the side of the sella turcica, is not naked and free, but is inclosed in a venous sinus, which consists of cells like those of the male penis, and in the heart of which the carotid lies bathed in the blood. It is also peculiar in all the arteries of the brain that they do not enter in trunks into its substance. This seems to be a violence which the soft texture of the brain could not bear; but all the arteries having perforated the dura mater,,attach themselves to the pia mater, a delicate membrane, which is the immediate covering of the brain; which follows all its divi- sions, lobes, and convolutions; which enters all its cavities, and lines its internal surfaces as it covers the external. To this membrane of the brain the arteries attach themselves; it con- ducts them every where along the surface of the brain, and into its cavities; and when the arteries are to enter into the substance of the brain, they have already branched so minute- ly upon the pia mater, that they enter into the pulpy substance in the most delicate twigs ; so that having injected the brain, at whatever level you cut into it, you find its white surface dotted with red points regularly, and like the dots of a pin. But in the lower animals, especially in the Calf, the Deer, the Sheep, which hang their heads in feeding, there is a pro- vision of so singular a nature, that we can have no doubt that these contortions of the great trunk and minute divisions of the smaller arteries in Man have the same final cause; for in those creatures, the carotid, before it enters the brain, first divides into innumerable smaller arteries. Not one of these is sent oft' for any particular function: they are immediately re-united again, and gathered together into one trunk; and then the force of the blood being thus broken, the artery divides a second time into branches of the ordinary form, which enter safely into the substance of the brain. It is still further supposed, that the arteries of the brain have this peculiarity, distinct from all others in the body, that as they enter the skull they lay aside one of their coats, and that of course the arteries of the brain are peculiarly weak. That the arteries of the brain want that outward coat of cellu- lar substance which all arteries passing through other cavities or along the limbs have, is no doubt true, and so far they are thinner: but how much they are weakened by this loss, it is not easy to say ; for they want none of the coats which are essential to the constitution of an artery; and this cellular 102 OF THE ARTERIES coat, though it constitutes much of the thickness of an artery, has, I believe, but little to do with its strength. Yet true it is, that the arteries of the brain, either from being weaker in them- selves, being less supported, lying upon the soft and pulpy substance of the brain, are more frequently burst by falls, or even by the slightest accidents, than the arteries of any other part, even the limbs, however much exposed. Our injections burst them very often ; the slightest blow or fall upon the head often produces an internal effusion of blood, which occasions death ; but that the arteries of the brain are so delicate as to be burst by a false step, so as to produce a fatal aneurism within the brain, is a truth perhaps not commonly known. A young woman, carrying in her arms her first child, about six months old, slipped her foot with a slight shock; but it was on plain and even ground, and she did not fall down. In the instant of this shock she was sensible of a sudden pain in the right side of her head : it was so peculiar, that she said she could cover the point with her finger; and though slighter at intervals, this pain never left her to the moment of her death. She walked home, went about her little family mat- ters, suckled her child ; but was seized that evening with sick- ness, not violent like that of any sudden disease, but rather like the easy vomiting of a pregnant woman. She continued very sick, with slight head-ach ; but still was out of bed all day long, went about her household affairs, and had no symptom which could lead one to suspect her very dangerous condition, or what a dreadful accident had hap- pened. She got up during the night after this accident for some cool drink, felt herself extremely giddy, was obliged to support herself by a chest of drawers which stood by her bed- side, and went to bed again immediately. On the evening of the second day she got out of bed, made tea as usual, was out of bed during the evening, had no complaint, except the continual sickness, slight pain of the head, and giddiness still slighter. That night she expired. Her pulse all along had beat low and weak, and never more than 60 in the minute. When I was brought to open the body, I heard nothing of the pain of her head, though it was fixed and constant, and without that nothing could be more puzzling than this combi- nation of circumstances. First, the sudden slipping of her foot, and the incessant sickness which ensued, suggested the idea of hernia; but no such secret was known among her re- lations ; and upon the opening the abdomen, no hernia was found, neither open nor concealed as in the thyroid hole. .\Text we were informed of a palpitation, which had been OF THE BRAIN. 103 usual with her. It appeared that she had complained chiefly about the period of her first menstruation, and some years be- fore her marriage. It seemed to be hysterical merely ; but upon opening the thorax, we found the heart wonderfully en- larged and crammed with a dark and grumous blood. But next a new scene opened upon us; and this enlarge- ment of the heart appeared to arise like that of the liver, which so often accompanies fractured skull, from the languid action of the heart and torpor of all the system in those who lie even for a few days comatose. Now, for the first time, I was informed that the shock of slipping her foot had caused a sudden pain of the head ; that it was pointed, confined to one single spot, incessant, accom- panied with perpetual vomiting or desire to vomit, and with giddiness during the night. Upon opening the head, I found the dura mater of a most singular appearance; livid, or rather like the gizzard of a fowl, with green and changing colours. Having cut it open, the pia mater appeared like red currant jelly, with fresh coagulated blood so firmly attached to it that it seemed as if driven into its very substance and incorporated with it. Upon cutting and tearing open the pia mater, each convolution of the brain was surrounded and separated from that next it by coagulated blood. Upon cutting into the ventricles of the brain, that of the right side was found to contain four ouuces of entire and coagulated blood ; the cavity at first view was like opening a ventricle of the heart; the blood, very dark and firmly coa- gualated, was forced out by the pressure of the surrounding parts 5 the coagulum became gradually firmer and whiter, till it turned to a very firm stringy clot, which stuck in the mouth of the middle artery of the brain. Being carefully ex- amined, it was found to be sticking firm in the mouth of the artery which had burst, as if by the separation of two of its rings. The blood, which thus filled the right ventricle, had also made its way down in prodigious quantity into the third and fourth ventricles, quite into the occipital hole ; but the opposite ventricle it had not filled. The quantity of blood ascending to the head is exceeding great; its free circulation in all the arteries is perfectly se- cured ; and the plan of its distribution is extremely simple, for the carotid entering by the os petrosum gives three branches. First, A branch which unites the two carotids with the two vertebrals, and forms the forepart of the circle of Willis. Secondly, It gives an artery to the great middle lobe, whence it is named the great middle artery of the brain Thirdly. An artery which is named anterior cerebri, as be- 104 OF THE ARTERIES longing to the forepart of the brain. But the vertebral, as it arises through the occipital hole, lies upon the cerebellum, and supplies all the cerebellum, and also the back part of the brain. One branch goes to the back part of the cerebellum, another to the forepart of the cerebellum, a third branch goes to the back part of the brain ; and thus there is formed betwixt the carotid and the vertebral, by means of the great inosculation of the circle of Willis, one great set of vessels: which should first of all be described free from all the inter- ruptions of trivial arteries, which go off from point to point, but of which the destinations cannot be important, which are hardly known, which do not go in any two subjects the same way. t OF THE INTERNAL CAROTID ARTERY. The internal carotid artery leaves the external carotid at the angle of the jaw: it is so inclined to contortions, that at this point it even bulges, and seems the outermost of the two. In mounting along the neck, it is tied by cellular substance to the forepart of the rectus or straight muscle of the neck, and it is also connected with the par vagum and intercostal nerve; the ganglion of the intercostal, or sympathetic nerve, lies by its side ; the nerve, before it forms this ganglion, comes down small and thread-like through the same canal by which the carotid passes into the skull. The contortions of the carotid are great, both before and after its passage through the bony canal; but within the canal it is forced to particular and successive bendings, such as in- dicate plainly some design of Nature ; for the canal for the artery is long and tortuous, while the nerves and veins pass through plain and simple holes. When the carotid first pre- sents itself to enter the skull, it is curved, and is a little be- hind its hole ; it bends forwards and inwards a little, and so enters the canal; in entering the canal it rises almost perpen- dicularly upwards, but soon bends forwards again, lying, as it were, upon the floor of the canal; then it bends again up- wards and forwards, to emerge from the canal; by which turn the portion of the artery which is engaged in the canal has the the form of an Italic/ ' Even after it gets into the skull, it must still bend once more sidewise and forwards, as if to meet its fellow, and to get to the side of the sella turcica; then it goes directly forwards till it touches the anterior clynoid pro- cess ; and then doubling back, or returning upon itself, it rises perpendicularly; and so perpendicular is this last turn, that f, . V , OF THE BRAIN. 105 when cut across, the mouth of the artery gapes perpendicu- larly upwards : here it begins to give its branches to the brain. It is by the side of the sella turcica that the cavernous sinus surrounds the artery. This sinus is formed by the two plates or lamella? of the dura mater, parting from each other and leaving an interstice full of cells, like those of the penis or of the placenta. It is filled with blood, by communication with several of the smaller sinuses or veins about the basis of the brain ; the ophthalmic veins bring into it the blood from the eye ; four or five small veins descending from the fossa Sylvii bring blood into it from the middle parts of the brain • the sinuses of the os petrosum (both on its upper and lower grooves) open into it, one high, another lower down, and that circular sinus or vein which surrounds the root of the optic nerves opens into it from either side. All this blood is poured into the cells, bathes the carotid artery which lies naked in it * and by the side of the carotid artery lies also that small nerve of the sixth pair which begins the great intercostal nerve, naked in the blood. Veussens first discovered this curious structure; Ridley denied it, and Haller at last in his turn confirmed it. Veussens believed that the sinus which deposited this blood conveyed it away again. Haller says that this is the peculiar office of that vein which accompanies the carotid artery, and which is named the vena sodalis arteris carotidis. It was once sup- posed that certain small arteries opened also into the sinus; but it has neither arteries nor pulsation. Thus we trace the carotid through its canal, through the cavernous sinus, up to the side of the sella .turcica, and about to enter the brain, to give off the arteries of the brain. But be- fore we describe these, it will be easy to count shortly those little twigs which it gives off in the canal and in the sinus. The carotid artery seldom gives out arteries before it enters the skull ; it is a lusus naturae, when it does happen that the occipital or pharyngeal arteries come off from it. The first twig, which in any case it gives off, is sometimes a small artery, which returns downwards along with the upper maxillary nerve;* next a small twig, accompanied by a branch from the meningeal artery, goes into the tympanum by way of the aquseductus Fallopii; and next, while the artery is within the sinus cavernosus, it gives out two little branches, the one forwards, the other backwards, named arteries of the RECEPTACULUM. 1. The little artery which goes backwards from the sinus or receptaculum goes chiefly to that paat of the dura mater ** The second branch of the 3th pair. vol. ii. • o 106 OF THE ARTERIES which covers the posterior clynoid process, and which covers the cuneiform process of the occipital bone; it gives twigs to the 4th, 5th, and 6th pairs of nerves and to the pituitary gland : in short to all the parts at the back of the sella turcica ; it ends in inosculations with those twigs of the vertebral artery which come off from the vertebral before it enters the skull. 2. The little artery which comes out from the receptaculum to go forwards, arises where the carotid is crossed by the 6th pair and has been mistaken for a nerve by those who suppose that the intercostal arises from a branch of the 5th pair. The distribution of this little artery is nearly the same with that of the first, for it belongs to the 3d, 4th, and 5th pairs of nerves and to the pituitary gland. The carotid having risen to the anterior clynoid process", gives out there a small artery, no bigger than a crow-quill, which enters directly into the orbitary hole, accompanies the optic nerve into the eye, furnishes the eye, the eyelids, the muscles, and the lachrymal gland, and sends out branches upon the forehead, viz. the frontal arteries in which it ends. This is a short history of the ophthalmic artery ; which, as it furnishes all the arteries of the eye, must be described apart. division of the internal carotid. The carotid, now about to enter into the brain, divides at the sella turcica into three arteries; one to the fore lobe, another to the middle lobe, and a third to form the circle of Willis. These arteries are usually so numbered that the com- municating branch is first described, next the anterior artery of the brain, and lastly the middle artery of the brain. But of this arrangement on one who is accustomed to observe the course of this artery can entirely approve; for when the caro- tid rises from the side of the sella turcica, it divides into its three branches all at once, in a tripod-like form : the middle branch of the tripod is largest ; the next, which goes forwards to the fore lobe of the brain, is smaller; the third, which is the communicating branch, going backwards to unite with the ver- tebral artery and form the circle of Willis, is the smallest of all. The middle artery of the brain then is, from its great size, to be regarded as the trunk. 1. arteria media cerberi. The middle lobe of the brain is separated from the an- terior lobe by a very deep sulcus, or furrow, which is nam- OF THE BRAIN. 107 ed fissura sylvh. This fissura Sylvii is formed by the transverse process of the sphenoid bone, or, in other words, by that very sharp line which runs out laterally from each of the anterior clynoid processes, and which parts the fore lobe, which lies in the shallow part of the skull upon the orbitary processes of the frontal bone, from the middle lobe, which lies in the deepest part of the skull behind the clynoid pro- cesses. The middle artery of the brain having risen from the side of the sella turcica, runs straight along this fossa Sylvii, and is really the continued trunk of the carotid ; it is larger than the artery at the wrist; it goes directly outwards, viz. towards the temple ; it runs along the fossa Sylvii, and is lodged deep in that cleft; where it lies deep, it divides into two* great branches, one deep and one superficial: it gives some branches to the anterior lobe, but it is chiefly limited to the middle lobe of the brain; its branches to the posterior lobe, or inosculations with any branches of the basilar artery, are comparitively few. Thus the artery ends by passing into the substance of the brain. But nearer the sella turcica, and before it enters into the fossa Sylvii, it gives some small and delicate arteries ; the consideration of which seems to be unimportant at first view, but which is really useful "in explaining the anatomy of the brain. It gives small twigs to the pituitary gland, to the optic nerve, to the tentorium, and especially to the pia mater cover- ing the basis of the brain. Among these small twigs certain sets of arteries make a very distinguished figure. 1. There is one small artery which runs up into the anterior horn of the lateral ventricle, and forms that great plexus which lies along the floor of the ventricle, named plexus choroides. This, then; is the artery of the choroid plexus. 2. There is a set of arteries, of considerable number, but varying in respect of number, small as sewing threads, which inosculate repeatedly with each other, and which are scatter- ed widely and beautifully over the crura cerebri and basis of the brain, forming in the pia mater a plexus or web of vessels. This part of the pia mater is named velum from its beauty and delicacy ; and this is what Wepfer, among other older authors, considered as a species at least of the rete mirabile : but that name implies a peculiar office, as in beasts, which this delicate net-work of vessels cannot have. 2. arteria anterior cerebri. The fore artery of the brain comes off from the middle artery at right angles nearly ; for the great or middle artery 108 OF THE ARTERIES runs directly outwards towards the temple, while this second artery rurts directly forwards along the fore lobe of the brain. It is sometimes the artery of the corpus callosum, because that of two great branches into which it is divided one goes to that part of the brain. The corpus callosum (a most ab- surd name for any part of the brain) is the white and medul- lary substance where the two hemispheres of the brain are /joined; and upon separating the two hemispheres with the fingers, the corpus callosum is seen like a large white arch, and the artery of the corpus callosum is seen also arching over its surface. The anatomy of the arteria anterior cerebri may therefore be explained thus: First it goes off at right angles from the middle artery of the brain, which is to be considered as the trunk, and there it often gives small twigs to the olfactory and optic nerves : next the two anterior arteries of each side, while they go forwards as if towards the crista galli, bend a little towards each other ; they almost meet but do not abso- lutely touch; they form a communication with each other, which of course is exceedingly short, but pretty large. It is this short communication which completes the circle of Willis at its forepart. This cross communication betwixt the arte- ries of the opposite sides passes just before the sella turcica and pituitary gland, and exactjy in the middle it sends off an artery, which goes down into the third ventricle, and gives branches to the forepart of the fornix and to the septum lucidum. * After this communication, both arteries rise with a large sweep, along the flat surface of that deep division which the falx makes betwixt the two hemispheres of the biain ; there each divides into its two great branches; one attaches itself to the corpus callosum, or that arch whicii we see upon holding apart the two hemispheres; it arches along with the corpus callosum so as to describe a semicircle ; it is the larger of the two branches; it is named arteria corporis callosi : the other branch keeps upon the flat surface of the brain, where the one hemisphere lies flat upon the other, aiW it rises in a beautiful arch within the pia mater, dividing into beautiful and very minute rami fixations before it enters actually into the sub- stance of the brain. These two great branches of the anterior artery are well dis- tinguished by Wepfer by the names of arteria profunda and arteria sublimis, (the deep and superficial of the anterior ar- tery,) as there is a deep and a superficial branch of the middle artery. The arch of the arteria anterior cerebri overhangs in a manner that of the artery of the corpus callosum, and both OF THE BRAIN. 109 of them inosculate under the falx with the arteries of the oppo- site side. 3. ARTERIA COMMUNICANS. The communicating artery goes as directly backwards from the middle artery as the anterior artery goes forwards. It is small, proceeds backwards, and a little inwards ; it goes round the sides of the corpora mamillaria, and is about a quar- ter of an inch in length before it meets the vertebral artery; and though it does give off small twigs, as to the infundibulum, to the optic nerve, to the crura cerebri, and especially one of greater size, to the choroid plexus ; yet all these are trivial ar- teries, such as every trunk at the basis of the brain gives off- It is not its twigs that are to be observed, but itself only that is important, as forming one of the largest and most important inosculations of the body. It unites the middle artery of the brain, which is the trunk of the carotid, with the posterior artery of the brain, which is the first and greatest branch of the vertebral artery. This anastomosis is the circle of Willis, too remarkable not to have been very long observed; it was drawn by Veslingius and by Casserius; it is but ill represented by Bidloo and by Cowper; it is not a circle, but is right lined, and of course angular : it is of very unequal size; in one body it is large, in another smaller, often even in the same body it is irregular, the one side being large, and the other small. This inosculation brings us round to the first branch of the vertebral arteries, the arteria posterior cerebri ; for the vertebral artery gives two arteries to the cerebellum, and one to the back part of the brain. OF THE VERTEBRAL ARTERY The vertebral artery, though but the secondary artery of the head, is a principal one of the brain, and conveys a very great proportion of blood; and its turnings and windings be- fore it enters the skull are almost as particular as those of the carotid itself. The vertebral is among the first branches of the subclavian artery, and comes off from it where it lies across the root of the neck. The two lower ganglions of the sympa- thetic nerve lie over it, and their threads surround its trunk, making curious net-works round it. The artery then enters into the canal prepared for it in the transverse prooesses of the 110 OF THE VERTEBRAL ARTERY. vertebrae, commonly getting in by the 6th vertebra : but in this it is irregular, sometimes entering into the 7th or lowest; and it has been seen entering into the uppermost hole but one. In this canal it ascends in a direct line from the bottom of the neck to the top; but like the carotid it makes great contor- tions before it enters the skull; for when it has reached the second vertebra, its transverse process being rather longer than those of the lower vertebrae, the artery is forced to incline out- wards ; and the transverse process of the atlas or first vertebra being still much longer, the artery in passing through it is car- ried still farther outwards; it is forced to make a very sudden turn, and is visible without cutting the bones. When the artery has passed through the transverse process of the atlas, it makes another very sudden turn, lies flat upon the circle of that verte- bra, so as to make a large hollowness or groove upon the bone, and then it enters the foramen magnum by rising in a perpen- dicular direction; and then again it bends and inclines for- wards, laying flat along the cuneiform process of the occipital bone, where it soon meets its fellow, and the two uniting form the basilar artery. This basilar artery lies, with regard to the bone, upon the cuneiform process of the os occipitis, and runs along it from the foramen magnum to the sella turcica; with regard to the brain, it lies upon that great tubercle which is named the tuber annulare or pons Varolii; and as the artery goes along in one great trunk, it gives out from each side little arteries, which belong to this tuber annulare. The brain has three arteries derived from the vertebral ar- tery as it has from the internal carotid; two are given to the cerebellum and one to the cerebrum. 1. arteria cerebelli posterior. The posterior artery, or lower artery of the cere- bellum, is small and not regular. It comes off from the basilar artery either immediately after the union of the vertebrals, or from the vertebral artery immediately before the union. It is often smaller bn one side than on the other, and sometimes it is wanting on one side. It moves downwards in a sort of retro- grade course betwixt the accessory nerve of Willis and the group of fibres which form the eighth pair, and dives in be- twixt the cerebellum and the medulla oblongata. Its larger branches spread out upon the pia mater, and then enter into the medullary substance. They belong to the cerebellumy OF THE VERTEBRAL ARTERY. Ill to the spinal marrow, and some of them to the pons Varolii. But there are also smaller and particular twigs, as twigs to the eighth and ninth pairs of nerves: one also which enters into the fourth ventricle, to form a sort of velum or choroid plexus there : and as this posterior artery winds downwards under the cerebellum, it gives many branches about the vermis, and small twigs which run betwixt the lower point of the pons Varolii and the pyramidal bodies. • Next the arteria basilaris proceeds forwards along the pons Varolii in one great trunk : now the pons Varolii Is just the" tuberosity produced by the crura cerebri and cerebelli, meeting and uniting to form the spinal marrow. The corpora olivaria and pyramidaha are just two bulgings at the root of the spinal marrow; and as every great artery, whatever its destination may be, gives twigs to those parts which it passes over, so does the basilar artery, giving twigs first to the corpora olivaria and pyramidaha, next to the crura cerebelli and to the crura cerebri; and as it runs along the pons Varolii it distributes little arteries to it from right to left. These little arteries also mark the sides of the pons with small furrows, which are seen when the arteries are dissected away. One of these transverse arteries, longer than the rest, looks like another posterior cerebri. It goes to the seventh pair, or auditory nerve, in the following way: The seventh pair of nerves pro- ceeds from the back part of the pons Varolii; and as it goes forwards, the two nerves which it consists of, viz. the portio dura and the portio mollis, are separated from each other by a small and very beautiful artery which shoots in betwixt them, and enters along with them into the ear. The basilar artery also gives twigs to the fifth and sixth pairs of nerves, which arise from the forepart of the pons, as the seventh pair arises from behind. Arrived at the forepart of the pons Varolii, the basilar arte- ry gives off almost at one point four great arteries, two to the right hand and two to the left. These are the anterior cere- belli and the posterior cerebri. 2. ANTERIOR CEREBELLI. The anterior artery of the cerebellum, or the upper ar- tery, as it is called, goes off at right angles from the basilar tery, and bends round the crura cerebri to get to the cerebel- lum. It gives its branches first to the crura cerebelli, to the cerebellum, and to the processus vermiformis. Secondly, There is a greater artery going over all the upper part of the 112 OF THE VERTEBRAL ARTERY. cerebellum, (where it lies under the brain,) and also another which keeps closer to the brain than to the cerebellum, branches over that velum or delicate part of the pia mater which is interposed betwixt the cerebellum and brain; and going along it supplies the crura cerebri, and arrives at last at the place of the nates, testes, and pineal gland, and attaches itself to them. Some of the twigs go down into the fourth ventricle. 3. arteria posterior cerebri. The posterior artery of the brain goes off immediately after this, is like it, runs parallel with it, is larger, goes to the posterior lobe of the brain, and receives near its root4he com- municating artery from the carotid, which forms the circle of Willis. Where this posterior cerebri and the anterior cere- belli run parallel with each other, the third pair of nerves rises betwixt them. The posterior cerebri first gives a small twig on either side to the bottpm of the third ventricle, which runs so far forwards as to give branches to the thalami, infundibu- lum, and to the crura fornicis. Then the main artery bending like that last described round the crura cerebri, and passing deep into the great division betwixt the cerebellum and brain, arches upwards towards the back lobes of the brain ; but be- fore it arrives there, it gives first small twigs to the crura cere- bri, and then another notable artery (though small) destined for the internal surfaces of the ventricles. This is a chief ar- tery of the choroid plexus; it enters the lateral ventricle by the inferior horn; goes along with the cornu ammonis: helps to form the choroid plexus; inosculates, of course, with the choroid arteries from the carotid ; and twigs also go from this artery to the nates, testes, and pineal gland, or in other words, to the velum which separates the cerebellum from the brain, which closes the ventricle behind, and which covers the pi- neal gland, and is a membrane or velum to it also; the pineal gland, nates, and testes, being situated neither in any of the ventricles, nor on the surface of the brain, but betwixt the sur- faces of the cerebrum and cerebellum, where the one lies upon the other. After this second branch to the internal surfaces, the great trunk of the posterior cerebri branches profusely like a tree all over the back part of the brain, inosculating forwards with the middle artery of the brain, and also with the artery of the corpus callosum. Thus is the whole brain supplied with blood ; and next in order come the arteries of the spinal marrow. ARTERIES OF THE SPINAL MARROW. 113 "\J 2. OP THE ARTERIES OF THE SPINAL MARROW. I have mentioned none of those smaller arteries which the vertebral gives off before entering the skull, because being destined chiefly for the spinal marrow, they belong to this se- cond class. The vertebral artery, as it mounts along its canal towards the head, gives at each step, or as it passes each vertebra, a delicate twig; these little arteries pass through the interver- tebral spaces, go to the deeper muscles of the neck, and in- osculate with the thyroid and cervical arteries. In like man- ner, other small arteries go inwards to the spinal marrow at the place where each nerve comes out. They enter into the sheath of the spinal marrow, and inosculate with the chief ar- teries of the medulla spinalis. As the vertebral passes through the atlas, both above and below that bone it gives out much larger arteries to the mus- cles> as to the recti, trachelomastoideus, and complexus, in- osculating largely with the occipital artery : often there is at this point one large and particular artery going out to the back of the neck. Again, as the vertebral passes through the occipital hole, it gives out a little artery, which accompanies the trunk it- self up through the foramen magnum, and goes to that part of the dura mater which covers the cuneiform process,' and there it inosculates with the twig of the carotid, which enters along with the jugular vein. This is the posterior artery of the dura mater. Next come the arteries of the spinal marrow, the anterior of which comes out from the trunk of the vertebral artery; the posterior (though it also sometimes comes off from the vertebral before the basilar is formed) more commonly comes off from the posterior cerebelli. 1. ARTERIA ANTERIOR MEDULLA SPINALIS. The anterior artery of the spinal marrow is the larger of the two. It was discovered first by Willis ; it had been looked upon, till the time of Veussens, as a nerve accompa- nying the spinal marrow; because, when empty of blood and uninjected, it is white, and not unlike a nerve. This spinal artery begins within the skull by two branches, which unite as they proceed down the spine. These two branches arise, one vol. II. P 114 ARTERIES OF THE SPINAL MARROW. from each vertebral artery, at the very point where the verte- brals are about to unite to form the basilar trunk: each artery passes down its own side of the spinal marrow, betwixt the corpora olivaria and the corpora pyramidaha; each artery, before it leaves the skull, gives twigs to the tuber annulare, and to the pyramidal and oval bodies, for they are the begin- nings of the spinal marrow; and soon after emerging from the skull* the two spinal arteries join so as to form one anterior spinal artery. This joining is usually at the top of the neck, or rather within the skull, but sometimes so low as the last vertebra of the back. Almost always they join within the head or near it; and the anterior spinal artery which they form descends along the spinal marrow in a furrow which it forms for itself. The peculiar office of this artery is to supply the spinal marrow and its sheath, which it does by sending con- tinual branches into the substance of the spinal marrow ; while other branches go into the sheath itself, and pass out from the spinal canal along with those nerves which go out from the spinal marrow, accompanied by little processes of the sheath, which are named processus denticulati. But this artery, being extremely small, would be soon ex- hausted, were it not reinforced with small arteries coming into the sheath: these pass through the vertebral interstices into the spinal canal, and are derived from every artery that passes near the spine. Thus in the neck the spinal artery receives twigtfrom the vertebral arteries, and from the thyroid and cer- vical arteries; in the back it receives twigs very regularly from each of the intercostal arteries, and it receives its twigs from the lumbar arteries when it has got down as low as the loins. But this spinal artery which is continually diminishing at last fails in the loins ; and where the cauda equina begins, viz. in the canal of the os sacrum, the medulla is no longer supplied by a spinal artery, but by the small branches of the sacral ar- teries, which enter by the ten holes of the sacrum. Of those adventitious branches which reinforce the artery of the spinal marrow as it descends through the spine, each gives several other branches; they give twigs to the muscles of the spine, twigs to the substance of the vertebrae themselves, twigs to the sheath of the spinal marrow; and, finally, twigs which inosculate with the spinal artery, and which sink into the nervous substance to nourish it. * The artery which accompanies the ninth pair or lingual nerve, often comes from the an- terior spinal artery, t ARTERIES OF THE EYE* 115 2. ARTERIA SPINALIS POSTERIOR. The posterior spinal artery differs in all essential points from the anterior: First; There are two posterior spinal arte- ries which arise, not from the basilar or vertebral arteries like the anterior, but usually from the arteria anterior cerebri; and they are smaller than the anterior spinal' artery. Secondly, These two arteries giv«' small twigs to the bottom of the fourth ventricle, and then go round from the fore to the back part of the medulla oblongata; but there, instead of uniting like the beginnings of the anterior artery, they continue se- parate, run down the spinal marrow as two distinct arteries, with very frequent inosculations betwixt them. This artery is also unlike the other in respect of its termination, for it dis- appears at the second vertebra of the loins. Its inosculations with the arteries from without are very free. ^ 3. ARTERIES OF THE EYE. The arteries of the eye come from one branch only, the ophthalmic artery, the branch which the carotid, when it touches the anterior clynoid process, sends into the orbit along with the optic nerve. But small as this original artery is, (no bigger than a crow-quill,) the system of arteries which arises from it is very great: whether we consider their number, the irregular parts which they supply, or the great inosculations which they form even with the outward arteries of the nose and face. These are reasons for setting this order of arteries apart; and even with all possible care in the arrangement, it is not easy to deliver an orderly intelligible history of this artery. The ophthalmic artery supplies not only the eye itself, (i. e.) the globe, but it supplies also the apparatus, if I may so call it, of the eye, (»". c) the muscles, the lachrymal gland, the eye-lids, and even the forehead and nose. 1st, It sends a great branch, which leaves the ophthalmic artery, and takes its own course outwards and upwards along the eye, to supply the lachrymal gland where it is exhausted. 2dly, The ophthalmic^supplies the eye itself, both by that ar- tery which enters into the centre of the optic nerve, called arteria centralis retina;, and also by other arteries which are named the ciliary arteries; because they go onwards to the forepart of the eye, where the ciliary circle is. 3dly, The muscles are supplied by an artery which comes from the same 116 ARTERIES OF THE EYE. place nearly with those ciliary arteries. 4thly, There are two arteries which go down through holes mthe socket into the bones and cavities of the nose; and these, as they perforate chiefly the aethmoid bone, are named aethmoidal arteries, Sthly, and lastly, Those arteries which go out upon the fore- bead and nose are so directly from the trunk of the ophthalmic artery, that they must be regarded as the termination of it. This is the system of vessels which comes now to be describ- ed, and this is, perhaps, the best order for the description. FIRST ORDER. I. ARTERIA LACHRYMALIS. The lachrymal artery is the first branch of the ophthal- mic ; but in order to know its place correctly, we must first ob- serve how the ophthalmic artery enters the eye. It comes off from the carotid, where that artery touches the clynoid pro- cess ; and is so close upon the process, that the setting off of the ophthalmic is almost covered by that projection. It then dives under the optic nerve, and appears on the outer side of it; and as the artery goes along through the orbit, it makes a spiral turn till it completely surrounds the nerve. The lachrymal artery goes off from the ophthalmic immedi- ately after entering the orbit,* though sometimes it arises from the artery of the dura mater; and then it enters by the fora- men lacerum, which is the next opening to the optic hole. It goes off from the ophthalmic about two or three lines after it has entered the socket. It goes all along the outer side of the or- bit, because the lachrymal gland lies in the outer corner of the eye. When it reaches the gland, it is branched out and en- tirely expended upon it, except that it sends some small twigs forwards to the eyelid. Of these vagrant branches, one twig goes to the periosteum of the orbit, perforates the cheek-bone, and so gets into the hollow of the temple, inosculating with the deep temporal artery; while another little branch goes to the tarsus of the upper eyelid, and another to the tarsus of the lower eyelid, and thus ends the lachrymal artery. SECOND ORDER. In the second order are included the arteries which go to the eye itself, viz. the arteria centralis retinje and the ci- * Sometimes it goes off one or two fines before the ophthalmic enters the optic bole, some- timet from the middle of the artery. ARTERIES OF THE EYE.. 11 "7 "uiary arteries ; of which arteries there is none more cu- rious than the arteria centralis retina?. 1. arteria centralis retina. This artery is so named because it perforates the optic nerve, runs up through its very centre or axis, enters into the cavity of the eye throaghi the very centre of the optic nerve; and spreads its branches all over the retina. It usually arises from the ophthalmic artery, where it turns in the middle of the orbit over the upper part of the optic nerve ;# it plunges into the nerve; and this artery, or rather the artery and vein, both (for the vein accompanies it) make so large a canal in the centre of the optic nerve, that it stands quite open and gaping when the nerve is cut across; and was long known to the older ana- tomists by the name of porus opticus, before the meaning of this orifice or hole was understood. When this artery arrives within the eye it branches out most beautifully upon the retina. The anglee and meshes which this artery makes give the name of retina or net-like to the whole; for the pulpy part of the optic nerve expands into a very thin and delicate web which resembles mucus. This web has all its strength from these branches of the central artery. The branches of the artery, and the mucus-like expansion of the nerve, lie in two separate layers; and hence some anato- mists reckon the retina a double membrane. The arteria centralis having given off sideways these innu- merable branches to the retina, still goes forwards, plunges through the substance of the vitreous humour, does not stop till it arrives at the back part of the lens, and is of course the arteria centralis oculi, the central artery of the eye itself. This central artery can no more be seen in the adult eye than the arteries of an unprepared bone; but by injecting the small arteries of the eye of a foetus, of a slink Calf, or of any young animal, the arteria centralis oculi is found to distri- bute its branches in the following way: As it goes forwards through the centre of the eye-ball, it gives off its delicate ar- teries from side to side, which go along the partitions of the vitreous humour (for the vitreous humour is divided every where by membranes into small honeycomb-like cells.) These cross arteries inosculate with those of the retina, and are plainly the arteries which secrete and support the vitreous humour. The central artery stops when it comes to the back of the lens : it is scattered in a radiated form, as if by the resistance, into a , ""* It may be found arising from the ciliary arteries, or sometimes from the muscular. 118 ARTERIES OF THE EYE. great many branches. These branches go round all the cap- sule of the lens, and meet again on its forepart ; where, unit- ing into one or more small arteries, they pass onwards into the opening of the pupil, and help to form that membrane which in the foetus shuts out the light, protects the eye, and vanishes very gradually. So the arteria centralis retinae passes first through the centre of the optic nerve ; next through the centre of the vitreous hu- mour ; next, after going round the eapsule of the lens, it passes through the posterior chamber of the aqueous humour, and terminates in the centre of the pupil. But as these last arte- ries, viz. of the pupil, vanish soon after birth, we may consider the central artery as ending in inosculations with those arteries, which coming upwards along the sides of the eye along with the retina, form a strong circle of arteries at the root of the ciliary process. 2. ARTERI/E CILIARES. The ciliary circle is known, upon looking outwardly at the eye, by that white line which borders the iris, and separates the iris or coloured part of the eye from the white or colour- less part. That circle marks the place where there is a great concourse of arteries. The corpus ciliare, or ciliary body, is the part within the eye which lies flat upon the forepart of the vitreous and crystalline humours, which is like a second iris behind the first, which is extremely vascular, and corresponds with the ciliary circle without. This corpus ciliare is radiated (that is a consequence of the peculiar order and arrangement of its vessels, which run in rays from the. ciliary circle, (*. e.) from the circumference towards the centre.) These radU coming from the ciliary circle are called the ciliary processes; so that the ciliary circle, corpus ciliare, and ciliary processes, are all parts of the same vascular organ. This is the part of the eye to which all those arteries go which are next to be described. 1. Two arteries of considerable size go off from the sides of the ophthalmic artery: these go along the sides of the optic nerve ; they go towards the ball of the eye; and the one on the outer side of the eye is named internal ciliary ar- tery, that on the inner side of the optic nerve is named the INTERNAL CILIARY. 2. These two divide themselves again into two subordinate branches: one of them as soon as it touches the eye, that is, just beyond the implantation of the optic nerve, enters its sob- ARTERIES OF THE EYE. 119 stance, and is spread out on its choroid coat in a great num- ber of branches, which are named ciliares breves, the short ciliary arteries : the other goes further forward upon the eye before it enters, and even after it enters, it still goes for- wards to the very forepart of the eye before it divides; hence named ciliares longje. 3. The anterior ciliary arteries are some small and uncertain branches, which come sometimes from one source, sometimes from another, but most commonly from the muscu- lar branches; and they go along with the muscles, and conse- quently enter the eye at its forepart just where the recti mus- eles are inserted. But, though small, these anterior ciliary arteries are of considerable number. From the places at which these several arteries enter the ball, one might guess a priori how they will be distributed through its coats. The ciliary arteries do not all of them arise from the oph- thalmic artery; many arise from the muscular branches. As soon as they touch the eye-ball, they enter into it near the in- sertion of the optic nerve, pass through the sclerotic coat (leaving for its nourishment a few twigs ;) they divide so, that just after they have entered, we can count twenty-five or thirty all round the root of the optic nerve, which go forwards in a radiated form, and are completely diffused upon the choroid coat; these are the posterior ciliary arteries. This coat of vessels lines the choroid all the way forward to the lens, goes still onwards to the forepart of the lens ; and then turning down upon the lens at right angles, it meets with the anterior vessels, and forms the ciliary circle, and the ciliary processes or radii; a few twigs go still forward upon the uvea and iris, so as to make a very important connection of all the i-ascular parts of the eye. Secondly, The longer ciliary arteries enter the scle- rotic a little further forward, and penetrate at a greater distance from the optic nerve. They are two arteries thus distinguish- ed ; they pass forward betwixt the sclerotic and choroid coats, and on approaching the ciliary circle, they each divide and - make a circle of inosculation. Their branches meet each ether and are now joined both by the shorter ciliary arteries and by the anterior ciliary arteries; by which conjunction an arterial circle is formed, which corresponds with the outer cir- cle of the uvea, and is called the outer ciliary circle : this again sends radii of vessels, perhaps thirty, inwards, which meeting, form a second circle, the inner ciliary cir- cle. Thirdly, The anterior ciliary arteries enter the eye at its 120 ARTERIES OF THE EYE. forepart, and immediately unite with these, as has just been explained ; they help to form the ciliary circle, which is the great conjunction of all the internal vessels of the eye. THIRD ORDER. In this order are included the muscular arteries, which are the least regular of all the branches of the ophthalmic ar- tery. From one or other branch of the ophthalmic there generally arise two muscular arteries ; the one for the upper, the other for the lower muscles*. I. arteria muscularis superior. The upper muscular' artery consists of small twigs, which go chiefly to the levator palpebrae and rectus superior; and these, though they sometimes arise as two small twigs from the ophthalmic artery itself, yet in general come off ra- ther from that artery which, as it goes out by the supra-orbita- ry hole, is named the supra-orbitary artery. These muscular branches of the supra-orbitary, then, supply the upper muscles of the eye, as the levator palpebrae, the obliquus major, the rectus superior, and the sclerotic or outer coat of the eye. 2. ARTERIA MUSCULARIS INFERIOR. The lower muscular artery is very generally an in- dependent artery, and pretty large. It comes off from that part of the ophthalmic artery where it is giving off the ciliary arteries. This muscular branch is large enough to give off sometimes the arteria centralis retinae, and often some of the short ciliary arteries arise from it; it is so long as even to reach the lower eyelid. The muscles which it supplies are all those which lie on the lower part of the eye, as the depri- mens oculi, abducens oculi, obliquus minor. It also gives vari- able twigs to the sclerotica, the optic nerve, the periosteum of I he orbit, and sometimes to the adnata and lower eyelid. FOURTH ORDER. The set of arteries which stand next in order are those which go down into the nose through the aethmoidal bone, whence they are named aethmoidal arteries. The aethmoidal ARTERIES OF the eye. 121 arteries are, like the other branches of the ophthalmic, pretty regular in their destination, but far from being regular in the manner in which they arise. 1. ARTERIA iETHMOIDALlS PObTERIOR. - The posterior ^ethmoidal artery is so named, be- cause it passes through the posterior of two holes which are in the orbit at the joining of the aethmoidal with the frontal bone.* It is an artery by no means regular in its place, com- ing sometimes from the ophthalmic trunk, sometimes from the lachrymal artery, very rarely from the supra-orbitary arte- ry. It is of no note : it is the smaller of the two aethmoidal arteries; it goes through its hole, and is scattered upon the bones and membranes of the nose. While it is circulating its twigs among the aethmoidal cells, it inosculates, of course, with the nasal arteries of the external carotid. 2. arteria jethmoidalis anterior. The anterior aethmoidal artery is rather more regular and more important ; it passes through a larger hole, and is itself larger ; it comes off more regularly from the ophthalmic trunk, and it goes not down into the nose, but upwards into the'skull. The ophthalmic artery, much exhausted by giving off many branches, has risen over the optic nerve, has completed its spiral turn, and has just got to the inner corner of the eye, where the aethmoid hole is, when the anterior aethmoid artery arises from it. It arises just behind the pulley of the upper oblique muscle, plunges immediately into its peculiar hole, and, passing along a canal within the aethmoid bone, it merely gives twigs to the frontal and aethmoidal sinuses, and passes up by one of the largest holes in the cribriform plate of the athmoid bone. When within the skull, it is under the dura mater, betwixt it and the bone ; it goes to the dura mater and to the root of the falx, and some of its delicate twigs turn downwards again into the nose, through the small holes of the cribriform plate accompanying the branches of the olfactory nerve. * In describing the sAull, these are named the internal orbitary holes. V Q, 122 ARTERIES OF THE EYE. FIFTH ORDER. The fifth order of arteries is very numerous, including all those which send their twigs outwards upon the face. They are the supra-orbitary artery, the artery of the upper eyelid, the artery of the lower eyelid, the artery of the forehead, and the artery of the nose. 1. ARTERIA SUrRA-ORBITALIS. The supra-orbitary artery is so named from its emerging from the socket by that notch in the superciliary ridge which we call the supra orbitary hole. It comes off from the ophthal- mic artery at the place where it gives off the ciliary and lower muscular arteries : it so often gives off the arteries whicii go to the upper muscles of the eye, that some have named it the su- perior muscular artery. It passes onwards, giving twigs to the levators of the eye and of the eyelid, and to the upper oblique muscles, and to the periosteum : and before it arrives at the supra-orbitary hole, it divides into two twigs; of which one lies deep, and supplies the periosteum of the forehead, inoscu- lating with the temporal artery; the other lies more superficial, but still is covered by the orbicularis and corrugator supercilii, on which muscles it bestows all its branches. 2. ARTERIAE PALPEBRALES. The two palpebral arteries arise from the ophthalmic after it has passed the tendon of the obliquus superior, when it has in a manner emerged from the socket, and is lying at the inner angle of the eye ; there it commonly gives off two small arteries, one to the upper and one to the lower eyelid; and often the two arise by one trunk. Arteria palpebralis inferior.—The artery ofthe low- er eyelik is the branch of the two which goes off first; but it is the smaller and less regular of the two. Its twigs go, one to the union of the two tarsal cartilages, to the caruncula lach- rymalis, and to the adjoining part ofthe adnata; another goes deeper, viz. to the lachrymal sac, and even into the aethmoid cells; and a third twig runs along the margin of the tarsus, named tarsal artery, supplying the Meibomean glands. Arteria palpebralis superior.—The aritery of the ur- ARTERIES OF THE EYE. 123 per eyelid arises along with the lower palpebral, or near it; it gives few branches; one keeps to the angle of the eye, and supplies the orbicularis oculi, the caruncula, and the tunica con- junctiva ; another having pierced the fibres of the oblique muscle, runs along the borders of the tarsus, inosculating with a similar branch of the lachrymal artery, and forming an arch along the upper tarsus as the other does below. 3. arteria nasalis. The nasal artery goes off at the edge of the orbit, rises over the lachrymal sac, and over the ligament of the eyelids; it first gives a twig upwards to the root of the frontal muscle ; then another goes down over the lachrymal sac, and after giving branches to the sac, goes to the orbicularis muscle, and inoscu- lates with the infra-orbitary artery; and lastly, the most re- markable branch of this artery, from which indeed it has its name, runs down upon the side of the nose, making a beauti- ful net-work, and inosculating with the last branch of the labial artery, called angularis, which runs up to meet it.* This is quite a cutaneous artery ; many of its twigs go to the skin, it is felt beating strongly ; it was often opened when arteriotomy vvas more regarded than it is now. 4. arteria frontalis. The frontal arteay is now to be distinguished from the bupra-orbital; for the supra-orbital rises deep in the socket, emerges by the supra-orbitary hole, passes along chiefly be- twixt the bone and muscles, and makes no remarkable figure upon the face; while this, the frontal artery, keeps chiefly upon the surface of the muscles, is quite subcutaneous, has nothing to do with the supra-orbitary hole, and rises beautifully upon the forehead. It is a delicate and slender artery, not so large as the nasal, and looks like one of its branches; it gives off first a branch to the eyelids, named superciliary artery, which supplies the root of the frontal and the upper part of the orbi- cularis muscles ; it sends an ascending branch which dives un- der the frontal muscle, and belongs chiefly to the os frontis and pericranium. This is the little artery which often makes a perpendicular groove in the os frontis. The chief branch of * Pome of its branches absolutely jienetrate the cartilages cf the D03e, :?nd so get acress to the Schneidi-rian membrane, and supply it with blood. 124 ARTERIES OF THE BRAIN. the artery continues subcutaneous, is felt beating along the forehead, belongs chiefly to the skin of the forehead and to the hairy scalp, and mounts to the top of the head, to the place of the fontanelle, where it has free inosculations with the temporal artery This last branch is the end of the ocular or ophthalmic ar- tery, of which the branches are so irregular in their origin, that the most diligent anatomists have declined that part of the de- scription, and yet have arranged the branches upon that scheme, viz. the points from which the several twigs arise : whereas I have thought it more prudent, since the branches are regular in respect of the parts which they supply, to ar- range them according to those parts, viz. the lachrymal gland, the eyeball, the muscles, the aethmoid cells, the face ; an order which also very nearly corresponds with the order in which the arteries arise. The learning and remembering these arte- ries, it is right to acknowledge, is a task more difficult than useful; more suiting the severe anatomist, than the practical surgeon ; who yet if he do his duty, will learn all; and as he learns much, must expect to forget much. CONCLUSION. Before I leave this difficult subject, I stop one moment to explain a point which might leave some confusion in the read- er's mind; and regarding chiefly those little arteries which be- long to the membranes of the brain. It is of great importance in studying the brain, to know the manner in which its membranes are connected with it; and it is especially to be remarked, that the internal surfaces, or, in other words, the cavities of the brain, need to be support- ed, nourished, and supplied with blood as much as the exter- nal surface; and that for this end the pia mater turns inwards and lines all the cavities of the brain. At different points the pia mater and its arteries take various forms, and are called rete mirabile, velum, or choroid plexus, according to that form. The retk mirabile has already been explained, as being that division and re-union of the branches of" the carotid ar- tery by which the force of the ascending blood is broken be- fore it enters the brain. In many of the lower animals this provision of nature is most curious and particular ; but in Man it would appear, that the erect posture in which he walks, the contortions of the carotid artery as it enters the skull, the man- ner in whicii it lies in the cavernous sinus, and, finally, the mi- ARTERIES OF THE BRAIN. \2b nute division which it undergoes by spreading over the pia mater before it enters the brain, are sufficient. In Man there is not the smallest vestige of a rete mirabile ; and whenever we find a rete mirabile described in Man, (as often it has been described,) we find invariably that it means no more than the plexus of delicate vessels which go out from the first twigs of the carotid artery, either to supply the membranes or to enter into the cavities of the brain; and accordingly we find these authors calling it " a beautiful beginning of a rete mirabile ;" " an imperfect rete mirabile," he. The velum, as it is called, is that netted form which the pia mater assumes often about the basis ofthe brain, whenever the smaller arteries are numerous; for the inosculations ofthe arteries are like a net-work; the arteries, full of blood or of injection, are opaque and are very apparent; while the mem- brane upon which they run is lucid, diaphanous, and is scarcely seen. A velum or net of this kind appears on every smooth and uniform surface ofthe basis ofthe brain ; but the most re- markable of all, is that which, beginning betwixt the cerebrum and cerebellum, is continued forward to the very centre ofthe brain betwixt the fornix and the third ventricle, extending from the plexus choroides of one side to the other. This is called the VELUM INTERPOSITUM. The plexus choroides again is merely another variety or form of the pia mater. This great choroid plexus is a mem- brane which lies upen the bottom of each lateral ventricle: it is netted and extremely vascular, not unlike the chorion of some animals, whence it is named. It consists partly of ar- teries, but chiefly of veins; it conveys some blood to the in- ternal surfaces of the brain, but returns much more. But although the choroid plexus of the two lateral ventri- cles be the chief ones, the third and the fourth ventricles have each their plexus or vascular webs. The chief points by which these vascular webs of the pia mater enter are by the anterior and posterior horns of the lateral ventricles; at which points, and indeed at all the lower parts of the brain, the ven- tricles must be considered as shut, since these vascular linings, as they enter, adhere on all sides: but may also be considered as open, since they admit these membranes, since they are shut only by their slight adhesion, and may be opened by pull- ing the parts gently asunder. This, then, is a general explanation of that vascular part of the pia mater which covers all the basis, and lines all the ca- vities, of the brain. It is one continuous membrane, under the various titles of rete mirabile, which some older anatomists- use of velum, a name chiefly repeated hv Haller: and of 126 ARTERIES OF THE ARM. plexus choroides, a name universally used for that net-work of vessels which lies out upon the floors of the ventricles. It will be seen hereafter how greatly a knowledge of these inflec- tions contributes to the right understanding of the brain and its parts and cavities. CHAP. If. OF THE ARTERIES OF THE ARM. JL HE subclavian arteries arise from the arch of the aorta. The left subclavian arises from the extremity of the arch, and just where the aorta is turning down towards the spine. It is longer within the thorax, runs more obliquely to pass out of the chest, receives in a less favourable direction the current of the blood. But the right subclavian arises from the aorta by that artery which is called the arteria innominata ; for it is an artery which can have no name, being neither the carotid nor the subclavian, but a trunk common to both. It is large, rises from the top ofthe aortic arch, receives the blood in the most direct manner; from which physiologists have deduced those consequences which have been already explained.* 1. The artery ofthe arm, as it proceeds, changes its name according to the parts through which it passes. It is named subclavian within the breast, axillary in the arm-pit, brachial as it goes down the arm, and when it divides at the bending of the arm, its two branches are named the radial and ulnar arte- ries, after the radius and ulnar, along which they run, until at last they join to form vascular arches in the palm of the hand. Nature has arranged and divided the parts of this artery; and the study of its branches becomes easy to those who will first condescend to observe this simple arrangement and the parts through which it goes. 1st, While the artery is within the breast, it lies transversely across the root of the neck; it supplies the neck, the breast, the shoulder; it gives all its branches upwards into the neck, or downwards into the breast: upwards it gives the vertebral to the inside of the neck (if I * Douglas says the left is shorter, which I can by nq means understand. ARTERIES OF THE ARM: 127 •may use an expression which cannot now be misunderstood,) the cervical, which, goes to the outside of the muscles of the neck, the thyroid, which goes to the thyroid gland. While it gives off from its opposite side downwards, and into the chest, the mammary, which goes to the inner surface of the breast; the upper intercostal artery which serves the space betwixt the uppermost ribs; the mediastinum and pericardium and even the diaphragm, though far distant, receives branches from this mammary artery. 2. When the artery, having turned over the sloping part of the chest, glides into the axilla, and lies deep there betwixt the scapula and the thorax, what parts can it supply, or what vessels can it give off, but scapular and thoracic arteries? Its branches accordingly are three or four slender arteries to the thorax on one hand, named the four thoracic arteries, which give twigs to the glands, the pectoral muscles, and the breast or mamma ; and on the other hand it gives off first great arti- cular arteries which surround the joint, arid still great scapular arteries which surround the scapula, and nourish all that great mass of flesh which lies upon it. 3. But when this artery takes the name of the humeral ar- tery, and passes along the arm, it must be simple, as the arm is simple; for it consists of a bone, of one mass of muscles before, and another behind; the artery of course runs along the bone, undivided, except that it gives off one branch, which runs parallel with the main artery, and running deeper among the flesh, is named muscularis or profunda. 4. It divides at the bend of the arm, in order to pass into the fore arm in three great branches. In wounds thus low, all danger of losing the arm from wounds of the artery, unless by the gross ignorance or fault ofthe surgeon, is over: we do not attend so much to the parts which it supplies, or, in other words, to its inosculations, as to the parts against which the great branches lie. We observe here, as on all occasions, the artery seeking protection, and running upon the firmest parts : its three branches now pass; one along the radius, another along the ulna, a third along the interosseus membrane. 5. In the palm of the hand we find the artery still follow- ing the order of the bones ; and as the carpal bones are as a centre or nucleus, upon which the metacarpal and finger bones stand like radii, the palmar artery forms a complete arch, from which all the fingers are supplied, by arteries issuing in a ra- diated form. Of all these subdivisions the subclavian artery is that which seems the least important to know; and yet without a perfect knowledge of it, how shall we understand manv important ar- 128 ARTERIES OF THE ARM. teries of the neck or shoulder ? How shall we understand the anatomy of the greatest of all the nerves, viz. the sympathetic nerve which twists round it ? How shall we judge rightly of tumours near it, or of aneurisms which so often mount along this artery from the arch of the aorta until they are felt here ? -----Of the second division of the artery, viz. where it in lies the axilla, the importance is most unequivocal; since every attempt to stop haemorrhages, by compressing this ar- tery, requires a knowledge of it; since every full bleeding wound near this place alarms us, and requires all our know- ledge ; since every tumour that is to be extirpated opens some of its branches; since we cannot cut off a cancerous breast, or the glands which should be taken along with it, without cut- ting the thoracic arteries.—Next, the artery of the arm, simple as it is, interests us greatly. It is this simple artery which is hurt in aneurisms; it is its delicate, I had almost said capillary, branches, which are to establish a new circulation, and to save the limb. We have indeed no apprehensions of losing the limb for want of blood (the continual success of our operations having established this point;) yet it is most interesting to observe the extreme smallness of these branches, as an assu- rance to us in other cases of danger; though I do indeed be- lieve, that there cannot in any simple wound in any limb be the smallest danger from this much dreaded obstruction of the blood. The arteries of the fore-arm are more interesting still; for if we will be so selfish as to consider the difficulties of the sur- geon merely, wounds of the arteries in the fore-arm are very distressing. These arteries lie deep among the muscles, drive their blood (when wounded) through the whole arm, and either occasion a difficult and most painful dissection, or cause a deep and gangrenous suppuration ; so that whether the sur- geon be so dexterous as to secure the arteries or so timid as to leave the arm in this woeful condition, the patient is to under- go such sufferings by pain or by a long disease, as must interest us greatly. The arteries even of the wrist and hand, though small, are important. The difficulty of managing wounds of these arte- ries stands but too often recorded in all kinds of books for us to doubt the fact. If many have died after frequent bleedings from these arteries, though under skilful hands, what ought we not to submit to in the way of study and labour to acquire and to retain a knowledge of these arteries; since by that alone every thing that is surgical in tumours, aneurisms, am- putations, is well or ill performed according to our degree of knowledge ; and since according to our degree of knowledge, we are disengaged in our minds, and have free possession of OF THE SUBCLAVIAN ARTERY. 129 our judgment, to do any thing which may be required ? In short, as we proceed aldng this artery we shall perceive that each division of it rises in importance; or at least that if wounds about the axilla be more dangerous, they are pro- portionably rare ; that if accidents about the wrist or hand be less dangerous, they are, however, more frequent, so as to deserve every degree of attention. I. OF THE SUBCLAVIAN ARTERY. This artery is so named from its passing under the clavicle by which his protected ; and we include under this division all that part of the artery which lies betwixt the arch of the aorta and the outside of the clavicle, where the artery comes out upon the chest. Here the artery is of a very great size ; it lies directly across at the top of the chest and root of the neck; and like a cylinder or axis, it gives its branches directly up- wards and directly downwards to the throat, to the neck, and the parts within the chest. Upwards it sends the vertebral, the thyroid, the cervical, and all the humeral arteries ; down- wards it sends the upper intercostal artery, and also the inter- nal mammary, which, besides its going along the inner sur- faces of the chest, gives branches to the pericardium, medi- astinum, thymus, and other parts. 1. ARTERIA MAMMARIA INTERNA. The internal mammary artery is the'first which the subclavian gives off; it is of the size of a crow-quill, long, slender, its ramifications very beautiful. On each side of the chest the mammary artery passes down along all the inner sur- face of the sternum, and ends at the cartilago ensiformis in numerous inosculations with the epigastric artery ; for the epi- gastric arises from the femoral at the groin, just as this does from the subclavian at the top of the chest, and runs upwards along the belly, as this the mammary runs downwards along the breast till they meet each other midway. This is an inoscula- tion, which fifty years ago was much noticed. Physiologists deduced the most important consequences from it, ascribing the connection of the breast and womb to the flux and reflux, to the alternate stoppage and acceleration of the blood in these vessels ; although the sympathy of the breasts and womb is plainly a connection which Nature has established upon other vol. h. R 15® OF THE SUBCLAVIAN ARTERY. laws, upon a kind of sympathy such as we see every where in the system, but can in no instance explain. The course of the mammary artery, and the order of its branches, is this: It goes off from the lower and forepart of •^the/dsifcfolRy artery; it lies on the outside of the membranous bag'ofthe pleura; and considering the pleura as ending in an obtuse and rising apex, the mammary artery lies at first a lit- tle behind the pleura, its first movement is to rise and turn with an arch over the top of the pleura or bag which encloses the cavity of the chest; there it descends again, and passes betwixt the ribs and pleura; the artery runs along the inside of the thorax under the middle of the cartilages. At the seventh or eighth rib the mammary itself emerges from the thorax, and becomes an external artery; it first sends a branch towards the ensiform cartilage, which plays round it, and then it goes to the upper part of the abdominal muscles by two distinct branches, the one of which is internal, the" other external. The internal branch goes into the belly or substance of the rectus muscle, descends nearly as far as the navel, and inos- culates with the epigastric artery. The external branch turns off to one side, goes rather to the lateral muscles of the abdo- men, especially to the two oblique muscles, and inosculates more with the lumbar arteries; and so the mammary ends. But as it passes down along the chest, it gives the following branches: First, Where it is passing the clavicle, bending to go down- wards, it gives a small retrograde branch which follows the course of the clavicle, and goes to the muscles and skin of the neck.* Secondly, It gives an artery, or rather arteries, to the thy- mus, arterije thymic^. These are in the adult extremely small, because the gland itself is so ; but in the child the gland is large, the upper part lies before the trachea, the lower part lies upon the heart, or rather upon the pericardium betwixt the two lobes of the lungs: the upper end then is supplied by the thyroid arteries : the middle part is often supplied by a distinct and particular branch, viz. by this arteria thymica coming from the mammary, is far from being always so ; the lowest part of the gland has twigs from those arieries which properly belong to the mediastinum, upon which it lies, or to the pericardium, or to the diaphragm. Thirdly, The mammary gives also the upper artery of the diaphragm, its lower artery being the first branch of the aorta * Sabbatier i* so confused, and copies Haller so ill, that he mistakes this for the trans* v*»r?alis laamen, wmch is really an important artery. OF THE SUBCLAVIAN ARTERY. 131 within the abdomen. This upper artery of the diaphragm is named arteria comes nervi phrenici, because it accompa- nies the phrenic nerve. The phrenic nerve is passing from the neck (where it arises) into the chest, by the side of the axil- lary artery, when it receives from the mammary this small artery which goes along with it; and this artery (which is so extremely small that nothing but its regularity can give it any importance) goes down through the whole chest, accompany- ing the phrenic nerve over the pericardium till they arrive to- gether on the upper surface of the diaphragm, and spread out there. This artery, small as it is, gives twigs as it passes along to almost all the parts within the chest. Fourthly, The mammary gives an artery to the pericardium, which may be called the upper pericardiac artery; and which is of such importance, that generally when it does not come off from the mammary, it comes from the subclavian itself, or even from the aorta. It belongs to the upper and back part of the pericardium. Fifthly, The pericardium has another artery from the mammary, which belongs to that part of the h^i which is/£>i united to the diaphragm : it is thence named by some arte- ria PHREN1CO-PER1CARDIACA. Sixthly, The mammary gives many small arteries to the mediastinum ; for the mammary is covered only by the sterno- costalis muscle, which is often hardly visible in Man, so that the artery may be said to lie upon the pleura, betwixt it and the ribs. The mediastinum is jusi that doubling ofthe pleura which descends from the sternum to the spine, and of course many small arteries go down from the lower surface of the sternum along the pleura into the mediastinum, and by that to the pericardium, or even to the membrane ofthe lungs. The mammary, as it goes downwards, sends branches through the interstices of the ribs; two twigs pass through each interstice, going to the intercostal muscles, and to the muscles which lie upon the thorax, as the pectoral muscles j also to the mamma, to the obliquus externus abdominis: they form loops of inosculations round the ribs with the proper in- tercostal and thoracic arteries. These twigs pass through the interstices ofthe six or seven upper ribs, but at the seventh the artery itself comes out. They are too numerous and too. small to be either counted or named. Seventh, The mammary, before it terminates in the two branches, of which one keeps the middle and goes to the rectus muscle, while the other goes outwards to the oblique muscle, as already described, gives about the place ofthe sixth rib, a branch, which in place of passing out of the thoraxj 132 OF, THE SUBCLAVIAN ARTERY. keeps to its inner surface, goes downwards along the seventh*, eighth, and ninth ribs, makes its inosculations there with the intercostal and other arteries, and ends in the side of the dia- phragm, and in the transverse or innermost muscle of the- ab- domen, which indigitates, as we call it, with the diaphragm. From this destination it is sometimes named the ramus mls- CULO-PHRENICUS. 2. ARTERIA THYROIDEA INFERIOR. The lower thyroid artery, whose branches go' to the neck; the shoulder, and the thyroid gland, arises from the forepart ofthe subclavian artery, close upon the origin ofthe internal mammary. It is there covered by the root of the mastoid muscle. It buds out from the root of the great axilla- ry artery, in the form of a short thick stump, which immedi- ately divides whip-like into four small and slender arteries. 1. The main branch of this artery is again named the ramus thyroideus arteriae thyroidea. This thyroid artery is the first great branch ; it does not ascend directly but moves a little inwards towards the trachea, from which the root is a good deal removed ; it bends behind the carotid artery, is tor- tuous, ascends by the side of the trachea till it touches the low- er lobe of the thyroid gland ; it spreads upon it like a hand, inosculates very freely with the upper thyroid artery, and nourishes the gland. This branch moreover gives some twigs upwards to the lower constrictors of the pharynx and to the oesophagus; but its chief arteries, besides those which plunge/ into the gland, are its tracheal arteries. These tracheal arteries, two or three in number, are reflected along the trachea, turn down with it into the chest, and reach even to the bifur- cation of the trachea, where, inosculating with the intercostal arteries, they form a most beautiful net-work. 2. The ascending thyroid artery, or thyroidea ascendens is a small and delicate branch, which lies pretty deep, going off rather from the back part ofthe artery; it supplies all the deep parts of the neck, and even penetrates the vertebrae ; it soon divides into an irregular number of branches ; the artery keeps almost close to the naked vertebrae, lying under most of the muscles; its general tendency is upwards, surrounding the neck in a spiral form. Its chief twigs are, first, some which go towards the surface, (t. e.) to the muscles which lie over the artery, as to the scalenus, the mastoid muscle, the levator scapulae, and the splenius; and twigs of this artery play over the rectus capitis and the anterior surface of the vertebrae, and OF THE SUBCLAVIAN ARTERY. 133 attach themselves to the eighth pair of nerves, and to the ganglion of the sympathetic nerve. Its deeper arteries again go to the inter-transversarii and other muscles which lie closer upon the neck; and these are the branches which pass in through the intervertebral holes, and penetrating the sheath ofthe spinal marrow, and following its nerves, inosculate with the spinal arteries. 3. The transverse artery ofthe neck, or transversalis colli, is an artery of the same kind with the last, viz. chiefly destined for the muscles, but more superficial. It passes obliquely round the neck outwards and upwards, goes under the trape- zius muscles, and covered by it sends branches as far as the oc- ciput. Its twigs are distributed thus: First to the mastoid muscle and to the skin ; next to the^trapezius, levator scapu- lae, and splenius; then a long branch passing obliquely upwards over the splenius, and under cover of the trapezius, gives twigs to those muscles, and ends in inosculations with the low- er branches ofthe occipital artery; and lastly, another branch goes downwards towards the scapula and shoulder. 4. The last branch of this artery is the transversalis hu- meri ; an artery so important in its destination, and so irregu- lar in its origin, and so frequently arising as a distinct and par- ticular branch, and having so little relation to these trivial branches of the thyroid artery, that I shall describe it by it- self. 3. ARTERIA VERTEBRAL1S. The vertebral artery arises next from the upper part ofthe subclavian artery; and running upwards and backwards but a little way, it plunges into the hole destined for it in the verte- brae ; and it has been already described through all its course both within the bony canal and within the brain. 4. ARTERIA CERVICALIS PROFUNDA. The deep cervical artery comes next in order; it is gene- rally the least important of all the branches from the subcla- vian artery, and the least regular in its place. It often comes from some other branch, and often it is entirely wanting ; its course resembles a good deal that of the transversalis colli, (i. e.) it goes to the deepest muscles ofthe neck, and to the ver- tebra1, and ends about the occiput; it usually arises from that part of the subclavian artery where it is just going to pass, or 134 OF THE SUBCLAVIAN ARTERY. has already passed betwixt the scaleni muscles. Its branches are few in number, it gives branches to all the scaleni muscles; others also which play over the anterior surface of the ver- tebrae and the deep muscles of the neck, as the spinalis colli, inter transversarii, the root of the splenius and trachelo-mas- toideus; the complexus also receives a branch, which usually inosculates with the occipital artery. 5. ARTERIA CERVICALIS SUPERFICIALIS. The superficial cervical artery is still less regular, being very often supplied by the thyroid. Its course is direct- ly the reverse of the last, running rather outwards and down- wards, or, in other words, belonging rather to the shoulder than to the neck. The subclavian artery has got from under the muscles, and has passed the splenii a little way before it gives off this superficial cervical. This artery immediately attaches itself to the plexus of the brachial nerve, and is in- deed hidden in the plexus: its first branch is given to the plexus, but its next and chief branch goes across to the top of the shoulder; it sends branches to the levator scapulae, trapezius, and even to the skin; while a deeper branch goes to the splenius and complexus, where these muscles arise in the neck; % and' when this artery is large, it sends branches along the mar- gin ofthe scapula, which go even to the serratus major, rhom- boidei, latissimus dorsi, &ic. After enumerating these jarring names, I perceive the ne- cessity of arranging once more those arteries which go to the neck. Let the student then observe, 1. ""That the vertebral artery goes to the brain, that the cervical arteries belong to the muscles of the neck. 2. That the thyroid gives two arte- ries to the neck, the thyroidea ascendens and the transversalis colli. 3. That when a second set of arteries for the neck begins to be enumerated, the name is changed; that of colli is dropped, and that of cervicis adopted. 4. That as there are two branches of the thyroid going \o the neck, viz. the ascending thyroid and the transversalis colli, there are also two entire arteries going to the neck, and which come off immedi- ately after the thyroid, viz. the cervicalis profunda more con- stant, and the cervicalis superficial which is less regular. 6. ARTERIA 1NTERCOSTAL1S 6UPERIOR. The upper intercostal is given to supply the intercostal space betwixt the two uppermost ribs, because the aorta which OF THE SUBCLAVIAN ARTERY. 135 gives out all the other intercostals, regularly, one for each rib, does not begin to give them off till after it has made its turn downwards ; of course it leaves the two upper ribs without ar- teries. To supply this, then, is the office of the superior in- tercostal artery, which is about the size of a crow-quill, and goes off from the subclavian generally next after the vertebral and thyroid arteries. It comes from the upper and back sur- face of the subclavian trunk; it turns downwards and back- wards, and lodges itself by the side of the spine in the hollow where the spine and the first rib are joined, and where the first thoracic ganglion ofthe great intercostal nerve lies. Before it takes its place betwixt the ribs, as the intercostal of the two upper spaces, it sends a branch upwards upon the face of the lower vertebrae of the neck, which is given to the scaleni. to the longus colli muscles, and to the nerves : next it gives off the highest intercostal artery for the space betwixt the first and second ribs, which artery divides into two branches; one perforates the thorax, and goes out upon the back, and sup- plies the muscles which lie flat upon the back of the chest; while another branch, the proper intercostal branch, runs along betwixt the ribs. Next it gives off a secdtad intercostal artery, which, also has <** its external and internal branches, and of which a branch inosculates over the third rib with the uppermost inter- costal ofthe aorta. Besides, these, it gives also small branches to the cesophagus, which inosculate with the tracheal arteries; and it gives branches to the spinal marrow, which pass into the canal along the holes for the nerves; and which not only supply the sheath, but also inosculate with the arteries of the spinal marrow itself. 7. arteria supra-scapularis. The supra-scapular artery, or the superior scapular artery, is one of such magnitude, and is so different in size and desti- nation from the cervical and other small arteries of the neck, that it ought to be described apart; though of great size and importance, it is yet so little known, that Sabbatier does not even describe nor name it. The supra-scapular artery very often comes off from the thyroid artery ; in which case it is the last in order of all the branches of the thyroid, that is to say, the nearest to the shoul- der, and then it is named transversalis humeri, because of its going across the root of the neck of the shoulder. Some- times it arises from the cervicalis superficialis; but then it is a small artery, and I suspect it reaches in such cases no further 138 Of the subclavian artery. than the tip of the shoulder, and does not descend to the •scapula. Often I see it arising as a distinct artery, large, very long, tortuous like the splenic artery, and almost equalling it in size ; running across the root of the neck, till at the top of the shoulder it dives under the acromion process; and then pass- ing through the notch of the scapula, supplies all the flesh of its upper surface. The reason of my naming it supra-scapular artery, is its passing thus over the scapula, while another, the largest branch of all those proceeding from the axillary artery, is'named sub- scapularis, from passing under the scapula. To repeat the origin then of this supra-scapular artery; it arises sometimes as an independent artery, and is so great, that we wonder it does not always do so: often it arises from thyroid, is its last branch, and is named transversalis hume- ri, authors not observing that it belongs absolutely to the scapula; it rarely arises from the cervicalis superficialis; and when it does so, it is small: often in a strong man it arises apart; and when it does arise from the thyroid or cervical ar- teries, it is so large as to annihilate as it were all the other branches of the artery from which it arises. Where this artery passes out of the chest it is covered only by the root of the mastoid muscle ; and it gives twigs to the % mastoid, to the muscles which ascend to the throat, to the sub- clavian muscle, to the fat, jugular vein, and skin. Next it gives a superficial branch to the skin, trapezius, and other superficial parts about the shoulder. Next it turns over the acromion process, passes through the supra-scapular notch, with many windings and contortions; spreads itself over all the outer surface of the scapula, both above and below the spine, and is the sole supra-scapular ar- tery. The manner of its spreading is this: having passed through its hole in company with the supra-scapular nerve, the instant that it has passed the hole and begins to lie flat upon the scapula, it sends off two branches, one on either hand at right angles; and of these one goes aleng the upper border of the scapula towards;its basis, the other goes in the other di- rection towards the shoulder-joint, and circles round the upper side of the spine or ridge ofthe scapula. The main artery having first perforated the scapular notch, and given these two small branches, next makes a second per- foration, viz. by passing under the root ofthe acromion pro- cess ; and then it again divides into large branches in which it ends. The one branch runs all along the root or base of the spine or high ridge; the other branch runs nearly in the same direction, but lower down, viz. nearer that edge where OF THE AXILLARY ARTERY. 137 the great sub-scapular artery runs; and with which, of course, it makes many free inosculations. This artery lies so across the neck that it may be cut, espe- cially in wounds with the sabre; and in a big man it is of such size as to pour out a great quantity of blood. It is necessary for the surgeon to remember the great size of this supra-scapu- lar artery, its long course over the shoulder, at what place it arises within the chest, and how it may be compressed. But in another sense aJso it is peculiarly important; for the supra- scapular artery makes inosculation with the lower scapular ar- tery, freer, and fuller, than in almost any other part of any limb. Onftcan hardly force tepid water through those small arteries which support the arm after the operation for aneurism; but the inosculations of this supra-scapular artery are so free, that often, though I have tied the arteries with great care, the very coarsest injection has gone round by it; and when I de- sired.only to inject the head I have found the arteries of the arm entirely filled. The conclusion which this leads to in wounds of the, axillary artery is too obvious to need any fur- ther explanation. II. OF THE AXILLARY ARTERY. This artery assumes the name of axillary, where it lies in the arm-pit or axilla. The scaleni muscles being attached to the ribs, the artery passes first through-betwixt the first and second scalenus; next it passes out from under the arch of the clavicle, where it was protected : then it falls over the breast in a very oblique direction ; it inclines outwards towards the axilla, lies flat upon the slanting convexity of the chest, is covered by the pectoral muscles, because the pectoral mus- cles arise from the clavicle, under which the artery passes; but far from being protected, it is so far exposed as to be easily felt beating, and it is at this point only that it can be rightly compressed. . It declines still outwards and downwards, till at last it gets so deep into the arm-pit, and so much under the scapula, as to lie betwixt the serratus anticus and sub-sca- pular muscles. There it is rightly called the axillary artery. In this hollow it lies safe, protected by the deep borders of the pectoral muscle before, and of the latissimus dorsi behind, surrounded with fat and glands, inclosed within the meshes of the plexus, or great conjunction of nerves, which go to the arm, surrounded also by all the veins of the arm, which twine round it in a wonderful manner. Here it gives off the tho- VOL. II. S 138 OF THE AXILLARY ARTERY. racic arteries to the thorax, and the scapular arteries to the shoulder. In short, the axilla itself is a complicated study; but in all that respects the arteries it may be made very easy and plain. But let the surgeon remember that it is only by a perfect knowledge of the arteries, a bold stroke of the knife, and a masterly use of the needle, that the patient is to be saved from bleedings after wounds hereabouts! for the whole story of compressing the axillary artery above the clavicle is now of no credit with any surgeon of knowledge or good sense. As the artery turns over the borders of the chest, it gives one or two twigs to the adjacent parts, as to the scaleni, and to the great nerves whicii lie over the artery, and to the ser- rated muscle, where it lies under the scapula: but these branches are so small that is unnecessary either to number or describe them. The thoracic or external mammary arteries are the first important branches; they are four in number, and they are named after their place or office. I. ARTERIA THORACICA SUPERIOR. The upper thoracic artery, being the first, lies of course deep in the axilla. It comes off about the place of the first or second rib; it lies betwixt the lesser pectoral and the great serrated muscles ; it gives its chief branches to these muscles, and it also gives other branches to the intercostal muscles and the spaces betwixt the ribs. But, upon the whole, it lies very deep, is small, is so short that the next is entitled thoracica longior; it is an artery of little note. 2. ARTERIA THORACICA LONGIOR. The long thoracic artery is more important, supplying all the great pectoral muscles and the mamma It was named the external mammary artery ; but we are the more willing to change the name, since it has no likeness to the internal mam- mary artery ; is in no respect a counterpart to it; it might be named the pectoral artery. It is long, not tortuous, but straight and slender, and about the size of a crow-quill. It is needless to describe an artery so variable in its branches as this is; it is sufficient to say, that after giving small twigs to the axillary glands, it terminates with all its larger branches in the -pectoral muscle, mamma, and skin, and in inosculations with OF THE AXILLARY ARTERY. 139 the intercostals and internal mammary; it is very long, de- scending sometimes so low as to give branches to the oblique muscles of the belly. 8. arteria thoracica humeraria. The thoracic artery of the shoulder goes off from the upper and forepart of the axillary artery. Its place is exactly opposite to that of the mammaria superior, viz. under the point of the coracoid process, insomuch that Haller has named it "thoracica acromialis. It is a short, thick artery ; if bursts through the instertice between the pectoral and deltoid muscles, and appears upon the shoulder almost as soon as it comes off from the main artery; it resembles the thyroid in shape, being a short thick artery, terminating all at once in a lash of slender branches, which go over the shoulder in various directions; but I never could observe any order worth des- cribing. One deeper branch goes to the serratus major, a branch goes along the clavicle, gives it the nutritious artery, and then goes on to the pectoral muscle, and to the skin of the breast: it gives small branches to the axillary glands, and larger ones to the deltoid and pectoral muscles and skin of the shoulder, for this is very much a cutaneous artery. The chief branch is that which is last named, running down betwixt the deltoid and pectoral muscles ; and the most curious branch is a small artery which accompanies the cephalic vein, and runs backwards along the course of the vein, a small and beautiful branch. 4. ARTERIA THORACICA ALARIS. Sometimes, though not always, there is a fourth thoracic artery. When it exists, we find it close by the last artery; its branches, which are sometimes numerous, belong entirely to the cup or hollow of the axilla; it goes to the glands and fat, and thence its name of alaris or axillaris. This is the deepest or backmost of these mammary arteries; it attaches itself to the lower border of the scapula, and we often see it running along the lower border a considerable length, and giving branches chiefly to the sub-scapularis muscle. These are the four mammary arteries which go to the breast. The arteries which go to the scapula follow next, and *re only three in number; one, which is the counterpart of 140 OF THE AXILLARY ARTERY. the supra-scapular artery, is the greatest branch from the axil- lary artery, supplies the lower surface of the scapula, and thence is named sub-scapula it artery ; one, which, as it is reflected round the joint by the outside, is named the exter- nal circumflex artery; and one, which, as it turns round the inner side of the joint, is named the internal circum- flex ARTERY. 5. ARTERIA SUB-SCAPULARIS. The sub-scapular artery is of a great size ; it is hardly described in books, I might say is hardly known to anatomists. Douglas, and most especially Sabbatier, have scarcely) named it, though it is in fact one of the largest arteries in the body, being absolutely as large as the axillary artery, from which it takes its rise.* The greatest mass of flesh in almost any part of the body is that which lies under and around the scapula in a strong man ; and this artery supplies almost all that mass. It goes off from the axillary opposite to the neck of the scapula, just un- der the long head of the biceps brachii: it no sooner comes off from the axillary artery, than it attaches itself to the lower border of the scapula; and as soon as it comes to the edge of the scapula (but sometimes lower down the edge, viz. where the head of the biceps comes off) it splits into two great branches; one of which goes to the upper, and one to the lower surface. But to describe each little artery among such a mass of flesh, or to expect to find them regular, would be very thoughtless ; the general course of them only can be de- scribed. First, The greater branch, which goes to the lower surface of the scapula, is the proper trunk of the sub-scapular artery; it divides into two great branches, which course all over the lower or hollow surface ofthe scapula : one of these is deeper, runs downwards along the naked border of the sca- pula, lies under the muscles upon the flat bone, and supplies the inner surface ofthe sub-scapular muscle with many branch- es. It sends a branch upwards, which runs along the inner surface of the neck of the scapula, runs still forwards under the root ofthe coracoid process, and its extreme branch goes round by the basis of the scapula to make an inosculation with the larger branch. * It is named often scapularis inferior or iufra-scapularis; it is better named subscapular both to harmonize with the name sub-scapular muscle, to which it belong1:, and also to con^ trast with its counterpart, the ^suprascapular artery, which comes from the subclavian Biteiy. OF THE AXILLARY ARTERY. 141 Secondly, The larger branch keeps nearer the surface, and supplies all the outer side ofthe sub-scapular muscle. Its general course is round the scapula, down the fore edge, then round by the lower angle, then up by the line ofthe basis scapula?, encircling it with what might be named a coronary artery. It first gives branches to the teres major; then passes down along that muscle to the angle of the scapula ; then turning along the angle of the scapula (which it does not do without leaving many branches behind,) it runs in,a waving line all round the basis scapulae, till it arrives at the upper corner, where it ends in free inosculations, both with its own deeper branch, and also with the supra-scapular artery which comes along the shoulder. Now this great branch, with all its arteries, belongs entirely to the lower surface of the scapula ; but the branch which leaves it at the neck of the scapula turns round under its lower edge, gets to the upper surface of the scapula, runs in under the infra-spinatus and teres major muscles, betwixt them and the bone; and although the supra-scapular artery from the shoulder supplies chiefly the upper part of the scapula, yet it is chiefly above the spine that that artery circulates, while the lower parts of the infra-spinatus and the teres minor muscles are left to be supplied by this reflected branch of the sub- scapular artery: thus this reflected branch gives its arte- ries, first to the teres, then it enters into the hollow under the spine, and besides supplying the infra-spinatus and the bone it- self, it also makes a circle, though a shorter one, and inoscu- lates with the supra-scapularis, just as the other branch of this same artery does on its lower surface. This branch descends nearly to the corner of the scapula before it begins this inos- culating circle; but it sends also another chief branch round the neck of the scapula, which advancing towards the supra- scapular notch, inosculates very largely with the supra-scapu- lar artery. Thus is the scapula encircled, and supplied with a wonder- ful profusion of blood by two great arteries; one, the supra- scapular artery, coming across the neck, over the shoulder, and through the scapular notch; another, the sub-scapular artery, which comes from the axilla to the lower flat surface of the scapula, and divides at the edge of the scapula into two great branches; one of which keeps still to the flat surface, while the other turns over the edge of the scapula, and supplies in part its upper or outer surface. 142 OF THE AXILLARY ARTERY. 6. ARTERIA CIRCUMFLEXA POSTERIOR. The posterior circumflex artery is a very large one. It arises either along with, or immediately after, the great sub- scapular artery ; the place of it is of course settled by the place of the shoulder joint, for it belongs so peculiarly to it that it is sometimes named the Humeralis, sometimes the Articu- laris, sometimes the R^flena Humeri. It goes off between the sub-scapularis and the teres major muscles; it passes in be- tween them to get to the joint; it then turns round the shoul- der-bone, accompanied by the circumflex nerves,'just as the supra-scapular artery is accompanied by the supra-scapular nerve ; it ends, after having made nearly a perfect circle, upon the inner surface ofthe deltoid muscle. Its branches are, first, Twigs to the nerve whicii accompa- nies it, and to the capsule of the shoulder-joint. Secondly, Branches to the coraco-brachialis and short head of the biceps, and to the triceps, and av twig to that groove in which the ten- don ofthe long head of the bicep lies. Thirdly, It sends large branches to the sub-scapularis, to the long head of the tri- ceps, &c. And, lastly, The artery, far from being exhausted by these branches, goes round the bone, turns over the joint under the deltoid musclej and ends in a great number of branches, still accompanied by branches of the nerve, which are distributed in part to the capsule, but chiefly to the lower surface of the deltoid muscle, where it lies upon the joint. 7. ARTERIA CIRCUMFLEXA ANTERIOR. The anterior circumflex artery, which goes round the forepart of the joint, bears no kind of proportion to that great artery which passes round the back. The anterior goes off from the same point nearly with the posterior, or sometimes arises from the posterior itself; it takes a direction exacily'op- posite; it keeps close to the shoulder-bone, passes under the heads ofthe coraco-brachialis and biceps; encircles the head of the os humeri just at the root of the capsular ligament, and goes round till it meets and inosculates with the posterior cir- cumflex artery. I never could find those muscular branches which are said to go the scapula, or have found them very tri- vial ; the whole artery belongs to the bone and its parts; it encircles the root of the capsule with a sort of coronary arte- ry ; it gives twigs to the capsule, the periosteum, and the ten- dons, which are implanted into the head of the bone; and ♦ OF THE AXILLARY ARTERY. 143 having given twigs to the heads of the biceps and coraco-bra- chialis, it gives off its only remarkable branch, which is indeed regular and curious; it is a small branch which runs down along the bone in the groove in which the tendon of the bi- ceps lies. Concerning the axillary artery in general, there is more to be observed than this occasion will allow. But these things must not be passed over in total silence. In the first place, the artery, as it passes over the border of the chest, and after leav- ing the arch ofthe clavicle, is felt beating, and there it can be compressed. The compressing of the subclavian artery with a tourniquet or with the thumb, attracted at one time so much attention, and incited so many to speak about it, that it came to be thought important, and has been ever since esteemed practicable ; and yet even those who have spoken the most confidently have ta- ken the thing merely upon vague report, have neglected to read the proper books, have described the way of compressing as above the clavicle, not knowing that it should be done below it. Camper, in his " Fabrica Brachii Humani," first mention- ed what he had demonstrated in his class, viz. that he could, by placing the thumb under the point of the coracoid pro- cess, so compress the axillary artery against the second rib where it lies upon it, that even the strength of a syringe could not push an injection through it.* And those who learn things by hearsay, have said that " the subclavian artery could be compressed by thrusting the thumb in above the clavicle ;'; al- though, in fact, the arch is so deep, the muscles so strong, and the artery so little exposed, that this is absolutely im- possible. From my speaking with a seeming interest about the pre- ference of one of these two places to the other, it may be thought that I believe this piece of knowledge useful: quite the reverse ! I know it to be dangerous; I know it to be less fracticable than authors report and believe; and I repeat what said on a former occasion, that " it is easy to stop the pulse of an artery, but quite another matter to stop the flow of blood * In cadaveribus plus semel in publico theatro monstravi, comprimi posse ititegram arte- riam ; lie.ibam arteriam aortam infra arcum, resecabam deinde axillarem dextram ac si- phone axillan sinistra? adaptala fortiler nquam impellens, solo digito eo modo moderare potui subclaviam, ut ne gutta quidem efflueret: qood quanti momenti esse queat in ampu- tationehumeri in arbeulonemo non videt In vulneribus sdopetariis, aliisque circa himieri arUculum mflictis, sanguinis profusionem similiter compescrre, si non penitus -Merc nosse- T • li* -e/V"/ the arm; it passes^f^K^pr the pronator muscle, emerges from under it above the middle of the arm, follows the long tendon of the supinator, and runs under it down to the root of the thumb ; it is at the root of the thumb only that it divides into its great branches : and a clear proof that in its course down the fore-arm it gives off none but small and irregular muscular branches, is this, that it preserves almost an equal diameter in all its progress from the elbow to the wrist. This is the artery which lies naked upon the radius at the wrist, where we feel the pulse. It lies more superficial, less imbedded in muscles, than the ulnar artery; for six inches above the wrist there is to be felt nothing but the naked arte- ry, the sharp tendon of the supinator, and the bone. The ra- dial artery, as to its course down towards the wrist, is direct; but with regard to itself, it is tortuous, with short and gentle wavings. Of its branches, as it moves down the fore-arm, there is not one that is worthy to be named. First, it gives a branch to the supinator, and to the extensors of the carpus: then it gives the radial recurrent, already described; then, having gone a little deeper among the muscles, it repeats its branches to the supinator and extensors; but being deep, it gives also twigs to the pronator and to the flexor radialis, inos- culating with the interosseous arteries. Next the radial artery, emerging from among the thickest,of the muscles ofthe fore- arm, becomes superficial, touches the naked radius, and runs OF THE FORE-ARM. 157 along it, with the belly of the flexor pollicis below it, and the long tendon of the supinator above it. Here are no muscles lying on the outside 01 it, nothing but the tendon; and there- fore all its twigs are downwards ' to the flexor pollicis, upon which it lies ; to the flexor digitorum, which lies next to that ; and to the flexor radialis and the palmaris longus. Next it gives deeper branches, viz. to the pronator quadratus; and al- so it gives small twigs, which accompany the several tendons along the naked bone. Arrived at the wrist, it does not divide, as authors have represented, into two branches, viz. a palmar and a dorsal artery; this is indeed a very rare occurrence : the radial artery passes on undivided to the root ofthe thumb, and there divides into three great branches; one to the thumb, one to the fore-finger, and one to the palm of the hand: it does, indeed, while it is passing the wrist, give two considerable branches, one to the palm, and one to the back of the hand; yet they are but branches. ARTERIA SUPERFIC1AL18 VOLiE. The first branch, then, of the radial artery, after arriving at the wrist, is that which goes across the palm of the hand, and may be named the superficial artery ofthe palm. It goes off just where the main artery is about to turn over to the back of the hand ; it passes in general through the flesh of the thumb, going under the root of the abductor brevis polli- cis. This artery we generally find dividing into three branch- es : The first is a more superficial branch, which crosses the palm of the hand, and gives its twigs to the skin, palmar apo- neurosis, annular ligament, and all the tendinous parts about the joint: The second is a larger and more important branch ; it is the middle branch of these three ; it goes deep ; and having given several branches to the muscles about the root of the thumb, and to one or two of the interossei muscles, it makes a large inosculation with the great palmar arch, which seems to be indeed the chief tendency of the whole artery : The third branch is less regular than the others; it mounts along the root of the thumb, and belongs to its outer edge.* The next branches of the radial artery are very small and nameless twigs, which go to the naked part of the wrist, to the tendons, ligaments, and the bones; and then comes the * This hranch anatomists have thought fit to call arteria ulnars radialis polmcis, which involves such a complication of contradictions, that, ugon reading it, one would na- turally turn to the tahle of errata. The artery is called radialis, because it conies from the radial artery; aDd ulnar'? pollicig, because it goes upon the ulnar side of the thumb. 158 OF THE ARTERIES artery opposite to this artery of the palm, viz. the artery of the back of the hand. ARTERIA DORSALIS CARPI. The artery of the back of the hand comes off from the radial, just after it has turned over the radial edge of the wrist. It takes its course directly across the back of the hand, over the carpal bones ; and by its frequent inosculations with branch- es from the ulnar artery, and with the dorsalis metacarpi or dorsalis manus, it makes beautiful net-works across all the na- ked part of the back of the hand. OORSALIS META'CARPI. The radial artery, continuing its course under the exten- sor tendons of the thumb, sends off the dorsalis metacarpi, which is an artery generally larger than the last; it takes its course across the back of the hand and over the metacarpal bones, and from this artery are given off the interosseous ar- teries. The first interosseous artery of the hand is large, long, goes up in a direct course to the fork betwixt the fore and mid-fin- gers, and plunges into the cleft of the digital artery at right angles with it. A second twig like this, and then a third are given off; named the first, second, and third interosseous arte- ries : but they are all smaller than the first, and all the three communicate with the arteries from the palm. Before the final division ofthe radial artery* into its three branches, it gives a third artery, or, as often happens, two arte- ries, to the back of the thumb. arteria dorsalis pollicis. The small artery, or the two small arteries, which, from going along the back of the thumb, are named arteriae dor- sales pollicis, come off either along with, or immediately after, the dorsalis carpi. When there are two, they run both along the back of the thumb, one on one side, the other on the op- posite side ; that which runs along the outer edge of the * Notwithstanding the inconsistency of retaining the name of radial artery, after the ar- tery has passed the wrist, and begun to run along the thumb, I venture to sacrifice verbal accuracy, and would make much greater sacrifices to obtain a clear arrangement. OF THE FORE-ARM. 159 thumb passes through under the tendons, and is rather shorter; that which inclines to the inner side of the thumb is rather longer. These small arteries on the back inosculate round the edges of the thumb with the great artery on the inner side; which is next to be described. Thus we have seen that the radial artery, having advanced to the wrist, turns quick around the wrist, over the head of the radius, and under the tendons of the thumb; it gives imme- diately before it passes, the artery of the palm ; it gives im- mediately after it passes, the artery ofthe back of the wrist; it gives immediately after that, the artery to the back of the hand ; and then the little arteries for the back of the thumb ; it then mounts along the thumb in that hollow which is by the side of the metacarpal bone of the thumb, till it arrives at the cleft betwixt the thumb and fore-finger. Here it divides into three arteries; one to the inner side of the thumb, very large ; another to that side of the fore-finger which is next the thumb, which branch is much smaller ; and one which exceeds these in importance, for it dives down into the palm of the hand, forms what is called the deep arch of the palm; and which, having crossed the palm, forms on the side next the little-finger that inosculation betwixt the upper and lower arches which is so much celebrated. ARTERIA RADIALIS INDICIS. The artery of the fore-finger proceeding from the radial artery is the first and smallest of these three branches. It goes off at the root of the metacarpal bone of the fore-finger, goes up along its interosseous muscle, and runs along all the edge of the fore-finger next the thumb, inosculating with the artery of the opposite edge, which comes from the ulnar arch ; it sends off twigs at its root, which inosculate with the small dorsal arteries of the thumb ; and it gives a branch to the ad- ductor indicis. ARTERIA MAGNA POLLICIS. The chief artery of the thumb rises along its metacar- pal bone, a single artery, and there splits commonly, I think, into three smaller branches. Two of these run along the fore- part of the thumb up to its extremity, and inosculate there ; the one running along the radial, the other along the ulnar side, till they meet at the point. These are, as it were, coun- 160 OF THE ARTERIES ter-parts of the dorsal arteries,.but greatly larger, the thumb being naked on the back; but fleshy where it looks towards the palm. Another branch of the arteria pollicis is one which turns to the palm of the hand, and runs towards the fore-fin- ger- ARTERIA PALMARIS PROFUNDA. The third branch of the radial artery and that by which it ends, immediately succeeds the artery ofthe thumb. It cros- ses the palm of the hand so as to form the deep arteria] arch, or the radial arch of the palm ; it lies under the aponeurosis, and all the tendons and muscles close upon the metacarpal bones. Having gone its circle so as to complete the arch, and having arrived at the root of the little finger, or rather lower, near the pisiform bone, it turns backwards with a sudden ser- pentine turn, and enters into the side of the ulnar arch, so as to make a complete inosculation. This deep palmar arch gives out many arteries; but as it lies close upon the bones, they are all ofthe smallest order of arte- ries, and go only to the bones and to the joints of the carpus and metacarpus. Those branches again, which run upwards, give little arteries to the interossei muscles, to the lumbricales, to the long tendons, and to the interstice of each bone. Small twigs are sent through to the back ofthe hand, which are named arteriae perforantes, and which inosculate with the dorsalis car- pi, or artery of the back of the wrist ; they also inosculate with the arteries ofthe fingers. ARTERIA ULNARIS. The ulnar artery, both from its size and its direction, is to be considered as the continued trunk of the humeral ar- tery. It dives downwards and backwards into the triangular hollow which has been described, till it touches the interos- seous membrane : it first gives off a small branch to the prona- tor teres and common origin of the flexor muscles, before it passes through them : sometimes it gives off here the recur- rent which should come from the interosseous artery ; in which case that branch, as it passes backwards through the interos- seous membrane, is named interossea posterior suprema. Next the ulna gives off the proper interosseous artery, which i* named interossea communis, because both the anterior and posterior arteries are branches of it. Then the ulnar artery, OF THE FORE-ARM. 161 lodged deep under all the muscles which go off from the in- ner condyle, as the palmaris, pronator teres, flexor ulnaris, &c. perforates one of them, viz. the flexor digitorum. But though it passes through betwixt the upper and lower flexor, it does not, like the radial, appear immediately as a superficial artery; it shows itself only about three inches above the wrist. The ulnar artery, running along by the tendon of the flexor carpi ulnaris, passes forward from the wrist to the palm of the hand by the side ofthe pisiform bone; it then forms the superficial arch ofthe palmar arteries, and supplies all the fingers, as the radial supplies the thumb. The arteries which the ulna gives out after it passes through the muscles, and before it arrives at the wrist, are merely muscular branches, extremely variable in size and number. To enumerate these, would be but to repeat the names of all the muscles which lie upon the flat part of the fore-arm. As the radial sends a branch over the back of the hand, named dorsalis radialis, so does this send a branch round the back of the little finger named dorsalis ulnaris. arteria dorsalis ulnaris. The dorsalis manus ulnaris, is a small branch which goes off from the ulnar artery as it advances towards the wrist. The ulnar artery goes forwards towards the pisiform bone, while this little artery turns off about two inches below, pas- ses under the tendon of the flexor ulnaris, and round the head of the ulna, to the back of the hand ; it then goes upwards along the back of the little finger, where it ends. It gives branches as it passes along to the pronator quadratus, to the extensor ulnaris, to the joints about the lower part ofthe wrist, and especially to the joining of the radius with the ulna ; and it finishes on the back ofthe hand by arteries given to the tendons and capsule, by inosculations with the rete which is formed upon the back ofthe wrist, by the radial artery, and by giving the dorsal artery of the little finger. Next the ulnar artery, before it begins its arch, gives small branches to the flexor tendons and forepart of the wrist; others to the pisiform bone, to the annular ligament, and to the pal- maris cutaneus, and then branches to the flexor, abductor, and adductors of the little-finger; or, in other words, to all that mass of muscular flesh which surrounds the root of the little- finger; and still, before it begins to bend into an arch, and just beyond the pisiform bone, it gives off that branch which may be called arteria palmaris profunda, vol. ii. X 162 OF THE ARTERIES ARTERIA PALMARIS PROFUNDA. The description of this artery is shortly this : It is but a small artery; it comes off a little lower than the pisiform bone; it often gives the last lateral artery of the little-finger; it then turns downwards and backwards with a large circle, passes through betwixt the two heads of the flexor digiti R. It comes off from the hepatic artery just be- fore it divides, or immediately after from the left hepatic. It turns backwards at an acute angle to the lesser arch of the stomach and having given small twigs to the omentum minus, it goes directly to the pylorus, inosculating with its upper and lower arteries. hepatica sinistra. The hepatic artery, now advanc *d to within about two inches of the liver, divides into its two great arteries. Both go to the porta of the liver; but the one belongs to the right lobe, the other belongs to the left. The artery which belongs to the left lobe of the liver is smaller, and when there is an hepatic artery from the stomach it is very small; it mounts over the vena portae, and enters into the liver at the fossa umbilicalis; its branches within the liver go chiefly to the left lobe, lobulus Spigelii and anonymous lobe. hepatica dextra. The right branch of the hepatic artery passes under the biliary ducts, enters along with them into the right lobe of the liver, and before it does so it gives off the arteria cystica, or artery of the gall-bladder, one of the most beautiful little ar- teries in the body. The cystic artery branches over the gall- bladder, betwixt its coats, in the form of a coronary artery, and having made a beautiful tree of branches over the gall-blad- der, it passes off from it, and goes to the substance of the liver. ARTERIA SPLENICA. The splenic artery is one ofthe most remarkable in the human body. The spleen is tied down to the left side of the diaphragm by a proper ligament; it is also connected with the greater or bulging end of the stomach by processes of the" omentum and by vessels. The splenic artery, the largest branch ofthe coeliac, as large as a goose-quill, turns off from the coeliac trunk almost at right agles, and runs across the ab- domen to get to the spleen. It is in all this course exceeding- ly tortuous; it runs along the upper edge of the pancreas, (which also lies across the abdomen,) andgives arteries to it j 176 OF THE ARTERIES when it approaches the spleen, it gives off that great artery which returns along the lower border of the stomach, and when it actually arrives at the spleen, it divides into a great many branches, which enter by the concave surface of the spleen, and plunge into its substance. The branches, then, of the splenic artery, are these : 1. It gives a great artery to the pancreas named pancreatica mag- na, which passes to the right under the pancreas, and belongs chiefly to the head ofthe pancreas, or that rounded end which is next to the duodenum. Though named magna, it is a varia- ble artery, and of little importance. 2. All along, as the splenic artery is passing to the left by the border of tbe pancreas, it sends short branches into it. They are named pancreatic^; parvje, or small pancreatic ARTtRiEs. 3. It often sends small arteries upwards to the back part of the stomach, named POSTERIOR GASTRIC ARTERIES. 4. The GASTRO-EPl' LOICA SINIS- TRA, or tbe left gastro-epiploic artery is a very large and prin- cipal branch ofthe splenic artery. It arises under the stomach, a little beyond the left or larger head of the pancreas; it makes a large arch, and then turns with a serpentine turn to- wards the stomach, returns along the lower border of the sto- mach, within the doubling of the omentum, and gives its arte- ries upwards to the stomach and downwards upon the omen- tum, so much like those of the right gastro-epiploic artery, that when they meet in the middle ofthe great arch of'the stomach, and: inosculate, we cannot distinguish where either of them ends; the chief difference is, that some of the epiploic branches of this artery are particularly large. 5. The vasa brevia are a set of three or four arteries which the splenic gives off just before it enters into the spleen; and as the.arte- ry lies close to the stomach, these arteries which go to the great bulging of the stomach are exceedingly short, and are thence named vasa brevia. The artery ends by eight or ten branches, which plunge into the spleen. Sometimes we see the artery pass, almost undivided, or divided into one or two branches only, into the bosom or sinus of the spleen. These are all the arteries ofthe stomach, liver, and spleen. the viscera which fill the upper region of the abdomen. OF THE ARTERIES OF THE INTESTINES. OF THE UPPER AND LOWER MESENTERIC ARTERIES. The bowels are so disposed within the abdomen, that the Targest of them, viz. the colon, the great intestine, encircles ©F THE INTESTINBS. 177 all the others. It begins on the right side in a blind sac call- ed the caput coli, or head of the colon: it goes upwards, and crosses the belly, so as to support the stomach, and sepa- rate the stomach, liver, and spleen, from the small intestines: it descends again into the pelvis at the left side, forming the rectum; and all the small intestines hang by their mesentery in the central part of the abdomen, surrounded by this great intestine; and the arteries lie within the two lamellae of the mesentery or supporting membrane of the intestines, so that they are called mesenteric arteries; and they follow the in- testines in the order in which I have named them. The GREAT Or SUPERIOR MESENTERIC ARTERY gives its first branches to the caput coli; its next branch to the middle of the colon under the stomach ; the thousand turns of the small intestines next absorb all its other branches. The lower mesenteric artery, which gives no branches to the small intestines, attaches itself to the left side, and especially to the lowest part of the colon, and goes down with the rectum into the pelvis, and ends there. This, then, may serve as a gene- ral plan or arrangement for the intestines and for the two mesenteric arteries. 1. mesenterica superior. * It is not surprising that the upper mesenteric is the largest cf all the abdominal arteries. It arises from the aorta, where it is still betwixt the legs of the diaphragm, and not more than half an inch below the coeliac artery. The coeliac and mesen- teric arteries lie close upon each other; only we are less sen- sible of their nearness by the axis coeliacae jutting perpendicu- larly forwards, and by the trunk of the mesenteric running very obliquely downwards, and by the head of the pancreas lying immediately over, the mesenteric and hiding its root. The trunk of the mesenteric artery passes under the pancreas, then through the mesocolon or mesentery of the colon, then into the proper mesentery of tbe small intestines. It turns first to the left; and then, by a second gentle bending, it turns again towards the right side of the abdomen. It runs very low into the abdomen before it gives out any branches; and then it gives them off in the following order. From the right side it gives branches to the great intestines, of which there are three chief arteries; but from the left side, where it gives arteries to the small intestines, it gives innu- merable branches, very large, and se inosculated with each YOh. n. 21 178 OF THE ARTERIES other, that they form a sort of mesh or immense plexus in the mesentery before they go onwards to the guts. The undivided trunk of the arterv is very large and long; the gentle curva- ture of it from left to right, gives it the form of an Italic /; the prodigious size of that mesh or plexus of vessels which goes to the great intestines is such as to carry the artery down to the left ilium or flank, where the caput coli or conjunction of the ilium with the colon lies. It is from the convex of this gently bending arch, and from . the right or outer side of the artery, that the following arte- ries to the great intestines go off* The colica media to the middle of the great intestine, the colica dextra to the right side of the great intestine, the ileo-colica to the joining of the ilium with the caput coli or beginning of the great intestines* colica media. 1. The middle colic artery passes along in the doubling, («. e.) betwixt the two lamellae of the mesocolon. It goes with a circular sweep upwards towards that part or corner (as we may call it) of the colon which lurks under the liver; but be- fore it touches the intestine, and generally at the distance of about three or four inches from it, this arteiy divides into two great branches ; one turning backwards, along the right side of the colon, inosculates with the colic arteries: the other, more like the continued trunk, turns upwards, bending ac- cording to the curvature of the arch of the colon, which sup- ports the stomach ; and having rounded the concave of this arch, and arrived at the left side, it there makes a great inos- culation with the left colic artery, which is a chief branch of the lower mesenteric ; and so completes the great mesenteric arch, one of the most celebrated inosculations in the whole body, that of the circle of Willis hardly excepted. colica dextra. 2. The right colic artery is enumerated as a distinct ar- tery chiefly for the sake of plainness; for though sometimes it arises apart from the general mesenteric trunk, yet in ninety- nine of one hundred bodies it proceeds from the upper or middle colic artery. It is a very large branch; it is set off * Often before giving off its greater arteries, the mesenteric gives to the pancreas several small arteries; and to the duodenum two or three, which are sometimes named under the title of duodenales inferiores. OF THE INTESTINES. 179 from the colica media at a very acute angle ; it moves along the right side of the colon, inclining also a little upwards to- wards the liver; it also splits when it approaches the gut into two branches ; one turning towards the upper side to inoscu- late with the middle colic artery, the other turning downwards towards the ilium or flank to inosculate with the ileo-colic artery. arteria ileo-colica. 3. The ileo-colic artery arises about an inch lower than the last. It is a long, small, and slender artery compared with the two last; which are short, stumpy, and with contorted angles. This artery goes to the place where the small intes- tines end, and the great ones begin ; of course the membrane which holds the intestines at this corner (I mean in the right haunch) changes its name from mezzo-colon (in the middle of the colon) to mesentery, or mezzo-enteron (in the middle* of the intestines;) and of course the ileo-colic artery runs down, not along the mesocolon but along the mesentery. It goes directly down towards the joining of the ilium with the colon; it ends in three regular branches; one passes straight onwards to the junction of the ilium and colon, splits into two branches, one going over the fore and the other over the back part of the caput coli, and having a very curious correspon- dence with the valve within, so that it might be called arte- ria valvil.se coli. While this branch goes straight for- wards over both sides of the caput coli, another branch runs backwards along the colon, and inosculates with the right colic artery; and another runs downwards along the ilium, and inosculates with the common branches of the mesenteric artery. It is from these two branches, which diverge like the rest of the colic arteries, that this is called ileo-colica. Even the appendix verniiformis has its little mesentery tying it down to the caput coli, and from the back of the caput coli a little artery runs down upon that mesentery to the appendix, passing along the whole length of that process. From this point all the remaining arteries of the mesen- terica superior go to the small intestines ; and they are so un- distinguished, and so prodigiously numerous, that no branches can be described or named ; there is nothing but a great net- work of arteries to describe. The first or radical branches whicii go to the small intestines, are thick, large, short, and vary from twelve to fifteen or twenty in number. But it is not 189 OF THE ARTERIES these that make this vast appearance of a net-work; these twelve branches are first joined to each other, as it were mouth to mouth, forming one great confluence of arterial arches : from these, secondary branches arise, and they unite again in like manner, and make a second row of arches; from the union of these still other arteries arise, and make a third, or fourth, and even a fifth, row of arches, before any arte- ries go to the intestines ; till at last the proper arteries of the intestines go out in straight lines from the last arch, and spread upon the coats of the intestine. In short, the mesentery has a very intricated and matted appearance; from the redoub- ling of these arches, which are more and more numerous as the artery proceeds lower, till the last of the twelve radical branches makes an arch, which serves the ileon or lowest of the small intestines, and inosculates with the ileo-colhs ARTERY. 2. MESENTERICA INFERIOR. The lower mesenteric artery is that which is nam- ed by Haller the left colic artery, because it goes only to the left side ofthe colon. It arises from the forepart of the aorta, below the two emulgent arteries, (i. e.) pretty low down. It goes off rather from the left side ofthe aorta; it goes off very obliquely, and keeps close to the left side of the aorta for a great way; and when it has descended as low as the bifurca- tion ofthe aorta, it gives off its great branch to the left side of the colon, viz. the left colic artery; and then turning down over the iliac artery of the left side, it descends into the pelvis, along with the rectum, and ends there. ]. Its first branch is the arteria colica sinistra. The lower mesenteric has run a considerable length, has passed as low as the bifurcation ofthe aorta, before this branch is given off. This artery soon divides into three large branches; the trunk itself is short and stumpy, the branches go off like those of the other side, at very acute angles : First, One branch ascends towards the angle of the colon, under which the spleen lies, and there divides itself into two branches ; one keeping closer to the intestine, nourishes it; the other keeping more to the middle of the mesocolon, or broad mem- brane of the colon, meets the branch of the upper mesen- teric, and completes with it the mesenteric arch, being indeed the larger and more important artery of the two. Secondly, Another branch goes directly across the right side ofthe colon, and when it approaches the gut, splits (as usual with the colic arteries) into two lesser branches, one turning upwards and the OF THE INTESTINES. 181 other downwards. Thirdly, The third branch of this left colic artery goes obliquely downwards to that part ofthe gut which lies in the hollow of the left haunch-bone, and which forms the turn named sigmoid flexure of the colon; and the membrane of the colon is here so fast braced down to the loins that this artery gives twigs to the loins inosculating with the lumbar ar- teries. ARTERIiE HJEMORRHOIDALES. The internal h«morrhoidal artery is one of considera- ble size ; it is just the trunk of the lower mesenteric artery, descending into the pelvis; it is often as large as a writing quill; it applies itself closely to the back part of the rectum ; it arrives at it by turning obliquely over the pelvis, and under the rectum, and passes down its whole length quite to the anus. It encircles the rectum completely on each side with its large branches, which meet again upon the forepart of tbe gut, and its branches lower down in the pelvis inosculate with the mid- dle hemorrhoidal artery, and sometimes with those of the bladder and womb. This is the artery which prevents us from operating when a fistula in ano has gone deep by the back of the rectum ; and which has given occasion to the esta- blishing of something like a general rule in surgery, that one should not operate when the fistula is more than two or three inches deep. It is the last of the arteries belonging to the loose and floating viscera. OF THE REMAINING ARTERIES OF THE ABDOMEN, VIZ. TO THE KIDNEYS TESTICLES, &C. ARTERIJE CAPSULARES. The capsuh-e atrabiliariae are two small bodies of a triangu- lar form, of thick walls and small cavities, filled in general with a black and bilious-looking liquor. The ancients thought this the atrabilis, and named them the capsulae atrabiliariae: the moderns, from seeing them placed immediately above the kidney, and observing no apparent connection but with that gland, have named them capsulae renales. They lie then above the kidney surrounded with fat, have straggling arteries from various sources, but none regular nor important. First, They have very generally soaae small branches from 182 Ul THE ARTERIES OF the phrenic arteries. These are the highest of the capsular arteries; they touch the uppermost point of this glandular body. They are named the upper capsular arteries. Secondly, They often have small arteries from the aorta pe- culiar to themselves, which come off about the root ofthe up- per mesenteric artery, go to the fat and glands, and play over the vena cava, (at least those of the right side do,) and go to the middle parts of the gland, whence they are named caf- sulares medie. Thirdly, They have their last arteries sent upwards to them from the emulgent artery, or artery of the kidney. They are named the lower capsular arteries. ARTERIA RENALES. The two renal or emulgent arteries, the two arteries of the kidneys, go off from the sides ofthe aorta, midway betwixt the upper and lower mesenteric arteries. Each goes to its kidney almost at a right angle, arching a little over the bulg- ing belly of the psoas muscle. The aorta is still a little in- clined to the left side, and so the left emulgent is shorter, and mounts over its accompanying vein; while the right kidney, being further off from the aorta, and somewhat lower, on ac- count of the liver being on that side, the right artery is longer, and is covered by its emulgent vein. When the emulgent ar- tery, which is short and very thick, arrives at the concave edge of the kidney, it is divided into three or four large branches which surround the pelvis, or beginning ofthe ureter, plunge into the substance of the kidney, and inosculate and make arches with each other. Then they, in supplying the kidney within its substance, form circles and arches over the roots of the papillae uriniferae. Before the emulgent arteries enter into the substance ofthe kidney they usually give off small arteries, as has been already mentioned, to the lower part ofthe capsulae renales, to the up- per part of the ureters, and to the fat surrounding the kid- neys. ARTERIA SPERMATICA. The spermatic artery, or artery ofthe testicle, is one of the most singular, both for its extreme smallness and great length, and for its important office. It. arises on each side from the lateral parts of the aorta; a little above the lower mesenteric artery. The left spermatic artery rises somewhat OF THE FIXED VISCERA. 185 higher, and often comes from the emulgent artery; it de- scends from the aorta almost in the same line with itself* it crosses the vena cava, and meets its accompanying vein upon the surface ofthe psoas muscle; it then forms the spermatic cord •and passes obliquely through the spermatic passage and abdo- minal ring ; before it goes down into the testicle, it gives out many very small twigs. First, It gives small twigs to the fat of the kidneys; Secondly, It gives small branches to the ure- ters ; Thirdly, Small twigs to the peritoneum ; and lastly, Small twigs to nourish the spermatic cord itself. When it has passed through the ring, it soon after divides into many small arteries for the several parts of the testicle, four or five in num- ber ; two of which go to the epidydimis, and two others, par- ticularly large, go to the testicle ; the largest of these branches turns round the testicle in a beautiful and serpentine form waving along the upper part of the testicle, viz just under the epidydimis, and sending beautiful coronary branches down- wards all over the semicircle or convex surface of the testis. These are the chief arteries, viz. those of the kidney and testicle. Those of the renal capsule I hold to be so irregular, that they hardly deserve the short description which I have given of them. The following classes of small and irregular arteries are equally insignificant; for few authors have been at the pains to enumerate the arteries going to tbe fat of the kid- ney ; and none (except Murray) have been at the pains to gather together into one class or description the trifling arte- ries of the ureter. ARTERIiE ADirOSiE. The arteries of the fat of the kidney are extremely small but numerous. The upper arteries come from the cap- sular and diaphragmatic arteries which are above the kidney; the middle arteries of tbe fat come from the renal artery itself from the spermatic, or even from the aorta ; the lower arte- ries come from the colic arteries, and one from the spermatic, which comes off below the kidney, and turns up towards its' lower end. ARTERIA URETERICJE. As the ureter is a long canal, its arteries come off from va- ious parts which it passes. Its upper arteries are from the enal artery itself, before it enters the kidney; and also from 184 OF THE ARTERIES the capsulars and spermatics. The middle arteries of the ure- ter are more particular and more important: they arise either from the aorta itself, or from the iliac artery, where the ureter crosses it; and they run far both upwards and downwards, along the canal. The lowest arteries of the-ureter arise from* those of the bladder itself. ARTERIiE LUMBARES. The lumbar arteries are those which succeed to the in- tercostal arteries, and which run parallel with them ; perform- ing the same office in the loins which the intercostals do in the thorax, viz. nourishing the spine and the muscles. The lumbar arteries arise from the sides of the abdominal aorta. The first arteries go off at right angles; the lower ones are a little inclined downwards. The right ones are longer, because they have to rise over the spine. The arteries of both sides, as soon as they have left the spine, sink under the psoas muscle, and go onwards behind, round the side, till they ter- minate in the lateral muscles of the abdomen. The upper- most lumbar artery is large ; and as it runs along the lowest rib but one, of course it gives arteries both to the transverse or innermost muscle of the belly, and also to the diaphragm, which indigitates with it in consequence of their both taking their origin from the same ribs. The two lower lumbar arte- ries are small, and begin to inosculate with the lesser arte- ries about the top of the pelvis. Each lumbar artery gives out like each intercostal two chief arteries : 1. One which goes to the spine, and which, splitting into two, gives a larger twig to the vertebra itself; and a smaller one, which enters the sheath, lies by the nerve, and passes into the spinal marrow. 2. A muscular branch, which is also di- vided ; for one branch of it supplies the psoas muscle, and then runs round within the muscles of the abdomen; while the other pierces the back, and supplies the sacro-lumbalis, longis- simus dorsi, and other muscles of the loins. ARTERIES OF THE PELVIS. The aorta divides into two great arteries, named iliac arte- ries. The two iliac arteries move downwards to the brim of the pelvis, where they meet the veins of the lower extremity ascending to form the cava, and also a vast plexus of lym- phatics from the legs and pelvis, whieh twist round the arteries OF THE PELVIS. 185 and veins. The two iliac veins lie upon the inner sides ofthe two arteries; and since these veins meet on the right side of the aorta to form the cava, of course the right iliac artery crosses the trunk of the cava. This bifurcation of the aorta is much higher than the pelvis; it begins upon the fourth ver- tebra of the loins, so that the abdominal aorta is in truth ex- tremely short, and the iliac arteries go off at such an angle, that they diverge very gradually; so that when they arrive at the top of the pelvis, they are just over the joining of the haunch-bone with the sacrum : and it is but a very little below this again that they divide into their two great branches; the one, named the external iliac, which passes straight forwards into the thigh ; the other, the internal iliac, which dives im- mediately down into the pelvis to supply the internal parts. arteria sacra media. The bifurcation of the aorta gives off only one artery, which proceeds exactly from the fork; and being in the middle, it is a single or azygous artery, which has not a fellow. It is small, long, very regular, and passes down so correctly in the middle of the bone, that it is named the middle sacral artery. It is about the size of a crow-quill; passes directly over the mid- dle of that projecting point which is named the promontory of the sacrum ; it descends expressly in the middle of the bone, quite to the point of the os coccygis. At the place of each vertebra (for the sacrum consists of vertebras now united to- gether,) it gives off cross branches, which go across the body of the sacrum to inosculate with the lateral sacral arteries. Besides these, it gives arteries to the substance of the bone, and not unfrequently small arteries to the rectum. This arte- ry ends near the point of the os coccygis in a forked or double inosculation with the lateral sacral arteries of each side. iliaca interna. The internal iliac artery is of vast size; it not only supplies all the parts within the pelvis, but sends out by the several openings of the pelvis those great arteries which sup- ply both the private parts, and the immense mass of muscle which surrounds the haunch. Thence the necessity and use- fulness of arranging them under two classes: first, of the lesser arteries which go to parts within the pelvis, as to the loins, to vol ii. A a 186 OF THE ARTERIES the sacrum, to the bladder, and to the womb ; and secondly, those larger arteries which go out through the several open- ings ofthe pelvis, the hips, the haunch, and the private parts. This artery we cannot describe in the adult, without attend- ing to its condition and function in the child ; for it is that in- deed which gives it the peculiar form which we have to de- scribe ; and which especially gives it that arch downwards, from the convexity of which all the great branches go off. For in the child, the internal iliac or hypogastric artery is extreme- ly large : first, it turns down into the pelvis with a large circle; then it goes close to the side of the bladder very low into the pelvis; then it begins to rise again by the side of the bladder, out of the pelvis, and going along by the urachus (which is a tube or ligament rather leading upwards from the bottom of the bladder,) it goes out by the navel, forming the umbilical artery. Now this sudden turn by tbe side of the bladder makes the artery convex downwards (i. e.) towards the parts which it has to supply. The artery keeps this same form in the adult; both in the child and in the adult all the great branches come off from the back of this arch. ORDER FIRST. The branches of the hypogastric or internal iliac artery, which remain within the pelvis. 1. ileo-lumbalis. This artery is so named, because it so resembles the lumbar arteries that it "might be mistaken for the last of them ; and because it belongs equally to the haunch-bone and to the loins. It goes off from the outer side of the iliac artery, about an inch below the bifurcation ; it is about the size of the lumbar arteries, or a little larger; it turns in behind the iliac artery, and passes under the psoas muscle ; its trunk is short, for it splits immediately into its iliac and lumbar branches. The lumbar branch goes off betwixt the last ver- tebra of the loins and the inner end of the ilium, and goes directly upwards ; it gives its branches about the psoas muscle. The iliac branch setting off from the same point, runs straight outwards, lodges itself under the edge or crista illii, and sup- plies the iliacus internus muscle by a superficial branch ; and it nourishes the bone by a deeper branch, which lies close i» the hollow of the haunch. OF THE PELVIS. 187 2. ARTERLE SACRiE LATERALES. The lateral arteries of the .sacrum are very generally three or four in number. Sometimes we find one general ar- tery coming off from the iliac, or from the ileo-lumbar artery, running down all the side of the sacrum, and giving off the lateral sacral arteries; but much more frequently we find three distinct arteries coming off from the sides of the iliac artery, which run across the sacrum in the following manner, to in- osculate with tbe middle sacral artery : First, each lateral sacral artery has one large branch, which runs along the fore- part of the sacrum, runs along the naked bone, and inoscu- lates with the middle sacral artery : Secondly, another branch, still larger, dives into each of the sacral holes, which not only nourishes the nerves, and the sheath ofthe cauda equina, and the bone itself by one branch, but penetrates by another branch through the posterior sacral hole, and supplies the periosteum, the great ligaments which join the ilium to the sacrum, and the root also of the sacro-lumbalis, and glutaeal muscles. From these two branches, (viz. to the spine and to the posterior muscles,) and from the regularity of these five arteries, (going from some artery or other into each sacral hole,) they resemble the intercostal and lumbar arteries, to whose office and place they have succeeded. ARTERIA HYPOGASTRICA. The hypogastric artery is the umbilical artery, of great size and importance in the child ; and even in the adult it still remains, in this sense at least, that though the forepart of it (where it turn up by the side of the bladder) is closed, even that part is still known by a round ligamentous substance, into which it is converted, and which we easily trace up to the navel, where the artery meets its fellow of the other sidej. This artery is even in the adult body pervious down to the side of the bladder, where in Man it gives one long slender artery, sometimes two, which go to the sides of the bladder; and in Women, small arteries to the womb, sometimes to the rectum; but these branches are quite irregular in number and size. 188 OF THE ARTERIES ARTERIA VESICALES. The arteries of the bladder are extremely irregular both in number and size ; for it is to be considered, that the bladder being a round body placed amidst great arteries, and being itself membranous, and needing but few or but small branches, it gets them from various sources. Very generally the hypogastric, just before it closes into a ligament, sends one or more small arteries downwards and forwards to the neck of the bladder, at that part where the vesiculae semi- nales lie ; and of course the vesicuh': and the prostrate gland get small twigs from this artery of the bladder; sometime, also the bulb of the urethra has a small artery from it. ARTERIiE HfiMORRHOIDALES. The arteries of the rectum are all named haemorrhoidal ar- teries. The upper haemorrhoidal artery is the great branch of the lower mesenteric continued to the pelvis. The middle haemorrhoidal artery is one whicii sometimes comes from the hypogastric artery, but very often from the pudic artery, in- somuch as to be reckoned among its regular branches. The lower, or the external haemorrhoidal artery, almost always is a branch of the pudic artery, or that artery which goes to the penis. Two great arteries, one going to the rectum and another to the womb, are the last which the hypogastric gives off before it degenerates into a ligament. ARTERIA HiEMORRHOIDEA MEDIA. The middle hemorrhoidal artery is not a large branch. Often we do not find it, but other arteries supplying its place; sometimes again it is so large as to give off both the uterine and the lateral sacral arteries; but in general it is small. It comes off from the hypogastric opposite to the gluteal artery (presently to be described ;) it touches the rectum below its middle, and descends curling and winding chiefly along its forepart quite to the anus ; and often it gives, as it runs be- twixt the rectum and bladder, arteries to the bladder, pros- trate gland, and vesiculue seminales. It is this artery also, which in women, gives small branches to the vagina. OF THE PELVIS. 189 ARTERIA UTERINA. The womb has four arteries, two from each side ; the up- permost, that which enters by the upper corners of the womb, comes from the aorta, corresponds with the spermatic in Man, runs along the broad ligament towards the ovaria. The lower artery of the womb, and the largest, comes from the hypo- gastric, enters the womb, where it is connected with the vagina, and runs upwards along the sides of the womb to meet the spermatic; and it sends also at the same time branches downwards into the vagina, and forwards upon the bladder, where it adheres to this part of the womb. This uterine artery arises from the hypogastric near the origin of the haemorrhoidal artery, and when it enters the womb it becomes very tortuous. These, then, are the chief arteries of the rectum, blad- der, womb, vesiculae seminales, and other parts within the pelvis. ORDER SECOND. OF THE ARTERIES WHICH GO OUT FROM THE PELVIS TO THE HAUNCHES, HIPS, AND PRIVATE PARTS. In this second class or order there are just four great arte- ries ; one which goes over the back of the haunch-bone to the glutaeal muscle, named Glutaeal artery : one going down- wards over the tuber ischii to the hip, named the Ischiadic artery; one which goes out of the pelvis, returns into it again, and passes out a second time by the root of the penis, named the Pudic artery ; and one which passes out through the thyroid hole into the deep muscles at the top of the thigh, named Obturator artery. All these larger arteries go off from the convex of that arch which the hypogastric forms, and move backwards and downwards, in order to escape from the pelvis. Let it be remembered, that the iliac artery forks just at the meeting of the ilium and sacrum ; that the great sacro-sciatic notch is formed by this joining of the ilium and sacrum, and is just under the junction of these two bones : that the glutaeal artery passes out by this sacro-sciatic hole; and that of course it is the first, as well as the greatest, of those three arteries which turn backwards out of the pelvis. 190 OF THE ARTERIES ARTERIA GLUTiEA. The gluteal artery goes off from the internal iliac imme- diately after the lateral sacral arteries. It is exceedingly large, thick, and short, within the pelvis, for it immediately turns over the bone ; the turn which it makes over the naked bone is backwards and upwards; it instantly divides itself into a great lash of vessels, which spread in every direction, sup- ply the two glutaeal muscles, and turn and ramify upon the back of the haunch-bone, just as the great scapular arteries play over the surface of the scapula. The pyriform muscle goes out from the pelvis at the same great opening with the glutaeal artery, and the artery is further accompanied by the great sciatic nerve ; the artery and nerve pass together over the pyriform muscle, betwixt it and the bone ; and when the glutaeal artery is to give out its branches, it splits into two great branches at the edge of the glutaeus medius muscle. By this splitting the gluteal artery is arrang- ed thus: First, one great branch passes under the glutaeus medius, of consequence it is naked upon the back of the ilium ; it sends one large and beautiful artery, which courses round the bone according to the line of the crista ilri, which supplies all the upper half of the haunch-bone with its nutritious arteries, and supplies of course all the upper half of the great or outermost gultaeal muscle, where it arises from the spine and dorsum ofthe ilium. Another large branch, still belonging to this deeper artery, passes under the thickest part of the belly of the glutaeus medius, lies upon the small fan-like muscle named glutaeus minimus, and gives innumerable great branches to the middle and lesser glutaei muscles, and to the joint ofthe thigh-Gone. The other great branch of the glutaeal artery slips in be- twixt the glutaeus major and the glutaeus medius; and as it lies betwixt these two great muscles, it gives a prodigious number of branches to each, but chiefly to the great glutaeal muscle. ARTERIA ISCHIADICA. The sciatic artery is so named, because, instead of going upwards with this crooked turn towards the haunch, it goes obliquely downwards to the hip, in the direction ofthe main artery from which it comes. It comes off from the iliac about an inch lower than the glutaral, and is next to it in size, OF THE PELVIS. 191 almost equal, when (as it often happens) the pudic artery is derived from it. The glutaeal artery should be contrasted with it thus: the glutaeal goes out above the pyriform muscle ; the sciatic goes out below it; the gluteal turns upwards over the haunch-bone, the sciatic turns downwards along the hip ; the gluteal spreads its arteries wide with sudden and crooked angles; the sciatic sends its arteries downwards in a gentle waving form, or almost straight; and so numerous as to be compared with a lash of many thongs proceeding from one shaft. Often the glutaeal artery, before it passes out ofthe pelvis, gives small twigs to the rectum, to the bone, and to the pyri- form muscle; and in like manner the ischiadic, before it escapes from the pelvis, gives also trivial branches to the rec- tum, and to the pyramidal muscle. The branches of so great an artery, ramifying merely among muscles, and among such a vast variety of muscles, can neither be named, nor are worth naming. All that is to be desired is, to know the trunk, and the general direction in which its great- er branches go. Among these branches there are few re- markable. First, The coccygeal artery turns quick backwards upon the sciatic ligaments, and lying under the glutaeus magnus; and passing along by the direction ofthe ligament, it arises at that part of the sacrum whence the ligament takes its rise; and turning downwards upon the coccyx, and upwards upon the back of the sacrum, it inosculates with the sacral arteries through the posterior holes. Secondly, Another branch, more remarkable for its office than its size, runs downwards along the sciatic nerve, supplying its coats, and substance. But the great branch of this artery sends a confused lash of arteries downwards, which give arteries, first to the glutaeal muscles and pyriformis, and then downwards to all those muscles of the back of the thigh which arise about the knob or tuber of the ischium. In short, all its chief branches are muscular; and the artery is remarkable for no other peculiarity than this, that its inosculations downwards with the reflected arteries of the thigh are so frequent, that these alone may save the limb in wounds of the femoral artery above its profunda, or that great branch which belongs to the thigh. 192 OF THE ARTERIES ARTERIA PUDICA COMMUNIS. The common pudic artery,* or the artery of the external parts of generation, is the third great artery which goes out from the pelvis backwards. And there is in the course of this artery a peculiarity which is never fully explained ; and being unexplained, makes the succeeding description quite defective and lame : and it is this. The pudic artery (which is nearly ofthe size of a writing quill) usually comes off as a branch from the sciatic artery ; it goes out from the pelvis along with the sciatic artery through the lower part of the sci- atic notch, under the lower edge of the pyriform muscle, over the upper saero-sciatic ligament. But no sooner has it made its appearance along with the sciatic artery, and emerged from the pelvis, than it returns into the pelvis again; it does not go over the outside ofthe tuber ischii, and so down to the perinaeum ; but it just appears out ofthe pelvis, rises over the upper sacro-sciatic ligament, gives out a few branches, turns in again under the lower sacro-sciatic ligament, or rather un- der the spine or sharp point of the ischium, whence that liga- ment arises: it is now. within the pelvis again; it lies flat against the inner surface of the ischium ; it runs along by the direction of that bone till it approaches the symphysis pubis, where the root of the penis is. It there dives into the root of the penis, having just before given off that branch which goes to the perinaeum. It is this long artery, running naked and unprotected along the whole inner side of the ischium, bending as the arch of the ischium and pubis bends, that is cut by ignorant lithotomists, which a broad gorget is sure to wound, and which can be safe only by our exchanging the gor- get for the knife. The branches of the pudic artery are chiefly these : First, Before it proceeds out of the pelvis, it usually sends branches inwards to the neck ofthe bladder, vesiculae seminales, and prostate gland. Secondly, When it emerges from the pelvis, and while bending over the sacro-sciatic ligament, it gives, like the sciatic artery, chiefly muscular branches; it gives twigs to the sacro-sciatic ligament and pyriform muscle ; others go to the gemini muscles, and turn over them to the great trochanter, and to the hip joint, reaching as far as the acetabulum ; others spread over the tuber ischii, to which they give arteries, which go outwards along the three muscles ofthe thigh which arise from this point; and it sends inwards * It is named often the circumflex pudic artery, the internal pudic artery, the middle ->mlic artery, the great pudic artery. OP THE PELVIS. 193 from this part an artery which encircles the verge of the anus, and belongs to the sphincter and levator ani muscles. This branch is named the lower or external hemorrhoi- dal artery : and it sends other branches forwards into the perinaeum ; but these are smaller and less regular arteries; they are not what are distinguished by the peculiar name of perinaeal arteries. This artery, like the ischiadic, ends every where in inosculations with the reflected arteries of the thigh. Thirdly, The artery returning again into the pelvis, and running along under the flat internal surface of the ischium, gives off many small branches to the bladder, prostate gland, vesiculae seminales, and rectum. But when it has reached the perinaeum, and is about to emerge from the pelvis a second time, and go into the root of the penis, it gives out three chief arteries; one to the perinaeum, one to the body of the penis, one to tbe back of the penis thus : When the artery has approached nearly to the musculus transversalis perinaei, it splits into two branches; one of which is the artery of the perinaeum; the other is the proper artery of the penis. arteria perinei. The artery of the perineum passes under the transversa- lis perinaei and betwixt the accelerator and erector penis; in short, it comes out from that triangular cavity which we cut into in lithotomy; in which operation of course this branch cannot escape. The artery having escaped from this triangu- lar cavity, runs forwards along the perinaeum for two or three inches, according to the size of the subject, growing very sensi- bly smaller as it goes along. It is chiefly for supplying the skin and muscles of the perinaeum ; and gives these branches : 1. When it has just come out from the triangular hollow, it gives off from its root one branch at right angles, which goes directly across the perinaeum ; it keeps the course ofthe trans- verse muscle ; it may be named arteria transversalis peri- NiEi, and ends about the sphincter ani. 2. It gives branches to the accelerator and erector muscles. 3. It gives branches to the scrotum; and being continued along the corpus caver- nosum of each side, it ends upon the tendinous sheath, which binds the corpora cavernosa. Thus ends the perinaeal artery. ARTERIA PENIS, The proper artery of the penis is the continued trunk of the pudic artery. It is much larger than this permaeaj branch ; vol. ii. Kb 194 OF THE ARTERIES is as bigas a crow-quill; it keeps still close to the bone, while the perinaeal artery goes outwards; it at last touches the sym- physis pubis, and of course pierces the corpus cavernosum, just where it takes its rise from the leg of the pubis: and here it splits into two great branches; one to the corpus cavernosum, and one to the back of the penis, or rather into three, since there is one alno for the bulb of the urethra. The bulb of the urethra is quite insulated in the perinaeum, while the corpora cavernosa arise from the bone. Now, first, as the artery of the penis is passing by the side of the bulb, it gives off an artery to the bulb sidewise, which in part plunges into the bulbous substance, and in part is scattered upon tbe accelerator, prostate gland, &tc. Secondly, Tbe artery having risen to the place where the root of the corpus cavernosum is, gives off that artery, which runs small and delicate along all the back of the penis, till it ends at last in a branch which encircles the corona glandis. This is named the arteria dorsalis penis. Thirdly, The artery now plunges deep into the proper sub- stance of the penis; the artery of each side goes into each corpus cavernosum at its root, and splits into two branches; these run chiefly along the septum, or partition betwixt the cor- pora cavernosa of each side. It is this artery which pours out blood so freely into the cells of the penis, and causes erection. These three, the glutaeal, the sciatic, and the pudic arteries, are the only ones which go out from the pelvis behind, and one only goes out by an opening on its forepart, or rather its lower part, viz. the obturator artery. KRyftRtA OBTURATORIA. The obturator artery is so named from its passing through the thyroid hole. No artery is less regular in its ori- gin ; arising sometimes from the iliac, sometimes from the hy- pogastric, and not unfrequently from the root of the epigastric artery: in which case it turns back again over the pubis, coming into the pelvis through the ring. But no artery is more regular in its destination ; a considerable artery always passes through the thyroid hole, to supply the muscles which take their origin from the membrane, and from the ramus of the os pubis. The obturator artery, arising from the iliac or hypogastric, runs along by the upper edge ofthe pelvis, by the lower edge of the psoas muscle, accompanied with the obturator nerve, which is to go through the hole along with it. Having arrived OF THE PELVIS. 195 at the forepart of the pelvis, it slips through the oval hole by a very small opening, which is in the upper part ofthe tendinous membrane, which closes that hole, and which is consequently at the upper edge of the obturator internus muscle. The ar- tery, before it passes out of the pelvis, often gives branches of considerable size downwards to the neck of the bladder, pros- tate gland, and vesiculae; to the iliacus internus, and psoas muscles, and to the lymphatic glands which lie upon them ; and there is always a bianch, which encircles the upper part of the foramen thyroideum, lies close upon the bone, and gives its twigs upwards into the muscles of the belly. After the artery has passed along with its nerve through the thyroid hole, it comes into the very heart or central part of the thigh. Almost all its branches are muscular; none are worth distinguishing by name ; it is only tbe general tendency of the artery that needs to be explained. It divides into two chief branches, taking opposite directions. The first is deep- er; it turns downwards and outwards towards the hip-joint. It perforins three services here; it gives first arteries to the periosteum, to the capsule, and to the gland within the aceta- bulum; it gives also large branches to the obturator quadra- tus femoris, and all the great muscles which immediately sur- round the joint; it also forms very large and important anas- tomoses round the joint, with the sciatic and pudic arteries from the pelvis, and with the reflected arteries from the thigh. The more superficial branch of the thyroid sends all its branches into tile great muscles upon the inner* side of the the thigh coming from the pubis. Its cMef JsAnches are to the upper part ofthe triceps muscle; it s^Hmrs gives branch- es even to the superficial muscles, as th^^Ecrris and sartorius ; always, at least, small twigs pass throuJPrese muscles to the skin of the thigh and to the scrotr^^Qf these two arteries, this superficial one encircles the innaBroge of the thyroid hole, or that which is next the pubis, with one of its branches; while the deeper artery encircles the outer edge, or that which is next to tbe hip-joint; so that they meet upon the bone inosculating with each other. 196 OP THE ARTERIES CHAP. IV. ARTERIES OF THE LOWER EXTREMITY. ILIACA EXTERNA. JL HE external iliac Artery is that branch of the com- mon iliac whicii descends under Poupart's ligament into -the thigh. The internal iliac or artery of the pelvis parts from this within the pelvis at the joining of the ilium and sacrum. The external iliac passes down into the thigh, by bending along the upper edge or brim of the pelvis, directed by the lower edge ofthe psoas muscle, which also descends into the thigh. This great artery is accompanied by the anterior cru- ral nerve ; its corresponding vein lies by the side of it; the lymphatics of the thigh creep upwards along this artery into the pelvis; and when the artery descends into the thigh, it passes so over the bulging part of the acetabulum and head of the tbigh-bone, that it is felt projecting there and beating with amazing force. ARTERIA EPIGASTICA. The Ep\G*«rR^URTERY, so named from its running up along the bell^Mj^Bfcff from the inner side of the external iliac artery aborJpSBfch before it passes out into the thigh. The epigastric, ^i^^irst given off, turns downwards with a full round turn ti]i|jtj Bpies Poupart's ligament. The pe- culiarity of its course'^we must be very carefully attended to. The femoral artery lies at the very outer margin* of the opening, called the crural arch. The Fallopian ligament forms the upper line of the crural arch. The epigastric ar- tery moves inwards and downwards with the Fallopian liga- ment, running along its lower edge; then it crosses the opening called the abdominal ring, behind the ring, and also behind the spermatic cord which passes through the ring; then it mounts by the border of the transverse muscle, and gets to the rectus muscle of the belly ; but it is pretty high before it touches the side of the rectus, and lying on the out- * Viz. that end of the slit or arch which is nearest to the haunch-bone: OF THE LOWER EXTREMITY. 197 side of the peritoneum, and on the inner surface of the rectus muscle, and keeping in the direct line of the rectus muscle near its centre, or rather nearer the outer edge of the muscle, and inclining inwards, it mounts from the groin to a little below tbe borders of the thorax, where it inosculates very freely with the internal mammary artery. These are the inosculations which were mentioned in speaking ofthe internal mammary artery. Through its whole course this artery is so large as to make its wounds important-: we should know where to stop it in wounds; we should remember to avoid it in open- ing or extirpating tumours. I have seen some confusion and much loss of time during an operation from not attending to this. The main artery must be remembered; its branches are of little value. The only branches which it is at all ne- cessary to mention are, first, one small twig, which it sends downwards along the spermatic cord ; soon after entering un- der the abdominal muscle, it gives off a large branch almost equal to the artery itself, whicii goes directly towards the na- vel, and ends there. This branch goes obliquely across the muscle, while the main artery follows the general line of the muscle, and gives branches on every side to the rectus, trans- versalis, obliquus; in short, to all the muscles of tbe abdomen, and spreads its last branches very freely about the lower bor- der of the chest. ARTERIA CIRCUMFLEXA ILIUM. The circumflex artery of the haunch is named cir- cumflexa from its turning directly backwards, and ilium from its passing along the hollow of the haunch-bone. It is smaller than a crow quill; it goes off from the outside ofthe external iliac artery opposite to the epigastric, or rather a little lower; exactly at that point where the outer end of the Fallopian ligament begins in the haunch-bone. It runs backwards in a curved line along the hollow of the haunch- bone, curving along the crista ilii, or ridge of the ilium, under which it lies. Its line is along the most naked part of the bone, where the internal iliac muscle begins on one hand, and the transverse muscle of the belly on the other; in short, it runs along all the upper edge of the internal iliac muscle, quite round almost to the lumbar spine, where it joins the ileo-lumbar artery by small inosculations; for at this place the reflected iliac artery, which grows gradually and sensibly smaller, is almost spent. There are no remarkable branches which deserve to be described or even to be named, unless it 198 OF THE ARTERIES be one which goes off early, near the head of Poupart's liga- ment, and gives branches to the ligament, to the sartorius mus- cle which arises at the same point of the haunch-bone, and to the edge of the iliac muscle. And as it runs along betwixt the iliac muscle on the one hand, and the transverse of the belly on the other, it gives many branches downwards to the internal iliac and psoas muscles, and to the substance of the bone ; and upwards it gives three or four branches into the abdominal muscles, which go so far along the belly as to inos- culate with all its other arteries. THE FEMORAL ARTERY. The projection of that part of the great artery which we must now call the femoral artery is occasioned not merely by the naked pelvis and the head of the femur; these parts are covered by the flesh and tendons of the psoas magnus and ilia- cus internus, which also come out from the pelvis to the thigh. The artery lies cushioned upon these muscles; the muscles dive very deep to get at the trochanter minor or inner tro- chanter of the thigh-bone. The artery follows them; and thus it is plunged as it were into a deep cavity, assumes a new position, and this constitutes a second point of description. The hollow in which the artery now lies may be compared with that of the bend ofthe arm. The artery now takes the name of femoral, lies deep in a hollow surrounded by much fat and many glands; the cavity is covered with a very strong fascia, or tendinous sheath, which descends from the muscies ofthe belly over Poupart's ligament, and whicii is greatly strengthened at this point by the general fascia of the thigh. Here the femoral artery, instead of sending off less effectual branches from point to point as it moves dowuwards, and which could not have conveniently penetrated through all the thick- ness of the thigh, sends off one great branch, which furnishes all the thigh without exception, whence it is named the mus- cular artery of the thigh. This great artery goes off from the femoral just like the ulnar from the artery at the bend of the arm, (i. e.) very deep among the muscles, in the triangular cavity above described. Thence it is oftener named profunda than muscular artery. The femoral artery having sent down this great branch, equal almost to itself in size, inclines outwards again, meets the inclined line of the sartorius, and follows its oblique di- rection, assuming a new character; for now it becomes a se- cond time quite superficial/ is covered by nothing besides the OF THE LOWER EXTREMITY. 199 strong fascia of the thigh and by the skin. It is felt beating along the line of the sartorious muscle; and by that line we apply the cushion of our tourniquet. It retires from our fuel- ing only about two hands breadth, or a little more, above the joint ofthe knee; at which place it perforates the triceps or great muscle of the thigh, gets from the fore to the batk part, or in other words, forsakes the thigh to go down behind into the ham, where it exchanges its name for that of popliteal ar- tery. The popliteal artery, when it has got into the ham, meets with its corresponding nerve, which is of vast size ; and the ar- tery lies now flat upon the back part of the thigh-bone, passes down in a hollow formed betwixt its great condyles, lies flat upon all the back of the knee-joint, is enclosed by the two great ham-string muscles from above, and by the two great heads of the gastrocnemii muscles below. But although we say it is protected, yet in truth it is not tightly bound down by a fascia embracing it, but lies on the contrary so loose and un- suported among the cellular substance, that we have the most certain evidence of its being often racked and strained in sud- den or awkward motions of the joint. From the ham the artery descends into the leg, under the heads ofthe gastrocnemii muscles; and being lodged behind the great bulging, or head of the tibia, below the joint, it there di- vides into three great arteries. One passing down behind the tibia is named posterior tibial artery; one perforating the in- terosseous membrane goes down along the forepart of the tibia, is named tibialis antica;the third artery, passing down behind the fibula, is named the fibular or peroneal artery. These may be justly compared with the three arteries of the fore-arm; and as those meet in arches upon the palm of the hand, these meet and form similar arches on the sole of the foot. Even from this slight and general description of this impor- tant artery, many conclusions' may be deduced not indifferent to the surgeon; for there are several points in the course of this artery very peculiarly marked. First, It is thrown so forwards by the bulging of the pubis, where it forms the socket for the thigh-bone, it beats so strong- ly just under the rim ofthe belly, that we cannot, at least till we try, doubt of its being easily compressed. I see, indeed, that Acrel, in very desperate circumstances, when his ligatures had given way even before his eyes, and the arteries burst, and after the surgeons had been twice deluged with the blood of the femoral artery, thought that he had suppressed this artery, by resting on it with his thumbs. But indeed the poor patient, 200 OF THE ARTERIES under these horrible circumstances, as Acrel justly calls them, must have fallen so faint and low, by a tedious alarming opera- tion, and by the repeated bleedings, that any thing might have suppressed the pulse in the femoral artery, when that of the heart itself wTas well nigh gone.* But this is one ofthe points in which it is the most necessary for every man to speak from his own experience. I have tried it in the most favourable circumstances in a slender young man; and when I thought myself sure of the point, behold the blood gushed out with a whizzing noise and prodigious force. I have seen others try it, and fail. It is perhaps not impossible to compress the femoral artery; but it is not an easy thing, and is an expedient never to be trusted where the life of a fellow-creature is immediately in danger. Secondly, The strong covering of the fascia gives a peculiar form to the aneurism of the thigh; it keeps it flat, forces the blood to spread abroad into the surrounding parts; and this deep driving ofthe blood among tbe muscles, together with the great size of the sac, and the putrefaction of three or four pounds of blood, causes that grangrenous and sloughing condition of the parts, by which we are so often foiled in our best concerted operations, and after the artery has been well and fairly tied. Thirdly, It is very obvious that the profunda might with more propriety be named the femoral artery, since it is the proper artery of the thigh ; and though Heister, and some of the best among the old surgeons, spoke of this division as one which only sometimes took place, we know that a leg could no more be without a profunda than without what we call the femoral artery; and we also perceive, notwithstanding the doubts and fears of some modern surgeons, that when the femo- ral artery is wounded, it is after all only a wound ofthe artery ofthe leg. Fourthly, The large branches which the profunda sends upwards round the haunch, inosculating with the sciatic and pudic arteries, and the branches which it sends downwards to the knee, inosculating round that joint with the arteries of the leg, make this branch of peculiar importance to the sur- geon ; for when the artery is wounded in the groin, above the profunda, this branch saves the thigh, by its inosculations round the haunch ; and when the artery is wounded in the thigh, be- low the profunda, or in the ham, it saves the leg by its inoscula- tions round the knee ; and when the whole line of the femoral artery has been obliterated, it has saved the whole extremity, as I have elsewhere proved, by receiving the blood from the arteries round the haunch, and conveying it down to the ar- * " His iu horrendis angustiis, cum nee nova ligatura, nee torcularis contractione haemor^ rhagia sisti posset, in trunco ipso, dum ex inguine prolabitur, poUicibus tirraiter adnwtss, oompiessionera instituere placuit, quo elfluxus sabstitit." OF "SHE LOWER EXTREMITY. 201 teries below the knee, being thus an intermedium betwixt the internal illiac artery and the arteries of the leg, capable of forming a new line of circulation behind the thigh when that before is shut up. Nor should it be forgotten, that the aneu- rism on the forepart of the thigh may be from the. profunda; and then the femoral artery which lies before it may be cut across by a rash or ignorant surgeon. Fifthly, Tbe place ofthe femoral artery passing through the triceps muscle is next to be observed, for these reasons. At that point it lies close upon the bone ; and as this happens ex- actly at that distance above the knee at which we usually am- putate, we expect in such amputations to find the great artery close by the bone. As the artery is at this point tied down by the tendon of the triceps, and is in fact passing through a ten- dinous ring, it sometimes happens that when we have cut near this, but not upon it, the flesh shrinks, in such a way that even this great artery, though it bleeds, is not easily found ; but one stroke of the scalpel, running along the bone, cuts the tendon up and exposes the artery with open mouth. This single point makes all the difference betwixt an aneurism ofthe thigh and ofthe ham ; it is peculiarly necessary to mark this, in or- der to ascertain the extent of the disease before beginning an operation. Nothing can have a worse appearance than that which has actually happened, viz. a surgeon beginning that ope- ration in the ham, which he should have attempted rather on the forepart of the thigh; and being forced to change his ground, and to begin a second operation on the forepart of the thigh, or, what is worse, to cut up the tendon, and follow the diseased artery to the forepart of the thigh, cutting, in short, first longitudinally betwixt the hams-trings, and, after an hour's working perhaps, cutting cross-wise to reach the fore- part ofthe thigh. Sixthly, Is it not a matter of very high importance to study the ham still more carefully than the axilla, since the artery is so often hurt at this place by rude motions of the joint? For it is a narrow cavity; the artery lies close upon the joint and bones; and when it is allowed to remain long in a diseased state, enlarging and dilating the ham, we perform in the end a hopeless operation; or if we had hopes when we began our operation, they are all over before it is ended : for the parts are found to be diseased, the bones carious, the joint spoiled ; there is no hopes even of present safety, and of the ligature holding, and much less any expectation of permanent cure. Often the greatest surgeone have been contented to finish such an opera- tion by cutting off the limb ! Seventhly, When the artery has gone down beyond the ham, vol 11. C c 208 OF THE ARTERIES and seems lodged safely under the gastrocnemii muscles, still it is not safe; it is bended tense over the back of the joint; it is pressed by the gastrocnemii stretching over it; and their vio- lent action has often been such, as to have torn the artery with a tumour so immediate, and with such excruciating pain, that the surgeon has been constrained in a manner to cut off the limb even upon the spot. Eighthly, Very often we are obliged to decide, whether a tumour ofthe thigh or a tumour ofthe ham can be cut away only by our knowledge of these arteries. How often the ante- rior arteries of the leg are cut by workmen, and how much they are exposed to the stroke of the adze or axe, every prac- tical surgeon must know : but the mischances that open arteries are quite unthought of. I have known a man standing care- lessly by his scythe, which was set upright, the blade along the ground, and the shaft resting upon his arm, cut the artery be- hind the outer ankle so as to form (when the wound healed) a large, livid, and strong beating aneurism ready to burst, and requiring immediate operation. The epigastric artery is in danger in operations for hernia. The femoral artery is the subject of frequent operations ; the popliteal aneurism is a disease of this artery in the ham ; and even the simple operation of amputating either the limb itself, or tumours in the thigh or ham, requires a perfect knowledge of all these arteries. But although no formal operation affected these lesser arte- ries, yet the main artery itself is so exposed, and so superficial where it runs down the thigh, that it is wounded in a hundred various ways. It is very singular how often it has been wound- ed by one particular accident, viz. the dropping of a pair of scissars, and with a sudden instinctive effort clapping the knees together to catch them. It has been wounded once or twice by a shoemaker clapping his knees thus together to catch his sharp pointed paring-knife. One of my pupils lay three months in London, uncertain whether his femoral artery was wounded ; for he had in this way catched his pen-knife, the point of which had run into his thigh, and wounded some great artery. It has been cut across by balls; it has been wounded even by a single slug; it has been uncovered by wounds which yet did not touch its coats, and has in consequence dilated into an aneurism. I have known a boy stab another with a pen-knife in the thigh, and strike so critically as to open the artery with a wound like that of a lancet. My friend Mr. Harkness gave me the privilege of dissecting an aneurismal limb which he was obliged to cut off; and in which the artery was (if I may use such an expression)broken or torn across the OF THE LOWER EXTREMITY. 208 upper end of the thigh-bone, which had been broken by a fall about three weeks before. All these accidents must come upon the surgeon very sud- denly ; and if they come upon him unprepared, all is in a mo- ment lost. I once saw a fine young fellow die from this alarm of the attendants and confusion of the surgeon. He was tall, stout, young man, who was sitting at table with his companions eaiing bread and cheese, taking his glass and telling his tale. He had in his hand a sharp pointed table knife, which he hap- pened to hold dagger-wise in his hand, and in the height of some assertion or oath he meant to strike the table, but the point missed, and slanted over the table; he had stabbed him- self in the femoral artery, and with one gush of blood he fell to the ground. When I came, I found the young man stretch- ed out upon the floor; he was just uttering his last groan ; the floor was deluged, all slippery, and swimming with blood. The wound was covered with a confused bundle of clothes which I instantly whirled off; and in that moment two gentle- men, who had been first called, and who had both run off for tourniquets (because tourniquets are used to stop bleedings) returned; and had the unhappiness to see that the hole was no bigger than what I could close, and had actually shut up with the point of my thumb ; and which, had it been shut and put together with a good compress, would have healed in three days, forming a large beating aneurism within, allowing time for a deliberate operation. In short, to enumerate the variety of accidents which may affect this artery would be impossible; but surely from the little that I dare venture to say in this place, it must seem one ofthe largest, the most exposed, and most dangerous, and by all this, the most important artery in the body ; and from these previous hints and general descriptions, the value of the several branches which are now to be enumerated will be more easily felt and understood. BRANCHES OF THE FEMORAL ARTERY. The femoral artery, until it gets down into the hollow which I have described, gives no branches, or none with which I would chobse to confound the description of the profunda or great artery of the thigh. The branches which the femoral gives off before that are only small twigs to the fat, glands, skin, or private parts; but one or two of these to the private parts are sometimes large. First, Twigs go out along the fe- moral ligament, and terminate in the skin. Secondly, Twigs 404 OF THE FEMORAL ARTERY. go to the fat, and lymphatic glands of the groin. Thirdly ? There ascends a small branch, sometimes towards the origin of the sartorius, to the middle gluteal muscles, and to the begin- ning ofthe fascia lata. Fourthly, Of those branches which go across the upper part ofthe thigh to the genitals, and which are named pudl je externa to distinguish their branches from those of the pudica communis, there are usually three. The uppermost is scattered about the fat of the pubis. The mid- dle one goes across the heads of the triceps ; it is longer and larger than the others ; it goes to the side ofthe scrotum and penis in Men ; in Women it is large, and runs into the labium pudendi. The lower one of the three goes to the lower parte of the scrotum, and to the skin of the thigh near it. ARTERIA PROFUNDA FEMOR1S. Then comes off the profunda femoris, the deep or muscu- lar artery ofthe thigh. It arises from the femoral artery about four inches below the groin, more or less according to the size of the subject. It turns off from the femoral artery with a bulging, which looks backwards and towards the outside ofthe thigh. It lies deep in the triangular cavity, upon the face of the iliacus internus and pectinalis muscles. It presently gives off two great arteries, which turn upwards along the joint; one round the outer side, the other round the inner side of the joint. Then it passes downwards, turns in behind the femoral artery, sinking deeper and deeper towards the back parts of the thigh. It passes down along the face ofthe triceps mus- cle ; and as it moves along its forepart, it sends through three or four great arteries to the back part, which are called the perforating arteries of the thigh. And, lastly, the profunda itself, or its last branch, passes through the triceps; and this last branch is named perforans ultima vel descendens femo- ris. arteria circumflexa externa. The circumflex artery, which goes to the outside of the hip-joint, proceeds from the very highest point of the profun- da. It takes its course outwards, passing under the sartorius, fascialis, and head of the rectus : it runs over the tendinous head ofthe vastus internus, where that muscle takes its rise from the outer trochanter: it divides very early into the fol- lowing branches. First, Branches go to the inner side, to OF THE FEMORAL ARTERY. 205 the internal iliac muscle, upon which this artery lies ; and round it they bend over the lesser trochanter, making inosculations with the internal circumflex artery. Secondly, An artery goes in the opposite direction, viz. outwards, to the iliac mus- cle, the sartorius, the head of the rectus, the fascialis, and round to the glutaeal muscles. Thirdly, It sends many lesser branches upwards and forwards into the heads of those mus- cles which 1 have just enumerated, and which lie immediately over the artery. Fourthly, It sends large branches round the root of the great trochanter, some of them going into the hol- low above the trochanter; others keeping so low as tbe root of the trochanter, where the greater glutasus is inserted. Fifthly, The most important of all its branches is a very long one, which it sends directly downwards under the rectus, or betwixt it and the vastus internus muscle. This artery is di- vided into two great branches, which run down the whole length of the thigh, somewhat resembling in their shape the profunda humeri : they are named the greater and Jesser descending branches ofthe circumflex artery, and they inoscu- late in a most particular manner with a large anastomosing branch from the femoral artery. The larger branch of this ar- tery emerges from betwixt the rectus and vastus externus, a little above the knee, to inosculate wirh one of the articular arteries of the knee. Its smallest branch inosculates with the anastomosing branch ofthe femoral artery. These two anas- tomoses seem to be the chief use of these two long arteries, though they do also send some branches to the muscles. But to give a more simple notion of this circumflex artery, it should be described thus. It is divided into three chief branches : 1st, A descending branch, which goes down to the knee-joint; 2d. A transverse branch, which crosses the upper part of the thigh, and turns round the neck of the thigh-bone ; 3dly, It sends a less important branch up upon the dorsum ilii. arteria circumflexa interna. The internal circumflkx artery is a thick short artery, which goes off opposite to the ball of the thigh-bone; and as the external one goes round the great troch nter, this goes round the lesser trochanter. It is a smaller artery ; it has not so many muscular branches ; it keeps closer to the joint; it goes off from the inner side of the profunda, just opposite to the circumflexa externa, or a little lower, but never more than an inch lower; it passes over the insertion of the psoas muscle, and under the belly of the pectinalis; it attaches itself then 206 OP THE FEMORAL ARTERY. to the lesser or inner trochanter, and goes round the neck of the thigh-bone round the joint, and is expended on the mus- cles at the back of the joint, as the quadratus femoris, ge- mini, &c. The artery having turned towards the inside, the muscles which lie there are the triceps gracilis, he. The first branches, therfore, which this artery gives off before it passes under the pectinalis, are to the triceps and gracilis. After having passed under the pectinalis, and while it is turning round the root of the lesser trochanter, it gives branches to the pectinalis and tri- ceps ; and especially it gives to the capsular ligament of the hip-joint an artery which is named articularis acetabuli. The artery now lying upon the pelvis, under the neck of the thigh-bone, divides itself into two chief arteries ; one goes up- wards and forwards along the triceps, till it ends at last round the symphysis pubis. The chief muscular twigs of thisbranch are given to the triceps, and to the obturator muscles; it is this branch which inosculates so freely with the branches of the obturator artery; it is a twig of this artery which enters into the cavity ofthe hip-joint, by that breach which is the inner edge ofthe acetabulum; and this branch entering then by its proper hole, goes to the gland in the bottom ofthe sock- et, or chiefly to it. The. other branch turns away in the op- posite direction, viz. backwards betwixt the little and the great trochanter, turning round the neck of the thigh-bone. It gives branches also to the triceps and obturator, inosculating with the obturator artery. But its chief branches are towards the other side, as to the capsule of the hip-joint, to the neck of the thigh-bone, to the quadratus femoris. It is this artery which gives most of those branches about the roots of the tro- chanters named trochanteric arteries; and it is from this arte- ry that many branches go backwards along the tuber ischii, to unite with those of the sciatic and pudic arteries. OF THE PERFORATING ARTERIES. The two fiist perforating arteries are very large; the two next perforating arteries are smaller and less regular ; the fifth perfo- rating artery is just the termination of the profunda. But still it must be understood that these perforating arteries are ex- tremely irregular in place, size, and number, as indeed all muscular arteries must be; and that there are besides the greater perforating arteries many like them in this part of the thigh, though not distinguished by name. OB THE FEMORAL ARTERY. 307 ARTERIA PERFORANS PRIMA. The first perforating artery is the largest branch of the profunda, bigger than both the articular arteries joined. It arises from the profunda, just under the lesser trochanter, be- twixt the pectinalis and triceps brevis; and perforates the tri- ceps about an inch below the trochanter, and close upon the thigh-bone. Here the artery lies under the lower edge of the glutaeus, and close by the origin of the biceps, semi-tendinosus and semi-membranosus muscles, the three muscles which form the ham-strings; and the chief division of the artery is into one great branch, going upwards along the glutaus, and another going downwards along the flexor muscles. First, The artery which goes upwards turns over the glutaeus, spreads innumera- ble branches about the great trochanter; and meeting with the trochanteric branches of the arteriae reflexae, make a most beautiful inosculation, or rather net-work of inosculations, over the trochanter. Another transverse branch of this upper artery turns quite round the lower part of the trochanter, and round the thigh, among the flesh of the vastus internus ; and a third branch of the same artery meets in inosculation with the lower branches of the sciatic artery. The lower or descending branch of the perforans prima goes down along the three flexor muscles of the leg, viz. the the biceps, semi-tendinosus, and semi-membranosus ; nourishes their fleshy bellies, and plays over their surface in beautiful net-work. ARTERIA perforans sf.cunda magna. The second or great perforating artery is a much larger and more important branch of the profunda than this first, at least it is so when the other perforating branches are wanting, and when this, as often happens, represents the con- tinued trunk of the artery: but I shall describe it as a second perforating artery to be succeeded by others.* The second perforating artery, conies off from the profunda, about two inches lower than the first; it passes through betwixt the first and second heads of the triceps, or through the flesh of the second; and turning obliquely downwards and backwards, close by the thigh-bone, it passes into the cellular interstice betwixt My reason for saying this is, that sometimes there nrr but two perforating arteries, while there are often five which nerd to be described. 208 OF THE FEMORAL ARTERY. the flexor muscles ofthe opposite sides, (i.e.) betwixt the bel- lies of the ham-string muscle, and ends there. Before it passes through the triceps, it gives branches to the triceps and vastus, and to the great trochanter, and to the thigh-bone. Its two chief branches, after it perforates the tri- ceps, are, first, one great transverse branch, which goes direct- ly across below the the tendon of the glutaeus, and gives one great branch up upon the glutaeus, and another to the vas- tus externus, making inosculations with the reflected arteries of the joint. Secondly, Its descending branch goes down in the hollow betwixt the great ham-string muscles, and its branches go into both muscles, but chiefly into the biceps, and in these the artery is exhausted. ARTERIA PERFORANS TERTIA. The third perforating artery comes off about a fin- ger's breadth lower than the former; it makes a gentle waving turn inwards before it pierces the triceps; and after having per- forated the triceps, it gives its branches to both the ham-string muscles, but chiefly to the semi-tendinosus. ARTERIA PERFORANS OJJARTA. The fourth perforating artery may be regarded as the last, or as the termination of the profunda, though some- times there is a fifth. It perforates again still lower, about a finger's breadth below the last, through the flesh of the triceps magnus. Its first branch, while on the forepart of the triceps, is the nutritia magna femoris, or proper nutritious artery of the thigh-bone ; and after it perforates the triceps, it gives its arteries to the two ham-string muscles, but more especially to the biceps; and so this last branch ofthe profunda ends. But this minute description of any important set of arteries never presents any clear idea to the reader's mind, nor any knowledge which he can easily retain, I expect rather to do so by one short description. The title of perforating arteries is one which compre- hends all the great muscular branches of the profunda, except the two reflex arteries belonging to the joint. They vary in number, as all muscular branches must do, and are proportioned in size and number to the bulk of the thigh. The profunda passes down along the forepart of the triceps, while it is giv- ing off these arteries; they must, of course, perforate the tri- OF THE FEMORAL ARTERY. 209 ceps before they can get to the back part ofthe thigh. When they do perforate, they come into a great muscular interstice or hollow which is formed by the ham-string muscles of oppo- site sides, by the biceps on one side, and by the semi-membra- nosus and semi-tendinosus on the other. It is to these two great muscles of the back part of the thigh that the branches of all the perforating arteries are chiefly directed. Each per- forating artery succeeds another at about the distance of an inch or more; each successively coming out into this interstice at a lower and lower point. Each artery gives branches to the triceps, he. before it perforates, and to the ham-string muscles, he. after it has come into the hollow. The two first perfora- ting arteries are the only arteries which are large and absolute- ly certain ; the third is always very much smaller; the fourth is generally the termination of this great artery; the fifth perfora- ting artery is rare. Such a general idea as this of their size and value, and situa- tion in the very heart or deepest part ofthe thigh, (for the pro- funda turns backwards from the very first, and all its branches keep the same direction,) is of more importance than a particu- lar knowledge of every branch of each perforating artery; a thing really unattainable, since they vary more in their ulti- mate branches than almost any other arteries in the whole bo* dy; for they have more space, and a greater mass of irregular muscle to wander in, and produce varieties. ARTERIA FEMORALIS. Though the profunda is plainly the artery of the thigh, yet from the Jignorance of anatomists, and surgeons (who never knew till about twenty years ago that there was more than one great artery,) the superficial artery has been named the artery ofthe thigh. The femoral artery makes a spiral or serpentine turn round the whole thigh. It appears first on the forepart; it turns obliquely round to the inner side, following the lower edge of the sarto- rius muscle ; it passes through the triceps, after it has got about two-thirds down the thigh, by which it gets into the ham, and its spiral turn is completed. It lies deep where it is giving off the profunda; it rises then, and is superficial all along the mid- dle ofthe thigh; and when it has advanced two-thirds down the thigh, it again gets too deep to be felt; but all along it is cov- ered by the thick strong fascia of the thigh. Through the whole of this course it gives no one branch out that is of any considerable importance. They are all muscular arteries, very small, nearly of one size, nameless, and undistinguished, going vol n D d 210 OF THE FEMORAL ARTERY. into the muscles ofthe forepart of the thigh; or if any are disv tinguished, it is only by their relation to other arteries, when the trunk gets low enough to make anastomoses with the arte- ries ofthe joint. The nameless muscular branches of the femoral artery go, in one word, to all the muscles on the forepart ofthe thigh; to the rectus, sartorius, vasti, gracilis, and triceps; to the glands, fascia, fat, and skin; and it thus continues giving successive branches to each of these long muscles as it passes the several points of them. There is no distinguished branch till, having arrived within two bands' breadth ofthe knee-joint, it gives out (just where it is about to pass through the tendon of the triceps) a larger branch named (like a similar branch of the humeral artery) RAMUS ANASTOMOTICUS MAGNUS. This branch goes out from the inner side ofthe femoral ar- tery just where it is about to perforate the triceps; it passes into the flesh of the vastus internus; it first sends smaller branches to the vastus internus and sartorius, and through the interstice of these two muscles to the skin of the knee. But having penetrated into the fleshy belly of the vastus internus, this ar- tery, which is itself very short and thick, sends out its slender inosculating branches: one goes downwards along the tendon ofthe great triceps; and when the tendon of that muscle stops above tbe inner condyle, this artery goes forwards over the condyle, makes a net-work upon it, joining in numberless inos- culations with the articular arteries from below, and gives twigs also into the joint. The other branches of this ramus anasto- moticus tend all forwards and upwards to join the descending branches of the reflexa externa, which come down along the rectus muscle. There are two other arteries lying close upon the joint, re- markable enough to deserve a name, and they are called per- forating arteries; not perforating like the branches ofthe pro- funda, to get deeper among the flesh; but perforating so as to get out from the cavity of the ham upon the surface of the thigh again. The upper perforating artery arises from the inner side of the popliteal artery, just after it has perforated the tri- ceps ; but it must not be accounted a popliteal branch, because it immediately perforates the triceps muscle again. It gives branches to the semi-tendinosus, semi-membranosus, and sar- torius ; in short, it turns its branches towards the muscles on the inner side of the knee, and is a smaller artery. The lower or second perforating artery goes off near- ly opposite to this. It is a much larger artery. In order to es- OF THE FEMORAL ARTERY. 211, wipe from the ham, it perforates the shorter head ofthe biceps, or outer ham-string muscles. It first crosses the ham at its very upper point, and within the substance of the triceps; it then perforates the shorter head of the biceps flexor-cruris; it then emerges upon the thigh by tbe belly ofthe vastus extemus muscle. Before it passes across the ham, it gives a branch to the semi-membranosus; while it is passing through the flesh of the biceps, it gives a lower nutritious artery to the lower and back part ofthe thigh-bone; after it perforates the biceps, all its branches are to the flesh of the biceps and vastus extemus, and its extreme branches are spent in inosculations with the de- scending branch ofthe reflex or articular artery of the hip-joint. But these branches, which are the last ofthe femoral artery, are extremely irregular. There is no artery from the profunda downwards worth naming, not even those which I have just described.* popliteal artery. The artery having passed through the ring or.tendon of the triceps which is formed for it, or rather having passed be- twixt the triceps and the bone, lies flat against the flat part of the thigh-bone as deep as possible in the cavity of the ham. There, as no muscles are lodged, it can give no muscular arte- ries of any importance ; none but trivial ones to the ham-strings or to the heads of the gastrocnemii. In its whole length from the place of its perforating the triceps tendon to its great di- vision, which is under the longer head ofthe solaeus muscle, it gives none but articular arteries, (i. e.) small arteries to the knee-joint, which are no less than five in number, and encircle it in all directions. First, The popliteal artery sends off from each side two mus- cular branches, not deserving a particular name nor descrip- tion ; the one goes to the biceps or muscle of the outer ham- string, the other to the semi-tendinosus and sartorius, or inner ham-string muscles. Then come off the arteries ofthe joint, which are thus ar- ranged: 1. The upper arteries coming off above the joint are three in number; one turning round the inner side of the joint, and one round the outer side, and one in the middle ; whence •"Confiteri tamen oportet, binos ultimos ramos in distribuendis suis surailis infinite Ludere, ita ut descript'tone ad quodcunque cadaver adaptata vix, ac ne vix quidem corapre- hendi possint. Ex repetitis tamen meis dissectionibus id pro certe habeo, duos vel tres, quo* perforantes appellare vellem, enoriri, ho« trunculis suis ad externum latus pracipue conflecti cumque rete yasculoso genu jungi, nutritiant inferiorem et iisdena gigni, et ramos insuper, nunc nauciorej, nuuc numerosiores, commuuicantes ad flexores cum profunda rie van." Arvidson, p. 36. 212 OF THE FEMORAL ARTERY. it is named azygous, as having no fellow. 2. The arteries be- low the joint are two only in number; one to the inner side, and one to the outer side, of the joint; and these directions of the arteries settle both the order of description and also their names. ARTERIA ARTICULARIS SUPERIOR EXTERNA. That upper articular artery which comes off above the knee^ and which turns round the outer side of the joint, arises from the popliteal artery above the outer condyle ; its trunk is like all these arteries about the joints, short and stumpy ; but its branches long and slender. It passes under the flesh of the biceps ; it appears again at the edge of the vastus externus : one branch plunges into the vastus externus, mounts upwards, and, besides supplying the muscle, inosculates with the long descending branch ofthe reflexa externa; while another branch turns as directly downwards over the face ofthe outer condyle, and spreads beautifully over the side of the joint, inosculating in many net-works with the corresponding artery from be- low. ARTERIA ARTICULARIS SUPERIOR INTERNA. The UPPER ARTICULAR ARTERY of the INNER SIIpE goes off in like manner over the inner condyle, pierces the tendon of the triceps, where it is implanted into the condyle, and passing under the edge of the vastus internus, turns towards tbe fore- part ofthe knee, proceeds towards the patella, and covers chiefly the inner side of the joint with its net-work of inoscu- lations ; its little twigs slip in under the great lateral ligament, and under the sides ofthe patella to the cavity of the joint it- self. It inosculates like the outer artery with the lower arte- ries of its own side. ARTERIA ARTICULARIS "MEDIA. The middle or azygous articular artery usually arises from the back part of the popliteal artery, but sometimes from one or other of those last described; but this branch, at all events, is seldom wanting. It runs down behind the main artery upon the back part of the joint, into the great hollow betwixt the condyles ; and all its branches are expended upon the back of the capsule, the posterior crucial ligament, the semilunar cartilages, and the fat about the back of the joint. OF THE FEMORAL ARTERY. 213 LOWER ARTICULAR ARTERIES. The lower articular arteries are more slender, longer, run downwards very low, and return upwards with a very sudden angle. ARTERIA ARTICULARIS INFERIOR EXTERNA. The external articular artery below the knee goes off from the popliteal at the middle or centre of the joint, turns downwards along with the popliteal artery for a considerable way ; it passes under the heads of the small plantar muscle and the outer head of the gastrocnemius, and having passed through, encounters the head of the fibula, and passes above it to the side of the joint, spreading its branches towards the patella. In the ham this artery gives muscular branches to the heads ofthe muscles, as ofthe gastrocnemius, solaeus, plautaris, and the popliteal muscle, that muscle which lies obliquely across the ham. When it reaches to the side of the joint, it passes under the external lateral ligament; and several of its branches, besides their external anastomoses, go into the cavity of the of the joint; one of which, within the joint, is especially large. ARTERIA ARTICULARIS INFERIOR INTERNA. The internal articular artery below the knee is larger than the external one. Like it, it bends downwards, passes un- der the inner head of the gastrocnemius muscle, crosses be- hind the head or rather neck of the tibia, on the inner side of the knee. It first gives arteries to the back of the joint; then it communicates downwards with a large recurrent artery from the tibialis antica; it inosculates upwards with the articularis superior interna; it contributes (as all the other articular arteries do) to the forming of that profuse net-work of arteries which is spread over the whole ofthe capsule ofthe knee-joint. It sends also, like the others, certain twigs, which creep under the internal lateral ligament, and go into the cavity of the joint along tbe borders of the semilunar carti- lages. Those who write on aneurisms of the ham talk much of these arteries. They compare them with the recurrents of the arm; and think, when they see five articular arteries, that 214 OF THE THREE ARTERIES it is a sure sign that at such a point all is safe; when these ar- teries are all destroyed by the long compression of the popli- teal aneurism, or are ingulphed in the bag of the aneurism. If they ever appear, it is not as inosculating arteries, ensuring the safety ofthe limb ; but as small branches bursting into the sac, embarrassing the operator, and confounding every thing, sometimes filling the sac anew with blood, after all was thought to be quite safe, and the patient laid in bed. Before the popliteal artery passes under the head of the solreus, it gives two long arteries, which run down upon the two heads of the gastrocnemii muscles. It often also sends small twigs to the head of the solaeus, and to the popliteal and plantar muscles. OF THE THREE ARTERIES OF THE LEG AND FOOT. The three arteries are, the tibialis antica, going on the fore- part of the leg ; the tibialis postica, passing deep along the back part of the leg; and the peronea, which is the smallest and least regular artery of the leg, and which has its name from passing down behind the fibula. The popliteal artery divides below the ham, under the longer head of the solaeus muscle, into two arteries, the tibialis antica, and tibialis postica. The tibialis postica continues its natural direction downwards under the solaeus muscle, and behind the tibia. ARTERIA TIBIALIS ANTICA. The tibialis antica makes a sudden turn forwards, perfo- rates the interosseous membrane just under the lower edge of the popliteal muscle; passes out towards the forepart of the leg, betwixt the heads of the tibia and fibula : but still it does by no means become a superficial artery; on the contrary, it lies deep betwixt the heads of the tibialis anticus and the ex- tensor of the toes; and is covered here with a very strong fascia. It is only about six inches above the ankle that the leg grows tendinous and naked; there this anterior artery can be felt beating : it lies betwixt the tendons of the tibialis anti- cus muscle and that of the extensor of the toes; it passes down along with these tendons through the annular ligament, OF THE LEG AND FOOT. 215 and over the bones of the tarsus; it sends one branch across the foot, another forward to the great toe ; but the artery itself dives betwixt the first and second metatarsal bone iu the middle of the foot, and so gets to the sole^ where it ends in inosculations with the back arteries. There is here something like a posterior recurrent artery; for the tibial artery before it passes out ofthe ham, gives a small branch which ascends towards the back part of the joint, and is distributed to the heads of the bones, viz. the tibia and fibu- la, and to the origin of some of the muscles. arteria recurrens. There is here an anterior recurrent, larger than any is the arm, and much resembling the recurrens interossea. It is a branch which comes off from the forepart ofthe tibial arte- ry, instantly after it has perforated the interosseous membrane; it turns immediately upwards under the flesh of the tibialis an- ticus; it gives many muscular branches, some to the head of the tibialis, others to the upper part of the extensor digitorum, and branches go round the head of the fibula to the origin of the long peronaeus muscle. One branch goes directly up- wards, and spreads all over the lower part of the knee-joint, mixing its branches in the common vascular net-work. The tibialis antica gives no other branch of importance, or which should be named, even from the place of this recurrent quite down to the ankle-joint; for this, like the radial or femo- ral, or any long muscular artery, continues giving off branches from either hand to the muscles betwixt whicii it runs, of equal size nearly, and all equally unimportant. The tibial artery, then, as it runs down the forepart of the leg, gives branches to the Tibialis Anticus on one hand; to the Common Extensor of the toes on the other hand; and to the Extensor of the great toe, which is the last of the three muscles that occupy the forepart of the leg. It also gives little arteries to the tibia, to the fibula, and to the interosseous membrane whicii lies be- twixt them ; but still it arrives unexhausted at the forepart of the ankle-joint. But before it crosses the joint (which it does by passing ob- liquely along with the tendon of the great toe) it gives out two malleolar arteries, (i. e.) two arteries, one to the outer, and one to the inner ankle. 216 OF THE THREE ARTERIES ARTERIA malleolaris interna. The artery of the inner, ankle goes off just where the head of the tibia begins to bulge. It turns over the inner an- kle in many small branches; some mounting upwards along the tibia, but more going downwards over the inner side of the joint, (?. e.) over the tibia or inner ankle, over the astragalus, and some down as low and as far backwards as the heel- bone. ARTERIA MALLEOLARIS EXTERNA. The artery of the outer ankle goes off a little lower down. It sends smaller branches upwards round the outer ankle, whicii go to the Peronaeus Brevis muscle, to the joint, and to the common extensor of the toes, inosculating round the outer ankle with the fibular arteries. But its chief branch de- scends along the forepart and outer side of the foot, gives twigs to the short extensor of the toes, and ends in inoscula- tions with the tarseal arteries, or arteries belonging to the fore- part of the foot. The arteries which belong to the forepart of the foot are usually three in number: one goes off from the tibial artery a little above the ankle-joint, and is named Arteria Tarsea, be- cause it crosses the foot over the bones of the tarsus. To this succeeds a second about the distance of half an inch from it, and which crosses the foot at the place ofthe metatarsal bones; it is named Arteria Metatarsea: and the one or other of these gives the interosseous arteries, accordingly as the one or the other is small or wanting. The third is that remarkable branch which goes forwards along the great toe, whence it is named Arteria Halucis. ARTERIA TARSEA. The tarsal artery, which is sometimes of a very conside- rable size, almost equal to the tibialis itself, comes off a little below the ankle, upon the forepart of the foot. It lies upon the second rank of the tarsal bones ; it passes under the head of the extensor brevis of the foot; it crosses the foot oblique- ly, so as to end in the abductor muscle of the little toe, and in inosculations with the arches of the sole of the foot. This branch gives small inosculating arteries upwards, which OF THE LEG AND FOOT. 21? first give branches to the joint, and then join with the external malleolar and peroneal arteries. Next it gives branches to the bones and joints of the tarsus, which it lies upon; as the cuboid and cuneiform bones, and their joints. Thirdly, It gives small arteries to the bellies of the extensor brevis, where it lies under it. But its greatest arteries are the interosseous arteries, which it sends along the interstices betwixt the metatarsal bones. These interosseous arteries are three in number; they run along in that interstice which holds the interosseous muscles; and when they arrive at the end of that furrow, or, in other words, at the place ofthe forking ofthe toes, each interosseous artery turns down to the sole ofthe foot, and goes into the fork of each digital arch, on tire lowest side of the toes. Sometimes these arteries give also small dorsal arteries to the backs of the toes. The tibial artery having proceeded along the tarsal bones, and arrived at the lower heads of the metatarsal bones, and having first given off some trivial branches to the joints of the foot on its inner side, and to the bones and muscles about the root of the great toe, next gives off a metatarsal artery.* ARTERIA METATARSEA. The artery ofthe metatarsus or instep goes off at the head of the first metatarsal bone. It bends across the roots of the metatarsal bones to the root ofthe little toe ; and it distributes branches to the tendons of the peronaei muscles, and ends in the abductor of the little toe, and in the skin over the outer edge ofthe foot. But sometimes it is a larger and more im- portant artery ; for when the tarsal artery is small or wanting, this metatarsal one gives off the ipterossei, and supplies its place. DORSALIS EXTERNA HALUC1S. The third branch is the artery of Ihe back ofthe great toe. This artery is of very considerable size; it gives no muscular branches, because it lies upon the bony part of the foot; it runs all along the metatarsal bone which supports the great toe ; and it ends at the forking of that toe in two great * N. B. Betwixt the tarsal and metatarsal artery, there is usually a small hranch going outwards totlje outer edge of the foot, (i. e.) in the same direction with both these arteries, but very small. ' vol. n. E e 218 OF THE THREE ARTERIES branches ; one the dorsal artery of the great toe, which goes along it to the point; another to the side of the toe next the great toe, which it also runs along, somewhat like the forking arteries ofthe thumb and fore-finger. The anterior tibial artery ends here (t. e.) (where it gives off the artery ofthe great ioe.) By sinking in betwixt the meta- tarsal bones ofthe great toe and of the toe next to it, and going directly into the arches of the sole of the foot, it produces a great and important anastomosis, similar to that ofthe radial and ulnar arteries. ARTERIA TIBIALIS POSTICA. The posterior tibial artery is so named from its pass- ing along the back part ofthe tibia. The anterior tibial ar- tery passes through the interosseous membrane only at the lower edge of the popliteal muscle: this artery comes off from the general trunk at the upper edge of the popliteal mus- cle, and passes obliquely towards the inside of the tibia, to take its place behind that bone. Its whole situation and gene- ral course is this : It lies over the tibialis posticus and flexor muscles; it lies under the bellies of the gastrocnemius and so- laeus ; it turns round the inner ankle close upon the bone. Having passed the lower head of the tibia, it goes down along the inside of the heel-bone, in its deep arch, upon which the body is supported ; it divides at the heel-bone, and advances along the sole ofthe foot in two great branches ; one running along the sole, next the outer edge of the foot ; the other along the inner edge of the foot : whence they are named external and internal plantar arteries. From this arch the artery gives branches to all the toes, and so it ends. This posterior artery is chiefly a muscular one, at least in its course down tbe leg ; and though it gives many branches as it passes along, there are hardly any worthy of being described : and from the knee to the ankle-joint there is one only which needs be distinguished by name, viz. the artery which nourishes the tibia. First, The tibialis postica often gives arteries to the heads of the gastrocnemii muscles; next it gives off the arteria nutritia ttbije, which begins a little below the lower edge ofthe popliteal muscle, runs downwards along the interosseous ligament, gives muscular branches to the popliteus, solseus, and tibialis posticus, and then sends the nutritious artery into the great hole in the middle ofthe tibia. It gives many branches to the periosteum of the tibia, and to the interosseous mem- brane all down the leg, and it ends near the lower end of the tibia in inosculations with the poroneal artery. " OF THE LEG AND FOOT. 219 Other nameless muscular arteries succeed to this, going to the tibialis posticus, to the flexor communis, and to tbe flexor of ;the great toe. When the artery arrives near the ankle-joint, it gives many small twigs to the periosteum, tendons, sheaths, and bursae mucosae behind the ankle; and then passing in the very deepest part of the ankle, under the annular ligament, and betwixt the tibia or process of the inner ankle and the heel-bone, it adheres closely to the bone and capsule of the joint; and there gives a great many little tortuous arteries, making net-works over this joint and its bones, as over the other joints already described. But especially two delicate arteries go out at this hollow at the side of the heel-bone : one forwards towards the side of the ankle-joint, the other down- wards and backwards over the heel-bone, which ramify very profusely and very beautifully. The artery now lying deep under the abductor magnus of the great toe, whicii arises from the heel-bone, forks into its. two great, branches, the external and internal plantar arte- ries. ARTERIA PLANTARIS INTERNA. The internal plantar artery is much the smaller branch, not to be compared in importance (though their names are contrasted) with the external plantar artery; and it is named internal, because as it runs along the sole of the foot it keeps to the inner edge, viz. that to which the great toe be- longs. It comes off under the head of the abductor of the great toe, and under the belly of that muscle, and close upon the bone ; its branches run forwards, quite up to the root of the toe, all along its metatarsal bone. The internal plantar artery has in general four branches, which all run pretty nearly in the same direction, viz. straight forwards. It gives, while under the head of the abductor, small branches, which go backwards to the joint, its capsule, and ten- dons, and some into the spongy substance of the heel-bone; some also to the short flexor of the foot, and to the massa carnea. But its four greater and more regular branches are these : The first lies nearer the inner edge ofthe foot; is the largest and most considerable; it runs along under the inner bor- der of the abductor; it goes quite up to the ball of the great toe, and unites with the proper artery ofthe toe. As it goes along it gives small twigs to the periosteum and bone. The second resembles the former, except that it does not 220 OF THE THREE ARTERIES come off so early by two inches ; it is of course shorter, but it passes along in the same direction, only a little distant from the first, lying along the middle of the metatarsal bone. It also advances up to the root ofthe great toe, and runs also into the proper artery of the great toe (whicii comes from the ex- ternal plantar branch) so as to enlarge and strengthen it. The third lies still nearer to the centre of the foot, and deeper among the muscles It runs the same general course, viz. along the side of the metatarsal bone up to the ball of the great toe, and ending like the others in the arteries of the great toe; but as it lies deeper, it gives branches to the short flexor, to the tendons, and to the inner surface of the aponeu- rosis plantaris, forming a sort of superficial arch. From these three arteries, much of the skin on the sole of the foot has its branches. The fourth and last branch of the plantaris interna, is one which goes down deep into the centre ofthe foot; it lies close upon those ligaments which bind together the bones of the tarsus, and under all the tendons, except those of the tibial muscles, which are like ligaments to the bones. Its destination is chiefly to the tarsal joints and capsules; its inosculation? with the external plantar artery can be of no importance. plantaris externa. The external plantar artery is the great artery of the sole ofthe foot, from which the arches of the foot and the in- osculations with the anterior tibial artery are formed. It turns outwards towards the outer edge ofthe foot; it runs its great circle round by the metatarsal bone ofthe little toe ;and its plantar arch, or the arch of the sole of the foot, passes over the middle of all the other metatarsal bones. It receives the anterior tibial artery under the middle of the metatarsal bone of the great toe. It is this great curve of the artery turning round in the sole ofthe foot that we name tbe plantar arch; and it is from it that all the proper arteries of the toes arise, expressly after the same order in which the fingers receive their arteries. The great or external plantar artery lies deep, but not upon the naked bones like the former. It passes through betwixt the heads of the short flexor and massa carnea; it turns its first turn outwards till it gets under the flexor and abductor ofthe little toe; then it turns inwards towards the centre of the foot, and lies under the tendons of the long muscles, and over the metatarsal bones and their interosseous muscles. OF THE LEG AND FOOT. 221 First, it sends a large branch backwards to the heel-bone, which belongs entirely to that spongy bone ; forms, like all such arteries, a sort of net-work over all the surface of the bone; it first touches the bone under its extreme point, or that which rests upon the ground; and it goes branching over it so high as to inosculate round the ankle with twigs ofthe tibialis antica; it gives branches also hereabout to the great ligament of the heel-bone. The external plantar artery next gives branches to those muscles betwixt which it lies imbedded, viz. the massa camea and flexor brevis; then advancing to the side of the flexor digiti minimi, it gives out two or three branches, which first go into the flesh of the abductor and flexor of the little toe, and then turning over the edge of the foot, termi- nate in inosculations with the arteries of the forepart of the foot and in the skin. It then begins from the root of the metatarsal bone of the little toe to form that great circle, which is named the arch of the foot, and which gives out two ranks of arteries: First, of interosseous arteries going to the spaces betwixt the meta- tarsal bones, upon which the toes stand; and, secondly, the proper arteries of the toes themselves. The first of these arteries proceeding from the tarsal arch is a small one, the artery ofthe little toe. It begins at the lower head of the metatarsal bone, lies under the flexor and abduc- tor muscles, gives branches to these muscles, and to the skin, and to the bone itself; it runs up the outer edge ofthe little toe, and this is immediately succeeded by the first interosseous artery; which lies deeper, passes along the first interosseous space, gives branches to the bones and interosseous muscle,, and inosculates betwixt the toes with the branches of the ante- rior tibial artery. The next artery is properly the first of the arch. It is what is called the ramus digitalis, or proper artery of the toes. It is a long artery, runs over the interosseous space lying upon the interosseous muscles; it advances to the root of the little toe, and like those of the fingers, divides into two branches, one to the inner side of the little toe, and the other to the side of the toe next it. A second and a third digital artery go out in the same manner, and split at the roots of the toes into two branches, and with so little variety that is needless to describe each part. In the interstices of each of these arteries lie two or three small perforating arteries, which, perforating betwixt the meta- tarsal bones, inosculate with the interosseous arteries which lie on the forepart of the foot. But the great external plantar artery, while it is giving out 222 OF THE THREE ARTERIES these arteries alternately, (i. e.) large branches to the toes, and smaller twigs to the interosseous muscles, and some smaller still which go off from the concave part ofthe arch, and go into the sole of the foot to the ligaments and joints; the great ar- tery goes still onwards, and completes its arch at the middle of that metatarsal bone which supports the great toe. There, a little behind the ball ofthe great toe, it receives the tibialis an- tica, which perforates from the forepart ofthe foot. This com- pletes the arch of the anterior and posterior arteries, and per- mits the blood to pass, according to the pressure, or other acci- dents, in either direction; and this union strengthens and enlar- ges the artery of the plantar arch so much, that it is not ex- hausted by the many branches which it has given off, but gives at this point the largest artery of all, viz. the artery which sup- plies the great toe, and one side of the toe next it. This arte- ry of the great toe is the very last or extreme branch of the aortic system. It very closely resembles the great artery of the thumb; it gives out three chief branches, viz. one to each side of the great toe, and to the inner side of the toe next it. This arteria pollicis pedis sometimes seems to proceed entirely from the perforating branch of the anterior tibial arte- ry ; at other times it arises fairly from the plantar arch. ARTERIA PERONEA. The fibular artery, orthe third artery of the leg, which is much smaller than these two, is to be regarded rather as a branch of the anterior tibial artery; and in its course and con- nections, and its being exhausted nearly by the time,it reaches the ankle-joint, it greatly resembles the interosseous of the fore- arm, which stops below the wrist, or passes it only with small and extreme branches. Where the tibialis antica passes through the interosseous ligament, the arteria peronea breaks off from it, almost of equal size with itself, and passes down behind the fibula, whence it has its name. It arises near the head or origin of the tibialis posticus muscle, and accompanies that muscle down to the ankle-joint, lying betwixt it and the flexor of the great toe. This is entirely a muscular artery for supplying those deeper parts which the other arteries do not supply. Its branches, like those of all muscular arteries, are extremely irregular j its chief branches are to the solaeus, to the peronaei muscles, to the tibialis posticus, to the flexor ofthe great toe. Several lit- tle arteries turn round the fibula from point to point, going to the forepart ofthe leg. All the way down the leg, it is giving off repeated branches to the same muscles; and in this course it OF THE LEG AND FOOT. 223 gives some little arteries, which pierce through the interosseous membrane, and also gives the nutritious artery of the fibula. When it approaches the ankle-joint, the fibular artery gives off an anterior branch, whicii perforates the interosseous mem- brane, passes through betwixt the tibia and fibula nearly where they are joined; it turns downwards over the outer side of the ankle, by the extensor pollicis and peronaeus brevis tendons. This is named peronea anterior, though it is an artery of little importance. Its branches are given not to muscles, for this is a naked and bony part of the foot; but are expanded upon the lower heads ofthe tibia and fibula, and upon the os cuboides. They nourish the tendons, ligaments, and bursae of the outer ankle; they end in inosculations with the malleolar artery, from the tibialis anterior, and with the tarsal artery. ARTERIA PERONEA POSTERIOR. As this anterior fibular artery branches over the fore- part ofthe outer ankle, the posterior fibular artery pas- ses deep behind the same ankle, and is just the continuation of the main artery; which, having passed down behind the acute angle of the fibula, sinks into that deep hollow which is behind it upon the side of the heel-bone. Behind the tibia the artery makes large inosculations with the posterior tibial artery, and gives many branches to the tendons. Branches also turn round the ankle, making a net-work of vessels upon it, and inoscula- ting with the anterior tibial artery. It continues to give the same small arteries to the outer ankle, to the peronaei tendons, to the outer side of the heel-bone, and to the abductor of the little toe. It ends usually in that muscle, and in inosculations with that branch of the external plantar artery which turns backwards upon the heel-bone and ramifies upon it so beauti- fully. These are the last branches of the three great arteries of the leg and of the aortic system. ( 224 ) CHAP. V. OF THE STRUCTURE OF ARTERIES. ijHEATH.—Every where through the body wherever a ves- sel passes, be it the largest or the smallest, a tissue of cellular membrane surrounds the proper coats of the artery, and forms a sheath. Around the larger arteries the sheath of cellular texture is very distinct: it is dense, but elastic or yielding ; it is connected by a looser cellular membrane to the outer coat ' of the vessel, and its use is to support the vessel in its action, and to convey minute vessels to the coats. We see this sheath for a long time supporting tbe artery, or withstanding the force ofthe blood when aneurism has taken place in the proper coats. The surgeon has particular occasion to notice this part of the structure; for in his operations, sometimes the artery shrinking within the sheath, he may mistake the latter for the artery, and tie the ligature upon the mouth of the sheath in- stead ofthe mouth ofthe artery. Ckllular coat.—The cellular coat is tbe loose external tunic, in which principally we see the vasa vasorum distri- buted. It is described by some as the outer lamen of the first tunic* Tendinous coat.|—The second true coat is strong, tough, and elastic. It is this principally which gives the form to the artery. It is the toughness of this coat whicii enables the ves- sel to resist the application of a ligature, when all the inner coats are cut or burst.J The term tendinous coat, or cellular coat, does not convey the idea of the very peculiar texture of this tunic. It is a modification of the cellular texture, as every tissue in the com- position ofthe frame, but it is not cellular; on the contrary, this tendinous coat consists of minute strong filaments, inter- woven with much regularity, and in a manner the most admi- rable, bestowing elasticity and strength. Muscular coat.—The third proper coat is the muscular coat, which from the peculiarity of its texture and appearance some have imagined to be a structure distinct from muscle. To me it appears purely muscular; and the opinion, that it is not muscular, I conceive to have arisen in error. The muscu- * Blumenbach. + Tendinous by Vesalius and Senac. $ Desault, Bicliat, Jone? OF THE MOTION OF THE BLOOD, &G. 225 iar fibres are connected by a very short and weak cellular tex- ture, to which circumstance it is owing, that this coat does not resist the ligature. The fibres run in a circular direction round the artery, and yet no one fibre completes the circle, but is lost in the uniting cellular tissue. The inner coat.—The last and internal coat of an artery is smooth, polished, and very close in its texture : there is no distinction of fibres observable in it; it is weak, especially when stretched in the transverse direction. When we make a section of an artery, we perceive that it consists of a darker internal ring, and a white external circle. The outermost of these, as Mr. Hunter observed, is composed entirely of elastic matter. The inner is composed both of elastic and of muscular substance, but chiefly of the latter. The darker internal layer or circle is scarcely to be observed in the larger arteries; but in making sections of the arteries further on in their course the proportion of the dark internal circle is uniformly increased. The powers of an artery in moving forward the blood, are elasticity and muscularity. The muscularity acts uniformly in contracting the artery. The elasticity operates in a manner less simple, for it assists both in contraction and in dilatation; that is to say, if the artery be dilated, the elastfc power of the coats contracts to a certain state or degree ; this, however, h not the whole contraction of the vessel, for the muscular power continues the contraction further* not only without the aid of the elasticity, but in opposition to it; and, consequently, when ihe muscular fibres have ceased to act, the elasticity regains its influence, and dilates tbe artery to a certain middle state. The use of the elasticity being to take off the jar of the heart's action from the artery, and to resist the shock, it is greatest in the coats of the arteries nearer the heart. The elastic power is weaker in the extreme arteries. The muscu- lar power of the arterial coats being in aid of the heart's mo- tion, it is least in the arteries near the heart, and is increased in the proportion in which the artery is remote from the heart. OF THE MOTION OF THE BLOOD THROUGH THE ARTERIES. There is no subject of physiology more important than the consideration of the causes which accelerate or retard the blood in the arteries, and none on which it appears to me that more extraordinary mistakes have been entertained. The increasing muscularity of an artery, as it extends from the heart, is a means of givingincrease of arterial power in pro- vol n. Pf 226 OF THE MOTION OF THE BLOOD portion to the diminution of the power of the heart. By this means the blood circulates with an equal velocity in parts near and in parts remote from the heart; yet the length of an ar- tery has been considered as a means of subduing the velocity of the blood, and the tortuous form of an artery has been con- sidered as the most effectual check to the force of circulation. Exactly the reverse of this is the case. A few examples will prove it. The blood mounts against the power of gravity to the head ; an increasing tortuosity distinguishes the arteries of the head : the arteries of the temple and the occiput increase in their tortuosity as they advance upwards. The arteries of the mamma go in a straight course while the woman does not give suck, but if he should die while nursing, then the tor- tuous form of the arteries is very remarkable. If a tumour grows upon any part of the body requiring or exciting a great- er flow of blood to the part, then we find that the vessels of the part which in their natural state are nearly straight assume a tortuous form at the same time that they are enlarged. The surgeon knows well that if he cuts a tortuous vessel in an ope- ration, the blood flows from it with a force much greater than from a vessel in its natural state. If the muscles of animals require much and long exertion, they require also more blood to preserve an increased irritability or power of action, and therefore they require tortuous arteries. Thus the muscles of the jaws of the lion, the muscles of such animals as cling and hang to branches of trees, possess tortuous arte- ries to carry on the circulation with more than common power during their long and powerful action. More numerous proofs might be given to shew that the tortuous artery being an ar- tery with an increased muscularity is ever a more powerful artery. It appears to me that the nature ofthe forces circulating the blood have been much overrated from the neglect of a princi- ple whicii more than any other should raise our admiration, and is important in the practice of surgery. They have calculated the power of the heart by the difficulties to be overcome in the circulation. They have made a fluid ofthe exact degree of viscidity of the circulating blood ; they have put this into a glass tube, the extremity of which was drawn into a capillary vessel; they have raised the fluid in the tube until it flowed through the capillary extremity, and by the height of the co- lumn they have calculated the force necessary to push the fluid onward. But the operations of nature in a living body are not thus by calculation, but by an infinite wisdom, which saw that such motion was impossible without the principle of life; and in this instance it does not operate merely by force of the con- THROUGH THE ARTERIES. 227 trading sides of the vessels, but in a manner still more admira- ble. The cohesion or attraction betwixt the fluids and the ves- sels is destroyed; there is no such cause of retardation as we witness in dead tubes in inert matter. A weak impetus pro- pels the blood, because it has not the force of attraction to overcome ; but if by injury, inflammation, or any other de- rangement, the peculiar influence existing betwixt the vessels and their fluids is deranged, then the blood adheres to the sides of the vessels, coagulates and stops; which is the occa- sion of the spontaneous stopping of the blood in cut vessels; and I must add, a principle most strangely overlooked in many ingenious books, which offer an explanation of this circum- stance. BOOK 111. OF THE VEINS. CHAP. I. X HE veins are the vessels by which the blood carried out- ward by the arteries is returned to the heart. The system of the veins, however, is not so simple as that of the arteries, for while there are only two great arteries carrying the blood from from the heart, viz. the aorta and the pulmonic artery, there are three great trunks of the veins, viz. the superior and infe- rior vena cava, which are the trunks of the great veins of the body; the pulmonic vein, which returns the blood to the heart from the circulation through the lungs; and- the vena portae, which collects the blood of the intestines, and conveys it to the liver. There are, besides, a greater variety in the dis- tribution of the veins than in that of the arteries. The French physiologists have departed from the old me- thod of Harvey, in explaining the circulation. He wisely took the heart as the centre of the system, and described the ves- sels going out from it, forming the two circulations, viz. through the body and through the lungs; but they have assumed the lungs as the centre; and the veins of the body, and the arte- ries of the lungs, they call systeme a sang noir, because it con- tains the dark coloured blood; and the pulmonic veins and the arterial system of the body they call systeme a sang rouge, because it conveys blood of the bright vermilion colour. This conceit is perhaps admissible, when introduced as an additional illustration of the relation ofthe lungs to the body; but it causes in a difficult subject an unusual degree of intri- cacy, and does not serve the purpose of demonstration: be- sides, the arteries and veins of the body, and the pulmonic ar- tery and vein, have that strict and mutual dependance in ac- tion, which shows how improper and how unnatural it is to make this change, and to separate them in explaining the general system. At all events, let those who adopt this novel- ty cease to speak of the two circulations, for although in re- gard to the heart, there are two circulations, yet as the move* OF THE VEINS IN GENERAL. 229 uient of the blood respects the lungs, there is only one. By this division, the blood returning from the body, and carried into the lungs, cannot be called a circulation; but only when k has passed through the lungs, and returned to the same point of its course through the body. I retain the old method, corresponding with what has been delivered in the preceding volume, and in describing the veins will follow the course of the blood through them. GENERAL CHARACTER OF THE VEINS. The capacity of the veins is greater than that of the arte- ries ; the coats are thinner but stronger comparatively, and ad- mit easily of dilatation to a certain extent. The coats of the lesser veins are comparatively stronger than those of the larger ones, and the veins of the lower extremity much thicker and stronger than in the upper parts of the body, as they have to bear a higher column of blood. The veins are transparent and the blood is seen through their coats. The veins have three coats. The outer coat is composed of a reticulated tissue of cellular membrane, which is wrapped somewhat loosely around the proper coats. The second coat or proper coat has the same character of an interwoven texture of filaments; but it is more ' dense, especially on its internal surface, where it approaches the inner coat. The inner coat is dense and unelastic, resem- bling the inner coat of the artery, but stronger, more pliant, and less easily ruptured by ligature. Betwixt all the coats there is a fine cellular substance interposed.* The inner coat being smooth and flexible is formed into valves in various parts of the veins; which valves are semi-lunar, and resemble those in the root of the great arteries in the heart. Vein inverted. In all the larger veins, excepting those ofthe viscera, ofthe * Unless near the auricle no muscular fibres have been observed. See Hafieri Opera Minora, j}. 17». 280 OF THE VEINS abdomen, and those ofthe lungs and brain, there are valves; but in the smaller veins there are no valves: these valves, as I have said, consist of the inner coat, forming folds like a curtain, hung across the calibre of the vein ; but at the same time at- tached so obliquely to the side of the vein, that they present a sacculated membrane to receive the refluent blood. The loose margin of the valve is somewhat stronger than the other part, and betwixt the duplicature some little filaments may be ob- served. Each valve consists, in general, of two semi-lunar membranes, the margins of which, falling together, prevent the blood from passing retrograde ; but they yield and give freedom to the current of blood when flowing towards the heart. Authors have not noticed a part ofthe structure essential to the operation of a semi-lunar valve. I mean the little sinuses or more dilatable part of the coats of the veins just above the attachment of the valve. These sinuses are of the same use here that they are in the origin of the great arteries from the heart. The blood running back dilates them, and thus catches the margin of the valve and throws it down. Without this provision, the valve being collapsed to the side of the vein. the blood might be permitted to pass retrograde A ligature high on the arm or thigh not only causes the veins to swell by preventing the free course ofthe blood back to the heart, but it shows the veins in their distinct and natural character, and causes the sinuses of the valves to rise, shewing the places ofthe valves. The sacs formed by the valves of the veins are much deep- er sometimes than the term semi-lunar implies, insomuch that the term pyriformis has been used. Neither are the valves always double, for sometimes they are single, and sometimes three in number.* They are best seen by opening the veins under water. As the veins are provided with valves only where they are exposed to occasional pressure, and particularly to the com- Eression of the muscles, the use of the valves would seem to e, to prevent the retrograde movement of the blood, in con- sequence of the occasional compression of the veins; but no doubt, they at the same time support the column of blood, as in the lower extremities : and when those veins suffer disten- tion by disease, a great aggravation is, that the valves lose their action, for the vein is now too large to be closed by them, and the whole column of blood presses upon tbe veins of the legs. Fabricius ab Aquapendente, who discovered the valves of the veins, though ignorant of the circulation, and ofthe true use * Fabricius de Venarum 03teolis. Morgagni Epiat. Anatom. XV. Kerckringi Spici. \egium Anatomicum, Tab. 4. IN GENERAL. 231 of the valves consequently, yet argues very ingeniously; for he imagined that exercise by heating the limbs would draw the blood from the trunk, to the injury and rup- ture of the vessels of the limbs, and the too great diminu- tion of nourishment in the vital parts, were it not for the office of these valves. But Harvey, observing the mechanism of these membranes, was drawn to conclude that the blood must always run in one direction in the veins, and consequently, that there must be a circulation ofthe blood. The commencement of the minute branches of the veins is from the extreme ramifications ofthe arteries; they are con- tinuous, and convey back the blood in that course which is called the circulation. In contemplating the capillary tissue of vessels, the most striking circumstance is, the predominance of the dark venous ramifications: and in general two sets of veins will, even in these minute ramifications, be observed; one superficial, the other more intimately blended with the minute ramifications of the arteries; but in the internal parts of the body, and particularly the viscera, the veins uniformly accompany the ramifications of the arteries, and in the solid viscera, a dense cellular membrane gives lodgment to both sets of vessels. In the extremities and head, indeed every where but in the viscera, the veins form two distinct sets; the deep and the superficial veins : the deep veins accompanying the arteries ; and the sub-cutaneous veins, which emerge from the compres- sion of the muscles, and run above the fascia. The union be- twixt the branches of the veins is very frequent, not only be- twixt the veins, ramifying in the same plane insomuch as to make them a mere net-work, but also betwixt the deep and superficial set of veins: such are the veme emissariae of the skull, the free communications betwixt the external and inter- nal jugular vein, betwixt the deep and superficial veins ofthe arm, &c. When in bleeding, the blood flows from the vein ofthe arm, accelerated by the working of the muscles, the blood escapes by the anastomosis, from the compression of the muscles, and fills the superficial veins ; but the increase of the jet of blood is principally produced by the swelling of the muscles, causing the fascia to compress the internal veins of the fore-arm. In the dead body "the veins are flat, but when distended they •resume the cylindrical figure whicii they possessed in the living body ; yet they are in general of the cylindrical figure for a very small part of their course only, owing to the irregu- lar dilatations by the side of the valves, or by the frequent union of their branches. The manner in which the branches 232 Otf THE VEINS join the trunk has a peculiarity which always distinguishes them from the ramifications of arteries: the arteries branch direct and at an acute angle, the veins in a direction more removed from the course of the trunk, and in general with a curve or shoulder. In infancy and youth, the veins are little turgid, and espe- cially the cutaneous veins are so firmly embraced by the elas- tic skin and cellular membrane, that they have a less degree of prominency than in more advanced years. In old age, .the veins are enlarged, and rise turgid on the surface, and the in- ternal veins also become enlarged and varicose. Soemmerring says, with increasing years the resisting power ofthe veins is diminishing, that ofthe arteries increasing.* I believe this to be incorrect in regard to both kinds of vessels. I do not consider the change in the vascular system as the effect of mere distention, or of the enlargement of the veins, from the long continued action of the arteries ; but as a neces- sary change in the proportionate distribution of the blood, which is preceded or accompanied with other peculiarities, the character of old age. When we consider the great size of the veins compared with the arteries, we must conclude that the blood flows but slowly in the venous system; that from the narrowness ofthe trunks ofthe veins near the heart the blood must be accelerated as it approaches the heart; and that re- ceiving the impulse from the ventricle, it must take a rapid course through the arteries, until, again approaching the ex- treme branches ofthe arteries and passing into the veins, its motion becomes more languid and slow. Jn youth, as the size of the veins is not in so great a proportion to the arteries as in advanced life, the blood in a young person must be in more rapid and quick circulation : but in old age, owing to the largeness of the veins and the accumulation of blood in them, the blood moves slowly through the venous system, and is almost stagnant in the dilated veins and sinuses; upon the whole, it moves less briskly through the vessels, and the pro- portionate quantity immediately under the influence ofthe ar- terial system is less than in youth. There is no pulsation to be observed in the veins, but what they receive laterally from the contiguous arteries. There is no pulsation in the veins, because they are removed from the heart; because they do not receive the shock of the heart's action in their trunk, but only by their widely-spread branches; becaur' the contraction ofthe heart and ofthe arteries so alter- nate with each other, as to keep up a perpetual and uniform. s Vol. v. "i ccxxyiii""" IN GENERAL. 233 stream of blood into the veins; whereas the pulsation in the arteries is owing to the sudden and interrupted contraction of the heart. In living animals 1 have undoubtedly seen the course ofthe the blood in the great veins near the heart alternately checked and accelerated in its motion. But this a subject which I have no disposition to pursue. This motion does not prove that there is here a muscular contraction.* I have distinctly seen a white fluid in the extremities of the veins of the human intestines. In this general account of the venous system, it remains on- ly to speak ofthe subject of absorption. Before the suite of experiments made on this subject by Mr. Hunter, a vague no- tion was entertained that the veins were absorbents; but about that time,t tbe doctrine that lymphatics were absor- bents having been established, the opinion that the red veins were also absorbents, was first questioned, and finally confuted, at least in the opinion of most physiologists. The chief argument to shew that veins, arising from cavities, particularly from the intestines, acted as absorbents, was, that some anatomist said they had seen white chyle in the blood taken from the mesenteric veins. It was however soon ob- served that the serum of the blood, taken from the veins of the arm, was sometimes white, which must arise from some other cause than the absorption of chyle.J The experiments of Mr. John Hunter proved that there is no absorption of fluid from aliment contained in the intestinal canal, by the veins of the mesentery, while the lacteals were rapidly absorbing. Emptying a portion of the gut, and the veins of their blood, in a living animal, he poured milk into the intestine. The veins remained empty and without a drop of the milk finding its way into them, while the lacteals became tur- gid with it. In another experiment, leaving the arteries and veins of the mesentery free, and the circulation through them perfect, still no white fluid could be discovered, tinging the stream of blood in the veins. Neither did pressure upon the gut in any instance force the fluid of the intestines into the veins. He repeated and varied these experiments, so as to show, in a very satisfactory manner, that chyle, or the fluid of the intestines, never is absorbed by the veins. Yet I must say that these experiments are still unsatisfacto- ry, as they regard the general doctrine of absorption by the * Hulkr found contraction produced in the veins by touching them with oil of vitrft*}. Opera Minora, p. 375. +1758. ; See Hewson, Esper. Essays and Lymphatic System VOL. II. Gg 2"J4 OF THE VEINS veins: in the intestines there is a peculiar set of vessels evi- dently destined to the absorption of the chyle and of the fluids ofthe cavity; but there remains a question which will not be easily determined : do not the veins throughout the body re- sume a part of that substance, or of those qualities, which arc deposited or bestowed by the blood ofthe arteries? Are we assured that in the circulation of the blood through the lungs, and in the extremeties of the pulmonic veins, there is no imbi- bing or absorption ? In the veins of the placenta, there is not only an operation similar to what takes place in the extreme branches of the pulmonic circulation, but the matter and sub- stance which goes to the nourishment of the foetus, is imbibed from the maternal circulation.* So by the vessels in the mem- brane of the chick in ovo, there is absorbed that which being carried to the chick, bestows nourishment and increase. For my own part, I cannot but suppose that, while the lymphatics absorb the loose fluids which have been thrown out on surfa- ces, or into cavities, the veins receive part of what is deposited from the arteries; but, which is not so perfectly seperated from the influence of the circulating system, as that which the lym- phatics receive ; and that there are certain fluids, which, by an affinity ofthe venous blood, they imbibe in the course ofthe circulation. We must at the same time acknowledge, that the conclusions made in favour of absorption by veins, from ex- periments upon the dead body, are fallacious, and have no weight. It is seldom we can determine whether minute injec- tions have taken a course by a natural or by a forced passage ; neither are the experiments of some ofthe older physiologists more satisfactory or conclusive. Lower affirmed that, by throwing a ligature on the inferior cava of a dog, he produced ascites. He tied the jugular veins of a dog, and the head be- came dropsical. Hewson repeated these experiments, but without the same result. And if the tying ofthe veins had al- ways produced cedema or dropsy, the experiment would have proved nothing more than is already established by the very common occurrence of cedema of the legs from the pressure of the womb on the iliac veins, or a tumour in the groin or in the pelvis. Now in these instances the compression of the vein does nothing more than cause a difficult circulation of the blood from the extreme arteries into the veins, and consequent- ly a greater profusion of the discharge into the cellular texture by the serous arteries. But even the experiments of Mr Hun- ter on the veins of the intestines, are not in unison with the ex- * Drs. Hunter, Hewson, &c. say that it is probable tiiere are many small lymphatics in the placenta, which open into the branches of the veins, and do not ta"ke a course along the cord. OF THE HEAD AND NECK. 235 periments of Sir Everard Home, who finds that the matter in the stomach and intestines is received into the system although the thoracic duct has been tied or cut. SECTION I. OF THE VEINS, BRANCHES OF THE SUPERIOR VENA CAVA. The superior vena cava, or the descending cava, is the su- perior trunk of the venous system ; which receives the veins ofthe head, neck, and arms, and throws the blood directly into the great right sinus, or auricle of the heart. But I hold it better to begin my description from the ex- tremeties ofthe veins, following the course of the blood. I therefore commence with the veins ofthe forehead. OF THE VEINS OF THE HEAD AND NECK. The anterior facial vein* The facial, or anterior fa- cial vein, runs down obliquely from the inner canthus of the eye, towards the angle of the lower jaw-bone. Here uniting with the temporal vein, it forms the external jugular vein. The most remarkable branches of veins which assist in forming the facial vein, are the frontal veins ; which receive the blood from the forehead and frontal portion of the occipito- frontalis muscle, and the ophthalmic vein, which is one of the emissariae, and comes from the cavernous sinus through the orbit. In its course down the cheeJt the facial vein re- ceives the several cutaneous branches orthe veins from the surrounding parts: but which have in reality no such import- ance as to require description.f The posterior facial vein ;"£ or great temporal vein. —This vein descends from the temple before the ear, through or under the mass of the parotid gland, and behind the angle of the lower jaw. This posterior vein receives those branches which are the proper temporal veins, and which are four in number, and de- scend upon the side of the head ;^ and those which answer to * Facial vein; V. Angularis; V. Triangularis. + Vena dorsalis nasi, superior et inferior—Vena palpebralis inferior externa et interna— Vena alaris nasi—Venn labiaUs magna et minores, &c.—Venae buccales, &c. j: Joannii Gottlieb llalteri, tab. ii. 65.—Venarum Capitis et Colli. ?■ Beino; in two sets, the deep, and superficial. Walter-, tah. ii.—Vena tempor. superf. 11(3. et I'cna temp, profund. 111. 136 OF THE VEINS the submaxillary artery, and also the vena transversa faciei/and the auricular veins. Finally, into some of the deep brapche* of this vein* the blood enters from the veins accompanying the arteria meningea. The posterior facial vein, uniting with the anterior one, forms a common trunk, which in general lies over the division of the carotid artery. EXTERNAL JUGULAR VEINS* The external jugular vein takes a course obliquely down the neck, and across the middle of the mastoid muscle. It lies under the fibres of the platysma myoides muscle, and drops either into the subclavian vein, or into the internal jugular vein. Sometimes there are two external jugular veins on each side; more commonly there are two branches high in the neck, from the anterior and posterior facial veins, which unite about the middle of it. When they are double they have this course ; the anterior and external jugular vein, may be said to begin from the anterior facial vein; it then receives the submental vein, which comes in under the base of the lower jaw—the' ranine veins also, and veins from tbe glands under the jaw join it here : where it is before the mastoid muscle, it forms free communications with the internal jugular veins; and here also, it receives veins from the side of the throat.f Almost all the ramifications of veins, which in one subject unite to the external jugular vein, and which come from the face and throat, do in others sink down into the internal jugu- lar vein. J Sometimes the atterior and external jugular veins join the internal jugular venr; sometimes the subclavian vein. The posterior external jugular vein is formed chiefly by the temporal vein, or posterior facial vein, which comes down from under the parotid gland ; it is then joined by the occipital veins,(i a little lower by the - cervical veins, and lastly, on the lower part ofthe neck it receives the muscular branches from the flesh of tbe shoulder; it then sinks into the subclavian vein. Of the thyroid veins.—The thyroid gland has two sets of veins as it has of arteries; the superior thyroid veins carry * Vis. Vena Pelerygoidece. \ Viz. The superior thyroid veins, and the deep laryngeal veins. 1> Walter loc. cit. tab. ii. 13. \ These communicate with tlie vertebral veins, and through the posterior mastoid for&i men with the lateral sinvr?. OF THE HEAD AND NECK. 23T back the blood from the muscles of the forepart of the throat, from the larynx, from the substance of the thyroid gland, and from the neighbouring part of the trachea and pharynx, and even from the fauces. Sometimes these thyroid veins enter the external jugular vein ; sometimes they descend upon tbe neck, taking the name of guttural veins, and unite them- selves with the internal jugular vein. The lower thyroid veins come from the lower part of the thyroid gland, and descend upon the forepart of the tra- chea, and enter the subclavian; or, more generally, the great, or internal jugular veins. Of the internal jugular vein.—Jugularis interna.*— Vena jugularis cerebalis.-I;—The internal jugular vein is formed by the conflux of the several great and posterior sinu- ses ofthe dura mater into the lateral sinus, whicii coming out by the foramen lacerum posterius of the basis cranii, ceases to be constricted into the triangular shape, and takes the form and peculiarities of a vein. From this foramen, common to the temporal and occipital bone, the jugular vein descends oblique- ly forward and downward, becoming from its deep situation somewhat more superficial, but in all its extent protected by the stemo cleido-mastoideus muscle, and passes under the omo-hyoideus muscle. The internal jugular vein is very ir- regular in its form; being sometimes much contracted under the angle of the jaw; bulging and much enlarged, or rather capable of being much distended in the middle of the neck; and again contracted before it joins the subclavian vein. The carotid artery, the internal jugular vein, and'the par vagum lie together in the same sheath of loose cellular membrane. The vein is to the outside of the artery, and the nerve is betwixt them. The internal jugular vein receives these communications and branches; behind the angle ofthe lower jaw, a branch of communication generally goes down from the posterior facial vein, and often it is joined by the internal maxillary vein : un- der the jaw it either forms free communications with the be- ginning of the external jugular vein, or it receives the ranine and guttural veins: at all events, there is a branch from the side of the throat, and the muscles of the os hyoides which passes into the internal jugular vein. From under the back part of the mastoideus muscle, it receives branches from the occipital veins, and forms communications with the vertebral veins. Near its termination the great jugular vein receives the guttural and lower thyroid veins. Ha)?0r, ifnn f Walter. 238 OF THE VEIN a Of the vertebral veins.—There is difficulty in assigning origins to these veins, for they are rather like a chain of com- munication ; they run in the holes of the transverse apophysis of the cervical vertebrae, and surround the processes with areolae. First, a communication is formed with the great late- ral sinus, then they receive the flat sinuses from under the du- ra mater, covering the cuneiform process of the occipital bone, (the basilar sinuses) and as they descend they form transverse communications, which receive the branches of that chain of inosculations, which runs down upon the spinal marrow. The vertebral veins, in their descent, send out divisions which run down upon the outside of the canal, and receive branches of veins from the muscles on the forepart of the vertebrae, and some of the proper cervical veins from behind. The vena cervicalis coming from the side of the neck, unites with the vertebral vein near its termination, in the back part of the sub- clavian, or sometimes in the axillary vein. SECTION II. OF THE VEINS OF THE ARM. The veins of the arm are in two sets, the venae comites; and the external or sub-cutaneous veins, being those without the fascia, and not subject to the compression of the muscles. Of these, the latter are the more important and require a par- ticular description. On the palm of the hand, the veins are few and small, be- cause they are the$| subject to compression in the frequent grasping of the hand ; but on the back of the hands and fingers, the veins are numerous and large. The veins creeping along the fingers, make a remarkable inosculation on the back of the first phalanges, and then passing in the interstices of the knuckles, form a great and irregular plexus on the back of the hand :* the principal branch of which sometimes takes the form of an arch.f The plexus of veins from the back of the hand is continued over the back of the wrist: when some of the larger branches, after playing over the heads of the radius and ulna, take a course, the one on the lower, and the other over the upper edge of the arm, whilst the back of the arm is left without any re- markable veins taking their course there. The veins on the back of the hand have nerves interming- 4 Plexus dorsalis raanus". ■f Amis venosa dorsali; OF THE ARM. 239 ling with them, viz. branches of the ulnar nerve, and the ex- treme branches of the muscular spiral nerve; so that it is a great mistake to suppose that bleeding in the back of the hand might be substituted- with advantage for the common opera- tion in the bend of the arm, in order to avoid pricking the nerves. Vena cephalica.—The vein ofthe back of the thumb run- ning into a trunk, which takes a course over the outside of the wrist, is called cephalica pollicis. From this vein and the division of the plexus of the back of the hand, a considerable trunk is generally formed, which takes its course on the radial edge of the arm, and is called cephalica minor, or radialis externa. This vein in its tract over the extensor radialis, and the supinator longus, has many lateral communications, particularly with the median vein. This vein, now joined by the median cephalic, and rising upon the outside of the humerus, is the great cephalic vein ; and it passes, first betwixt the biceps and triceps bra- chii*, and then betwixt the deltoides and pectoralis major mus- cles. Several small cutaneous veins play over the belly ofthe biceps muscle, and communicate with the basilic vein; a little below the external condyle of the os humeri, the cephalic vein detaches a branch which ascends betwixt the brachialis inter- nus and supinator longus, and which afterwards forms inoscu- lations with the basilic vein, on the back of the arm. The great cephalic vein passing up betwixt the tendons of the pectoralis major and the deltoid muscles, sinks into the axilla and joins the axillary vein. Vena basilica.* We trace the origin of the basilic vein from those veins which, being continued from the plexus, on the back of the hand, take their course over the lower head of the ulna. (A conspicuous branch of these veins, from the little finger, was called salvatella! by the ancients.) From this origin, the basilic vein takes a spiral course on the ulnar edge of the fore-arm, sometimes in one great trunk, oftener in two, sometimes in a plexus of veins; here it may be called ULNARIS SUPERFICIALIS, Or CUB1TAL1S INTERNA. This Vein, now arising before the inner condyle of the humerus, passes on the inner margin of the biceps flexor muscle; here it forms very free and numerous connections with the in- ternal or brachial vein, the satellites and cephalica; now passing up, until it sinks by the outside of the tendon of the pectoral muscle, it joins the axillary vein. The great basilic vein, or the great trunk, after it has as- * Brachialis. The ancients termed thfe basilic vein ofthe right arm, the vein of the liver, or vena hepatica brachii, and that of the left the vena splenica brachii. ■"• S.ilvatella mia^i Salvator bring opened as a sovereign remedy in Melancholia. 24U OF THE VEINS cended above the elbow, and received the median basilic, is joined by several deep branches of veins, as those which ac- company the brachial artery, called satellites or comites, a vein which is called profunda brachii; and still nearer its ter- mination, it receives the addition of the vena subJtiMrterttlis, or articularis and the vena, scapulares, viz. those answOring to the arteries of that name. Vena mediana major.*—This is a vein which runs up the middle of the fore arm, beginning from the plexus of veins, •which play over the flexor tendons, and come from the ball of the thumb ; it is a vein which is very irregular, being some- times double, and sometimes rather in tbe fform of a plexus, than to be considered as a regular trunk; often it is particularly short, and can be considered as a trunk, only for a few inches as it approaches the bend of the arm ; not unfrequently it is entirely wanting, and, as if annihilated by the greater size of the branches of the cephalic or basilic veins. But, for the most part, when this vein has ascended on the middle ofthe fore-arm, near to the bend of the arm, it divides; one branch passes obliquely outward, and joins the cephalic vein, the other inwards and unites with the basilic vein, the first is of course the median cephalic vein,! the second the MEDIAN BASILIC VEIN. These are the two branches which the surgeon most com- monly selects for bleeding. Around the median cephalic the cutaneous nerves play more profusely, and under the median basilic vein the humeral artery passes. It is by the awkward plunging of tbe lancet into the median basilic, that the country bleeder sometimes produces the aneurism of the artery; but the dreadful symptoms following the pricking of tbe nerve, are more frequently produced by bleeding in the median cephalic; cases however occur of the pricking ofthe nerves, while bleed- ing in the median basilic vein. Axillary vein.—The trunk of the veins of the arm passes through the axilla, until it arrives betwixt the first rib and clavicle, under the name of axillaris. Here lying by the side of the artery it receives many muscular branches from the flesh of the shoulder, the external and internal scapular veins, and the thoracic veins; in general where it passes by the head of the humerus it receives the cephalic vein. Subclavian veins.—The axillary vein continuing its pro- gress over the first rib, becomes the subclavian vein, and is join- ed by the external jugular vein. It then takes a direction downward, and being joined by the great internal jugular vein, * Vena media; vena superlicialis conrrouni?. Fabricii fig. brachii viva. 1 Portio cephalica, A. B. loc. cit. OP THE ARM. 241 and having received the trunk of the absorbent system just at the angle ofthe meeting with the great jugular vein, it termi- nates in the superior cava. On the right side the subclavian vein is shorter, and descends more directly ; on the left it is longer, but still its direction is downward and across the up- per part of the chest; passing before the treachea and the branches of the arch of the aor la, it joins the subclavian of the right side, and together they form the superior cava. Besides the jugular veins, the left subclavian vein receives these, a vein from the shoulder and lower part of the neck, the vertebral vein, with some lesser plexus of veins descending from the neck, and the thyroid veins. From below they receive the lesser internal thoracic veins, and the mammariae.* SECTION III. THE SUPERIOR VENA CAVA, THE VENA AZYGOS, AND LESSER VEINS OF THE THORAX. The superior vena cava is the trunk of all the veins ofthe head, neck, arms, and of the parts in the thorax; soon after it is formed by the subclavian veins, it is joined by the vena azygos, and receiving the internal mammary veins, and the venf. thymicje and pericardiac branches, the intercostal and bronchial veins, it descends into the pericardium, and dilates or opens into the right sinus or auricle. Vena AZYGOs.f This is the principal vein ofthe thorax, and chiefly of the walls ofthe thorax. It is observed to take its origin upon the vertebrae of the loins from some of the lumbar veins, or by inosculations with the renal, spermatic, or lesser branches of the abdominal cava, receiving the first and second lumbar veins, as in its ascent in the thorax, it receives the in- tercostal veins on either side ;f ascending betwixt the crura ofthe diaphragm, and by the side of the aorta, it sometimes receives the lower phrenic veins; in the thorax lying on the right side of the bodies of the vertebrae, and before the inter- costal arteries, it receives the bronchial veins from the root of the lungs, and from the trachea it receives the veins of the posterior mediastinum and oesophagus; through the inter- costal veins, it communicates with the external and internal mammary veins, and with the venal circles ofthe spinal mar- row. Upon the third vertebra, the azygos vein separates from the * Haller, Icon. Anatomic. Corporis humani Fasciculus III. tab arter. Pectoris. f Sine pari. t We except some of the veins from the interstices of the higher ribs, particularly on the right side, which enter the subclavian vein. vol. 11. H h 242 OF THE VEINS spine, and with an aroh, and bending round the root of the lungs, it opens into the superior cava, just where it is about to enter the pericardium : where "it opens into the great vein, it is guarded by a valve. This vein, however, like most others, has considerable vari- ety, and does not always merit the name of azygos, for some- times it is double, a division ascending on the left side of the spine, and uniting with the branch ofthe other side, just as it is about to enter into the superior cava. Of the lesser veins in the thorax.—The ven^ mam- mary take a course by the side of the internal mammary artery, and require no description. Like the arteries, they spread their branches on the muscles of the belly, and com- municate with the diaphragmatic and lumbar and epigastric veins. The left mammary vein terminates in the left sub- clavian vein, the right in the superior vena cava. The venje thymioze enter, either into the union of the subclavian veins, or they enter into the guttural veins, or the infernal mammary veins. The pericardiac veins gather their branches from the peri- cardium, from the aorta, trachea, and lymphatic glands ; they send down branches by the side of the phrenic nerve, which inosculate with the veins of the diaphragm ; they enter the internal mammary vein, or the superior cava, or the termina- tions of the right subclavian. The superior intercostal veins.—The right and left in- costal veins differ in their size and distribution; the right is small, and reoeives only one or two of the upper intercostal veins, which do not enter into the azygos vein. The vein of the left side begins even so low as the interstice of the seventh rib; it receives branches from the pleura, pericardium, and lungs, (viz. the bronchial veins,) and from the oesophagus; they enter the subclavian veins. CHAP. II. OF THE VEINS WHICH UNITE TO FORM THE INFERIOR VENA CAVA. J. HE inferior vena cava receives the veins of the lower ex- tremities, the hypogastric and abdominal veins, and the veins of the viscera of the abdomen; but those of the membranous contents of the abdomen are received by it only indirectly, and through the circulation of the liver. OF THE LEG AND THIGH. 243 OF the veins of the leg and thigh. We have observed that the veins of the extremities are iu two sets ; the deep and superficial. In the leg and thigh, the deep seated veins accompany the arteries, and receive the same name: the cutaneous veins are the saphena major and minor Saphena major.*—-A large and beautiful plexus of veins is formed on the forepart of the foot, and coming from the back of the toes, and outside of the foot. Two principal veins arise from the arch which these form : one takes the course behind the inner ankle, and is the saphena major; the" other passes over the outer ankle, and forms the saphena minor. The great saphena may be traced from the great toe, from the inside of the foot, and behind the ankle; it receives one or two branches from the sole of the foot. Sometimes the principal branch passes behind the lower head of the tibia, sometimes before it, or it forms circles here : a little above the ankle a vein from the middle of the metatarsal arch comes obliquely over the tendon of the tibialis anticus, and joins it. The saphena, now a considerable trunk, runs up the leg be- fore the inner margin of the belly of the gastrocnemius muscle, and on the inner ridge ofthe tibia. In this course it receives numerous cutaneous branches, and backward, over the belly of the muscles, it forms inosculations with the lesser saphena. From the inside of the leg the trunk ascends on the inside of the knee, where it receives several branches, coming round the joint, and over the head of the tibia. Now passing some- what obliquely, it ascends upon the thigh, and at the same time turns from the inside to the forepart of the thigh. In the the thigh the great saphena receives many branched and is not always a single vein: for sometimes the branches collecting form a small trunk, running collateral to the greater vein, and which joins it in the groin. In all this course, the saphena vein is superficial and lies imbedded in the cutaneous fat; with but a very slight and imperfect aponeurosis inclosing it; while it is external to the proper fascia of the leg and thigh. As it ascends upon the thigh, however, it does not dive sudden- ly under the fascia; but is gradually enveloped and embraced by the condensed cellular membrane and fascia. When it was more the practice than at present to bleed in S.iphena magna, interna 244 OF THE VEINS the ankle, the saphena major was the vein selected : but as in all the course ofthe vein, from the great toe to the knee, it is connected with the nerve which bears its name, there are not wanting instances of those bad effects from pricking of this nerve, which not unfrequently follow the bleeding in the arm. Saphena minor.*—This vein arises from the plexus on the outside of the dorsum pedis: it runs over the outer ankle, and above the fascia, covering the tendons of the peronei muscles. Here receiving many branches and forming frequent deep in- osculations, it mounts on the outside of the vagina or fascia, which covers the back of the leg, until arriving betwixt the ham-string tendons it sinks into the popliteal hollow, terminat- ing in the popliteal vein. The other veins of the lower extremity which accompany the arteries in their course, need little description. Anterior tibial vein.—The veins accompanying the an- terior tibial artery form many inosculations, and when minute- ly injected, almost conceal the artery. They are the anterior tibial veins, and only unite into a trunk, where perforating the interosseus ligament it joins the popliteal vein. Posterior tibial vein.—In the sole of the foot we have the external and internal plantar veins, which uniting into trunks, accompany the artery behind the inner ankle. In its course betwixt the soleus and the tibialis anticus muscles, it cannot be called tbe posterior tibial vein; for it is a mere net- work of veins surrounding the posterior tibial artery. It re- ceives, near its termination, a branch called suralis, from the gastrocnemii and soleus : it terminates in the popliteal vein. The VENiE teroneje, are the venae comites by the tibial ar- tery, and are two or three in number. All these veins have free inosculations with each other. The popliteal vein.—This vein is formed by the three di- visions of dieep veins accompanying the arteries of the leg, and the saphena minor. It lies more superficial than the artery, and seems to cling round it. As it ascends, however, it twists round the arttry, the artery being nearest the bone—a little above the joint it receives the lesser saphena. This vein, perforating the tendon ofthe triceps, comes to the forepart ofthe thigh, still united to the artery : it is now the crural vein. As it ascends it gets from behind the artery, so that in the groin it lies nearer the pubes than the artery does : opposite the trochanter minor it receives the internal and ex- ternal circumflex veins, and the vena proeunda femoris. * Vena saphena parva externa. OF THE LEG AND THIGH. 245 About an inch below Poupart's ligament the crural vein re- ceives the saphena major, and the small external pudic veins. External iliac vein.—The femoral vein lying on the in- side of the artery, or nearer the pubes, enters the abdomen under the femoral ligament, and passing by the side of the Psoas muscle becomes the external iliac vein. It receives several lesser veins just within the ligament, particularly the epigastric vein from the muscles and integuments of the belly, and the veins accompanying the arteria circumflexa ilii. The external iliac vein is joined by the hypogastric vein which ascends from the pelvis. It requires no minute description ; it answers to the distribution of the hypogastric artery. This, which is the internal iliac, joining the trunk from the thigh, forms the common iliac vein. Vena cava abdominalis.*—A little lower than the bifurca- tion of the aorta, the right and left common iliac veins unite. By this union they form the vena cava. This vein ascends upon the right of the aorta. It receives fewer branches than would naturally be imagined, because the veins of the viscera take their course by the porta into the liver. It receives the lumbar veins, the spermatic veins, the renal, super-renal, and phrenic veins. Passing upward, it is received into its appro- priate fossa in the liver, and seceding a little from the spine it receives the ven.e cavje hepatice, and perforates the dia- phragm ; entering the pericardium, it expands into the great sinus, or right auricle of the heart.f Renal veins.J—These veins are less irregular than the arteries of the kidney, which relation of the veins and arteries is uncommon. From the relative situation of the kidneys to the cava, it is evident that the right vein must be short; the left comparatively longer, and taking a course from the kidney over the aorta.^ Supra-renal veins.—These little veins are like the arte- ries in their course. The right one enters sometimes into the vena cava, sometimes into the renal vein. The left some- times receives the phrenic vein of that side and enters into the renal vein. Spermatic veins.—The veins of the testicles return from the minute extremities of the spermatic artery, distributed in the body of the gland and in the epidydimis. As these veins reach the cord they become very tortuous, and encircling the * Vena Cava inferior. t Vena? Cavae lusus. Act. Petrop. torn. xii. p. 262. Sandifort Thes. vol. i. p. 348. X Emulgent veins. $ The Renal veins, however, sometimes vary iu their number, the right being double or triple, the left even sometimes in four branches. 246 OF 1HL VEINS OF THE LEG AND THIGH. convolution of the spermatic artery, form a thick vascular body. The higher these vessels are, the nearer to the ring, the less convoluted they are, whicii makes the cord of a py- ramidal shape. This is most remarkable in brutes; and in them chiefly have these vessels got the name of corpus pam- piniform e.* The spermatic vein before it enters the abdomen, has col- lected the principal branches and is fortified with valves. These valves, however, sometimes lose their office in conse- quence of dilatation of the veins, and then comes a very un- pleasant varicose swelling of the spermatic cord. The spermatic vein coursing round the loins, gathers branches from the fat of the kidney, the ureter, &c. The right vein is generally double, the left smgle; the one joins the cava, the other the emulgent vein. * Pampiniformis, (i. e.) resembling the tendrils of the veins. Icon. Anatomic. Corporis humani Fasciculus iii. tab. Arter. Pectoris ( 247 ) BOOK IV. OF THE LYMPHATIG AND LACTEAL SYSTEMS OF VESSELS. CHAP. I. VV E have understood that the red blood circulates in the body through vessels (the arteries and veins) which have a direct communication at their extremities by inosculation; that although these vessels lie parallel to each other, and ex- tend from the heart to the remotest part of the body, yet the blood is said to pass through the circulation, because it is transmitted from the veins into the arteries through the cavi- ties of the heart; and from the extremities of the arteries di- rectly into the veins, returning again to the centre. In this transmission of the blood through continuous tubes, there is in the coats of the vessels an alternation of contraction and relaxation which impels it forward. But besides these arte- ries and veins carrying the red blood through the body, there are other pellucid vessels more remote in their connection with what is generally called the circulating system. SECTION I. OF THE CAPILLARY VESSELS, AND THE PHENOMENA PRESENTED BY THE MICROSCOPE. The capillary vessels are those extreme branches which are as minute as hairs; but this, though the literal, is not the general meaning of the term. By capillary vessels is rather understood those branches in which the changes are wrought from the blood, and which are either so minute as not to al- 248 OF THE CAPILLARY VESSELS. low the promiscuous flow of the particles of the blood, or possessed of such a degree of irritability and appetency, as only to allow certain parts of that fluid to be transmitted. It is proved, that in the living body there is no exudation; but no sooner is the animal dead, than the fluids exude from the vessels, the secretions pass through the coats of those receptacles which formerly contained them, and parts partake of the colour of that which is contiguous. From this fact, we are led to think that a property exists in the living fibre, which repels the fluids. Admitting this, it is very natural to suppose that the fibres, and more particularly the vessels in the capillary texture of each organ, possess sensibility, which has its relations to the fluids passing through them, or to be se- creted from them. The most beautiful phenomenon may be seen by the aid of the microscope, in the circulation of the blood, that is, the i transmission of the blood from the arteries into the veins. When the web betwixt the toes of a frog is submitted to the microscope, the eye at first discovers only a confused motion of particles. But by a steady continuance of the observation, we are soon able to observe the motion of the red particles ofthe blood. We do not discover the coats of the vessels, but con- \ elude, that they exist from the confined and certain course of i the particles which are in motion. We distinguish the arte- ! ries by the rapidity of the particles passing through them in single files, and pursuing these particles, they are observed to turn suddenly into larger vessels. These vessels, by the num- ber and slower motion, and altered direction of the red globules, are recognised to be the veins. When the animal is disturbed, there is a general acceleration of the motion ofthe blood in the small vessels. When the web or membrane is pricked and irritated, (as with salt and Cayenne pepper in so- lution upon a needle,) the motion of the particles in the arte- ries are accelerated in a very singular manner; if tbe excite- ment to inflammation be continued, the veins are seen to en- large, and an accumulation of red particles takes place in them by which they are visibly distended. These accumulated par- ticles are urged forward with a difficulty which seems to be occasioned by the attraction of the fluid to the sides of the coats. It is remarkable, that while we admire this proof of the cir- culation, we see the influence of the heart's action upon the blood in-these minute veins; for at each pulsation ofthe heart the red globules are sent forward, being stationary, or recoiling during the diastole. During the disturbance of the circulation of the part by the OF THE CAPILLARY VESSELS. 249 application of stimulus, there seems to be a certain attraction or cohesiveness betwixt the sides of the vessels and the red globules, which occasions the remora and accumulation of the red globules. The same was the consequence of cutting the vein across, for the blood, instead of flowing from the cut, be- came arrested in the vessel. Since we see that in an inflammatory state the pellucid veins transmit red blood, and that this red blood must be sup- plied by the serous arteries ; then it is proved that answering to the pellucid arteries (in their natural state) there are pellucid veins. We acquiesce, therefore, in the opinion that supposes both the arteries and veins to have pellucid capillary branches answering to each other, collateral to the larger and more evi- dent anastomosis of their red extremities. These anastomos- ing branches of the arteries and veins in which the red blood is seen to circulate, perpetuate the flow of the greater part of the blood back to the heart, while the several secretions are performed in the cappillary vessels; but there is no reason to suppose that the fluids sent from the arteries into these pellu- cid capillary vessels are all poured out in form of secretions : part returns into the extremities of the circulating veins. The secreted fluids and solids are either carried away by ducts into their receptacles, or thrown out from the body; while those fluids, which are exuded on the cellular membrane and cavities, are re-absorbed by the system of absorbing lym- phatics. We say then that arteries terminate, first, in red veins; which 'is proved by the microscope, and by mercurial and other in- jections ; secondly, in glands; thirdly, in cells receiving red blood ; fourthly, in lymphatic veins; fifthly, in exhalents, whicii pour their fluids into the cellular membrane, cavities, joints, &c. and which fluid is taken up by the valvular lymphatic ab- sorbents. But these absorbent vessels, of which we are now to treat under the division of lymphatics, do also perform a circulation, inasmuch as they convey back to the centre of the system the fluids which have been thrown out from the extremities of the arteries. But as these lymphatic vessels are not continued from the extremeties ofthe arteries as the red veins are, as they imbibe the fluids, which have been thrown out of the other sys- tem of vessels; their fluid contents cannot be conveyed through them by the force of the heart and arteries; these vessels must be peculiar in having powers within themselves, first of absorb- ing and then of propelling their fluid onward to the heart. The lacteals are vessels which, distributed to the intes- tines, absorb and convey into the system the milky opaque vol. ii. T i 25$ OF THE LYMPHATIC SYSTEM. fluid which is generated in the intestines by the process of di- gestion . The common property of absorption in the lymphatics, ab- sorbents, and lacteals, and their being connected with the same trunk, occasions their being considered as one system of ves- sels ; looking upon the general economy ofthe living body, we find them ministering to very different purposes. The one branch of the system, the lymphatics, convey the waste of the body again into the circulating system. The lacteal vessels, on the contrary, are those vessels which opening upon the in- ner surface of the intestines receive into them the nutritious fluids prepared by the organs of digestion, and suited to sup- ply the incessant waste and destruction of the solid and fluid parts of our frame, which have been absorbed and carried away by the lymphatics. Following this simple view, although the absorbent system be commonly divided into the thoracic duct, lymphatics, lacteals, and glandular apparatus attached to them, 1 shall throw the present section into the division of the lymphatics and of the lacteals. SECTION II. OF THE LYMPHATIC SYSTEM IN PARTICULAR, \ c at. \ x A The lymphatic vessels are tubes whose coats are perfectly pellucid, having a remarkable power of contraction, which causes them to shrink, and disappear, so as to render it difficult to demonstrate them. Indeed they are only to be observed by an eye accustomed to make lymphatic injections. They are called lymphatics, or ductus aquosi, from their trans- Ejtplanation of the Plate. I. The appearance of a lymphatic, injected with mercury, and dissected out *-* point to the two most pe> feet valves of this vessel. II. A lymphatic glaud injected with mercury, and dissected out. A. The gland apparent- ly consisting of mmy vesic.es or cells. P. The lymphatic entering the eland. T Lym- phatics emerging from the gland. - OF THE LYMPHATIC SYSTEM. 251 mining a fluid colourless as water. When they are distended with their fluids, they shew that they possess a very distinct character from the other vessels. They are irregularly dis- tended, knotty, and sometimes like a chain of beads, or little irregular vesicles, connected together. This irregularity is owing to their numerous valves, which are semilunar mem- branes, like those of the veins, hung across their cavities, so as to catch and interrupt the refluent lymph.* They say in gene- ral, that in the space of an inch the lymphatic vessel has three or four pairs of valves. But this bears no certain pro- portion ; for as these vessels run where they are exposed to oc- casional compression from the surrounding parts, or bear the weight of a high column of fluid, their valves are more fre- quent. The lymphatics are improperly called cylindrical tubes, since they are irregular from their valves, branching, and frequent communications. The coats of the lymphatic vessels a»e the strongest of any in the body; for although extremely thin and pellucid, they give resistance to distention beyoud a certain point, and bear a column of mercury which would burst through the valves of veins, and tear the coats of arteries. If there be a muscular coat, and no one ever denied the muscu- larity of the lymphatics, then we may reckon three coats: First, The inner coat, which is the continuation of the inner tunic of the veins, as may be observed in the opening of the thoracic duct into the left subclavian and left jugular veins. It is smooth and polished, forms duplicatures or valves, and pre- vents the transudation of their fluids: it is connected by cellu- lar membranes to the middle coat. Secondly, The muscular or middle coat, which consists chiefly of muscular fibres, which, according to Sheldon, run in every possible direction, though the greater number take the circular direction. And, lastly, The outer coat, which is connected with the general investing cellular membrane. As the inner coat must chiefly form the valves, and as the valves possess so wonderful a power of resist- ing the column of mercury, I conceive that the inner coat is that on which the strengh and resistance to distention of the lymphatics depends, though it has been said that it is to the outer coat that they owe this property- The muscularity of these vessels is rather inferred than proved : it is inferred from the unassisted action which they have to perform in pressing the absorbed fluids onward to the heart. Nevertheless we sometimes see the lymphatics of the lower extremeties of a colour so red and fleshy, that we may say their muscularity is demonstrable. * Ruyschi Dilwidatio Vahnilarum. Vet. Oper. Vol. i. 252 OF THE GLANDS OF THE ABSORBENT SYSTEM. The lymphatics seem to possess, little elasticity; when they are blown into, they rise with the slightest force, and remain dis- tended, although the passage of the air forward be uninterrupt- ed ; whereas, had they considerable elasticity, they would con- tract and disappear. Indeed, when empty, in the dead body they may be rather said to be collapsed than contracted. Al- though the lymphatics can be distended with the slightest infla- tions, yet when distended, as we have already observed, they firmly resist further dilatation. This is a quality necessary to their valvular structure, for if they were elastic beyond this de- gree of dilatation, the calibre of the vessel would be occasional- ly so enlarged as to render the valves incapable of meeting, and consequently of preventing the retrograde movement of the fluids. SECTION III. OF THE GLANDS OF THE ABSORBENT SYSTEM. Every where throughout the body and viscera betwixt the extreme branches of the absorbent system and the trunk, glan- dular bodies are interposed. Though of various forms they are generally of an oval shape, and they vary in size from the twentieth part of an inch to a full inch in diameter. Sometimes they are segregated, sometimes accumulated and clustered to- gether. The colour of those bodies is various in the several parts of the body: in young animals they are redder, and be- come pale only with age. They are redder and stronger in the outer parts ofthe body, as in the thigh, axilla, &.c. less so within the abdomen and thorax. 2. The latter will not bear so high a column of mercury as the former. The mesenteric glands are said totally to disappear in old age.* They dimin- ish in a very remarkable manner. It would appear that the glands of this system are of more importance to young animals than to adults. In the foetus and in children, the lacteal and lymphatic glands are exceedingly numerous; but they shrink or disappear with old age. In the foetus they can be of no very essential use ; they are then rather in a state of preparation for the actions necessary in in- fancy and youth. It is during infancy and youth that they are most liable to disease, and seem more irritable and ready to inflame, especially in superficial situations. About the age of fourteen or fifteen this disposition is changed, which is * By Ruysch, Morgagni, Haller, Sheldon. OF THE GLANDS OF THE ABSORBENT SYSTEM. 263 commonly said to proceed from the increased vigour of the constitution, and the change which then takes place on the organs of generation. It is rather to be attributed, however, to the diminution of irritability and activity of the vessels of the glands at this age, for, as we have said, the glands are now smaller and paler. We may further observe, that the lym- phatic glands, even in the scrophulous diseases, are seldom primarily affected : they partake of diseased action from an impression on the surface, or from an affection of the intes- tines, or from the absorption of matter. The structure of these glands has not been satisfactorily investigated; or the inquiry is attended with insurmountable difficulties. Some anatomists have said, that they consisted of the convoluted absorbent vessels ; others, that they are of a cellular structure. When they affirm that these cells are totally distinct from the lymphatic vessels, it is not so easy to understand them : for cells communicating with each other, and into which the lym- phatic vessels enter, are very much the same with a series of convoluted, varicose, and irregularly dilated vessels. If we could dissect this series of cells, as Haller did the vesiculae seminales, we should have represented to us the appearance of a convoluted varicose vessel. There is a coat of cellular membrane which surrounds the glands. This coat is pervaded by a peculiar fluid which has given rise to some speculation. It is observed chiefly in young animals, and is for the most part, though not always, white and milky, and in the glands of the lungs it is of a black- ish colour. This is the fluid which having globules in it was supposed by Mr. Hewson to be the first stage ofthe formation ofthe red globules of the blood. It is distinct from the ab- sorbed fluids, and is a secretion from the arteries. Physiolo- gists have not determined the nature or use of this fluid. At present there seems no better hypothesis to be offered regarding the use of the lymphatic and lacteal glands, than that they serve to check, controul and measure the flow of the absorbed fluids into the mass of the blood: without them it appears to me probable that at one time the lymph returning from the body, or at another time the chyle, might flow too rapidly, and in a disproportioned quantity into the veins and heart. But by the check which the glands imposes upon this flow, giving a remora, and serving as receptacles ofthe absorbed fluids, the fluids are poured with a more uniform and constant flow upon the heart. 254 ORIGIN OF THE LYMPHATICS, SECTION. IV. ORIGIN OF THE LYMPHATICS, AND OF THE DOCTRINES OF ABSORPTION. The lymphatics, forming a system of absorbents, we might say, in general, that they take up all the fluids whicii have been thrown out upon the surfaces of the body. Thus they arise from the pores of the skin ; from the surface of the cavities and viscera covered by the pleura and peritoneum ; from the cells of the interstitial and adipose membrane, &tc. ' This is the simple use assigned to this system of vessels: but whether they are the only system of absorbents, whether they carry away all the parts of the system, fluids, and solids; whether they absorb the muscles, membranes, bones, tendons, &c. of which the solid body consists, is a question requiring severe examination. It cannot be denied that although the system and doctrine of absorption be the most beautiful and interest- ing, and apparently the simplest in the whole economy, yet it is founded on very few facts, while there is much doctrine tacitly acknowledged, which seems in symmetry with the facts and the laws of the economy, but which is not founded in ab- solute proof. We shall first examine the proofs ofthe lym- phatics being the vessels which absorb the fluids of the cavities and surfaces of the body. The animal machine universally partakes of motion. A principal provision for this mobility of parts, is the looseness ofthe cellular membrane which every where pervades the body, and supports the vessels and con- nects the several parts. This interstitial membrane is elastic, and being cellular, to allow motion, its surface is bedewed with serous exudation. This fluid is perpetually passing from the extremities or sides of the lymphatic arteries or capillaries into the cellular membrane, and upon all the cavities of the body. The fluid extravasated is called serum, and some have supposed that it passes through inorganized pores, an expres- sion that is not very intelligible; but if by this is meant ( as has sometimes been explained) " accidental pores" in the sides of the vessels, it is a supposition quite improbable and unlikely* The pores or vessels from whicii this fluid exudes are called * Dr. Hunter supported this opinion, (Commentaries, p. 40.*) viz. " that the fluids of cavi- ties were collected by transudation, and uot thrown out by exhaleuts j" an opinion which could only have arisen from not correcting the ideas received in making injections in the dead body by the phenomena of the living system. See Hewson on the Lymphatic System, chap. viii. where tbe opinion of inorgaukal filtering is successfully combatted.—See also rruickshanks. AND OF THE DOCTRINE OF ABSORPTION. 265 exhalent; and their action is no doubt as completely secretion as that which produces the fluids, which in our wisdom we call more perfect secretions. That the lymphatics take up the fluids thrown out in the cavities ofthe body, as the abdomen, thorax, pericardium, Sic. there is what nearly amounts to an absolute proof in compar- ing the fluids of those cavities with that contained in tbe ves- sels ; for by the experiments of Hewson, it is found that if the fluid moistening the cavities be collected, it will form a jelly- when exposed to the air, as the contents ofthe lymphatic do. Thus, if a lymphatic vessel be tied up in a living animal, and then opened so as to allow the fluid to flow into a cup, it will form a jelly like the coagulable lymph.* Tbe fluid of cavities alters in animals diseased ; sometimes retaining its coagula- bility, and even acquiring stronger powers; sometimes losing it altogether. But what is most essential to our present pur- pose, it has been observed, that whatever change takes place in the fluids of the cavities, the same is found to have taken place in the fluids of the lymphatics. But the student naturally asks, How is the lymph taken into the lymphatic vessels? and here it must be confessed, there is too much field for conjecture. It was thought formerly that the lymphatic arteries termi- nated in small pellucid veins: these veins carrying only the thinner, and refusing the red part of the blood, were called lymphatics. When the anatomist threw in his minute injec- tion, and saw the coloured fluid return by the red veins, and the colourless fluid return by the lymphatics,f it was held as a suf- ficient proof of the accuracy ofthe pre-conceived notion, and tallied with observations of Leewenhock, and the theory of Boerhaave. See introduction to the account of the viscera. When, however, anatomists more carefully examined the state of parts, they found that the lymphatics were not filled, unless the cellular membrane was previously injected by the extrava- sation of the fluid from the blood vessels. Finding that this alleged experiment was really no proof of the anastomosis, and direct communication betwixt the extreme arteries and lym- phatics, they conceived that it was a proof that these lympha- * But, by disease, the fluids in the cavities and cellular membrane is altered. In dropsy, for example, the fluid of the abdomen losses the property of coagulating on mere exposure; it comes to resemble more the serum of the blood : this were suflicient proof that the col- lection is not owing merely to the diminished absorption, but that there is a change of action in the vessels of the peritoneum, pleura, pericardium, &c. An inflammatory action of the vessels will throw out a fluid more coagulable, and which, in a high degree of action, will form a film of coagulable lymph or even pus on the suiface. But in a state the reverse of inflammation, such, for example, as the debility following inflammation, a serous effu- sion will he poured out having little tendency to coagulate. i It was probably Nm k who firtt injected the lymphatics from thearteries 256 ORIGIN OF THE LYMPHATICS, tics took their rise from the cellular interstitial texture. Then injecting with mercury, they found that when the vessels burst, and the column suddenly descended, and the cellular mem- brane was filled, the mercury was seen to rise in the lym- phatics. Following up this, they blew air, or injected various fluids directly into the cellular membrane, and injected the lymphatics. Thus by an error, by an accidental effect of their injection, the minds of Drs. Hunter and Monro were opened to a freer discussion of the received opinions and approved authorities. Soon, however, it was understood by those con- versant with anatomy, that these accidental injections of the lymphatics did not prove the lymphatics to take their origin either from the cells or from the extreme arteries; but already this good effect, at least, was produced, that men's minds were excited to inquire after new facts, and to follow a new train of observation. It was now recollected, that a strict analogy and correspondence subsisted betwixt the lymphatics and lacteals; the proofs of the lacteals being absorbents, were recalled to memory; new proofs of their being the sole absorbents of the intestines were brought forward; the nature of the fluids ef- fused into the various cavities and cells of the body was attend- ed to; and the conviction followed, that the most essential use of the lymphatic vessels was to serve as a system of ab- sorbents, to take up the extravasated fluids. They reflected that to distend the intestine with injection would never fill the lacteals; and were convinced that the injection of the lym- phatics could not be supposed to be through the proper ab- sorbing mouths of these vessels opening upon the cells; but rather that the injection had entered the vessels by the rupture of their extreme branches. Thus the theory ofthe lymphatics being a system of absorbents, came to rest on analogy, and the observation of the phenomena of tbe living body. The chief proof of the lymphatic absorption has been de- rived from the manner in which the venereal virus is received into the system. Venereal matter being allowed to lodge upon the delicate skin of the glans penis or preputium, causes an ul- cer there. The matter of this ulcer is absorbed by the lym- phatic of the part; an inflamed line is sometimes to be traced into the groin ; and the lymphatic gland of the groin, receiving this absorbed matter, inflames and forms the bubo. Here, then, is a proof that the red veins do not absorb, and that lym- phatics do : else why are they inflamed ?—and why are the lymphatic glands inflamed to suppuration ? We must observe, however, that there is here by no means an absolute proof of absorption of venereal matter. Although, therefore, we believe in the general system, we mav hazard AND OF THE DOCTRINE OF ABSORPTION. 257 these queries : If this matteris absorbed, why is there no infec- tion without ulcer (chancre) of the glans ? If this ulcer be pro- duced by absorption, how comes it that the constitution is not "infected by the first absorption of the matter, and before it has formed an ulcer? Is it not probable that the irritation ofthe venereal matter, lodging on this vascular surface, and without being absorbed, causes a peculiar inflammation, the tendency of which is to form a pustule, and to produce matter similar to that which originally infected the part with the specific and peculiar action ? Again it will be said, however the venereal pustule was originally produced, it appears evident that the absorption of this matter, the conveying of it along the lym- phatic, inflames the vessel, and the next lymphatic gland into which it enters, receiving the venereal matter, inflames and suppurates, &ic. But again, I choose to say, with every show of likelihood, that neither is this a proof of absorption; but that the lymphatic vessel being very irritable, and always re- ceiving its stimulus to action from its extremities, it has par- taken of the venereal inflammation; that this inflammation has been propagated to the gland ; that, the gland being form- ed of the convoluted lymphatic vessels, the effect of this inflam- matory action is there accumulated to so great a degree as to destroy the function of the gland and lead to suppuration.* And further, that the disease is received into the constitution only in consequence of the system at large partaking of the irritation (a word which but imperfectly expresses the change) of the local action of vessels. Matter might be absorbed and taken into the constitution, and the disease propagated accord- ing to the common explanation; but, according to that offered here, there must be a primary and local disease, from which the general affection is propagated. If we are to take the in- flammation and hardening of the lymphatics and axillary glands as a symptom of absorption from a diseased mamma, we must acknowledge the same proof in evidence of the veins absorb- ing. The lymphatics arc more active, and their activity de- pending on the state of their origius and extreme branches, they are more liable to inflammation than the veins; yet are the veins affected in a way that would, on this proof being ad- mitted, prove them to be absorbents. We see how they en- large around a diseased breast, become prominent and hard, and lose their softness and elasticity; how they show them- selves on the surface of a white swelling, or on a cancerous tu- mour. But, as we would not say that this is a proof of ab- * If a chancre be indolent, although matter be formed in it, no bubo will be produced; but if the surgeon applies some corrosive dressing, which, instead of entirely destroyiii£ the diseased spot inflames it, then will the gland in the groin sympathize and risp into a bubo. vol. n. K k 258 OF THE ABSORPTION'OF SOLIDS. sorption by the veins, neither is the proof unequivocal that ther<- is absorption by the lymphatics. Again, a suppurating stump, with bad in animation, will cause inflammation ofthe lymphatics, and suppuration in the glands of the groin ;* a proof of absorption of the matter of the stump ; but do we not find that from such a stump the veins ascend, inflamed and suppurating, while sometimes a chain of abscesses is formed for a considerable extent? This, we can have no doubt, is the effect of the inflammation continued along the vessel; and is not the inflammation produced precisely in the same way it* the lymphatic ? 1 found my opinion of the lymphatics being absorbents,— first, on the circumstance that their structure is adapted to this action ; secondly, on the analogy between them and the lac- teals, in which absorption is proved ; thirdly and lastly, upon their continuing to receive and transmit their fluids, after the heart and arteries have ceased to beat, and the red blood to circulate : for then how can they act, but by their own powers? How can they receive fluids, but by absorption? Finally, this phenomenon shows in the lymphatics a greater degree of irritability, and stronger principle of activity and tenacity of life, than actuates any other set of vessels. OP THE ADSORPTION OF SOLIDS. On examining the works which within the last forty years have contributed to throw light on this subject, we at once ac- knowledge how necessary it is for that part of a systematic book of anatomy, which professes to treat of absorption, to take the form of a critical inquiry. When the absorption of the fluids of the cellular substance, or in the cavities, was uni- versally assented to, physiologists did not make sufficient dis- tinction betwixt the absorption ofthe fluid thrown out of the influence of the circulating vessels, and that matter which continued to be involved in the membranes and vessels, and which formed the solid part of our frame. It will readily he allowed that the fluid thrown out upon the surfaces ofthe body and in the cells, might be absorbed without inferring that every part of the body, solids and fluids, were also taken up by the lymphatic absorbent vessels. But physiologists observing that the solid parts of the body were suffering perpetual change • that the whole body and vessels themselves were formed, de- composed, and carried away; they hesitated not to attribute * See Hunter's Commentaries. OF THE ABSORPTION OF SOLIDS. 259 this to the deposition from the arteries, and the absorption from the arteries, and the absorption by the lymphatics. This alternate destruction and renovation of parts, the perpetual change which ;be whole body suffers, has been universall) ac- knowledged to be the operation of the i> mphat;c system, with- out any other proof than a slight analogy. There is proof that the interstitial fluids, and the fluid in the cavities, are imbibed by the absorbing mouths of the lym- phatics on the surface of the membranes; but where is the similarity between this and the destruction of solid parts? It has been said that the absorbents eat down the solids, and nibble like the mouth of a worm ! a mere conjecture and most improbable. The solids are raised by the agency of the ves- sels on the chemical affinities of the circulating fluids. They must be resolved by a process, reducing them again to the state of fluids; or the secreting vessels throw out fluids which dissolve the in : an operation anterior to their absorption. From the comparative simplicity ofthe fluids of the circulating ves- sels, and in the absorbents, we are authorized to conclude, that as from the blood the several secretions, solids, and fluids are formed; these fluids, before they are again taken into the ac- tive system of vessels, are resolved into their original simple and constituent parts. We are not then to look for the mat- ter of the component parts ofthe body in the absorbing sys- tem of vessels more than in the blood, from which these parts were originally formed; nor are we at liberty to suppose that they are taken down by a process like eating or abrasion. I conceive that the absorption of the solids depends but in a limited degree on the agency of the absorbents; and that there must be a change in the aggregation of the matter pre- vious to the absorption. Mr. Hunter says that his conception of the matter is, that nature leaves little to chance ; and that the whole operation of absorption is performed by an action in the mouths of the absorbents. Physiologists have laboured, he observes, to ex- plain absorption on the principle of capillary attraction, be- cause it was familiar; but as they were still under the neces- sity of supposing action in the vessels after the matter was ab- sorbed, they might as well have carried this action to the mouths of these vessels. One never could have ventured to suppose the extravagant conclusion to which this idea, once entertained, has led Mr. Hunter He proceeds to consider the many kinds of solids the lymphatics have to carry away, and the variety of mouths in different animals, suited to the great variety of substances -•(JO 01" THE ABSORPTION OF SOLIDSv they have to work upon, and then draws the conclusion, or leaves his reader to do so ; that not only are the mouths ofthe lymphatics calculated to absorb fluids; not only do they carry away the solids, but each vessel, according to the hardness and toughness ofthe material upon which it has to operate, has a mouth adapted for the work. He admits that oil, fat, and earth of bones had always been considered as subject to absorption ; and that some other parts of the body liable to waste bad been supposed to suffer by ab- sorption ; but that any solid part should be absorbed, he sup- poses to be entirely a new doctrine. Now, I think we may venture to affirm, that not only was it known that solid parts of the body were taken away during life; but that physiologists knew each and every part of the living body to be undergoing a perpetual decay and renovation. Nay, we may venture fur- ther to say, that Mr. Hunter did not comprehend, in its full ex- tent, the relation in which the secreting and absorbing vessels stand to each other. He is fond of calling the absorbents modellers,—" modellers of the original construction of the body,"—" modellers of the form of the body while growing." Mr. Hunter could contemplate no change in the body du- ring growth, decay, or disease, where there was an alteration of form or quantity of matter, without attributing it to the " mo- delling absorption." A bone cannot be removed without ab- sorption ; nor a part which is useless to the economy (as the alveoli of the teeth, the ductus arteriosus, the membrana pu- pillaris, the thymus gland,) diminished in size or totally carried away, without the absorbents being in action. This, he con- tinues, is the only animal power capable of producing such ef- fects; and like all other operations of the machine, it arises from stimulus or irritation, &c. On the contrary, I conceive thai the absorption of parts in the natural action of health or in disease, is not owing to increased stimulus, but often to a di- minution of it. Does it not strike us forcibly that when a gland swells, and leeches and blisters are applied, and it subsides, this can be no means of exciting absorption; that when pressure is made on a part, and that part is absorbed, this is a strange way of stimu- lating ? Or, when we bleed, is it not odd that this should give new power to the lymphatic system ? For these are the means of giving a counter irritation, and of suppressing ac- tion. Mr. Hunter has given to the lymphatics the higher attributes of intellect. They do nothing without forethought and inten- tion; when they absorb, it is because they have found the parts useless in the economy. He has carried this notion so OF THE ABSORPTION OF SOLIDS. 261 far, that he does not only speak of the absorption of the thy- mus gland, membrana pupillaris, alveoli of the teeth, &tc.; but of the body in fever as a consequence of its becoming useless when under disease!—The following may perhaps appear to be the more natural supposition. In a living body we may observe the agency of the nervous, vascular, and absorbing systems: and the phenomena of life, are not to be attributed to any one, but to the whole of these. We must also observe, that life, or the mutual action of parts producing the phenomena of life, is proceeding from excite- ment, and as in the whole system, so in the individual parts of the body, the healthy action depends on the influence of this excitement to action. The tendency of the growth of the body to peculiar forms, and the increase of parts in disease are produc- ed by it. It acts upon the vascular system in disease, by produc- ing increased action and secretion; as a muscle, in the use of frequent and strong action, will become more fleshy and vascu- lar; as a gland, will be excited to greater action and more pro- fuse discharge, whilst it enlarges and swells up. When a part enlarges in consequence of the stimulus to increased action, either arising from the natural law of the constitution or from disease, it proceeds from the secreting vessels preponderating over the absorbent vessels. There is a disposition of matter which the latter are unable to take away. But diminish this action of the arteries, or take away their excitement, or cause an excitement of some neighbouring part, and thereby sub- due their action, relieve them of their fulness, and the ab- sorbents regain their propotioncd actions, and the swelling subsides. The parts ofthe body, which in the natural changes from youth to age, are absorbed and carried away, are those in which there is no longer the stimulus to vigorous action, and of course the lymphatics overcome the power ofthe secreting vessels, and the part gradually diminishes, loses its apparent vascularity, loses its redness, and is at last totally absorbed. And as the tooth of a child after lying long hid under the jaw. when it partakes of the stimulus to the action of its vessels, grows, and rises up, and the alveoli, partaking of this natural excitement also, form around it; so when the tooth decays and falls out, the alveoli will also decay and be absorbed ; be- cause the moment these vessels have ceased to partake ofthe increased action, their absorbents, though acting with no great- er powers than formerly, do yet so preponderate, that a gradu- al wasting is the consequence. Thus we have to consider, not the action of the absorbents merely, but the relation which their action has to that of the arteries. I should conclude that a part which has ceased to be of use 262 OF THE ABSORPTION OF SOLIDS. in the economy, and is absorbed, has not been carried away by the stimulus applied to the modelling lymphatics; but in conse- quence of a want ofthe usual excitement ofthe arteries to ac- tion, and ofthe consequent preponderance ofthe action of tbe lymphatics; not by an increase of their action, but merely 6y the continuance of it, they being less dependent on the state of excitement of the part. This more uniform state of action, or lesser degree of dependance on excitement, will not be denied when we see them continuing their action after the death of the animal, and after the other phenomena of life have ceased. As to the absorption of the body in general from disease, as in fe- ver, it appears to be simply the effect of the continued absorp- tion, while neither the organs for digesting and assimilating new matter, nor the vascular system for conveying the fluids, are in a state to minister to the wants ofthe system, but suffer under unusual irritation, and disordered function. We speak very commonly of stimulating the lymphatics to absorb by mercury; for example :—There may be a speck on the cornea, corrosive sublimate is given to excite absorption. The practice is good, but surely this is the language of an erro- neous theory. An inflamation from general disorder of the sys- tem or ofthe viscera has taken place, where it is most of all like- ly to take place; a course of mercury corrects this disposition; the cause removed, the inflammation subsides, and with that the speck. The same argument suits the phenomenon when a tumour or enlargement of a viscus is diminished, better than to say, that the mercury excites the lymphatics to the absorp- tion ofthe tumour. As to pressure causing absorption and producing the wasting of parts, I cannot agree with .Mr. Hunter in supposing that the lymphatics are here excited to action ; but should rather infer that the nerves of the parts being benumbed, and the action of the arteries suppressed, the lymphatics continue to do their of- fice, while the arteries are prevented from depositing new mat- ter.—For example, when we see a curvature of the spine, from a habitual inclination ofthe body to one side, and consequently greater pressure on the one side of the bodies ofthe vertebra; it is natural, at first sight, to say, since the one side of the ver- tebra.- is of its natural depth, and the other diminished, that the side whicii is deep has remained, but the other side has been absorbed ; but, when we inquire further into the phenomenon which has taken place, we recollect that the matter of bone is undergoing a perpetual change, and that the matter of both sides ofthe vertebra is changed ; we then comprehend that the pressure may not have excited the vessels to greater action so as t j cause absorption; but that the pressure has prevented the de- • OF THE COURSE OF THE LYMPHATICS. 263 position of new matter, when the old was taken away in the na- tural routine of the system. Mr. Hunter has assigned five causes of absorption, which I conceive may be very naturally resolved into one.—These are, I. parts being pressed; 2. parts being irritated; 3. parts being weakened ; 4. parts being rendered useless; 5. parts be- coming dead: ofthe first we have already spoken ; the second I should deny, unless when it resolves into the third; for irrita- tion does not cause absorption, unless when it is to an extent sufficient to destroy the natural action and weaken the part. The third and fourth come under the effect of the loss of the natural and accustomed stimulus to action in the arterial sys- tem, which of course gives a preponderance to the absorb- ents : of the fifth we can have nothing to add illustrative of the living system. CHAP. II. OF THE COURSE OF THE LYMPHATICS. J. HE lymphatics, in their course and relation to the fascia and muscles of the extremities, bear a great analogy to the veins; for there are two sets or grand divisions,—the dkep lymphatics which accompany the arteries in their branchings amongst the muscles; and the superficial set which run a course external to the fascia. SECTION I. Ov the foot, leg, and thigh.—Even in the toes the same distinction of the origins of the lymphatics may be obser- ved, as in the limb. For while a plexus covers the toes super- ficially, and runs up upon the foot with the veins, deeper branches accompany the arteries on the side of the toes. When we observe the course and origins of the greater and lesser saphena vein, we cannot fail to understand the course of the several sets or divisions of the lymphatics of the foot and legs. From the toes, dorsum, and edges of the foot, the lympha- tics climb up the leg in four classes. 1. One takes a course from the root of the great toe and inside of the foot, over the tendons of the great toe and tibialis anticus tendon. It then passes on the inside of the tendon of the tibialis anticus muscle, 264 OF THE COURSE OF THE LYMPHATIC?. and before the head ofthe tibia, following the principal branch of the great saphena vein; and then continues its course in company with the saphena to the inside ofthe knee. 2. There is at the same time a considerable number of lymphatics, tak- ing their origin from nearly the same place, viz. the inside of the foot, and before the inner ankle ; but they take a different course on the leg from the last class; for they pass behind the lower head of the tibia: they attach themselves to some branch of the saphena vein, and join the former set of vessels on the inside of the knee. From this they ascend superficially above the fascia to the glands of the groin. 3. From the outside of the foot there ascend several lymphatics; a division of which passes before the outer ankle and across the tibia to join the lymphatics, parasites of the great saphena vein, and here they sometimes form plexus and contortions; others turn in behind the outer ankle, and join the branches accompanying tbe lesser saphena vein. The lymphatics which turn round behind the outer ankle pass on the outside ofthe tendo Achillis; and accompanying the lesser saphena vein, sink into the popliteal hollow. Here they unite with the lymphatics which have accompanied the several arteries of the leg and foot, and particularly the pos- terior tibial artery. The deep lymphatics accompany the arteries, as we have said ; and to inject them we may seek for a very large vessel which is coming out from under the plantar aponeurosis to rise behind the inner ankle. Popliteal glands.—The glands of the ham-string cavity are generally three in number, and very small. They receive the lymphatics, which pass with the posterior tibial artery and with the lesser saphena, and they of course swell and become inflamed in consequence of sores on the calf of the leg, out- side ofthe foot, and sole of the foot. From the popliteal glands there ascend two large lym- phatics, which accompany the popliteal artery and vena; comites, and ascend with the latter through the adductor mag- nusto the forepart of the thigh. They run irregularly, or form a kind of net-work round the great vessels. On the forepart of the thigh, and still deep, they enter the lower and deep inguinal glands. Sometimes these deep lymphatics, instead of being accu- mulated into larger trunks, divide into many branches, and only unite in the glands ofthe groin. Inguinal glands.—The inguinal glands are in number from five to ten; they lie involved in cellular membrane on the outside of the femoral ligament. Some of them are OF THE COURSE OF THE LYMPHATICS. 265 superficial and moveable under the integuments; some in- volved in the laminae of the fascia, descending from the abdo- minal muscles; some are close on the femoral artery and vein, and under the fascia. Nearer to the pubes may be ob- served a division of these glands which belong to the lym- phatics of the penis, perineum, &tc. The greater cluster of glands on the top of the thigh be- comes affected from disease of the integuments on the forepart and inside of the thigh and leg ; and of that part ofthe foot where the great saphena vein commences; nay, further, the inguinal glands swell from sores ofthe buttocks, about the anus and private parts. They will even swell from disease of the testicle ; but this only by sympathy. Lymphatics of the parts of generation in both sexes. —From the penis there run backwards two sets of lymphatics : superficial ones,,which take a course to the groin; and deeper ones, which take a course along the arteries of the penis into the pelvis, or under the arch of the pubis. The superficial lymphatics are the cutaneous vessels, and take their origin from the prepuce, and it is these which, either absorbing the venereal matter of chancre, or sympathizing with the venereal action, form sometimes an inflamed line along the penis, and cause the bubo in the groin. But as there are two sets of lymphatics, the chancre may be in a place where the deep- seated vessels are the absorbents, and consequently the consti- tution is contaminated without any bubo in the groin; and in- deed it has been observed, that a venereal ulcer of the prepuce will, in general, produce bubo, when an ulcer of the glans will not.* When the tract of the matter is through the deep lym- phatics which enter the pelvis from below, the gland through which the vessels pass, is not inflamed to form a bubo ; neither do the lymphatic glands within the ligament of the thigh in- flame to the extent of forming a bubo, either from chancre or from bubo in the groin. This, says the celebrated Mr. Cruick- shanks, is very fortunate ; for if the external iliac glands, like the inguinal glands, should suppurate, they could not be open- ed by the lancet, they must be left to themselves; they might burst; the pus might fall into the cavity of the abdomen; might produce peritoneal inflammation; and might probably destroy the patient Now, there appears no reason to dread any such catastrophe. The matter of these glands would form an abscess, which, like other abcesses in the tract of these vessels, would fall down upon the thigh. The fact, however, is curious; that when the lymphatics diseased entor * Cruickshanks, pag;c 13f> VOL. II. h 1 266 OF THE COURSE OF THE LYMPHATICS. one set of glands, there will be no bubo ; when they take a course to the other, they inflame and suppurate. This I be- lieve may be explained, from considering the position of the inguinal glands, as being immediately under the skin : for ex- perience shows that a part near the surface will inflame and proceed to suppuration much more readily than a part deep- seated, though suffering from the same degree of excitement. In the external parts of a woman (by Mr. Cruickshanks's observation) there are also two sets of lymphatics. Those near the clitoris pass up in a direction to the ring; and those from the lower part of the vulva and perineum to the glands ofthe groin. Lymphatics and glands within the ligament of the thigh.—The vasa efferentiaof tbe inguinal glands are in num- ber from two to six. The deep lymphatics which accompany the femoral vein and artery, lying under, the cellular mem- brane, pass under the ligament, and soon form a large net- work of vessels accompanying the iliac vessels, in which they are joined by the branches of lymphatics from the superficial glands : sometimes the trunks accompanying the great vessels of the thigh pass into a gland immediately within the ligament; sometimes one or two of them only enter into the glands high in the loins; nay, sometimes a large vessel passes on directly to the thoracic duct. From six to eight or ten glands are seated in the tract of the external iliac vessels, under the name of external iliac glands. And upon the inside ofthe brim of the pelvis, and on the hypograstric vessels the glands are called the inter- nal iliac glands. In proportion to the frequency of disease in the pelvis, these external iliac glands, being in the tract ofthe lymphatics of the private parts and rectum, &.c. are particu- larly subject to disease. Those glands also which are called sacral glands, as lying on the meso-rectum, and in the hol- low of the sacrum, have been observed to be often diseased. On the psoas muscle, and on the loins it is impossible to trace the vessels as single trunks; we may observe that one net- work of vessels ascends upon each psoas muscle from the thigh ; that there it is joined by the lymphatics ofthe pelvis. These vessels are in a manner united to those which cover the prominency ofthe sacrum, and pass under the bifurcation of the aorta. The two great lumbar plexus of lymphatics con- tinuing their ascent, many of the vessels enter into the lum- bar glands ; and on the loins they are joined bv the absorb- ents of the testicle. By the union of the lymphatics ascend- ing from the right and left side, with several large trunks of the lacteals from the root of the mesentery, the thoracic duct is formed Ofojfee third and fourth vertebra of the loins. OF THE COURSE OF THE LYMPHATICS. 267 OF THE LYMPHATICS OF THE ARM. In the arm, as in the leg and thigh, there are two sets of lymphatics :—the superficial and deep-seated. The first of these accompany the cutaneous veins, the latter the deep arteries. As in general there are two great veins on the fore-arm, the basilic and cephalic veins; but particularly as the veins which gather into the basilic trunk, on the inner and lower edge of tbe fore-arm, are the larger and more numerous class; so it is found that the course of the more numerous class of lymphatics is on the lower and inner side of the fore-arm, and that they accumulate about the basilic vein. These are derived from the palm of the hand, and from the ulnar edge of the hand. This set sometimes passes into the glands, seated on the brachial artery, near the inner condyle ofthe humerus. The absorbents which accompany the cephalic vein arise from the side of the thumb and fore-finger upon the back ofthe hand; they run on the radial edge of tbe arm, with the veins whicii ascend to form the cephalic vein. From the bend of the arm, these vessels take a course on tbe outer edge ofthe biceps, and then get betwixt the inner edge ofthe deltoid, and outer edge ofthe pectoral muscles; they then pass under tbe clavicle, and descend into the axillary glands. This set of absorbents receives the branches from the outside of the arm in their whole course. There are absorbents arising from the back of the hand, next the little finger, which following some of the branches of the basilic vein (a larger branch of winch is called the ulnaris externa) turn round the ulnar edge of the arm, are inserted into a gland, very commonly found before a little above the inner condyle of the humerus. From this gland a large lym- phatic passes upwards, and attaching itself to the brachial arte- ry, splits and plays around it. The deep-seated lymphatics of the arm accompany the ar- teries in the same manner as the venae comites do ; in general two with each artery. They all terminate in the glands ofthe axilla, and can require no particular description. The lym- phatics, from the muscles and integuments on the back of the shoulder, also turn round and enter into the glands of the axilla. The glands of the arm are small, and irregularly placed in the course of the humeral artery, from the condyle to the axilla. They are from three to six in number. 268 OF THE COURSE OF THE LYMPHATICS. The glands of the axilla are large and numerous; they receive the lymphatics from the arm, breast, and shoulder;* they lie in the deep cavity of the axilla, formed by the ten- dons of the pectoralis major, and latissimus dorsi muscles. They are imbedded in a loose cellular membrane, which, while it surrounds and supports the vessels of the axilla in the motions of the joint, gives them strength from its elasticity. These glands do not all surround the axillary artery; but a lower cluster is attached to the branches of the sub-scapular artery, going forward on the side of the chest, and to the tho- racic arteries. These are the glands which become indurated from cancer of the breast. The glands of the axilla when greatly enlarged close upon the artery and plexus of nerves, so as to preclude the possibility of an operation ; they compress the veins and benumb the arm by pressure upon the nerves. When they suppurate, they cause a condensation of the cel- lular membrane which surrounds them, and in consequence, a compression of the axillary nerves and a shrinking of the arm. When a wound or puncture, such as that which the student of anatomy may receive in the dissecting room, has been made on the little or ring finger, the red lines which often appear in . *♦ consequence of it, have taken the course of the ulnar edge of the fore-arm, and terminate in the inside of the arm, near the condyle; in some instances they have been continued into the axilla. If venereal matter be absorbed at any part of the hand, near the little or ring finger, or by a sore on those fin- gers, the gland at the inner condyle of the humerus, or some one in the course of the brachial-artery, will most probably in- flame and form a bubo, and the surgeon will be aware of this ab- sorption ; but if the venereal matter be absorbed on the thumb or fore-finger, it is possible that it may not pass into the glands until it comes into the inside of the clavicle. These glands being out of our sight and feeling, the patient may be infected without the surgeon suspecting it.f lymphatics of the head and neck. Of the absorbents of the brain, little is known precisely ; but none can deny the probability, that the arteries, veins, and lymphatics bear the same relations in the brain as in the other parts of the system. Lymphatic glands are observed iu the * " Tlioy even receivo absorbents from the cavity of the chest, artd I have known theai -well from pleurisy, pnipneiunony, and iraWi.aiy consumption." Cnaickshanks. 1 Cruickshanks, p. 13'.'. OF THE COURSE OF THE LYMPHATICS. 269 course of the internal jugular vein, and even in the foramen caroticum, which are understood to belong to the lymphatics of the brain. The lymphatics of the head are to be observed in the course of the temporal and occipital arteries ; the latter class terminate in glands, seated behind the mastoid process of the temporal bone. The lymphatics of the face have been observed very numerous, accompanying the facial and tempo- ral arteries. But those from the internal parts of the face and nose accompany the internal maxillary artery, and fall into the glands under the parotid, or in the course of that artery. These glands are consequently liable to disease, from absorp- tion of matter of abscess in the face, throat, and nose, and their extirpation is a very hazardous operation. The lym- phatics from the gums and jaws also accompany the internal maxillary artery, and emerge under the angle ofthe jaw; and some of them joining the external jugular vein, pass through glands near the top of the shoulder. The lymphatic vessels from the tongue and parts about the os hyoides, take also the same course. To know the glands about the face and jaws is of the greatest importance to the surgeon, for nothing is more common than the necessity of cutting out indurated lymphatic glands. These are sometimes mistaken for diseased salivary glands; now tbe salivary glands are rarely diseased, the lymphatic glands often. And it will be a guide to the sur- geon to inquire into the origin of the induration, (perhaps a suppuration in the throat, nose, or jaws,) and to know precisely the gland diseased, its depth, and connections. On the side of the face, there are in general several small lymphatic glands on the buccinator muscle, immersed in the surface of the parotid gland, and under the zygomatic process. There are also glands to be carefully noted, which lie under the tip of the parotid gland, where it extends behind the angle of the jaw, and also lying under the base of the jaw-bone, close to the sub-maxillary gland, and on the course of the fa- cial artery. The glands and absorbents of the neck are very nume- rous, and the latter form an intricate and beautiful plexus, se- veral branches of which are to be observed accompanying the external and internal jugular veins. Some of the glands lie immediately under the skin, and in the cellular membrane, on the outer edge of the platisma myoides; many under that muscle, and in the course of the external jugular vein. But there are many seated deep, for the greater number accompa- ny the internal carotid artery, and internal jugular vein, or their branches. The lymphatics of the thyroid gland have been raised by i£70 OF THE COURSE OF THE LYMPHATICS Mr. Cruicksbanks, by plunging a lancet at random into the substance of the gland, and blowing into it, or throwing quick- silver into its cellular membrane. The trunks of these lym- phatics join the thoracic duct on the left side; and on the right side the right trunk, just as it is about to enter into tbe vein. of the trunks of the absorbent system. The larger and proper trunk ofthe lymphatic system is gene- rally called the thoracic duct, because it was first observed by Pecquet* to be a vessel which conveyed the cfiyle through the diaphragm, and which took its course through the whole length ofthe thorax, to throw its fluids into the veins near the heart. Before his time the lacteals which were discovered by A.sellius,f were supposed to terminate in the liver. The first discoverers of the thoracic duct, described it as beginning from a pyriform bag, to which they gave the name of »:eceptacu- lum chyli. In dogs, fish, and the turtle, such a cistern or bag may be observed ; but in the human body nothing further is to be observed than an irregular dilatation of this vessel, like a varicose distention, where it receives the accession of the lac- ""eals from the root of the mesentery. The origin of this great trunk called the thoracic trunk, is the union ofthe vessels, which running by the side of the common iliac vessels, are derived from the pelvis and lower extremities. Upon the third and fourth vertebrae, and under the aorta, this trunk is frequently joined by a large trunk of the lacteals, and then ascending, it receives the greater number, or the larger trunks of the lac- "eals. On the vertebrae of the loins, the thoracic duct is by no means regular, either in its course, or size, or shape; often it contracts, and again irregularly dilates, as it seems to emerge from under the aorta. On the uppermost vertebra ofthe loins, the thoracic duct lies under the right cms of the diaphragm, and then passing the septum with the aorta, it gets on the right anterior surface of the spine, and runs up betwixt the aorta and the vena azygos; it then passes under the arch ofthe aorta, and there it is considerably enlarged, from the contracted state which it assumes in the thorax. Sometimes it splits, and again unites on the vertebrae of the back. Having passed the arch of the aorta, it crosses to the left side of the spine, and we look for it under the pleura on the left side of the oesophagus. * In the year 1651. ■*■ In the year 1622.—About the year 1632, the other branches or the system, which take their course to every part of the body, were discoveml by Rudbeck, Jolyffe. and Thorn. Bartholin. OF THE COURSE OF THE LYMPHATICS. 271 The thoracic duct now emerges from the thorax, and lies deep in the lower part of the neck, behind the lower thyroid artery, and on the longus colli muscle. , It gets above the level of the subclavian vein of the left side, and here it receives the absorbents of tbe head and neck (of the left side,) and descends again with a curve, and terminates in the angle of the union of the subclavian vein and jugular vein of the left side. Sometimes there are two thoracic ducts; but this is very rare. Sometimes the duct splits near its termination, and the two branches enter the veins separately; but, in general, when it splits in this manner, it again unites before it terminates in the vein. There is constantly a trunk in the anterior mediastinum un- der the sternum, almost as large as the thoracic duct itself, which is sometimes inserted into the termination ofthe thora- cic duct; sometimes into the trunk ofthe absorbents of the left side, to be immediately described.* the trunk of the absorbents of the right side. The absorbents, from the right side of the head and neck. and from the right arm, do not run across the neck, to unite with the great trunk of the system ; they have an equal oppor- tunity of dropping their contents into the angle betwixt the light subclavian and the jugular vein. These vessels then unit- ing, form a trunk which is little more than an inch, nay, some- times not a quarter of an inch in length, but which has nearly as great a diameter as the proper trunk of the left side. This vessel lies upon the right subclavian vein, and receives a very considerable number of lymphatic vessels : not only does it receive the lymphatics, from the riuht side ofthe head, thy- roid gland, neck, he. and the lymphatics of the arm; but it re- ceives also those from the right side of the ofthe thorax and diaphragm, from the lungs of this side, and from the-parts sup- plied by the mammary artery. Both in this and in the great trunk there are many valves. » * OF THE LACTEALS AND LYMPHATICS OF THE INTESTINAL CA- NAL. • We shall afterwards have to observe the great length of the intestinal canal, the effect of the imperfect valvular structure. Truickshanks. 272 OF THE COURSE OF 1HE LYMPHATICS. in extending the inner coat to a great length ; we have re- marked that while every surface of the body secretes, it is at the same time an absorbing surface; and finally, that while we chiefly contemplate the intestinal canal, as imbibing and receiving the nourishment, we must not forget that it is also a secreting surface of the first importance to the economy. But at present we have merely to understand that structure and or- ganization, which by this canal absorbs the nutritious fluid, the chyle, from the food. In the first place, as to the terms lacteals and lymphatics, we presume that the absorbents throughout the whole length of the canal have the same structure and use; and that the term lacteals has been suggested merely by the colour of the fluid, which is absorbed from the small intestines. At one time these lacteals convey a milky fluid; at another a transpa- rent fluid like that which the stomach and great intestines in general absorb. The lacteals, as it is natural to suppose, were the first dis- covered of any part of the system of absorbents ; or, at least, they were first understood to form a part of an absorbing sys- tem. For although Eustachius, a Roman anatomist, disco- vered the thoracic duct in the year 1563, yet he had very im- perfect notions of its importance, and the discovery was very little attended to, till after the discovery of the lacteals by Asellius in 1622. This anatomist, in opening living animals, to observe the motion of the diaphragm, observed white fila- ments on the mesentery, which he took at first for nerves; but, on puncturing them, and observing them to discharge their contents and to collapse, he proclaimed his discovery of a new set of vessels—a fourth kind.* Had Asellius only chanced to observe these vessels, his me- rit would have been inconsiderable ; but he also investigated and announced their peculiar office, viz. of absorbing the chyle from the intestinal canal, and carrying it into the blood. For some time, however, after the discovery of the vasa lactea, the opinion of Hippocrates and Galen, viz. that the mesenteric veins absorbed the chyle from the intestines, and conveyed it to the liver, still prevailed. Even after the dis- covery of the lacteals was known and received,# part of the old system was still retained, and it was supposed that those vessels carried the fluids absorbed from the intestines into the liver; and that the fluids were there converted into blood. About twenty years after the discovery of Asellius, Rud- beck, a Swede, and Bartholin, a Danish anatomist, saw Asel- The nerves being counted as vessels. OF THE COURSE OF THE LYMPHATICS. 273 lius's vessels in many other parts of the body; discovered the trunk of the system, and showed that the lacteals did not pass to the liver, but that they were branches of a great and dis- tinct system ; they also demonstrated tbe unity of this system. We have seen from this sketch that the ancients supposed the veins of the intestines to be absorbents; and even after the discovery of the lacteals, this idea has been retained by some of the best modern anatomists, and principally by Hal- ler, and Professer Mickel of Berlin. If the veins absorb from the surface of the intestines, their doctrine would imply that they are also absorbents in general throughout the body. Al- though Bartholin, in his epistle to Harvey, had asserted and given sufficient proof that the mesenteric veins were not ab- sorbents, yet the controversy was left in so undecided a state, as to give occasion to the series of experiments in the school of the Hunters, which seems to have put the question to rest, in as far as it is connected with the lymphatic system* We have already mentioned that Asellius was employed in opening the belly of a living dog, when he first discovered the lacteals. He perceived upon the surface of the intestines and mesentery a great many small threads, which, at first sight, he took for nerves, but soon discovered his error; and to dissipate his doubt, opened one of the largest white cords, when no sooner had the incision been made, than he saw a fluid like milk or cream issue from the vessels. Asellius says he could not contain his joy at the sight of this phenomenon; and turn- ing himself to Alexander Tadinus, and the senator Septalius, who were present, he invited them to enjoy the spectacle; but his pleasure, he adds, was of short duration, for the dog died, and the vessels disappeared. The natural and simple narra- tion of Asellius represents his astonishment, and gives an idea of the sensation, which the anatomist experiences in the in- stant of making an interesting discovery.f Origin of the lacteals.—When the young anatomical student ties the mesenteric vessels of 2tn animal recently kill- ed, and finds the lacteals gradually swell: when he finds them turgid, if the animal has had a full meal, and if he has allowed time for the chyle to descend into tbe small intestines and empty, or containing only a limpid fluid if the animal has wanted food; he has sufficient proof that these are the vessels destined to absorb the nutritious fluids from the intestines. Again, when coloured fluids are thrown into the intestines of a living animal, and they are absorbed, he has sufficient proof of their free and ready communication with the inner surface of * See the Veins in this volume. •(• Sheldon, Portal. vol, u. ^Ira 274 OF THE COURSE OF THE LYMPHATICS. the gut; but the actual demonstration ofthe absorbing mouths of the lacteal vessels is very difficult. The difficulty arises from these vessels being in general empty in the dead body, from the impossibility of injecting them from trunk to branch in consequence of their valves; and, lastly, from their orifices never being patent, except in a state of excitement. The anatomist must therefore watch his opportunity when a man has been suddenly cut off in health, and after a full meal. Then the villi of the inner coat may be seen turgid with chyle, and their structure may be examined. Perhaps the first ob- servations which were made upon this subject by Lieberkuhn, are still the best and the most accurate. The villi are apparently of a cellular structure; for although they are flat or conical, or like filaments when collapsed ; yet when minutely injected, and especially when they are full of chyle, they take a globular form, and are called the ampulul*. Their distention, in consequence of a minute injection of the veins or arteries, is probably owing to a cellular structure (which they seem to have) into which the injection has extra- vasated. The most probable account of the structure of these ampululae is, that this cellular structure is a provision for their distention and erection by the blood, when excited by the presence of the chyle in the intestines; that this erection gives rigidity to the orifice of the lacteals; and that the first step of absorption is by capillary attraction, while the further propul- sion of the fluids in the extreme absorbents is by the contrac- tion of their coats excited by the presence of the fluid. Thus the absorption is not by an inorganized pore, but depending on excitement and action. Lieberkuhn's observations of the villi are the most accurate and curious. He observes, that having opened and washed a portion of the small intestine, its whole surface will be found covered with little pendulous conical membranes of tbe fifth part of a line in size, and the bases of which almost touch each other. From the vascular membrane, to whicii they are at- tached, he observes there is given off to each villus a branch of a lacteal, an artery, a vein, and a nerve. He found it difficult by injection to show both the vein and artery, the fluid passed so easily from one into the other. He found that the extreme branch of the lacteal was distended into a little vessel within the villus. And on the apex of which, with the microscope, he saw one, or sometimes several openings; with his glasses he observed the arteries to ramify on the globules or ampulula? and again collect into veins; and he supposed that still more minute branches plunged into the centre. But be made a still more minute observation than this. Insulating a piece of OF THE COURSE OF THE LYMPHATICS. 275 intestine betwixt two rings, only leaving a space for the en- trance of the ramification of the artery which supplied it he injected with a column, and examined its progress at the same time with his microscope. As he raised the tube he saw the artery going in serpentine turns to the villus, and the injection returning by the veins; at last it passed into the ampulia lac- tea, distended it and made its exit by the foramina. He pre- pared the villi in another way :—he inflated the ampululoe, and kept them so until they dried ; then he cut them with a razor, and found them cellular. This cellular structure Cruickshanks thinks is the common cellular substance, uniting the vessels of the villus. When this gentleman examined the villi of a pa- tient who died suddenly after a meal, he observed some of them to be turgid with chyle, so that nothing of the ramifica- tions of the arteries or veins were to be observed; the whole appeared as one white vessel without any red lines, pores, or orifices; others ofthe villi contained chyle in a less proportion; and here the ramifications of the veins were numerous, and prevailed by their redness over the whiteness of the villi. In some hundred villi he saw the trunk of a lacteal forming by radiated branches, one branch in each villus. Mr. Cruick- shanks and Dr. Hunter counted fifteen or twenty orifices in some of the villi. Mr. Cruickshanks has remarked a deep and a superficial set of lacteals on the intestines; but for this division there seems no necessity. Deep in the coats the lacteals seem to accompa- ny the blood vessels; but when they get more superficial, they take a course longitudinally on the canal, and turn deviously, or after runing a little way, take a sudden turn towards the mesentery. As the greater frequency of the valvulae conniventes in the jejunum, greatly increase the extent of its inner surface of the gut, and consequently give a greater extent of origin to the lacteals; and, as here the chyle must be in the greater quanti- ty, so the lacteals of this portion of the gut are larger and more numerous than in any other part ol the extent ofthe ca- nal. The lacteals do not attach themselves to the vessels of the mesentery, but take a more superficial course. Before tbrey enter the mesenteric glands, they have been called lacteals of the first order; when they emerge from the first into the se- cond glands, secondary lacteals, or glands ofthe second order. The manner of their entering and going out of glands is ex- actly the same with that of the lymphatics. The lacteals (or perhaps we should now say the absorbents merely) ofthe great intestines are smaller and less numerous than those ef the 276 OF THE COURSE OF THE LYMPHATICS. small intestines; for although the intestines be large, still their inner surface is by no means so extensive: besides the chyle is absorbed, and the contents of the gut altered before they have descended into the great intestines. Both Winslow and Haller, however, assert, that they have seen chyle in the ab- sorbents of the great intestines. We know that the lacteals absorb chyle when it is presented to them: while at other times they absorb other fluids. That the absorbents of the great intestines imbibe the fluid contents is evident, from the change produced on the faeces in their passage. Copious and nutritious injections have been given, which did not return in the same liquid form, and which have supported the strength for some time. Clysters of turpentine give the urine a smell of violets; and the Peruvian bark has cured fever when given by the rectum. The absorbents of the stomach form three divisions: one set accompanies the coronary artery and vein, and enters the glands on the lesser curvature and omentum minus. Those of the second set accompany the left gastro-epiploic artery, and are joined by the lymphatics of the omentum. The third pass down upon the upper part ofthe duodenum, following the arteria gastrica dextra : these descend to pass into the same class of glands, which receive the lymphatics of the liver. They are joined in their course by the lymphatics of the right side ofthe omentum. The lacteals on the mesentery pass from one gland to ano- ther till they form one or two large trunks only. These accom- pany the trunk ofthe superior mesenteric artery, and run down on the right side ofthe aorta, and join the thoracic duct. The absorbents, from the rectum and colon of the left side, pass into their glands, or sometimes into the lumbar glands, and join the thoracic duct separately; those from the right side of the colon join or mingle with the lacteals in the root of the mesentery. • OF THE REMAINING ABSORBENTS OF THE SOLID VISCERA. •Where the lymphatics ofthe lower extremity descend over the brim ofthe pelvis, they are joined by the absorbents ofthe bladder, vesiculae seminales, and other parts of the pelvis :— small glands belonging to this set are attached to the internal iliac vessels. In the female the lower set of lymphatics, from the womb and vagina, also come by this route to join those of the lower extremity, or run mingling with them. Another set of lymphatics of the womb pass up with the spermatic vessels. OF THE COURSE OF THE LYMPHATICS. 27? The lymphatics ofthe testicle are very numerous. They come in distinct sets from the body of the testicle, from the epidydimis, and from the tunica vaginalis : then reaching the cord, form six or ten trunks, and run up direct to the ab- dominal ring; passing the ring, they turn outward, and then pass over the psoas muscle and into the lumbar glands. The lymphatics ofthe kidney are in two sets, superficial and deep-seated; but the former are seldom to be observed. Sometimes disease makes them distinct. The internal lym- phaticse are demonstrated by blowing into veins, or tying alig- ature and kneading the substance of the kidney with the fin- gers; when they rise, they are seen attached to the emulgent vessels, and goto join the lumbar glands, or terminate in large lymphatics near the aorta. It is needless to repeat that the absorbents ofthe spleen are deep and superficial,—for this arrangement is general Emer- ging from the spleen, the lymphatics pass along the splenic ves- sels, and enter into glands attached to the splenic artery in its whole course. In this course they receive the absorbents from the pancreas, and near the head of the pancreas, they are blend- ed with those of the liver and with them join the thoracic duct. The lymphatics of the liver are the most easily detected, and may be injected to greater minuteness, than in any other part ofthe body. Although they have many valves, yet they do not seem to close the vessels entirely, nor interrupt the mercury from passing from trunk to branch. Tbe superficial lymphatics, which are so numerous that we may sometimes see the mercury in them covering completely a considerable space, have free communication with the internal set of vessels which are also numerous and large. The principle route of the lymphatics of the upper surface of the liver is by the broad ligament: these perforating the diaphragm join the trunk, which we have noticed under the sternum, and in the anterior mediastinum. It would appear, however, that these lymphatics of the broad or suspensory ligament, are by no means constant and uniform in their course: for sometimes they run down towards the lateral ligament, and perforate it there ; sometimes they pass down into the thoracic duct while still in the belly. Other lymphatics of great size run off from the convex surface of the liver upon the lateral ligaments, and pierce the diaphragm. The lymphatics on the lower or con- cave surface of the liver are more irregular than those of the convex side. They unite with the deep lymphatics coming out of the porta along with the vena porta?, enter into the glands, which are seated on the trunk of that vessel, and join the thoracic duct near the root ofthe superior mesenteric ar- Irrv. 278 OF THE COURSE OF THE LYMPHATICS. The lymphatics ofthe lungs are nearly as numerous as those of the liver; but, indeed, in regard to this expression, it is more in relation to the facility pf injecting and demon- strating the lymphatics, than to their comparative number. For example, if the lymphatics ofthe other viscera could be injec- ted to as great minuteness as those ofthe liver, we should cease to consider that viscusas more abundantly supplied than other parts. The superficial lymphatics of the lungs form areola?, and cover the surface almost completely. They take a course to the root of the lungs, where they are joined by the deep- seated vessels, and together pass into the bronchial glands, and here the lymphatics of both sides freely communicate. The glands ofthe lungs are constantly found both before and behind the bifurcation ofthe trachea : often these glands are of a very dark colour; nay, their substance is sometimes found resolved as it were into a sac of inky-like fluid. Upon the arch of the aorta, and the root of its great branches, are the cardiac glands, which receive the lymphatics from the heart. The absorbents of the heart are small, but very numerous, and their larger branches attach themselves to the coronary vessels. They then pass to the cardiac glands, and mingling with those from the lungs, join the thoracic duct. ( 279 ) THE ANATOMY OF THE BRAIN AND NERVES. OF THE NERVOUS SYSTEM. X HE nervous system embraces the brain, nerves, and or- gans of sense. The brain is defined to be that soft mass contained within the cranium from which the nerves are propagated. The nerves are those white cords visible every where in the parts ofthe body having sensation. The endowment of thought and feeling, and the power of putting the muscular machine into action, are the attributes of the nervous system. This is a division of the anatomy of the human body, the most curious and important in whatever view we take it. By the knowledge of the nervous system the physician is inform- ed how the viscera are united, and how the disease of one h sometimes like a disease of the whole, or sometimes affects a single and remote part. Through a knowledge ofthe nerve? he is enabled to discover diseases by their symptoms, for ex- ample, internal disorders by the outward pains and motions they give rise to, through the connection of nerves. In the same way, by knowing the distribution of the nerves and the sympathies they occasion, the surgeon can trace the course of the wounds through the great cavities by the pains or motions they produce in the limbs and outward parts. By the study of the nervous system the physician's occupations are con- nected with all that is most curious in natural knowledge or in. the history of the mind. ( 280 ) CHAP. I. STRUCTURE OF THE NERVES. L HE nerves are certain white cords visible in the dissected body, which by their connections and the phenomena they exhibit, are proved to be the instruments of sensation and voli- tion. We speak of the course of a nerve, its origin and pro- gress ; but my reader must be careful to remember that this is spoken metaphorically, or it will lead to very false ideas. Nerves are of different forms, sometimes flat, as the ischiatic nerve, or round, as the nerve of the eye, or irregular. They are bound up in firm membranes, and blood vessels accompany them or run in their centre. Each nerve consists of many fibriles, and the cellular texture and the blood vessels are interwoven with their fibriles. The matter of the nerve ib soluble in alkali, so that the white and opaque matter of the nerve is washed away, leav- ing the cellular texture. By this the analogy of the structure of the nerve with that of bone is made out; and if we had a solvent for the muscular fibre which would leave the cellular texture, the analogy would here be complete also. From the washing away the matter of the nerve by a solvent which leaves the cellular texture, we may conclude that there is a peculiar matter on which the phenomena presented by the nerve in the living animal depends. This view is con- firmed by the following facts. The natural and healthy ap- pearance of a nerve is a white opacity, but a paralytic limb has the nerve transparent. The optic nerve of a blind eye is paler than the nerve of the sound eye, and the nerves of a limb whose muscles are red with action are remarkable for their white opacity. The matter of a nerve is in consistence something betwixt fluid and solid ; for its apparent solidity is owing to the man- ner in which it is bound up, as the oil in the adipose mem- brane appears solid ; and this matter is rrot fibrous or striated, for that appearance is owing entirely to the tubular form of the membrane which contains the proper nerve. The texture of the nervous fibriles varies consiberably in its internal arrangement. Thus in my Collection my reader may see that the olfactory nerve, the optic, the par vagum, the sympathetic, the diaphragmatic, differ in the texture of their fibres. STRUCTURE OF THE NERVES. 281 There are three distinct membranes which belong to a nerve; 1. an outer sheath; 2. a fine dense and strong mem- brane, like to the tunica aracnoidea of the brain ; and 3. a soft delicate and vascular membrane which invests the proper matter of the nerve, and follows it in its minute subdivisions, conveying the blood-vessels to it, and nour- ishing it: it is equivalent to the pia mater ofthe brain. The matter ofthe nerve and the medulla ofthe brain has the same sensible qualities, the difference being only such as may be attributed to the cellular texture which envelopes them. The corrosive sublimate and the muriate of soda har- dens this matter, and alkali dissolves it. The matter both of the brain and nerve becomes yellow by drying. They both * putrify in heat and moisture, and become green. We observe the brain to putrify very soon, while the nerves remain white among putrid parts; but this, like other appa- rent peculiarities, is owing to the membranes which envelope the nerves, and where the membranes of the nerves are less distinguishable from those of the brain, as in the nerves of the nose and the ear, they are observed to putrify and change co- lour like the brain ; and so we shall find that these nerves, by maceration in water, may be dissolved into a kind of emul- sion like the substance of the brain. The matter of a nerve does not seem capable of any kind of contraction. When the membranes which surround the nerve shrink from being plunged into hot water, the proper matter of the nerve projects from their sheaths, which is a proof that this contraction is of the membranes of the cord only; and, accordingly, if the experiment be made on the brain, or on the spinal marrow, the same effect is seen; that is, the membranes contract, but the matter of the brain or marrow is forced out through the sheath or membranes, and does not contract. If the matter ofthe nerve has no elasticity or power of con- traction, how does it accommodate itself to the motion of sur- rounding parts ? If I cannot show this, I must confess that the matter of the nerve has contractibility. In examining a nerve we find that it is distinguishable into smaller filaments : these appear to run a straight and parallel course; but on observing more narrowly, we shall find that these filaments do not run in a straight course, but zig-zag, like a thread drawn out of a stocking. By this admirable structure, a filament possessing no elasticity whatever is capable of elongating and contracting by the elasticity of the cellular texture which sur- rounds it. False analogies are the greatest source of misconception. vol. ii. N n 282 STRUCTURE OF THE NERVES. % I Our first authorities in the present day are of opinion that sen- sations are not produced merely by impulses made on the nerves, but by actions excited by such impulses^ and which actions are continued to the sensorium. This opinion appears to me to be without any foundation whatever. The capacity of conveying impressions which is in the nerve is a quality peculiar to life, and which we shall in vain seek to compre- hend : it is more philosophical to admit that we cannot com- prehend the nature of this power inherent in the nerve more than we can the falling of a heavy body. I must be satisfied with saying, that the nerves are merely conductors, and in that capacity minister to the brain and or- gans of the senses, and to the muscular frame. At all events ^ the proper matter of the nerve is neither elastic nor capable of contraction, and the structure of the nervous filaments is such, that while the nerve is elongated or contracted by the elasticity of its coats, the proper substance of the nerve is at the same time passive. In treating of the structure of the nerve, it is natural to consider if there be any distinction of this substance in the different nerves, as there is evident difference of texture ; and whether this distinction observable in them will be sufficient to account for their difference of function. Physiologists, both in this country and in France, have of late expressed an opi- nion, that the difference of sensibility of nerves results from a variation of their organization. I do not believe that there is any difference of the substance of the nerves. The olfactory nerve is very peculiar within the cranium ; but when we trace it into the nose, it resembles other nerves. The optic nerve is peculiar in the eye, and, in some degree, at its origin in the brain; but in its middle passage it is constituted like other nerves having fibriles. The plaiting of tbe eighth pair of nerves is not like that of the sympathetic nerve, and both arc unlike the phrenic : but the structure of the individual fila- ments is still the same. The next enquiry may be, whether a nerve of one sense does actually convey the impression adapted to another? Undoubtedly it does: thus the same impetus will be conveyed along the nerve of the eye, and of the ear, and the galvanic fluid will at once cause smell, taste, vision, and sound. The dependence of the nerves upon the vascular systpm is very intimate. The blood-vessels of the nerves come irregu- larly from the surrounding trunks, like those of the perios- teum. Though sometimes one branch more considerable en- ters the body of the nerve ; (we may observe it in the prepa- rations of the optic nerve, or of the sciatic nerve;) as soon as STRUCTURE OF THE NERVES. 28S it has pierced the sheath of the nerve, it branches, and these branches run betwixt the filaments, and in a direction parallel to them. A nerve minutely injected is quite red ; and when further prepared by washing away the opaque nervous matter, the arteries and veins appear particularly distinet. Pressure, by impeding the circulation of tbe blood in these , vessels, soon affects the sensibility of the nerve ; for however the function of the nerve may directly result from its organi- zation, yet the life and vital energy is received from the blood in the circulation through it, and cannot long continue if that blood be interrupted in its course. We trace the nerves into the brain, into the organs of the senses, into certain knots called ganglions, into the muscles, and generally to all surfaces. These are called the termina- tions of the nerves. The connections of nerves are exceedingly intricate, and the explanation of these intricate connections has hitherto been attempted in vain. I hope presently to give a satisfacto- ry explanation of this subject; but, in the mean time, I shall only state, that nerves are associated for the convenience of distribution, or connected in order to bestow two or more dif- ferent properties of sensation upon the same part; or finally, they are united to form a connection and sympathy betwixt parts ofthe system which must be united to perform their office. I am at a loss to speak with due respect of those eminent men who from time to time have offered us explanations of the manner in which sensation is conveyed along a nerve. Some will have it, that there is a fluid contained in tubes, the motion of which conveys the impulse ; others call this fluid a spirit; others an aether. It is sometimes the electric fluid whicii is considered as the agent, and, now of late, some of my learned friends speak confidently of the galvanic fluid as the agent of sensation. Others still there are who support the idea of sensation being a vibration, or a contraction propa- gated in the length of the fibre- While I have no objection to the expression of the life of the nerve being like the galvanic fluid, yet there is no more foundation for supposing it the same than for supposing it any gross and material substance. The galvanic fluid will pass like electricity along the surface of bodies in contact, as well as those in union ; but if a nerve be cut, it is no longer capable of propagating sensation, though the cut surfaces may be laid in contact. If the galvanic fluid be transmitted equally along a dead and a living nerve, or along a wet thread as a wet nerve, it implies in a manner the most distinct, that it is dissimilar to the vital fluid, or rather we ought to say, to that endowment of life in the nerve. 284 STRUCTURE OF THE NERVES. There is such a disposition in us to connect animation with motion, that the ideas of Dr. Darwin, Sir Everard Home, and Mr. Abernethy, are likely to have made converts. But the first notion of the contraction of the nerve was founded in palpable error, and it has been supported by a false analogy made betwixt the life of the nerve and the life of the muscu- lar fibre. Dr. Darwin, seeing the ragged and seemingly fibrous structure of the optic nerve, set up a theory of con- traction being the means of propagating the impression on the senses. But the sentient part of the retina is a pulp, and what he saw was the cellular texture and vessels, which are called tunica vasculosa retina, and no part of the proper organ. Besides, is it not extraordinary that they should overlook the following circumstance ; that in allowing the nerve a capa- city of contraction upon an impulse being made, they are es- caping from this question, of what nature is this susceptibility of impression, or this sensibility ? They have allowed that a sensation is impressed ; is not the impression and the pro- pagation the same thing, and performed by the same endow- ment of sensibility? It is possible that the law of muscular contraction, and the law of nervous sensibility, may have something in common, but they are properties of life quite distinct. The nerves contract the least of any part of a limb ampu- tated, and what contraction there is, belongs to the surround- ing coat of cellular texture. Thus the nerves stand out from the stump, and the nervous threads stand out from the extre- mity of the nerve, and the nervous matter pushes out from the tubular structure of the membrane; and thus of all the parts of a limb cut across at the moment of extreme pain, the ner- vous masses contract the least; in fact, they are incapable of contraction, even if you were to throw the nerve into boiling water, or the brain into boiling water, no contraction is obser- vable in the proper nervous matter. There is another circum- stance which proves how insufficient this contraction would be to the propagation of sensation: muscles when they contract have opponent fibres, or some controling power, to be their antagonists, and to restore them to the state of rest after con- traction ; but supposing that a nerve contracted in receiving a sensation, how is the filament to be elongated again to repeat the impulse ? Here the analogy fails us. For many ages philosophers disputed about the nature of gravitation, of fire, of light, of heat, and of cold; but at length they saw the vanity of their pretensions, and by chemi- cal and physical experiments, set themselves to question na- ture, and to observe; and these experiments, instituted with OF GANGLIONS. 285 less ambition, were followed by the most astonishing discove- ries. So we may hope to see it in the department of physi- ology. OF GANGLIONS. The ganglions are small reddish tumours seated in the con- flux of the nervous filaments. They are laid in a regular suc- cession in the whole length of the body, and in tbe vertebral animals, form a regular series down each side of the spinal marrow, and the nerve of communication among them is the great sympathetic nerve. But besides the spinal ganglions, there are others seated in the head, neck, and cavities ofthe chest and belly, which are very irregular in their situation and form. Of the latter, the most important from situation and connection is the semilunar ganglion, which with its fellow forms the grand centre of con- nection to the nerves of the abdominal viscera. All the ganglions are in the recesses of the body, and placed like parts of important function protected from injury. Around the ganglion there is a firm, minute tissue of cellular mem- brane, or we may describe it as a firm dense net-work of fibres so interwoven as to cover the proper substance ofthe ganglion, at the same time that it enters more intimately into its com- position ; so that it has a firmness independent of its proper matter, and indeed foreign to the general character of nervous matter. No fat is deposited in the membranes of the gang- lions or of the nerves. The colour of the ganglion differs from that of the nerves; it is redder, which is owing to the greater number of blood-vessels : when blanched of the blood the ganglions are greyish, and when putrid they are of the green colour of putrid brain. I conceive that these bodies consist ofthe same matter with the brain, and that all the difference observable by boiling, ma- cerating, and applying chemical agents, is merely owingtothe firmer texture of the membranes which surround them, the intention of which is evidently to protect the proper matter of the ganglion. Dr. Monro conceived that there was cineritious matter in the ganglions, and so undoubtedly there is. Scarpa thinks they do not differ from plexus, being only very minute subdivisions ofthe nervous filaments. An appearance which countenances this opinion may undoubtedly be given to them by maceration and dissection; but during this process we see that a softer composition peculiar to the ganglion is washed away and lost, 286 SKETCH OF THE CO.MPARITIVE ANATOMY and Scarpa admits such a substance betwixt the filaments. Bi- chat errs on the other side, by affirming that there is nothing fibrous in their appearance, and that they are uniform and homogeneous. This complicated and beautiful structure of nervous matter, protected by situation and by tbe support of peculiar mem- braneous texture supplied bountifully with blood-vessels and consisting of white and cineritious coloured nervous matter, has been supposed to be only a means of cutting off the course of sensation to the brain along those nerves whicii possess such knots or ganglions. But they are undoubtedly organs of impor- tance ; and 01 how great their importance may be to the system will be better gathered from the following comparative view of the system of the brain and nerves. SKETCH OF THE COMPARATIVE ANATOMy OF THE NERVOUS SYSTEM. I have before me the dissection of the nervous system of the leech : we cannot call it a simple system of nerves, yet it exhibits the rudiments only of the more complicated structure of man. A number of small knots or ganglions extend through the whole length of the animal. These ganglions are con- nected by intermediate nerves, and from them there pass out (for such is the licensed language of description) nervous fila- ments to the surrounding parts of the body and viscera. The ganglions are largest at the middle of the animal, and they and their connecting nerves diminish gradually towards the ex- tremities ofthe line which they form. What relation have these knots and nerves to the system of perfect animals ? It is evident to what part of the system they have the greatest resemblance; for there is in the human body a nerve called the sympathetic, which takes its course from the head to the lower extremity, having in all this course a series of knots or ganglions formed upon it; and the re- semblance of this system of the nerves ofthe viscera (nerves which, to us unconscious, hold a controul over the operations of the body,) is very strong to the system of nerves in such imperfect animals as the leech. Having examined the nerves of the snail, I would say it re- sembles the leech, only that we are drawn to notice the rela- tion whicl^that imperfect organ of outward sense, the feeler, has to the anterior ganglion. Besides the line of nerve running in the length of the animal's body, there is a circle continued •orward w'j-ch surrounds the oesophagus, and two tubercles are OF THE NERVOUS SYSTEM. 287 observable on the forepart of this circle into which the nerves of the feelers enter, or we may say from which they pass out. In the nervous system of the lobster, which is before me, we have the advantage of examining the parts in a larger scale. The extended line of the nerves of the body resembles those of the leech. It consists of two nerves running paral- lel to each other. These at regular intervals are united to- gether into ganglions. The anterior ganglion sends forward two nerves, which embracing the oesophagus unite or terminate in a mass which we perhaps may still call a ganglion. We must in that case call it the ganglion ofthe organ o? the senses, in other words the brain. Nerves pass inward from the eyes; nerves pass back also from the ears, and from the antennae; and the ganglions be- longing to these nerves are united into a square mass whicii I say we may call the brain. The brain is thus proved to be in its commencement the ganglions corresponding to the nerves of the senses. It is that collection of internal organs which correspond with the out- ward organs of the senses. But if we examine the brain of animals higher in the scale of existence, we shall discover both the original ganglions of the organs of the senses and a part superadded or accumulated upon the radical parts of the brain, which brings the whole mass to a nearer resemblance to the perfect brain. Thus in fishes, while we see the olfactory nerve or the optic nerve taking its course to corresponding tubercles, we may, by making a section of these tubercles, find cavities within them, corresponding to the ventricles of the more per- fect brain, and am approach towards the lobes of the cere- brum. • In fishes we see the commencement of a cerebellum, and while we see that no nerves enter into it we may observe its connection with the spinal marrow. The spinal marrow is formed in fishes ; there being no longer a mere chain of gang- lions, but a column of nervous matter corresponding with the divisions of the brain, and constituted of four fasciculi or columns united. In the higher scale of animals, the parts of the brain origin- ally depending on the outward organs of sense and their nerves are more accumulated and united together, while each portion of the brain holds its relation with the spinal marrow. Thi? gives an intricacy which occasions a necessity of setting oft' anew to describe the texture ofthe brain. 288 ) CHAP. 11. INTRODUCTORY VIEW OF THE ANATOMY OF THE BRAIN. JL HE brain is a mass of soft matter, in part of a'white colour. and generally striated; in part of a grey or cineritious colour, having no fibrous appearance. It mjs grand divisions and sub- divisions : and as the forms exist before the solid bone incloses the brain ; and as the distinctions of parts are equally observa- ble in animals whose brain is surrounded with fluid, they evi- dently they are not accidental, but are a consequence of inter- nal structure. On examining the grand divisions of the brain we are forced to admit that there are four brains. For the brain is divided longitudinally by a deep fissure ; and the line of distinction can even be traced where the sides are united in substance. Whatever we observe on one side has a corresponding part on the other; and an exact resemblance and symmetry is pre- served in all the lateral divisions of the brain. And so, if we take the proof of anatomy, we must admit that as the nerves are double, and the organs of sense double, so is the brain double; and every sensation conveyed to the brain is con- veyed to the two lateral parts; and the operations performed must be done in both lateral portions at the same moment. I speak of the lateral divisions of the brain being distinct brains combined in function, in order the mofe strongly to mark the distinction betwixt the anterior and posterior grand divisions. Betwixt the lateral parts there is a strict resem- blance in form and substance : each principal part is united by transverse tracts of medullary matter; and there is every pro- * vision for their acting with perfect sympathy. On the con- trary, the cerebrum, the anterior grand division, and the cerebel- lum, the posterior grand division, have slight and indiref-t connection. In form and division of parts, and arrangement of white and grey matter, there is no resemblance. There is here nothing of that symmetry and correspondency of parts which is so remarkable betwixt the right and left portions. After observing the great divisions of the brain, the distinc- tions observable in this substance demand our attention. All the outer surface of the cerebrum and cerebellum is of a grey or cineritious colour. Certain central spots of the cerebrum ANATOMY OF THE BRAIN. 289 and cerebellum present the same appearance. The ganglions have also cineritious coloured matter in their composition ; it is found in the spinal marrow and in some of the nerves. Encompassed by the grey cortical matter, there is a large central portion of white matter, commonly called the medullary substance of the brain. This white substance is striated, and the striae have a regular order. First grand order of strle.—The stride which first draw the attention are those which run across from side to side of the brain: they form the media of communication be- twixt the two lateral divisions. In the cerebrum, we find these stria? converging from the circumference towards the centre, and accumulated in the centre to form the great commissure. In the cerebellum, the same convergence takes place, and the commissure formed is what is called the pons varolii. Second grand order of stria:.—From the inner surface of the cineritious or cortical matter, striae of medullary mat- ter descend towards the base of the brain. They converge as they descend ; and the striated structure becoming more distinct and more resembling the nerves, they at last appear extricated from the covering of the cineritious matter, and are what we call the crura cerebri. As the crura cerebri are formed by the descending striae of the cerebrum, so are the crura cerebelli formed by the de- scending and converging fibres ofthe medullary matter of the cerebellum. Certain cineritious masses (insulated from the great cortical mass of the same appearance) are observable in the course of these medullary striae: these masses have hither- to received the names, corpora striata, thalami nervo- rum OPTICORUM, CORPORA DENTICULATA, &C. If we continue to trace the crura of the cerebrum we shall find them still converging and assuming a smaller diameter and passing under the commissure of the cerebellum (or pons Va- rolii,) and joining to the crura cerebelli they develope into the portion called medulla oblongata, and this last portion con- tracting again is continued into the spinal marrow or medul- la spinalis. The medulla spinalis has a central division, and also a distinction into anterior and posterior fasciculi, corres- ponding with the anterior and posterior portions of the brain. Further, we can trace down the crura of the cerebrum into the anterior fasciculus of the spinal marrow, and the crnra »f the cerebellum into the posterior fasciculus. vol. ii. O o 290 INTRODUCTORY VIEW OF THE OF THE CINERITIOUS MATTER OF THE BRAIN. Surely physiologists have been mistaken in supposing it necessary to prove sensibility in those parts of the brain which they are to suppose the seat of the intellectual operations. We are not to expect the same phenomena to»result from the cutting or tearing of the brain as from the injury to the nerves. The function of the one is to transmit sensation ; the other has a higher operation. The nature of the organs of sense is dif- ferent ; the sensibilities of the parts of the body are very vari- ous. If the needle piercing the retina during the operation of couching gives no remarkable pain, except in touching the common coats of the eye, ought we to imagine that the seat ofthe higher operations of the mind should, when injured, ex- hibit the same effects with the irritation of a nerve ? So far therefore from thinking the parts of the brain which are insen- sible, to be parts inferior (as every part has its use,) I should even from this be led to imagine that they had a higher office. And if there be certain parts ofthe brain which are insensible, and other parts which being injured shake the animal with convulsions exhibiting phenomena similar to those of a wounded nerve, it seems to follow that the latter parts which are en- dowed with sensibility like the nerves are similar to them in function and use ; while the parts of the brain which possess no such sensibility are different in functions and organization from the nerves, and have a distinct and higher operation to perform. * If in examining the apparent structure ofthe brain, we find a part consisting of white medullary striae and fasciculated like a nerve, we should conclude, that as the use of a nerve is to transmit sensation, not perform any more peculiar function, such tracts of matter are media of communication, connecting the parts of the brain ; rather than the brain itself performing the more peculiar functions. On the other hand, if masses are found in the brain unlike the matter of the nerve, and which yet occupy a place guarded as an organ of importance, we may presume that such parts have a use different from that of merely conveying sensation; we may rather look upon such parts as the seat of the higher powers. Again, if those parts ofthe brain which are directly connect- ed with the nerves, and which resemble them in structure, give pain when injured, and occasion convulsion to the animal as the nerves do when they are injured; and if on the contrary such parts as are more remote from the nerves, and of a dif- ferent structure, produce no such effect when injured, we may ANATOMY OF THE BRAIN. 291 conclude, that the office of the. latter parts is more allied to the intellectual operations, less to mere sensation. When we compare the structure of the brain in different animals we find that in certain lower classes there are no con- vulsions, the surface of the cineritious matter is uniform. As we ascend in the scale of beings we find the extent of the cineritious matter encreased. To admit of this, it is convo- luted ; the depth of tbe sulci are the consequence of the ex- tension of the cineritious mass; and in man above all other animals are the convolutions numerous and the sulci deep, and consequently the cineritious mass great, and its extension of surface beyond that of all other creatures. The circumstance which points out the importance of the cineritious surfaces of the brain is, that every portion has a fibre of medullary matter which runs across and forms a com- missure with the corresponding portion of the opposite side. Unless the cineritious masses were important organs, why should there be commissures or nerves forming a distinct sys- tem arising and terminating in nothing ? But if we take them as commissures, i. e. bonds of union betwixt the correspond- ing sides of the great organ of the mind, we at once perceive how careful nature is to unite the two lateral organs together, and out of two organs to make one more perfect. If we grant that this cineritious matter of the brain is an organ or organs of importance, then we may also acknow- ledge that the portions or masses of cineritious coloured mat- ter which we discover in remote parts of the nervous system minister to some office performed by such parts, as the gang- lions and the spinal marrow, the medulla oblongata, &c. I have found at different times all the internal parts of the- brain diseased without loss of sense ; but I have never seen disease general on the surfaces of the hemispheres without derangement or oppression of the mind during the patient's life. In the case of derangement of mind, falling into lethar- gy and stupidity, I have constantly found the surface of the hemispheres dry and preternaturally firm, the membrane sepa- rating from it with unusual facility. If I be correct in this view of the subject, then the experi- ments which have been made upon the brain tend to confirm the conclusions which I should be inclined to draw from anato- my ; viz. that the cineritious and superficial parts of the brain are the seat of the intellectual functions. For it is found that the surface of the brain is totally insensible, but that the deep' and medullary part being wounded, the animal is convulsed and pained. At first it is difficult to comprehend, how the part to which 292 INTRODUCTORY VIEW OF THE every sensation is referred, and by means of which we be- come acquainted with the various sensations, can itself be in- sensible; but the consideration of the wide difference of function betwixt a part destined to receive impressions, and a part which is the seat of intellect, reconciles us to the phe- nomenon. It would be rather strange to find, that there was no distinction exhibited in experiments on parts evidently so different in function as the organs of the senses, the nerves, and the brain. Whether there be a difference in the matter of the nervous system, or a distinction in organization, is of little importance to our inquiries, when it is proved that their es- sential properties are different, though their union and co-ope- ration be necessary to the completion of their function, viz. the developement of the faculties by impulse from external matter. All ideas originate in the brain: the operation producing them is the remote effect of an agitation or impression on the extremities of the nerves of sense ; directly they are conse- quences of a change or operation in the proper organ of the sense which constitutes a part of the brain, and over these or- gans, once brought into action by external impulse, the mind has influence. It is provided, that the extremities of the nerves of the senses shall be susceptible each of certain quali- ties in matter; and betwixt the impression of the outward sense, as it may be called, and the exercise of the internal or- gan, there is established a connection by which the ideas ex- cited have a permanent correspondence with the qualities of bodies which surround us. OF THE CEREBELLUM. Although the cerebellum be composed of the same ner- vous matter with the cerebrum, and although there be here also the distinction of cineritious and medullary matter, yet in form and in internal arrangement it is quite unlike the cere- brum. Betwixt the lateral portions of the cerebrum there is a strict resemblance, and an intimate connection is preserved by the commissures; that is to say, every part is united by transverse tracts of medullary matter, and there is every provision for their acting with perfect sympathy. On the contrary, the cerebrum, which is the anterior grand division of the brain, and the cerebellum the posterior grand division, have slight and indirect connection. In form and division of parts, and in the arrangement of white and grey ANATOMY OF THE BRAIN. 293 matter, there is no resemblance betwixt them; therefore, there is nothing of that symmetry which is so remarkable in com- paring the sides of the brain. There cannot therefore be a correspondence in their functions. The more important the organ, the sooner is it brought to maturity: this law we may observe in the the developement of the parts of the foetus, and afterwards of the child. In an infant the cerebellum bears in size a smaller relation to the ce- rebrum, even as one to ten, or even to twenty, while in adults it is one to five or six. Gall, and Spurz. There are grounds of believing, that the cerebellum has more reference to the strength and perfection of the bodily frame. In monsters, when there are two bodies, there are two cere- bella. There never occurs a monstrosity in one side of the brain, but often in monsters the cerebrum exists without the cerebellum, or the latter without the former. Often the cere- brum is double, and the organs of sense double; often the ce- rebellum is double, and the body double, while the cerebrum is single. From anatomy then, and without having recourse to expe- riment, we are led to conclude, that the grand divisions of the brain, viz. the cerebrum and cerebellum, have no consent like that established betwixt the organs of sense, and that the cerebrum and cerebellum perform different functions. ( 294 ) A. A. Hemispheres of the Cerebrum. B. Corpus Callosum. C. Rapha. CHAP. III. OF THE MEMBRANES OF THE BRAIN, AND OF THE SUB- STANCE AND TEXTURE OF THE BRAIN ITSELF. OF THE DURA MATER. JYlANY authors, while they describe the cranium as con- taining the brain, conceive that it also gives its shape. But the brain is formed before the bones which invest it. The first thing that we observe in the embryo is the disproportion- ate size of the brain to the diminutive body. The ossifica- tion of the bones of the scull is a gradual process. The brain, already formed, is invested with the strong membranes; and betwixt the laminae of the outer membrane the points of ossi- fication commence, and are not completed until the ninth year. \roi. m p. (S L"".v /•■»'; the Scull cap of a Child before it le fully Ossified . 1 the Fontanellc. 2 the Pericranium extremely Vascular . .1 the Longitudinal Sinus opened by cutting up the membrane in the direction of the Sagittal Suture . OF THE MEMBRANES OF THE BRAIN. 295 The bony matter, which is deposited betwixt the layers of this membrane, retains a firm connection and interchange of vessels with the now apparently distinct membranes on its in- ner and outer surfaces. The outer layer, which is so strong in children newly born, becomes the delicate pericranium, whilst the inner layer is the dura mater. Thus we find that the bones of the head are moulded to the brain, and the peculiar shapes of the bones of the head are determined by the original pecu- liarity in the shape of the brain.** This view corrects an error into which many have fallen, that the dura mater and the vessels ramifying upon it impress their form upon the solid bones, and wear channels upon their surface by their incessant pulsation. The membranes and vessels precede the formation of the bone, and the osseous matter is deposited so as to be moulded round the vessels.f Thus the dura mater may be considered as the internal peri- cranium.J The dura mater ^ is a firm and somewhat opaque membrane. When the scull-cap is torn off, and it is cleaned from the blood which escapes from the ruptured vessels, it is seen marbled with azure and rosy colours. It partakes more of the former in youth than in those advanced in years, or in the robust and sanguineous. || Its outer surface is rough, from the adhesions to the bone being torn up; but on the surface lying in contact with the brain*, it is smooth, shining, and of a pearl colour. Although the dura mater is really the strongest membrane of the body, it is yet divisible into laminae ; these are strength- ened and firmly connected by the intertexture of strong fibres. Most anatomists describe it as composed of two lamina3.1T— Some, however, describe three laminae—the outer lamina, or squamosa ; the middle, or filamentosa ; and the internal (being smooth and uniform,) the lamina membranosa.** But to se^**' * Certainly the skull is adapted to the form of the brain. But there is a deeper ques- tion which air craniologists have forgotten. Is the brain constituted in shape with a re- ference to the future form of the head ? No doubt it is. f Albini Acad. Anat. " Quomodo cranium crescendo accomodat se eis qua; continet." Fischer, Dissertatio de modo, quo, ossa se vicinis accomodant partibus. t Some regard only its external lamina as the internal pericranium. Haller, t. iv. p. 92. Fallopius Brst viewed tlie dura mater in this light, and he is followed by the best anatomists. .«.,,.. fj The membranes of the brain have the name of mater, because they defend the brain, and protect its tender substance ; or according to some anatomists of the Arabian school, be- cause the other membranes of the body are produced from them. Before Galen, the terui Meninx was common to all the membranes of the body, afterwards it was appropriated to those of the brain. || Malacarne Encefalotonaia Nuova, p. 19. T Soemmerring Corp. Hum. Fabrica, t. iv. p. 26. Haller, t. iv. p. 91. ** Malacarne, p-2'2. It is described as partly tendinous, partly ligamentous; that is to gay, of a nature resembling these, yet not altogether the same. Vicq d'Azyr found it separated by purulent matter into two lamina*, the fibres of which had a different, direction. Acad, des Sciences, An. 1781. p. (107.—Bartholin Sp. Histor. ^natnnw'. 296 OF THE MEMBRANES OF THE BRAIN. parate the dura mater into such laminae, it will, I believe, be necessary to dry it and tear it into shreds. No doubt it may be possible thus to tear it, as some have done, into four, six, seven, or even eight laminae or squamae. It is to be regretted that anatomists should have been proud of such dissections. The dura mater is insensible ; it has, in the way of experi- ment, been pricked and injured by every possible contrivance, by mechanical and by chemical stimulants; yet the animals, the subjects of such cruel experiments, have given no sign of pain.* Before the fact of the insensibility of the dura mater was thus established, physicians regarded this membrane as the seat and origin of many diseases, f Formerly the natural connection of the scull and dura mater was so resolutely denied—so hotly contested among the va- rious parties in anatomy and surgery, that we might, by read- ing their disputes, almost doubt one of the plainest and most obvious facts, were not the closeness of this connection suf- ficiently proved by the manner of the original formation ofthe cranium, by the resistance to the tearing up of the cranium, and by the bleeding surface of the dura mater 5 or, if further proof be required, we may macerate these bones and their membranes in acids, when the laminae of the dura mater will be seen intimately connected with the bone, while the peri- cranium and outer laminae of the dura mater are seen to be continued into each other,"]: by the intermediate cellular texture in which the earth of the bones was lodged. || The dura mater adheres more firmly to the bones in young subjects, because the bone is yet imperfect, and its surface spongy and rough ; and, for the same reason, it is more firmly attached to the skull in the chronic hydrocephalus, because the ossification is imperfect. It frequently adheres so firmly to the skull-cap, as to leave its outer lamina adhering to the skull when it is raised. GLANDS OF THE DURA MATER. Upon the external surface of the dura mater there are little, •Zinn. Exper. circa corpus callosum, cerebellum, duram meningem.—Mem. par Haller sur les parties sensibles et irritables — Blegny Journal de Med. An. 1. p. 16. t See Hoffman Med. Ration part 2. sec. ii.c. 1 i 2. and Boneti Sepulch. Anat. lib. i. sec. i. 1 Virq d'Azyr Memoir, de l'Acad. Roy. 1781, p. 497., and Malacarne (Aderenze della U. M. allepareti interne del cranio,) p. 24. || Taking a portion of the dura mater betwixt the finger and thumb, we can move the two lamina upon each other, owing to a slight degree of laxity in the connecting cellular sub- staDre. This cellular texture is demonstrated by Malacarne, by forcibly injecting quick- silver betwixt the layers of the membrane. OF THE MEMBRANES OF THE BRAIN. 297 holes, from which emerge fleshy-coloured papillae, and which, upon examining the scull-cap, will be found to have corres- ponding fovea?. These are the glandulae Paccbioni.* They are in number from ten to fifteenf on each side, and are seen chiefly lateral to the course of the longitudinal sinus. These bodies were supposed by Pacchioni to be glands. When pressed they give out a fluid ;J but in this they do not differ from the loose common cellular membrane. As they are chiefly seen along the line of the great sinus, and are not scattered over the whole dura mater, their supposed use of moistening the surface of tbe membrane^ is quite improbable; and, indeed, this is apart of that unfounded hypothesis which supposed an interstice betwixt the dura mater and scull, and as- cribed motion to this'membrane. The surfaces of the dura and pia mater, where they are in contact, being of the nature of the secreting surfaces of the investing membranes of the other viscera, require no such further aid in moistening them, or preventing their adhesion. Many glands are described by authors in the substance, and upon both surfaces of the mem- brane. Of the bodies which adhere to the surface of the pia mater, and of those also which are to be seen in the sinuses, we shall speak afterwards, when considering the veins which enter the longitudinal sinus. ARTERIES OF THE DURA MATER. This membrane must necessarily be supplied with vessels for its own nourishment, for that of the contiguous bone, and for the perpetual exudation of the fluid which moistens or bedews its internal surface. We may divide the arteries of the dura mater into anterior, middle, and posterior. The first pro- ceeding from the ophthalmic and ethmoidal branches of the internal carotid; the second from the internal maxillary and superior pharyngeal; the posterior from the occipital and ver- tebral arteries and posterior auris. || The principal artery of the dura mater, named by way of distinction, the great artery of the dura mater, is derived from the internal maxillary artery, a branch of the external carotid. It is called the spinalis, or spheno-spinalis, from its passing in- * See M. Littre Acad. Roy. des Sciences, 1704. Hist. p. 32. art. 19. •*> Haller, El. Phys. p, .106. Mem. par M. Vicq. d'Azyr. Mem de l'Acad. Roy. 1781. p. 497. Malacarne. Viz. the opinion of Fantonius. || Soemmering C. H. Fabric. A. Murray, Descrip. ArteriarumT in tab redact. VOL. II. P p 298 OF THE MEMBRANES OF THE BRAIN. to the head through the spinous hole of the sphenoid bone; or menmgfea media, from its relative situation, as it rises in the great middle fossa of the scull. This artery, though it some- times enters the scull in two branches,* usually enters in one considerable branch, and divides soon after it reaches the dura mater into three or four branches, of which the anterior is the largest; and these spread their ramifications beautifully upon the dura mater, over all that part which is opposite to the an- terior, middle, and posterior lobes of the brain. Its larger trunks run upon the internal surface of the parietal bone, and are sometimes for a considerable space buried in its substance. The extreme branches of this artery extend so as to inosculate with the anterior and posterior arteries of the dura mater, and through the bones (chiefly the parietal and temporal bones) they inosculate with the temporal and occipital arteries.-}- The meningeal artery has been known to become aneuris- mal and distended at intervals; it has formed an aneurism, destroying the bones, and causing epilepsy. J The skull-*ap with the dura mater adhering. ^ '" Ja]xl 2" Tiptonum- 3. Longitudinal Sinus. 4. 4. Great Lateral Sinuses. 5. Foiath bums. <5. Artery of the dura mater. * Soemmering de Corp. Hum. Fab. torn. v. p. 142. This is not the sole artery sent to thii dura mater from the internal maxillary, a twig also rises from that branch which goes to the pterygoid muscles and parts about the Eustachian tube—it enters the skull, and it distributed to the fifth pair of nerves, and to the dura mater and cavernous sinus. Another enters with the inferior maxillary nerve by the foramen ovale, and rises upon the dura mate* t Malacarne.—Soemmering, torn, v. p. 142. \ Malacarne, p. 1. sec. 10.5. OF THE MEMBRANES OF THE BRAIN. 299 Or THE SEPTA. WHICH INTERSECT THE BRAIN. Those septa, or, as they are called, processes of the dura mater, being extended across from the internal surface of the cranium, support the brain in the sudden motions of the body, and prevent the mutual gravitation of its parts; but I believe they are chiefly useful in retaining the sinuses in their triang- gular form. These partitions are formed by the reflection of the inter- nal lamina of the dura mater. The falx is the largest of the partitions ; it is attached to tbe cranium in the line of the sagittal suture, and reaching from the crista galli of the ethmoid bone to the middle of the tentorium, or to the crucial ridge of the occipital bone, it pas- ses deep into the middle of the cerebrum, and divides it into its two hemispheres. It is in shape like a scythe, for anteriorly it does not pass so deep into the substance of the brain; but it gradually becomes broader, or descends deeper betwixt the hemispheres, as we follow it backwards, which, with the curve it necessarily takes from the shape of the cranium, has obtain- ed it the name of falx: it is also called septum sagittale, verti- caje, or mediastinum cerebri.* The tentorium separates the cerebrum and cerebellum. It stretches horizontally over the cerebellum, and sustains the posterior lobes of the cerebrum. It is formed by the inner lamina of the dura mater, reflected off from the os occipitis along the whole length of the grooves of the lateral sinuses, and the edge or angle of the temporal bones. This septum, thus running round the cavity of the cranium divides it into two departments ; the upper one for the lodgment of the cerebrum, and the^lower for the cerebellum. But to allow the union of these two great divisions of the encephalon, a circu- lar opening is left upon the anterior part of the tentorium, which is called the notch of the tentorium. There is a little process of the dura mater, which may be called the falx of the cerebellum. It runs down upon the internal spine of the occipital bone from the tentorium, gradu- ally contracting until it terminates on the margin of the great occipital foramen. It serves as a kind of ligament strengthen- ing the tentorium, while it divides the cerebellum. It enters, however, but a little way betwixt the lobes. The falx and tentorium being connected and continued into * The falx has not been found in some subjects. GareDgeo Splanchnologie.—Mr. Car- lisle, Medical Transactions, 1793. 300 OF THE MEMBRANES OF THE BRAIN- each other at their broadest part, they mutually support each other, and are quite tense. This tenseness depends on their mutual support, for when one of them is cut the other falls loose.* The lateral extremities of the tentorium are continued for- ward into acute lines, formed by the duplicature of the dura mater coming off from the edges of the pars pelrosa of the temporal bones, and take firm hold on the posterior clynoid processes. From these two points a fold of the membrane stretches forward on each side to the anterior clynoid process, forming thus a hollow or cell for the lodgment ofthe pituitary gland. Another fold or duplicature of the dura mater, runs onwards a little way from the edge of the little wing of Ingra- tius. These are the sphenoidal folds. Where the internal lamina of the dura mater forsakes the external to form the falx and tentorium, it leaves a channel or triangular canal; the basis of which triangle is the lamina of the membrane investing the cranium, while the tension of the partitions carries the apex out into an acute point. This forms a channel for receiving all the blood ofthe veins, and this tension and triangular shape gives a degree of incompres- sibility to the canals. These are the sinuses which re- ceive the veins of the encephalon, and guard them from com- pression :— Section of the longitudinal sinus. I. the Skull. 2. the dura mater. 5. the extremities of the artery of the D. M. passing into the bone. 3. the falx. 4. the sinus 6. a branch of the temporal artery passing into the dura mater. Upon the surfaces of the dura mater there are many lacer- ti, or slips of fibres, which are interwoven with the main body of the membrane, and strengthen it. These fibres are pecu- liarly strong in the angles, where the duplicatures pass inwards, giving firmness to the sinuses, while they allow the veins to in- sinuate their trunk betwixt them ; these fasciculi or slips of •Mc OF THE MEMBRANES OF THE BRAIN. 301 fibres, on the sides of the sinuses, are the cordae Willisianae. They were considered by Baglivi and Pacchioni* as the ten- dons of the muscles of the dura mater, Pacchioni conceiving that this membrane was muscular. Vicq d'Azyr observes, that in inflammation of the dura mater he has seen it red, and of a fleshy appearance; and that such a circumstance might have deceived Pacchioni, and made him believe that there were muscular bellies.f These physicians conceived that the contraction of the falx and dura mater raised the tentorium; they even conceiv- ed that the action of the heart depended upon this motion of the dura mater.J They were deceived by the pulsation in the arteries of the brain, communicated by the dura mater, after the operation of trepan, or in their experiments on living ani- mals.^ The motion communicated to the dura mater, those Italian anatomists conceived to depend on the rising of the tentorium. This motion, whicii is occasioned by the beating of the arte- ries of the brain, had been long before observed :|| some con- ceived it to be a motion in the brain itself, others believed it to depend on the sinuses.1T The motion caused by respiration was likewise observed.** M. de Lamure's conclusion was, that the motion of the brain was caused by the reflux of the blood towards it from the vena cava in expiration.ff He undertook to demonstrate this ; and he conceived his proof to be good, when, by pressing the ribs of a subject, he saw the refluent blood swelling the jugular and abdominal cava. Haller observed the jugular veins swell, and become turgid, during expiration; and he concluded, that the motion of the brain was occasioned by the refluent blood dis- tending the sinuses of the brain. But he did not believe, as Lamure did, that this motion took place before the opening of the cranium, as well as after it. * These were Italian anatomists. Pacchioni was physician to Clement the Xlth. t Mem. de l'Acad". Roy. 1781. i Duverney. § There is a distinction in the movement of the dura mater to be observed upon opening the skull; one depending upon the pulsation of the arteries of the brain; the other caused by an obstruction to the exit of blood from the cranium, depending upon the lungs. " On " voyoit bicn Li pulsation des arteres du cerveau, qui communiquoient quelque mouvement " k la dure mere, uiais ce mouvement n'avoit aucune symmetric avec celui de la respiration. " Fatigue de ne rien voir apr*>s avoir si bien vu je comprimai la poitrine de l'animal: aussi- " tot le cerveau si gonfla, evidemraent par le reflux du sang de la poitrine qui remplissoit la " jugulaire.—Je lachai la poitrine, et le cerveau redescendit."—Ex per. 78. Mem. ii. par. Haller sur le Mov. du Cerv.—" II arrivoit pourtant de terns en terns et sans que cela con- " tinuat que le cerveau se soulevoit dans l'expiration, et se laissoit repomper dans l'inspiia- " tion." Ejjper 79. s. chat. || By Coiterus, Riolanus, Bartholin. "I Diemerbroeck. ■** M. Schlichting Mem. d"s Snvans Etrangers, 1774. Lorry, Mem. present, a l'Acad. des Scien. par divere Savans grangers. ft M rle Lamure ; vide I Acad des Science*, 1714. 302 OF THE MEMBRANES OF THE BRAIN. When the skull is opened by a wound, the dura mater still protects the brain, resisting inflammation, and giving the ne* cessary and uniform support to the more delicate substance and vascular membrane of the brain; but when the dura ma- ter is lacerated by the trepan, or punctured, or worn by the pulsation against'the edge of the bone, there may be sudden hernia of part of the brain from coughing, or a rapid and dis- eased growth from the pia mater forming a fungus. Such fun- gus I once thought was, in some degree, peculiar to children, but it is not; it is occasioned, I conceive, by the taking away of that due compression which the resistance of the dura ma- ter ought to give.* OF THE PIA MATER AND TUNICA ARACHNOIDEA. While the dura mater is closely connected with the cra- nium, and in contact with the surface of the brain, but still unconnected with it, (except by means of veins entering the sinuses and that only in the course of the sinuses) the pia mater is closely attached to the brain, and passes into its inmost recesses. While the dura mater is firm and opaque, and not prone to inflammation, the pia mater is de- licate, transparent, extremely vascular, and peculiar in being easily inflamed.f Like the dura mater, it is not endowed with sensibility ;j it is of great strength, considering its appa- rent delicacy.^ The pia mater, which was formerly considered as a simple membrane, consists, in reality, of two membranes, the tunica arachnoides, or meninx media, and the proper pia mater, or tunica vasculosa. || The Tunica arachnoidea was discovered and commented upon by a society formed by Blasius, Sladus, Quina, and Swamerdam.1T They called it Arachnoides, because of its extreme tenuity, comparing it to a spider's web. It was call- ed also Membrana Cellulosa, from the appearance it took * I have seen in one day seven wounds of the head with fracture; of these, three had the bones thrust through the dura mater. And they died with fungus cerebri; the others did well. f Mr. Hunter on the blood. \ Haller, Oper. Minor, de Part. Corpor. Humani sent. & irrit. § Sir C. Wintringham Exper. Essays. Taken comparatively, it is stronger than the wirta. I| There are many, however, who with Lieutaud consider the arachnoid coat as the exter- nal lamella of the pia mater. IT This was in 1665. I am, perhaps, not correct in saying they discovered it; for Varo ins describes it plainly, covering the medulla oblongata. OF THE MEMBRANES OF THE BRAIN. 303 when they insinuated a blow-pipe under it, and blew it up, se- parating it from the pia mater.* This membrane is without the pia mater; and while the pia mater sinks down into the sulci of the brain, this covers the surface uniformly, without passing into the interstices of the convolutions, or into the ventricles.-]- This membrane is so extremely thin, that it cannot by dis- section be separated for any considerable space from the pia mater, and least of all, over the middle hemisphere of the brain. By the blow-pipe, indeed, we may raise it into Cells, but it immediately subsides again ; on the posterior part ofthe cerebellum, on the spinal marrow and base of the brain, it is very easy raised and demonstrated.! It does not pass deep into the sulci of the brain, but unites them by an extremely delicate cellular texture. OF THE PROPER PIA MATER, OR TUNICA VASCULOSA. The pia mater is a simple membrane, without either tendi- nous, aponeurotic or muscular fibres. It is extremely vascu- lar, but it is transparent in the interstices of its vessels; it is the membrane which immediately invests and connects itself with the substance of the brain; and although delicate, it forms the support and strength of the cineritious and medulla- ry substance. All vessels distributed in the body, however minute, are always conveyed in membranes; the pia mater then follows, or rather conveys the vessels not only into the cavities of the brain, but to every part of its substance, it be- ing intimately blended with it.-\j We see it more distinctly de- scending in strong plicae into the interstices ofthe convolutions; nor is it into them only that it enters, but into every pore which conveys a vessel. || The pia mater, as it passes into the sub- stance of the brain, divides and subdivides into partitions and cells, and every capillary vessel, and every mollicule of the substance of the brain, is invested and supported by its subdi- * Ruysch. Tab. 10. Epiat. Anat Prob. viii. t Haller Elemen. Phys. torn. iv. sec. viii. p. 7. {F. Ruyvhii Responsio ad A. os Goelecke Epistol. ix. SeeBidloo, table 10; but the membrane i< so delicate that it can be but very imperfectly represented by engraving. See also Sandifort Thesaur vol. ii. p. 291. fj Columbus, the assistant of Vesalius, and afterwards professor in Rome, explained this in- tertexiure of the pia mater with the proper substance of the brain, so far back as 1559. || When we tear off the pia mater from the brain (for it cannot be called dissection,) it does not adhere merely at the sulci, but to the whole surface of the convolutions, and everywhere small vessels enter, and with these vessels descends also the lamina of the pia mater. 304 OF THE M&MBRANES OF THE BRAIN. visions. The pia mater is to the brain what the cellular mem- brane is to the other viscera and parts of the body : for it k the peculiar matter lying in the interstitious cellular mem- brane (as in muscles, bones, he.) that gives the peculiarity of character to the parts;* the cellular membrane itself is nearh alike in all; therefore, in my judgment, the pia mater is rightly- considered by some anatomists as a cellular substance.f Malacarne says, I am much inclined to consider it with the illustrious Haller as being composed of lamina like common adipose membrane, and that the extreme arteries ramify- through its cells, for, with a blow-pipe, we can raise it into cells like the common membrane ; and if this be carefully done, the air may be made to pass from cell to cell, following the arteries in their course betwixt the lobuli, and in the sub- stance of the brain.f We can follow the pia mater into the ventricles, by tracing it betwixt the posterior lobe of the ce- rebrum, and the cerebellum, where it forms the velum inter- positum of Haller and passes under the fornix. We can follow it also into the posterior horn of the lateral ventricles from the base of the brain, where the branches of the middle artery of the cerebrum pass into the lower part of the choroid plexus; we trace it also into the bottom of the fourth ventricle. The pia mater lining the ventricles is more delicate, and less vas- cular than that seen upon the surface, and betwixt the convo- lutions of the brain. It has been said that the ventricles of the encephalon served lo increase the surface of the pia mater, and that whatever purposes are served by that membrane and its vessels on the surface of the brain, we must suppose the same performed by it within the ventricles.^ This seems more like a satisfactory conclusion than it really is. As the tunica arachnoidea is of a peculiar nature, and has few if any vessels, and as it covers the external surface of the brain only, it seems to me probable that this membrane is the cause why effusions in the ventricles are so common, and why fluids are so seldom found betwixt the surface of the brain and the dura mater. When by the diseased action of the vessels of the pia mater on the surface of the brain an effusion i;- thrown out, it very seldom lies uuconfined upon the surface; * See Leeuwenhoek, Epist. Phys. xxxiv. •j- Bergen. Program, de Fia Matre. See Haller Anat. % See Albinus Ann. Acad. vol. i. lib. i. cap xii. and the beautiful plate iii. See Ruysch lab. 8. Epist. Anat. vii. & tab. 15. Sucffis the profusion of vessels distributed to incon- ceivable minuteness, that it has been considered as entirely composed of vessels: it has re- ceived the name of chorion, from the membrane of the sccundines. Galen de Uau Part. 1. ■i»i. cap. 8. Malacarne, part i. sec. 243. j Dr. Monro's Nervous System, chap, vi, OF THE MEMBRANES OF THE BRAltt. 305 but frequently fluids are contained in sacs of the arachnoid coat, betwixt the convolutions of the brain, or raise pellucid vesicles upon the sunface. The want of a tunica arachnoidea upon the pia mater of the ventricles, may be a cause of the fluids being so much more readily secreted into these cavities. The raising of the arachnoidea into vesicles by the" action of the vessels of the pia mater, is rather an argument for the distinct nature of these membranes. The tunica arachnoidea is raised by the action of the vessels of the pia mater, as the cuticle is raised into blisters by the inflammatory action of the vessels of the cutis, while no other membranes of the body present such an appearance in their disease. They inflame, indeed; they thicken; their lamina become more distinct, or their cellular substance fills with water, or hydatids are formed in them; but this appearance of water secreted under the tu- nica arachnoidea is quite peculiar. OF THE SUBSTANCE OF THE BRAIN. The cerebrum and cerebellum consist, as we have said, of two substances very different in colour, viz. the cineritious and medullary matter, first described by Picolomini. The cineri- tious, or ash-coloured matter, forms the superficial or outer part of the encephalon, and is therefore called also the cortical part. This cortical matter is of a reddish grey colour and se- mi-transparent, but varies considerably ;* in the crura cerebri it is very dark; in the pons varolii it is redder ; in the corpora olivariaf it is yellower. The consistency of this matter also varies considerably in different parts ; it is soft in the base of the brain, betwixt the optic nerves and anterior commissure, and in the third ventricle. The medullary matter is chiefly in the internal part of the brain, forming a kind of nucleus or white central part; but in many parts of the brain, there is a mixture of these which form strise ;{ and in some of the emi- f Cuvier describes it black in some places. f Vicq d'Azyr—" Exterior cerebri totius facies, donee in spinalem medullam abeat, pie- '' rumque colore est subrubride cinereo, vel languide russeo. Fusciora sunt cerebra saii- '' guine ditia, e. g. hominum apoplexia enectorum, vel hominum crassioris sanguinis ; palli- *4 dissima vero sunt cerebra hydropica vel hominum pituitosorum vel haemorrhagia mortuo- " rum. Dubior procul color cerebri sanguinis temperaturam sequitur, et ideo pallidius est 11 infantibus, quam adultis." Soemmerrmg Hum. Corp. Fab. vol. Iv. p. 4l. As Boerhaave never saw, ow observed, but merely imagined, he ought not to be regarded ; now we may look for a better purpose into Albinus. Annot. Academ. vol. Ii. c. xii. J. Thus the cineritious substance is mixed with the medullary matter in the corpus callo- sum, in the coi'|)ora striata, the thalami nervorum opticorum, in the tuhercula quadrige mina, the enunenentia inamiUaria; in the crura cerebri; in the pons Varolii ; in the co; pora olivaria, and medulla spinalis vol. ii. Q q SOS OF THE MEMBRANES OF THE BRAIN. nences, the internal part is cineritious, while the external part, or what we might here call the cortical part, is medullary. The cortical or cineritious substance does not blend gradu- ally with the white medullary matter, but on the contrary, their line of distinction is abrupt: an intervening substance has been observed. In inflammation of the brain, particularly^. it has been said, that this third substance has been found. This may be merely the effect of light upon the union of the two substances. We, however, often observe an appearance of successive coloured circles upon the edge of the medullary matter of the arbor vita;, in the cerebellum. It has been asserted by M. Ludwig* that the masses and striae of the cineritious substance, dispersed through the in- ternal parts of the brain, have a communication with each other. This, however, is denied, by Vicq d'Azyr. f He conceives that the cineritious substances of the pons varolii, or ofthe corpora olivaria, have no communication with the cineri- tious substance in any other part of the brain ; and that in se- veral parts of the brain the cineritious substance is surrounded and isolated by the medullary matter. Its great importance (which should never have been doubted) has been deduced from its being so generally found towards the origin of the nerves.*]; The cineritious substance seems to have a much greater quantity of blood circulating in it than the medullary substance. Its vessels come by two distinct routes, partly from the extre- mities of those arteries which appear in large branches upon the surface of the brain, and partly by vessels which pene- trate through the medullary substance from the base of the brain. Ruysch and Albinus have made the most minute in- jections of this part of the brain. The former conceived it to consist entirely of vessels; but Vicq d'Azyr and Albinus found always in their experiments, that a great proportion of it re- mained colourless after the most minute injection. It is, in- deed, very improbable, that so soft a body should be entirely composed of vessels. How, for example, can we suppose the commissura mollis, or cineritious matter, on the sides and bot- * DeCiueria Cerebri Substantia. Lepsite. f Hid. de l'Acad. Roy. an. 1781, p. 507. X II faut que les usages de la substance gi ise soient tres-importans; car independamment de la portion de cette substance que les circonvolutions contiennent, et qui semble appartenir 3 la masse blanche du cerveau, bu en observe des amas plus ou moins considerables pres des diverse? ongmes des nerfs: ainsi pres de la premiere et ladeuxieme paire, soot les corps strns etles couches optiques ; la troisieme paire est pres d'un espue uoiratreque je decrirai ailleurs: la quatrieme par e lort au dessous des tubeicules quadrgumeaux, dont le noyau est com[)o?e de substance gnse, la cinquieme, la sixiemc, la septieme, se trouvent aux environs de la protuberance ammlaire, ou la substance grise est mel£e avec la blanche ; la huitieme «t la neuvierr.e sont places pres de Imminence olivarie, ou j'ai observd un melangeparliculier de substance grise. Mem. de l'Acad. Scien. an 1781. p. ,007. OF THE MEMBRANES OF THE BRAIN. 307 lorn of the third ventricle, or the almost transparent lamina, which we find in some parts, to be composed of vessels ?* The white medullakv substance appears to be a pulpy mass. We observe no peculiarity of structure in it towards the surface of the brain, where it is contigious to the cortical .•natter ; but towards the origin of the nerves it takes a more fibrous appearance. This appearance of fibres is not owing to any peculiarity in the medulbiry matter, but to the manner in which the pia mater involves it. The medullary matter, being chiefly internal, has every where through the brain a commu- nication from the fore to the back part, from the upper part to the base ; from the great central part it extends in form of striae, into the corpora striata and thalami; it invests the emi- nences in the lateral ventricles; and those upper parts have communication with the medullary substance of the base. M. Mickel found, upon comparing the brains of an Euro- pean and of a negro, that the medullary matter differed very much in colour. In the negro, instead of the whiteness of the European, the medullary matter was of a yellow colour, and nearly like the cineritious matter ; he observed also, that this very peculiar distinction of colour was only to be observed when the section was recently made, and that the darker colour of the medullary matter became fainter when exposed to the air.f op the observations made upon the minute structure OF THE BRAIN. The opinions regarding the structure of the brain have had a dependance on the general doctrines of the structure of the secreting organs, and it is, of course, connected with the dis- putations of Malpighi and Ruysch, because the doctrine of the glandular nature of the brain, and the belief of the nervous fluid, being a secretion, has, in all ages, formed the basis of the most favourite theories. J Malpighi found, on throwing in black and fluid injection, that there remained always particles colourless, and to which * The centrical and cortical substance of white blooded animals present no difference of i-x>lour. Cuvier. J" La moelle du negre etoit d'un jaune clair, tirant un peu sur le gris, tandis que celle e l'Europeen etoit d'une parfaite blancheur. Celui du negre etoit d'un jaune noiratre " et celui de l'Europeen d'une couleur blanche—Prolongeant ensuite la dissection jusqu'aux " grands ventricules du cerveau j'ai coup6 horizontalemeut les corps stries et les couches des " nerfs optiques. C'est la ou la difference a paru vraiment etonnante, le corps strie dans "|le negre etantpresque de la couleur brune d'une ecorce d'arbre, au lieu que celui de •' l'Europeen etoit couleur de chair pale tirant au cendre," &c. X Indeed this doctrine of the glandular nature of the brain has descended from Hippo- crates—" Caput quoque jpeum glapdulag habtt cerebrum, enim est ut glandula album est efc friabile," &c. 308 OF THE MEMBRANES OF THE BRAIN. the injection did not penetrate. He conceived these to be glandular folicules, and that the cineritious substance of the brain consisted of this folicular or glandular structure, while the medullary matter of the brain was merely the fibrillae of the excretory duct. This opinion was founded on conjecture, with but a very poor show of experiments, viz. by boiling the substance of the brain in oil, he found it take a granulated ap- pearance, as if formed of small grains, or little glands.* Such was the received opinion until Ruysch, with a despo- tical authority, swayed the opinions of physiologists: he al- leged, in proof, only his own experiments and preparations, in which other anatomists could not follow nor refute him, and therefore they acquiesced. His most unanswerable and most insulting argument was u veni et vide."f According to Ruysch, the cortical substance of the brain is entirely vascular, and has no appearance of a glandular or foli- cular structure ; nay, he conceived it to be entirely composed of arteries.J This opinion Albinus confuted, and Malacarne observes, though we suppose the extremities of the arteries of the cineritious substance to be more minute than those which are distributed to the microscopal corpusculi of the smallest visible insect, there must still remain some part, which is not composed of vessels; and in regard to the veins of the cine- ritious substance we may appeal to Albinus, who, from the substance of the brain, finds many veins connected with the arteries of the cineritious substance when he carefully lifts the pia mater. But there is this peculiarity in the distribution of the blood-vessels of the brain, that though the cineritious sub- stance be the most vascular, yet, in the medullary matter, we see the vessels with large open mouths, and more distinct than in the cineritious substance. In following the blood-vessels from the base of the brain into the medullary substance, we see them distinct, and of considerable magnitude ; but when they are about to enter the cineritious substance, they disperse into minute branches.^ In the same manner those arteries, * " Pedamentum, supra quod posita est philia in qua conservator portio cerebri in liquore, "• quam decoxi in oleo olivarum per horas, sicuti, facere assolet Dr. Vieussens. F,a autein " plane mutiliset perversa est preparaHs, nam nihilum quidein vasculosi visui occurrit post " decoctionem in dicto oleo, et quod imusquisque tentare potest ita ut inventor neuliquarn " hahendus sit Dr. Vieussens Sc. quod cerebri cortex nil sit, nisi extremitates vasorum san- " guineorum : in ea autem nemo hactenus (quod sciam) me imitari poterit aut analogura quid "fecit" Ruysch Thes. An. x. No. xxxii. + " Milites quando hostium adventum audiunt, clament ad anna ! ad arma ! sic ego dico " hie ad visum J ad visum !" Responsio ad J. Ch. Bohliuiu. J Vieussens was latterly of the same opinion, and is accused of plagiarism by Ruysch. Accordingly, we find, that in some parts of his works he describes the glands and ducts of Malpighi i* Leeuwenhoeck saw, in the suhstance of the brain, but especially in the cortical sub- stance, red blood-vessels, but so delicate that he could not comprehend how the globules of ♦he red blood could pass along them; and what appeared more particular, l hey were of a OF THE MEMBRANES OF THE BRAIN. 309 which are carried into the sulci of the surface by the pia mater, branch into extreme minuteness before they finally penetrate the cineritious substance.* Leeuwenhoeclcf observed, in the cortical substance of the brain, a pellucid, chrystalline, and to appearance oily matter : he calls this, therefore, the substantia pellucida et vitrea. When he had put a small portion of this under his glass, he saw a fluid, which he at first conceived might have escaped from the globules that were necessarily cut by the knife. This fluid also be found to consist of very minute globules, thirty- six times less than those of the blood. J These small globules he conceived to have probably constitued a fluid, which, during the life of the animal, was moveable, and in vessels, though now in death congealed and fixed.^ The colour of the cortical substance he found to depend upon the minute ra- mification of the vessels which were of a dark brown colour, while, in the medullary part, they were clearer and more transparent. Independently of this distinction of vessels, he could observe little difference in the medullary and cineritious substance; the refraction of the rays of light amongst the transparent globules being the cause of the whiteness of the former. R. Delia Torre, || in his microscopical observations, de- scribes globuli in the brain ; he says, that he saw them float- ing in a pellucid viscous fluid. But ProchaskalF thinks Delia Torre must be mistaken in this, for when he took a small por- tion of the brain, he saw it consisting of innumerable glo- bules, which continued to adhere to each other, even after three months' maceration in water; and thence he concludes, that it could not be as R. Delia Torre conceived, that these spherical bodies moved from the brain on towards the extremi- ties of the nerves; nor do these bodies lie imbedded in a glutinous fluid (he continues) but they are connected by the extremely minute and pellucid sepimentae of the pia mater, deeper colour than the red particles themselves; for, when seen singly, they appeared to have very little colour. This he explained by an experiment made upon a louse. After it had sucked blood very plentifully, he observed that the blood was broken down by digestion, and conveyed through the limbs and horns of the creature, so as to make it uni- versally red. So here he conceives that the globules of the blood may be broken down and altered in their shape to enter the minute vessels of the brain. * Malacarne, Part ii. sect. 18. . + He was horn in Delft in Holland, 1632, and died 1723. He iscelebrated for his mi- croscopical discoveries ; his papers are chiefly in the Transactions of the Royal Society of London, about the year 1674. X Anatomica Contemplatio, 30. Ridley Anat. Cerebri, cap. xi. f) Among those globules of which the brain is composed, he saw also globules of the blood which it was easy to distinguish by their roundness. These red globules, he supposes had escaped in consequence of the minute vrssels having been cut by the knife.. || Nuove oservazioni Microscopiche, Napoli, 1776. "I Tract. Anatora. de Struct. Nervorum 310 OF THE MEMBRANES OF THE BRAIN. and by the vessels which pervade both the cortical and medul- lary matter, and which nourish as well as support and connect these corpusculi. Fontana,* on submitting a portion of the medullary matter to the microscope, thought he discovered it to consist of small winding tubes filled with a transparent gelatinous humour. This he chose to call the intestinal substance of the brain. Prochaskaf cannot, from his own observations, determine whether the globular bodies of Delia Torre be convoluted vessels, or what they are. R. Delia Torre had observed, that they were largest in the cortical part, less in the medullary substance, still diminishing in the medulla oblongata, and least of all in the nerves; but succeeding observations did not sup- port this assertion-! Malacarne expresses himself to be near- ly of the same opinion in regard to the vesicular structure of the cortical substance of the brain. The minute processes of the pia mater, says he, embrace and support the medullary substance, which is surrounded with a matter of a darker co- lour, and less distinctly fibrous, but not less essential, and which is composed of corpuscules, that, in figure and arrange- ment, resemble the vesicles of the pulp of a lemon.fy Many authors endeavour to support their conjectures re- garding this vesicular structure of the brain by morbid dissec- tion. || We see the brain frequently degenerated into hyda- tids, or into little vessels, or into knobular glandular-like scirrhosities. I have seen this vesicular appearance in great portions of the pia mater. I have seen the pia mater with in- numerable little bodies like miliary glands upon it; and also the whole upper and external part of the brain degenerated into one mass of disease It was hard, scirrhous, tuberculated, and like a diseased gland.1T But I cannot conceive that any conclusion, in regard to the natural structure of the brain, can be drawn from such appearances. They are to be considered as the diseases of the vessels and membranes, rather than of the peculiar matter of the brain. Thus, 1 have given more place to these observations on the minute structure of the brain than in my judgment they deserv- ed, rather to prevent the repetition ofthe folly b/such as * Fontana's Treatise on Poison, and on the Primitive Structure of Animals, translated. t Professor of Anatomy at Prague. t This was certainly a theoretical deception : it is like the accurate observation of Fra- oassati, who could distinguish a difference of taste in the medullary and cineritious substance of the brain. 5 Malacarne, page 2. sect. 4. ' || Wepfer de Cicuta Aquatica. Mangetus—Malacarne, <.Vc. f There has been observed a structure like the bronchial gland. Huber, Observation* Anatom.—Acta Helvetica, 1758. torn. m. OF THE MEMBRANES OF THE BRAIN. 311 might conclude they were pursuing an unexplored path than from any hope of the subject proving useful. When the brain is examined in the foetus ofthe early months, although tbe substance ofthe brain is extremely soft, and even of a fluid consistence, the membranes and vessels are fully formed, exquisitely minute, and perfect in all their processes, so that they give form and firmness to the brain. As the brain is perfected, and as it is covered by a firmer bone, it acquires more con- sistence and firmness. With this firmness it does not acquire strength, for the brain of a child will suffer more injury with- out destruction of organization, than the brain of an adult. The substance of a child's brain is soft and yielding, while the bones of the cranium are loose and yielding, and for the same purpose, to admit the compression of the head at birth. OF THE SENSIBILITY OF THE SUBSTANCE OF THE BRAIN. It cannot but appear strange, that the very source or centre, to which every sensation is referred, should itself be destitute of sensation; yet we are assured, by the experiments of Hal- ler and Zinn, that the cortical substance of the brain has been irritated, without the animal being convulsed, or giving signs of pain,* but when the# medullary part of the brain is irritated, the effects are instantaneous and the animal is convulsed. It has been observed, that as the injury of a nerve causes con- vulsions, so does that of the central parts of the brain, from which the nerves originate; but this sensibility! diminishes to- wards the surface of the brain.J We see a distinction be- twixt the structure and the function of the nerves and of the brain ; or rather betwixt the cineritious substance of the brain and the nerves. For, although we must necessarily conclude, that the cineritious substance is an important, and, perhaps, the most essential part of the system, still it does not evince, by the immediate effect of injuries, that strict sympathy and uni- versal connection which belong to the nerves. The circumstance has been thus explained. The nearer to its source that a nerve is pricked, the greater is the effect of the injury. As it recedes from the base towards the superfi- *But, like the insensible membranes, it becomes irritable by disease: or by pressure, which affects the universal function of the brain. Vander Linden, in.his Medicina Physiolo- gica (IGI3,) brings proof of the bsensibiirty ofthe brain. See the general enumeration of the effects of vounds in the brain. Haller Physiol, torn. iv. &c. Observations par M. de la Peyronnie de dtcouvrir la partie de ctrvean ou l'ame exerce les functions.—Acnd. Roy. des Sciences. Boerhaave, torn. ii.; with the Commentary of Haller, p. 595. for the effects of pressure. t It is in eftcct different from pain or sensation: it shakes the body with violent convulsions t Socmmei ring, torn. iv. 312 OF THE MEMBRANES OF THE BRAIN. cies of the brain, the effect is lessened, because the connec- tions of the part are diminished in number, proportionally to their distance from the central parts of the brain; a puncture in the centre injures more filaments from their being concen- trated to form nerves. This reasoning is not satisfactory. Several ounces of the brain have been lost in consequence of wounds, without death, or loss of memory, or intellect.* There is a very marked distinction betwixt puncturing, cut- ting, or even burning, the surface of the brain, and pressing it. In the first there is little or no effect, or even pain. In the latter there is stupor, pain or convulsion. The reason is, that in the first it is a local irritation in a place which has lit- tle, if any feeling, while in the latter, the effect of the pres- sure spreads extensively. CHAP. IV. OF THE VEINS AND SINUSES OF THE BKA1.N. J_ HE brain is very profusely supplied with blood, insomuch, that the blood has been supposed to circulate in the brain in a proportion four times greater than in any other part of the bod[y. This is the most moderate calculation, and it has been formed from a comparison of the quantity of blood circulat- *M. dela Peyronnie had a patient wholes* a very large spoonful of brain, but wlw life and intellects remained. OF THE VEINS OF THE BRAIN. 318 ing in the head, with that which circulates in the arm. Boer- haave and Kiel, comparing the area of the arteries of the cere- brum with that of the ascending aorta, made a most erroneous calculation ofthe proportion of blood circulating in the brain, compared with that ofthe rest ofthe body. Had they com- pared the quantity of blood within the head with that of the lungs, of the liver, of the spleen, or of the kidney, the differ- ence would have been less striking. Wherever there is great arterial vascularity, we are sure to find also peculiarities in the venous system ofthe part; wherever we find an accumulation of tortuous arteries passing to a gland, we shall also find the veins tortuous and large; or wherever the arteries of a part take a diseased action, the effect of this action will be found most perceptible in the change which the veins undergo. In short, the effect of disease is much more surely to be discovered in the venous than in the arterial sys- tem ; and no where is this better exemplified than in the brain. The following appear on the first view to be the most strik- ing peculiarities in the veins ofthe brain ; their size ; the lit- tle connection they seem to have with the surrounding cellu- lar membrane, and the inconsiderable support which they ap- pear to receive from it; their having no valves ; there being in their course distinct from the arteries ; and lastly, their not being gathered into great trunks, but emptying themselves into tbe sinuses of the dura mater. It is not easy to conceive how the veins of the brain should have been so much overlooked by the older anatomists; but from the dissections of Albinus, and the mircroscopical obser- vations of Leeuwenhoeck, we have authority for what is, per- haps, in itself sufficiently evident, that the veins ofthe surface of the brain are derived from minute ramifications conveyed in the delicate pia mater; and that these, as in the other parts ofthe body, proceed from the extremities ofthe arteries, without any apparent peculiarities in the connection betwixt the extremities of the arteries and the veins ofthe brain.* I divide the veins of the brain into the external and internal, or those which emerge from its substance, and are seen upon the surface; and those which, coming chiefly from the sides of the ventricles, are convoluted in the plexus choroides, and terminate in the fourth sinus. * The observation is trivial; but we must recollect, that Vesalius contradicted Galen, and affirmed, that the sinuses received also arteries which gave them their pulsation. This opinion was refuted by Fallopius, but adopted by Vieussens, Wepfer, and others, upon the jdi ,1 of the facility with which injection passes from the arteries into the sinuses. See Rid -.»y, cap. vi. de Cerebri Mota, rjusque fcinubus. VOL. II- Rr 314 OF THE VEINS OF THE BRAIN. OF THE VEINS WHICH ARE SEEN UPON THE SURFACE OF THE BRAIN. Vicq d' Azyr has been minute in his attention to the veins of the surface of the brain. He confirmed the observation, that almost al! the veins which pass into the longitudinal sinus, open in a direction contrary to the stream of blood in the sinus.* These superficial veins of the surface of the hemis- pheres, are in number generally from ten to fifteen on each side. They really do not seem to be worthy of the minute attention which Vicq d'Azyr has bestowed upon them; he has most carefully described each individual branch, and that not in general terms, but first those ofthe right, and then those of the left side. Now, although these veins do not enter the sinus opposed to each other, nor in pairs, still the irregularity is trifling, and were it important, does not admit of descrip- tion. Those veins do not lie in the sulci of the brain, but pass occasionally along the interstices, or over the convolutions of the brain ; they take in general a course from before back- wards, but previous to their entering the sinus, are turned for- wards. We have already observed, that the pia mater and dura mater have no connection, but at the place where those veins enter the lamina of the dura mater ; and here their con- nection is somewhat peculiar. It is not a simple adhesion of the pia mater and dura mater; but a white spongy substance seems to connect and strengthen them, and when torn asunder, it leaves a soft fatty kind of roughness upon the pia mater. These appear to me to be the'same bodies which Ruysch so frequently mentions as little particles of fat, and which others have taken to be the glands of the pia mater.f Vicq d'Azyr, in his xxxiiid plate, fig. 14. has confounded them under the name of the glandulae Pacchioni.f Of these veins lying upon * From Vicq d'Azyr's table we should he led to conclude, that the veins did not de- cidedly all open with their months opposed to the stream of blood. Ridley asserts, that one half open backwards. Sautorini also observes great variation iu the direction of these veins. Lower, while he observed this direction backwards, describes them, at the same \ time, as passing obliquely betwixt the coats, like the gall duct in the intestine, or the ureters into the bladder. Sabhatier stiys decidedly, that they enter with their mouths opposed to the course of the blood in the sinus. From Malacarne, we should be led to conceive (what I believe to be the truth) that they open very irregularly. f " Portio pia> matris in liqtiore, cuius superficies exterior ohsita variis particulis promi- " nentibus exisuis, qusis pro glandulishaKueiunt nonnulli: cum autem sint diversa? formae, ' et colore _ pinjuidinem representent, pro pinguidine potius i'.las habeo, praesertim cum " inter duplicnturam pia? mntris aliquoties pinguidinem invenerim." Thesaurus Anat. ix. No. xlii. Epist. ix. p. 8. Thes. v. No. 1. X We see also what he says in the Acad, of Sciences, An. 1781, p. 502 " Elles etoient " plus ou moins reconverted, vers leur insertion par les glandules de Pacchioni; les ayant Li examines dans plusieurs sujets, j'ai observe qu'elles etoient a peu-pres, de chaque c6te au OF THE VEINS OF THE BRAIN. 315 the surface of the brain, there is one, or very often there are two large veins on each side, and which enter generally pretty far back in the sinus, and are somewhat peculiar from their greater size, and their semicircular course. These, from their state of dilatation, and the colour and fluidity of their blood, will be found in morbid dissection, to mark sufficiently, in many instances, the character of the ve- nous system of the brain. There is again another vein some- what peculiar in its course ; whilst those take a superficial course, and are upon the level of the longitudinal sinus, it gathers its branches upon the internal flat surface of the left hemisphere, and rises so as to insinuate itself into the inferior part ofthe sinus.* All these veins ofthe surface ofthe cere- brum have very free inosculations with each other. [ cannot any where better observe the negligence of authors, in regard to the glandulae Pacchioni, than when speaking of the mouths of those veins which open into the great longitu- dinal sinus. I cannot help thinking, that many of our best authors have overlooked entirely the importance of the glandulae Pacchio- ni ; and many also have been entirely ignorant of them. We have already mentioned, that a few small bodies, by no means constant nor regular, were to be seen upon the external sur- face of the dura mater, in the course of the longitudinal sinus, or at no great distance from it. We have mentioned also those fatty-like adhesions of the roots of the veins, as they enter the sinus, and which rather belong to the pia mater. Both these are called the glandulae Pacchioni improperly. The bodies which engaged Pacchioni and Fautonus in such violent disputes, are seen on the inside of the longitudinal sinus, and are connected with the opening of the veins ;f they appear of a fleshy colour, projecting like papillae, or like the granulations of a sore. Pacchioni says, " Ovorum instar " nombrede dix, douze, ou quinze." Ridley calls these "carnous adnescences," betwixt the membranes, p. 8. As to the glands which Willis affirms to he scattered over the tunica arachnoides, I could never see them. Ridley. * Vicq d'Azyr. f" In Iongitudinali sinu immediate, sub membranosis expansionibus, in areolis chorda- " rum Williyanarum, quin et supra easdem chordas consita? sunt lnnumerse glandula? conglo- •' bata?. propria, et tenuis>ima membrana, veluti in sacculo conclusae ; quar racem uni ut " pluiimum coeunt; rnro sparsim disponuntur: hae glandule utrmque ad latera falcis mes- " soriae, ab ejusdem apice ad basis usque posticam paitem miro prope modum artiteio pi - " cedentes, dorso lacertonun accuinbunt, & partim ab liorum fibns, pnrtnn ab i», que a " chordis emergunt, firmantur, atque invicem alligantur, ita ut non nisi laceratacu difjuug " possint." Vide Pacchioni, p. 126. . " Sinu longitudinali aperto, in conspectum vemunt corpuscuw rotunda, & sunrotnna " milii forma, (a clariss. viro Pacchiono detecta) ha*c magnitudiflfln acicuke vulgaris ca " haud «u|jerant, nisi per microsropium introspiciantur, aut ex duobus corpuscuhs cor " nentur " Ruysch, Thes. vii No xxxiv. From this wc see how various the si:. these bodies is. In the next paragraph he observes, " Vix et ue vix quidem ulhwn ex c. % " corpusculis videre potest." 316 OF 1HE VEINS. OF THE BRAIN. " bombycinorum apparent," which describes their conglobate appearance ; but they are of a pale fleshy colour, which Pac- chioni says is owing to their being surrounded with muscular fibres. The preparation from which Pacchioni had taken his plate, was previously macerated in vinegar. These bodies being soft and vascular, have allowed the minute injection to transude in some of the experiments of anatomists, which has given rise to the opinion of the actual communication of the arteries of tbe dura mater with the sinuses. As to their use,* I atn in considerable doubt. Joan. Fautonus (in his letters to Pacchioni) conceives that they give out a fluid into the sinus, to dilute the venous blood, f Pacchioni describes ducts passing from them to the pia mater, (which are those connections that we have already remarked,) and conceives that they lubricate the surface, or communicate with the substance of the brain; and that they are pressed, and their secretion promoted by the motion of the chordae Willisiana?, and the action of the dura mater.J I should rather conceive that they had a valvular action on the mouths Of the veins; they project from the mouths of tbe veins into the sinus, and the blood passing from the veins must filter through them, and be checked in its retrogade course, and perhaps obstructed in its natural course when they are enlarged. As (hese bodies differ very much in the variety of subjects, they must sometimes impede the free egress of the blood from the veins of the cerebrum into the longitudinal si- nus, and cause disease, especially as they are softer and larger in old men.^ At all events, they are too much overlooked in morbid dissection. "*?-< The veins which answer to the arteria corporis callosi, and which are seen lying upon the corpus callosum in a very fine cellular membrane, rise and pass into the inferior longitudinal sinus, that sinus which is formed in the laminae of the inferior edge ofthe falx. * It is curious that these bodies are confined to tbe longitudinal sinus. " Minim, & aeque " animadversionr dignum est, hasce glandulis ad solim longitudinalis sinus latera repeiiri " cuin in latcralibus inibus vel iiunquam, vel rnro ndmorium per pauca eanindem vestigia " adnotenlur, ubi pi-rrsertim pra?fali canalas deorsum inclinare inripiunt, antequam abin- " teiseptoiiiin doiso discedant." Pacchioni, o. Jl'7. t" Ego_ aqueum humorem in glandulis ecrepn i, fluere lympham in tubul'v quos tecum *' lyniphaticos apello, nuuquam nep'.verim, sed Iiquidi fluxuin ab utrisque versus sinum " magis, quam versus ambitum cerebri verisiinileiii, nn»isquc naturae legibus consonum " ri-se aflrinno." Fautonus Epist. D. A. Tacch. Oper. faciei). 177. X " Ex iis autem in minimum quidem vascuiuui lymphaticum prodire conspicere potui."__ Ruysch. fj"Fibris carneis tenui-Mmis circumambiuntur singula?, unde colorem carnea pallidum " nancisc' videnlur: in beniiius vero, in qiiihuslnijusinodi fibr ilia contentus, quo iidem spiritus in peni- " tion ac medullari substantia idonei errculentur, BaJnei minoris, & magis temperati loco u esse videtur." Willis, Cerebri Anat. p 47. 5 Galen gives a good description of the choroid plexus; he describes the innumerable veins of which it is composed, and their joining the fourth sinus by the vein which retains his name. Some bave confused themselves with a passage of Ruysch, Thes. iii. No. lxv. &c. in which he is speaking of the clioroid plexus, where it appears in the base of the skull from the bottom of the fourth ventricle. They have understood him to sav, that the plexus was covered not with the pia mater, but with the tunica arachnoides, first described by Mor- gagni, and whose authority we may consult for much of this part of anatomy. Adversar. Anat vi Animad. 1 & sequent. |[ " Huncce plexum nil es«e nisi arteriolas, ad visam succosas, a naturali constitutione arte" " nosa non nihil recedentes, mirumque in modum contortas, serpentinoque modo reptantest " g'andulasque representantes." Ruysch, Thes. v. Asser. quartus, No. lxviii. Not. 2. OF THE VEINS OF THE BRAIN. 319 I conceive the use of these loose and vascular membranes, is to secrete the fluid of the cavities. They are undoubtedly the parts of the brain the most excitable, for if but a tempora- ry change takes place in the circulation of the blood in the brain, it will upon dissection be manifested in the state of ful- ness of these veins in the vesicles, which are formed in their folds, and in the accumulation of fluid in the ventricles. The blood of the two plexus of the lateral ventricles, and that of the third, is conveyed into the velum interpositum, or that membrane which stretches under the fornix, and over the third ventricle. The branches of veins also which extend themselves upon the sides of the lateral ventricles, and into the processus digitalis, being gathered together upon this membrane, open into the vena Galeni, or rather form it. The most remarkable branches of veins in the lateral ven- tricle are these: a considerable vessel is seen to collect its branches upon the anterior part of the ventricle, and in the anterior sinus, or horn of the ventricle. This vein runs back towards the anterior crus of the fornix, and dips under it, just above the communication of the ventricles; and joins the veins in the velum of Haller. Other small veins are seen collect- ing their branches upon the corpora striata; and, passing un- der the centrum semi circulare geminum, connect themselves with the plexus. Again several branches of veins are extended in the posterior part of the ventricle. These are from the me- dullary substance of the posterior lobe of tbe cerebrum. They passunder the posterior crus of the fornix and join the vena Gale- ni. Lastly, a vein remarkably tortuous, frequently full of blood, passes forward, and is seen at intervals in the plexus choroides. This vein, taking an acute turn, joins its fellow under the ante- rior crura of the fornix, and is reflected backwards and under the fornix, so as to form the beginning of the vena Galeni. The vena galeni then is the great central vein of the brain. It stretches from the extremity of the fourth sinus into the internal part of the brain, to receive the blood from the membrane lining the ventricles,—from the substance of the brain,—from the plexus choroides,—and from the velum in- terpositum.* It lies under the posterior part of the corpus callosum, under the fornix and above the nates and testes. It is entangled in the velum itself. It consists of two great branches which lie parallel to each other, and which some- times have the appearance of being twisted, and these unite before they enter the fourth or strait sinus. * The velum lying upon the nates and testes, and adhering to them and the pineal gland, ' he vem Galeni receive? hero also veins from those bo;':es, and from the upper part of the ,'erebellum. 320 OF THE VEINS OF THE BRAIN. In the basis of the brain the veins are not remarkable, nor do they require any description distinct from the sinuses into which they open. They are small, having little way to run : and before they become large trunks, they empty themselves into the nume- rous lesser sinuses*betwixt the dura mater and base of the skull. This is perhaps a provision against the pressure of the brain. In passing into those sinuses, the veins take a long oblique course betwixt the lamelhe of the dura mater ; which has given occasion to anatomists to describe many intricate lesser sinuses. OF THE PARTICULAR SINUSES. By the term sinus we are to understand the great veins of the brain, where they are received into the triangular canals of the dura mater. SUPERIOR LONGITUDINAL SINUS. This is a triangular channel running in the falx from the crista galli of the aethmoid bone to tbe crucial ridge of the occipital bone. It is not constant in its origin. Sometimes it begins from a blind foramen before the crista galli.* Some- times from the orbital sinus.-)- In some subjects it begins only opposite to the fontanellc, or even further back, and then at once swells out to a large size. As the sinus passes backwards it is gradually enlarging for the reception of the veins from the surface of the cerebrum. The course of the sinus corresponding with the form of the skull is a curve answering to the sulcus, which runs in all the length of the cranium, from the sethmoid bone to the crucial ridge of the occipital bone. The angle formed by the split- ting of the internal layers of the dura mater, to form this sinus, i; strengthened by strong slips of fibres, sometimes called chordae Willisian-e, which upon the inside of the sinus have the effect of making the canal irregular, so that it has the appearance of cells, into some of which the probe enters, and leads to the veins on the surface of the brain; others are blind, or lead to lesser sinuses, whicii not unfrequently run parallel for some length to the gre*at sinus; or the probe passes from one of * Malacarne, Haller, Gautier. f These sinuses as frequently are continued into the inferior longitudinal sinus or into the circular or elliptical sinus; they are like azure streaks under the dura mater covering the •rbital process. tot m. Put. Y//V f'/ //l<" J/Z/lt/JCJ *~~^i*~* OF THE VEINS OF THE BRAIN. 321 these cells to another. Sometimes the sinus has no such irre- gularities, but is straight and smooth through its whole length.* This sinus has in some rare instances been found of a square shape ; its lower surface serving as a roof for another sinus of a triangular form, which, for some way, ran parallel with the great sinus, and which was of course also included in the lamina the falx—these Malacarne calls seni subalterni. Irregular lesser sinuses are by no means uncommon, and they form, some- times, communications through agreat extent of the longitudi- nal sinus ; or again it will be found that the longitudinal sinus deviates considerably, in some subjects, from the straight line, taking a curve or circle, generally behind the fontanelle; or it sends off branches, which again unite with it; or it is fairly divided. In all these cases the chords or fasciculi of tbe dura mater stretch out over the sinuses, and protect them from compression. Instead of reaching backwards to the crucial line upon the occipital bone, tbe longitudinal sinus has been found to divide at the beginning of the lambdoidal sutures, and to follow them in a direction towards the petrous bone,f while the lateral si- nuses, running in the duplicature of the tentorium, were redu- ced to a very narrow compass. From the strength of the connections ofthe sinuses, and from the languid course ofthe blood through them, I cannot believe that the sinus has ever suffered the distention which Malacarne says he has observed. I should rather suppose that what he men- lions had been natural and congenital enlargements; especially, considering that the sinuses, like the other veins of the body, are frequently irregular. lateral sinuses, or the first and second of the an« C1ENTS. The lateral sinuses are formed by the splitting of the lami- na of the tentorium, as the longitudinal sinus is formed by the falx. They are continuations of the longitudinal or first sinus. From the crucial ridge of the occipital bone they stretch near- ly horizontally, going off right and left, following the connec- tions of the tentorium in a direction toward the petrous bone; then they take a curve downwards and forwards, to terminate in the internal jugular vein; passing through the foramen lacerum betwixt the temporal and occipital bones. * The internal membrane of the sinus is perfectly smooth, and is continued into the coats »l* the internal jugular veins; it is of the same nature with the internal coat of the vein. )• Malacarne, parti 148. VOL. II. S S 322 OF THE VEINS OF THE BRAIN. Very frequently the one lateral sinus is larger than the other —generally the right is the larger, and sometimes the left is entirely wanting.* They diverge from the termination of the superior longi- dinal sinus at the crucial point ofthe occipital bone ; but some- times they are irregular, diverging higher, and even passing1', round in the circle of the posterior part of the cranium, at some distance from the tentorium.f The right lateral sinus for the most part begins higher than the left. It is generally longer, and may be considered as the continuation ofthe longitudinal sinus*. Nay, in some subjects, the right or left lateral sinus begins from the longitudinal one, while that ofthe other side is continued from the fourth, and then the lateral sinuses are separated at their origin by a mem- branous isthmus. If one of the lateral sinuses receives the the superior longitudinal one, it will be found to be four times the size ofthe other.f I have seen a more remarkable variety ofthe lateral sinuses. The blood which should flow from all those parts of the brain from which the superior and inferior longitudinal sinus, and the vena Galeni, and fourth sinus are derived, instead of passing by the root of the tentorium, forsook these channels, and con- sequently the lateral sinuses were left diminutive; and the blood took a course in the tract of the posterior occipital sinus- es} and, after encircling the foramen magnum, they gained their usual outlet.^ The angles of the lateral sinuses are strengthened by membranous fasciculi; betwixt these the veins enter as in the longitudinal sinus; where the sinus descends from the level of the tentorium in the angle formed by the occipital and petrous bones, there are many strong irregular fasciculi of fibres: under this point, being no longer protected from compression, by their triangular shape and the tension of the tentorium, the sinuses are irregular; they are now sunk in the sulci of the bones, and the dura mater spreads its sheath over them. The great irregular cavity.U in which the extremities of th» lateral sinuses lie,1f and the foramen lacerum have much varie- ■'•"■ Lieutaud, Anat. Hist. -f Malacarne. J? See Morgagni Adversaria VI. tab. 1. fig. 1. 5 There are instances ofthe lateral sinuses opening into the external jugular vein. |1 Lower conceives that the size ofthe jugular fossa was the effect ofthe reflux ofthe blood ; and that the greater size of the sinus of the right side was to be traced to the practice of nurses laying their children chiefly on the right side! See also Morgagni Adversaria An<"t. T See Willis Anatom. Cereb. Hum. p. 29. and the plate: OF THE VEINS OF THE BRAIN. 323 ty, and their straightness seems to affect the size of the sinus in its whole length.* OF THE INFERIOR LONGITUDINAL SINUS. The inferior longitudinal sinus, or the lesser, or inferior sinus of the falx, runs in that edge ofv the falx which pene- trates betwixt the hemispheres of the cerebrum. It is ex- tremely small towards the forepart of the falx ; but, as it pas- ses backwards, it goes on increasing by the accession of veins which come from the hemispheres, and corpus callosum, and from the falx itself. It is formed betwixt the lamina of the falx. Sometimes it runs in its very edge, but as frequently a little way removed from it; sometimes it is found beginning very far back in the falx. The forepart of it is more like a vein running in the falx than a sinus. It is in general to be seen more superficial, and in every respect like a vein, (there be- ing no provision for preserving it from compression,) upon one side ofthe falx. It very often takes a waving course upon the falx ; while it receives veins, which branch in the substance of the falx, and from communications betwixt it and the superior longitudinal sinus. It opens into the straight or internal sinus, called also the fourth, near the edge of the tentorium. OF THE INTERNAL, STRAIGHT OR FOURTH SINUS.f I would call this the internal sinus, from its situation, but more particularly from its receiving the veins from the internal part of the brain. This sinus is formed chiefly by the vena Galeni; which, coming out from betwixt the corpus callosum and tubercula quadrigemina, enters betwixt the lamina ofthe middle part ofthe tentorium, where it is united to the falx; so that by the tension of these two partitions, this sinus is drawn into a triangular form, and is as incompressible as those sinuses which run connected with the bone. It opens, for the most part, by an oval mouth, formed by strong pillars of fibres into the left lateral sinus, rather than di- rectly in the middle ofthe communication of the three great sinuses. We shall find this like the other sinuses suffering con- * Some very large veins open into the lateral sinus; they are derived from the posterior lobes ofthe cerebrum and the cerebellum. These insinuating irregularly betwixt the lami- na of the tentorium, and running for some way, have been considered as additonal sinuses. See Haller, torn. iv. p. 149. f Sinus quartus, Perpendicular's. Haller.—The fourth sinus ; the two hiteral being the first and second, and the longitudinal being the third sinus. 324 OF THE VEINS OF THE BRAIN. siderable variety; or irregular smaller sinuses will often be found running beiwixt the lamina of the tentorium. POSTERIOR OCCIPITAL SINUSES. These are so called in opposition to some irregular and small sinuses, which run upon the occipital bone before the great foramen. The posterior occipital sinus lies in the Kttle fairs of the cerebellum ; it rises upwards, and opens into the common union ofthe longitudinal and lateral sinuses; it commonly, however, lies rather to the left, and empties itself into the left lateral sinus. It is by no means constant; like the other lesser sinuses, it is subject to great variety ; and, be- fore it rises into the tentorium, or empties itself into the larger sinuses, it has a communication or emissarium, by which part of the blood may pass into the external veins, through a fora- men in the central ofthe occipital bone.* THE INFERIOR LATERAL SINUSES. The inferior lateral sinuses are still more rarely to be found than the last, insomuch that Vicq d'Azyr says he never has seen them. They run in the lamina, or under the dura mater ofthe posterior fossa ofthe base ofthe skull; that is, the hol- low ofthe occipital bone, which is under the tentorium. They are so irregular that they frequently occur in one side only. They communicate with the posterior part of the foramen lacerum; with the posterior petrous sinus or vertebral veins ; or lastly they occur as an irregular collection of channels run- ning in the several neighbouring sinuosities.t We see then that there is a point of union for all these sinuses, which we have not as yet described : we see that the superior longitudinal sinus, the two lateral sinuses, the fourth (and consequently the inferior longitudinal sinus,) and the pos- terior occipital sinus, unite at the crucial spine of the occipital * Malacarne —This sinus is sometimes double; or it has two branches encircling the pos- terior margin of the occipital hole; or, as I have already observed, it takes the office of the great superior lateral sinuses, and empties it into the foramen lacerum ; or it communi- cates with the vertebral veins. See observations sur uu dilatation singuliere des sinus occipi- taux, Mem. de l'Acad. Roy. Anno 1781, p. 596. t " Independente dai seni lateralis inferiori ho veduta tra le rohuste lamine e le fibre, " dalle quah incomincia crassissimo l'imbuto vertebrale intorno al maggior folo del cranio " una quantita di cayerne, di cellule communicanti insieme, le quali foruiavana mi seno cir u colare irregolarissimo appoggiato sulla parte superiore, o sia sul marline interno del for* " medissimo." Malacarne, p. 113, 111. jy OF THE VEINS OF THE BRAIN. 325 bone. This is the torcular herophilt,* torcular, lacuna, PLATEA, TERTIA VENA, PALMENTUM, PELVIS, LAGUNCULA. It was natural that the attention ofthe ancients should be drawn to this part; for, upon opening this union of the ^sinuses, we find a large irregular cavity, which seems to be" particularly strengthened by these strong fasciculi of fibres, which indeed are the support of the sinuses.f Ignorant of the circulation, imagining that the blood ascended by the great jugular veins to tbe lateral sinus, and seeing that the lateral sinuses opened into this centrtd cavity, they conceived that the blood destined for the brain underwent an operation there, and was thence sent through every part of the brain.| OF THE LESSER SINUSES IN THE BASE OF THE SKULL. Besides those larger sinuses which we have described, and which convey back the great proportion of blood circulating in the brain, there is a set of lesser sinuses which lurk betwixt the dura mater and the anterior part of the base of the skull. These last are fully more intricate than the others; they lie upon the irregular surface of the sphenoid, temporal, and oc- cipital bones; and tend backwards to the great embouchoir formed by the irregular hole in the temporal and occipital bones. THE SPHENOIDAL SINUSES. The superior sphenoidal sinuses are seated in a fold of the dura mater, on the internal margin of the wing of Ingras- sias, and before the great wing of the sphenoid bone ; they receive the blood in part from the orbit and from the dura ma- * Herophilus was a Greek physician, a disciple of Praxagoras, and cotemporary with Erasistratus. t" Deinde et illia per sectionem scalpellum injiciens, sursum adigere conoberis ad usque " verticem ubi venae duae invicnrn congrediuntur; quam regionem Herophilus nominat lenon "torcular. Galen." Lib. NonusdeCerebri, &c Dissectione. X " Coeuntes autem in vertice capitis, quae sanguinem deducunt meningis duplicatura, in '*• locum quendam vacuum quasi cisternam (quern sane ob id ipsum Herophilus torcular " solet nominal*,) inde velnt ab arce quadara omnibus subjectis partibus rivos mittunt • " quorum numrrum nemo facile dixerit, quod partium nutriendirum nuinerus sit infinitus! " Manant autem rivorum nonulli quidem ex medio ipso laco in totum cerebellum, secti, ac " derivati, eodem prorsus modo, quoii qui in areolis, alii autem ex parte anteriore feruntur, " ea scilicet qua torcular excipit dixeris utique velut rivum quendam sanguinis, quern et ip» " sum ex crassa meninge admodum ingeniose fabricata est, partibus enim ipsius meningis quae " sanguinem duxerunt ad torcular appulsis, dimissaque illinc aliqua in partes subjects?, non " amplius, quod superarat, uni venae concredidit, sed preterea ex crassse meningis partibus " anterionbus extensis rivulum efficit, ex quo priinum multos rivulos per totam viam pro " dnxit." Galen, cap. vi. de. tortnlnr. Et quo pacta venir intri cerrhrum di*tribuantur 326 OF THE VEINS OF THE BRAIN. ter; they open into the cavernous sinus, or perhaps into the ophthalmic sinus, which of course, for tbe most part, conveys the blood into the Superior or inferior longitudinal sinus. The inferior sphenoidal sinus is very irregular and in- constant. It is in the dura mater, covering the great wing of the sphenoidal bone : the blood of this sinus is emptied into the cavernous sinus, or escapes by emissarii into the trunk of the temporal veins. The clynoid sinus.—The posterior clynoid sinus, or elip- tic sinus, and the circular sinus, are one and the same ; the difference only consists in the manner of describing tbem ; the circular sinus lies within the clynoid processes of the sphe- noid bone, and surrounds the glandula pituitaria.* As this circular sinus opens upon each side into the caver- nous sinus, it is not unaptly divided into two ; the anterior half of the circle, being the anterior clynoid sinus of some authors; the posterior half (which is in general wider.) the eliptical or posterior clynoid sinus, or semilunar. This sinus, like most of the lesser sinuses, is irregular in its shape, its size, its communications, and its origin.f Its natu- ral communication is with the cavernous sinus, which in fact encroaches upon its side; it will be found to communicate also with the sphenoidal sinuses, and the oblique or petrous si- nuses :"j: at one time the anterior half of the circle is wanting ; at another the posterior.^ the cavernous sinus. The cavernous sinus is a great irregular centre of commu- nication with the lesser sinuses in the base of the skull. This sinus is sunk upon each side of the sella turcica, and is formed in the irregular splitting of the lamella of the dura mater: it is of a triangular shape j it extends from the sides of the sella turcica, to the foramen spinale.|j The pointed extremity of the tentorium, which extends forwards from the angle of the *Ridley describes it in these words: " Another I discovered by having injected the » SL . warx:. T"* round !he Punitory gland on its upper side, forwardly within the « S£SlUM°f tied*ur? ,ma,ter' backwardly between the dura mater and pia mater, there « maTe^n nftH^J *"**?* T' ** "J1*"*"1 ^ad itself' and ,atera»y » » sort of 3 « whirh hfhlw? ^V a}F*5 and t,le carotid arterJ' on each °"b"fe of the gland, which, by bemg fastened to the dura mater, above and below, at the oasis of the skull sinus 7 ahtt,e,,,tereticebetw«t itself and the gland. "-BrunnenV describes S •"• Malacarne, p. 123. X Haller, torn. iv. p. I54. » Ll^defi^'nL?^1305-16^ *& a?tiS ai?p,io';est J DUQC anterior nunc posterior ejus Soemmerrif^volTp ^ deS,deratur' 1,lterdufl> >"«* dnplieem fuisse, referum?" (] Malacarne. OF THE VEINS OF THE BRAIN. 327 petrous bone to the posterior clynoid process, covers and pro- tects it The cavernous sinus is different from all the others; it is irregular, having fibrous cords traversing it, which gives it a kind of cellular appearance. It is like a diseased part into which the blood had been driven, till the cellular texture had been distended and partly destroyed. After a minute injec- tion, small arteries are seen to ramify among these fibres; the internal carotid artery rises through it, and the sixth pair of nerves is involved in it, in their passage from the skull. This sinus is the centre of the little sinuses and veins of the anterior part of the base of the brain and cranium : four or five veins pour their blood into it, from the anterior lobes of the brain and the fossa silvii; sometimes, even the ophthalmic veins open into this receptacle.* The superior and inferior petrous sinuses, and the basilar sinus, open into it behind; the circular before; the sphenoidal sinuses and veins of the dura mater upon the side ; while tbe right and left sinuses often communicate by means of the transverse sinus. Besides these the petrous sinuses have several communications, or emissaria as they are called, viz. by the inferior orbitary foramen, the funnel of the carotid artery, through which descends a vein, (the vena sodalis carotidis,) which terminates in the pterygoid plexus of veins, the sphenoidal fissure, the interrosseous sinus of Malacarne.f The transverse or posterior clynoid sinus, runs across from one lateral basilar sinus to another behind the posterior clynoid processes.J In its form it is not peculiar, nor is it very regular. Petrous sinuses.—These are three small sinuses which may be called petrous, from lying betwixt the dura mater and petrous bone : one runs near the angle formed by the pars squamosa and pars petrosa of the temporal bone; another occupies the groove on the salient angle of the bone ; and a third is rather belonging to the cuneiform process of the oc- cipital bone, and might with propriety be called lateral BAMLAR SINUS. The anterior petrous sinus runs upon the anterior face of the petrous bone : from near the spinal hole ;^ whence making a semicircular curve in the angle of the petrous and * This vein, the vena angolana, makes a very remarkable emissaria, but it is more pro- bable that the blood in such veins runs inwards than that it escapes from the skull to the external veins.—Cum venis posterioribus frequentes nexus init. Sommcrring, vol. v. p. 354. •"■ The Emissaria, 4to of Tabarini. Observ. Anatom. p. 42. et seq. j. In truth, the superior and inferior, or oblique sinus, the cavernous and the transverse, meet nearly at a point. { And here it has a transverse branch of communication with the cavernous sinus, which inns under the extended pomt or the tentorium. h 328 OF THE VEINS OF THE BRAIN. squamous portions of the temporal bone, it terminates in the lateral sinus. The posterior petrous sinus* lies in that pointed ex- tremity of the tentorium, which stretches forward, connected wit.h the acute angle of the petrous bone. It is narrow ; and a sulcus or groove on the angle of the bone gives a partial lodgement to it; it passes from the cavernous sinus to the great lateral sinus. The lateral basilar siNUsf is shorter and larger than the last; and it makes an oblique curve from the cavernous sinus under the pointed extremity of the tentorium, which is conti- nued by the side of the sella turcica, to the termination of the lateral sinus, or rather into the beginning of the jugular vein by a channel, separated by a bony lamina from the termi- nation of the lateral sinus ; or it is continued into a vein in the base of the cranium, which afterwards joins the great jugular vein. The middle basilar sinus.—This scarcely deserves the name of sinus. It consists, in general, of a few cellular-like communications, formed in strong fibres of the dura mater, which here partakes of the nature of a ligament. These open into the last-mentioned sinus, or sometimes into the vertebral vein. The vertebral sinuses are veins included in tbe lamella? of the dura mater; and, divided into right and left; they de- scend into the tube of the vertebrae, on its forepart, and pass down even to the sacrum. They are connected in all their length with the vertebral, dorsal, and lumbar veins. These sinuses or veins, at each vertebra, are joined by a transverse branch ; they are connected at the top of the spine with the basilar or anterior occipital sinuses. emissaria santorini. "■ Venje emissaria" is but another term for those lesser veins which form communications between the sinuses within the head, and the external veins in the base of the cranium. These, then, are chiefly . the ophthalmic,! mastoidean, and * Or superior petrous sinus. Vicq d'Azyr. f The inferior petrous, or oblique sinus. X " Je me suis convaincu, par des dissections multiplies, que les sinus caverneux & orbi- " taires comniuniquent, p;ir un plus grand nombre de veinules avec les arrieres-narines, de '« sorte que les hemorrhages critiques qui se font par les nez, dans les fievres aigues, ou la " tete est affectee, s'expliquent facilement par ce nioyen," &c. Vicq d' \-yr, Acad Roy- ale, 1781, p 504. OF THE VEINS OF THE BRAIN. 329 vertebral veins. But the vena sodalis arteria? carotidis, the small vein which penetrates tbe parietal bone by the side of the sagittal suture, even the venae arteria? meninga? sodales, and the little veins which pass with some of the nerves, or through the fissure of the bone, are also brought into account. To these a much greater importance has been attached than they merit; particularly in apoplectic affections of the head, they have been supposed to be eminently useful in emptying the surcharged sinuses and veins of the brain into the external veins. But those lesser passages for the blood, supposing us to be assured that the blood flowed through them, from the sinus to the external veins, are insignificant, when compared with the great out-let of the internal jugular vein ; to which we have seen all the sinuses tend. But the accumulation of blood in the vessels of the brain is seldom mechanically pro- duced ; it is a diseased action of the system of the brain, to which we become more and more liable as we advance in years: and perhaps it is owing to the same gradual change which is operating on the venous system from infancy to old ase- The importance of the sinuses in the circulation of the blood in the brain, is either vaguely described, or imperfectly understood by authors. We find it said, that the sinuses sup- port the blood against compression, and protect its free cir- culation. This to me seems an erroneous idea. The lesser veins are, as in other parts of the body, and have no such pro- vision : and since, within the head, there can be no such par- tial compression as in the limbs, any cause which would com- press the greater veins, were they not supported, must fall upon their extremities with worse effect. The circulation is the only power which can act mechanically upon the brain ; but this can never cause a compression of its veins, because the increased action of the arteries must tend more to the dis- tention of the veins than it will be the occasion of the brain compressing them. The more general idea conceived of the use of the sinuses is nearer the truth; viz. to prevent the sudden and violent ac- tion of the muscles of respiration, or of the muscles of the head and neck, from injuring the smaller veins of the brain, that the sinuses prevent that impulse from being communica- ted to the blood in the small and tender veins of the brain, which might endanger a rupture of them.* Yet this is not exactly the manner in which the sinuses preserve the lesser * Monro, Nervous System, p. 4 vol. u. T t 330 OF THE VEINS OF THE BRAIN. veins; they do not suffocate nor take off the force of the im- pulse from the regurgitating blood, so much as they would do if they were like the trunks of veins in other parts distensible ; because, being incapable of distention, they throw the undu- lation of the blood, (when it is thus checked in its exit,) back- wards upon the extremities of the veins. But then the effect is, that no particular vein or trunk receives the shock; all suf- fer in a lesser degree, and equally, which is their safety. All the veins in the base of the brain, which would be liable to rupture, or distention, from receiving, in their sudden turns, the shock of the blood, are preserved by being inclosed in si- nuses, and covered by the strong lamellae of the dura mater. The lesser vessels again are removed from the shock: its force is spent because it has spread among many branches; and it has become a general impulse upon the brain, which the brain resists, because it is incompressible. That the brain does receive such an impulse, in violent coughing and straining, is sufficiently evident from the rising of its surface seen on these occasions, when it is accidentally laid open by fracture, or the trepan.* Although the obstruction of the jugular veins were to cause no regurgitation of the blood; although the sinuses were sup- posed to have an effect in preventing the distention of the veins, or return of the blood to the head ; still one effect of the continued action of the arteries is, to increase the plethoric state of the brain, when there is a stagnation, or more or less remora, of the blood in the sinuses; and thence it is, that in every interruption to the free exit of the blood, the distention must ultimately fall upon the extreme vessels.f We ought not to confound the idea of incompressibility of the brain with that of a solid substance, which would allow no "motion in the vessels within the cranium, and would require ns to invent some specious means to account for the circula- tion of the blood in the brain, different from that of the other viscera of the body. Were the brain thus incom- pressible, or rather solid, so as to prevent a free action of the vessels within the cranium, then, as the blood enters * The older physicians, observing the connection betwixt the motion of respiration and of the brain, conceived that the air was drawn through the nose aud cribriform bone into the brain, so as to distend it. Upon this hypothesis followed many wonderful cases. We have already mentioned the hypothesis which supposed compression and relaxation or the cerebrum and cerebellum alternately, by the action of the falx and tentorium. f We shall say that these vessels cannot suffer distention, unless there be space given for thwr inordinate dilatation, by blood proportionally sent out from the cranium. But there is a degree of distention upon them, a tension which cannot be relieved, nor the contraction of the arteries allowed. The impulse from the heart and arteries is still continued and is increasing the evil. Bleeding here relieves this action, and diminishes the danger - and by this means we can suit the. activity of the vessels entering the brain, to the tempora- ry remora in those which convey the blood out of the head. OF THE VEINS OF THE BRAIN. 331 with an evident pulsation, it must necessarily have return- ed by the veins with a distinct pulsation; but this pulsa- tion is lost here, as in the other vessels of the body, be- fore it returns by the sinuses. When the blood is sent into the arteries of the brain, by the stroke of the heart, they dilate; and this dilatation the pliability of the brain allows, by throw- ing a comparative degree of pressure upon the veins. Again, when the arteries (during the dilatation of the heart) are in action, and contract, their blood enters the veins, so as to give to them a degree of dilatation equivalent to their former com- pression, and which now gives .the freedom of contraction in return to the arteries; without any compression, therefore, of the brain into a lesser space, there is an activity allowed in the vessels. This degree of motion, communicated through the brain is very small, nor does it affect the function of the brain; as we see, when the skull is laid open, and the pulsations of the ar- teries are, as it were, accumulated, in their effect, to one point; for here the patient does not suffer, although the brain beats so as to be sensible to the eye. The circulation of the blood in the brain may be obstructed, or it may be accelerated, until this velocity affects the function :* or too much blood may be accumulated within the cranium ; but during this accumulation of the blood there must be a proportional space, freed by the absorption of the brain itself, or the partial accumulation in one part of the vascular system of the brain, must be accom- panied by a deficiency in the other.f * There is much sound reasoning and ingenuity wasted on the subject of the circulation of the brain: As the gentle murmuring of a stream, says Lower, lulls to repose, while the mind is disturbed, or the imagination awakened by the din of a cartaract; so sleep is in- duced by the gentle flow of the. blood in the brain, or is disturbed, when the circulation is accelerated. As the fatigue and rest of the body required a variation in the impetus of the blood towards it, the necessary consequence was a variation in the degree of velocity in the circulation and quantity of blood in the head, and this to Lower is the reason ofthe vicis- situde of wakefulness and sleep. The simple fact ofthe effect of pressure upon the surface of the brain inducing an oppression of the senses has occasioned all their theories of sleep to Jura upon this one idea of pressure on the brain. •*■ Experiments are making in Windmill-street on the circulation of the blood within the »rani urn. ( 332) CHAP. V. OF THE BRA1K, AND PRINCIPALLY OF THE INTERNAL PARTS. J.T has been usual to disengage the brain from the skull, and to examine it in its different aspects, and looking upon it thus to divide it, first into the cerebrum the greater and anterior brain, and the cerebellum the lesser and posterior brain, and into a third part which appeared obviously the part common to both, viz. the medulla oblongata. The medullary masses of both cerebrum and cerebellum being visible, as it were descending in form of crura, they seem, and have always been described as combined in the nodus cerebri, to form this prolongation into the third grand division, the medulla oblongata, and this last portion, though much less than the other grand division, has always been held important from its manner of formation or its connections. After this first division into cerebrum, cerebellum, and me- dulla oblongata, anatomists have made a further subdivi- sion of the cerebrum into hemispheres, viz. those two grand lateral divisions visible on the upper surface, and turning these hemispheres up so as to exhibit their irregularities correspond- ing with the base of the skull, they have further marked the division into anterior, middle, and posterior lobes. The cerebellum is described in the same manner; first we distinguish a central part sometimes called corpus vermiforme, and two great lobes or hemispheres corresponding to the grand division of the cerebrum. The medulla oblongata is divided by a rapha on the fore and back part into two lateral portions. Having noticed these divisions, and the part of the skull and its membranes to which they have reference, we proceed to inspect the interior of the brain. To explain the connections of the several parts of which the brain consists, there have always been two methods : the one commencing with the base of the brain, splitting and turn- ing up the crura, and prosecuting them in this course back- wards ; the other by sections commencing on the upper part of the cerebrum, and dividing its substance, to inspect the cavities. These two methods were followed by Mr. John Bell in his lectures, and have always been followed by me, since I OF tHE VENTRICLES OF THE BRAIN. 333 gave public lectures; and they have been followed by the old anatomists, and must be followed while the object of this study is acknowledged to be, first, to understand the connection, and secondly, to understand the morbid anatomy of the brain. Those who would neglect the method of dissection from above downward are equally ignorant of the uses of the ana- tomy ofthe brain with those who in fine enthusiasm declare their admiration at Dr. Gall's and Dr. Spurzheim's demonstra- tion from below upwards; and these gentlemen say, they are vindicated in their ignorance, since the brain was never dis- sected before ! The demonstration of the connection of the parts of which the brain consists, and the relation of the parts to the origin of the nerves, is necessary to the comprehension ofthe structure ; but the dissection of the brain is a higher department of the anatomy, for it is the ultimate object to detect the appearance of disease ; and for this reason we must begin from above, so shall we continue to explain the appear- ances in the following order. OF THE CAVITIES OF THE BRAIN IN GENERAL. There are within the brain many tubercles and irregular surfaces, of which it is infinitely more difficult to convey an idea by description than of the external parts. These sur- faces, as the name implies, lie in contact without adhering ; and form what we call, though not perhaps with strict proprie- ty, the cavities of the brain. Not being separated, they are scarcely to be considered as cavities, although they be capable of distention by the infiltration of the fluid into them. The surface of the cavities or ventricles of the brain is naturally bedewed with a fluid or halitus, which flows from the general surface of the ventricle, and from the plexus choroides. This moisture preserves those surfaces from adhesion ; during life and health it is not accumulated so as to form a fluid ; but in many diseases, and after death, it is effused or collected into a fluid. The external convolutions of the brain we have seen to be cineritious on the surfaces: the internal surface of the brain may be considered also as forming convolutions; but they arc chiefly medullary, and are more irregular, or rather have a greater variety of shape, than those ofthe outer surface. In regard to the use of the ventricles of the brain, since the hypotheses of the older physicians have been tacitly rejected, no opinion has been offered, except this, that " they seem to be made of a necessary consequence, and towards the greater use and distinction of parts;" or, as we have already had oc- casion to mention, that tbe Ventricles serve to increase, thf sur- 334 OF THE VENTRICLES OF THE BRAIN. face of the pia mater, and that whatever may be the* purposes which are served by that membrane on the surface of the brain, we must suppose the same to be performed by it within the ventricles. But this is a conclusion which may not be al- together satisfactory to an inquisitive mind. It is necessary to take into consideration the general pecu- liarities of the brain : we find that within the skull there is no adipose substance, though it pervades every other part of the body. We at once see a reason for this. It is evident that as the fat is so incessantly undergoing changes (being alternately absorbed and deposited;) as at one time it is deposited in °reater quantities and at another absorbed; as it is in perpetual variation according to the prevailing habits of the body, the proportion of exercise taken, or the state of the health ; its continual changes would have the very worst consequence up- on such a part as the brain; that if accumulated it would op- press the circulating vessels; if rapidly absorbed it would be followed by accumulation or surcharge of the vessels; for the skull does not allow of distention, nor is it possible that the cavity of the cranium can admit of depletion. The ventricles of the brain are in their natural state merely surfaces in contact. The forms of these internal surfaces are resulting from the internal conformation of the substance, as the great external convexities are, and as the superficial convo- lutions are ; in fact, they are not external, for we can arrive at these" anterior surfaces by splitting up the divisions of the brain without tearing the substance. The next enquiry is, Why this evident difference of surface of those interior surfaces and the superficies ? The cavities, as we shall continue to call them, have no arachnoid coat, they have therefore secreting surfaces. Here is the real distinction of the external and internal surfaces of the brain. It has long appeared to me that these cavities and tbe provision for secre- tion into them had a very particular influence, it preserving the due relations of the parts of the brain, which would otherwise be deranged or unequally pressed. A collection of water in the ventricles of the brain is perhaps the most frequent of all diseased appearances, and when within the ventricles it is much less injurious than in the external surface; when collected on the surface, under the tunica arachnoidea, it is ever attended with oppression of the faculties. It is not to be supposed that the ancients, so fertile in their hypotheses, and so easy in their proofs, could neglect the evi- dent importance of the ventricles of the brain. We accord- ingly find that the spirits were manufactured in these cavities ; that they were the " spirituum animalium offieina," whence the OF THE VENTRICLES OF THE BRAIN. 335 spirits were conveyed over all the nervous system* They were again degraded from the higher office, and became the mere receptacles of this excrementitious matter of the brain (meras cloacas esse asseruerint ;)f and Willis seems inclined still fur- ther to degrade the importance of the ventricles, by consider- ing them merely as of secondary importance ; or rather as re- sulting solely from the accidental conformation of the brain.J Again, we find it a prevalent opinion that the ventricles con- tained air; that the air supported the soft medullary sub- stance of the brain; and that it gave motion to the whole mass, so as to circulate the spirits in the substance ofthe brain. ^ OF THE CORPUS CALLOSUM AND CENTRUM OVALE OF VIEUSSENS. The corpus callosum is a medullary body which is a cen tre of communication ; or it is the great commissure'" passing betwixt the hemispheres of the cerebrum :1T it is seen without incision by merely separating those hemispheres with the fin- gers. It is a white body, firmer than the rest of the medullary substance. It is but slightly convex upon its upper part, but turns convex downwards upon the fore and back part. As the corpus callosum is the continuation of the internal medullary substance of the brain, it is superfluous to say that it is con- tinued down, anteriorly, into the medullary matter betwixt the corpora striata, terminating in its pedunculi; or, back- * Lately, by chemical aids, (which makes the cineritious substance black, or dark brown, while the medullary matter remains white or takes a slight greenish tinge,) the origins of many of the nerves have been traced into the substance of the brain even to the surface of the ventricles, which has given occasion to the revival of similar ideas of the use ofthe ven tricles. f Willis Cereb. Anat. p. 32. X " Porro si qdis cerebelli fabricara exacto considerat, et Eerioperpendit, quod hi ventn " culi non ex primaria naturae,intentione efformentur, at secundario tantum ct accidentalitc; " de cerebri complicatione resultent," &c. 5 Malpighi. || Commissure is a term applied to those tracts generally of medullary matter, which, pa.ss ing through tbe brain, are supposed to be media of communication. 11 Willis conceiving the spirits to lodge and circulate in the superficial convolutions of the brain, (.upon the conformation of whicii depended the capacity or ability,) gives to the cor pus callosum the property of collecting and concentrating the spirits, " quasi in publico em- porio comraorantur;" and here they were depurated by repeated circulation.—But the language in which all this is delivered, better veils the absurdities of the doctrine: " spiritus " recens nati undequaque ab extiraa hujus corporis ora vei^us anteriorem istius corporis cal- " losi partem, uhi crassimuin existit, perp^tim blande scatent; ibideinque, si opus fuerit, aut " iumginationis actuj impenduntur, aut medulla: ohlongata; crura subeuntes, appendiceni ner- M vosani actuant ct inspirant." What remains superfluous ofthe spirits returns backward> and circulates through the fornix, and is still farther subtilized, " hoc rnotu subtiIioi>* " quosdam phantasiie actus peragunt." 3S6 OP THE VENTRICLES OF THE BRAIN. wards, that it is continued with the fornix and cornua ammonis and the surface of the posterior prolongation ofthe lateral ven- tricle; We see upon the surface ofthe corpus callosum, two medul- lary lines considerably raised, running parallel to each other* in the length of the body. Betwixt these salient lines there is of course a kind of rut, called sometimes the rapha, or su- ture, which may be" considered as dividing this body into two equal parts, and which, in truth, forms the accurate division of the two sides of the whole brain.f Other lines, less elevated from the surface, are to be observ- ed running across these, as if passing from one hemisphere to the other. If the corpus callosum be cut horizontally, and the section be continued into the substance of the hemispheres, we still can perceive those transverse lines, and observe them to be lost in the medullary matter ofthe hemispheres.;}; This body is properly called the great commissure, (com- missura magna,) for it is the great part of medullary matter, which, formed by transverse striae, incorporates and unites intt one whole, the two lateral divisions of the cerebrum, CENTRUM OVALE. The centrum ovale is merely the appearance which the white and internal part of the cerebrum takes when the brain is cut horizontally on the level of the corpus callosum ; for then the corpus callosum is the centre of the great medullary mass of the cerebrum, and the cineritious matter being on the external edges only, forms the central white mass into an irregular oval. THE SEPTUM LUCIDUM. The two lateral ventricles lie Onder the" corpus callosum and medullary centre; they are divided by a partition, which de- * They are not strictly parallel in all their length ; we find them often separated both Upon the tore and batk part; but generally more separated upon the back part, and even sometime? they are curved. f In which conceit Duverney calls this " clef du cerveau," from its being the centre of communication. Tom. i. p. 39. \ The necessity of explaining paralysis and convulsive motions of that side ofthe body opposite to the side of tho brain injured, have made anatomists attend to those transverse lines, in the hope of finding such a decussation of these lines as would account for it. Sab- "Jatier suys, they have brought themselves to believe that there was a decussation, but after careful investigation he cculd find no such thing. See Winslow. Ludwig (de Cinerea Cerebri, sub. p. 5j observed striae of eiherittOTsV.'.-i'.ance in the corpus callonrm. j?ee DF THE VENTRICLES OF THE BRAIN. 337 scends from the lower surface of the corpus callosum, and rests upon the fornix. This septum of the ventricles is transparent, and consists of two lamina, and each of these consists of me- dullary and cineritious matter.* Betwixt these lamina is the cavity of the septum lucidum.f The size and shape of this cavity differs in a variety of subjects. It is of a triangular shape, and from eighteen to twenty lines in lengtb.4 It has a fluid exhaling into it like the ventri- cles, and is by some counted as a fifth ventricle : accord- ing to Santorini it opens in the base of the brain, opposite to the union of the optic nerves. Vieussens describes it com- municating with the third ventricle.^ Winslow also has seen it reaching a great way backwards, and conceives it to open into the third ventricle. Soemmerring describes it as large in the middle, contracted backwards, and having no commu- nication ; but he asserts that it is shut in on every side.1T In the base of the brain we find a narrow longitudinal sulcus be- twixt the pedunculi ofthe corpus callosum. In the bottom of this cavity there is a medullary lamina, which Vicq d'Azyr calls " Cloison a la cavite du septum lucidum." And the sulcus he calls " Fosse de la base du septum lucidum." By a careful section of this medullary substance we lay open the cavity of the septum lucidum. LATERAL VENTRICLES. Under the corpus callosum and medullary centre, and on each side of the septum just described, are the lateral ven- tricles. They are distinguished into right and left. They are of a very irregular shape, stretching .into three prolongations or cornua, whence they have the name of tricornes. They are the great ventricles of the brain; the third and fourth being comparatively very small. What may be considered as the principal chambers of these ventricles are formed betwixt the corpus callosum and the convexity ofthe corpora striata and thala'mi nervorum opticorum. Following the cavity for- wards, we find what is called its anterior horn or sinus; it is formed betwixt the more acute convexity of the corpus striatum and the anterior part of the corpus callosum: the posterior horn stretches into the posterior lobe of the cerebrum, which rests upon the tentorium. It makes a * Vicq d'Azyr. f It was discovered by Silvins. See also Santorini; X Sabbatier. "j "In qua pellucid urn non raro reperimus aquamque haud dubie in tertium illabitum ** ventriculum." Vieussens de Cerebro, p. 59. IT l)e Corporis Huraani Fabrica, torn. iv. p. 55. VOL. 11. 1 '1 338 OF THE VENTRICLES OF THE BRAIN. curve outwards, and at the same time inclines a little down- ward. The inferior or descending horn is like the continued ca- vity ofthe ventricle : it takes a curve backwards and outwards, and then turning forwards and downwards it descends into the middle lobe of the brain. The lateral ventricles do not terminate in the others by any of those prolongations; but they communicate, upon a very high level, with the third ventricle and with each other, by a wide opening, formed under the forepart of the arch of the fornix. This communication we easily find by following the choroid plexus forward and under the fornix: it is a space be- twixt the most anterior part of the convexity of the optic thalami and the anterior crura of the fornix. OF THE PARTS SEEN IN THE LATERAL VENTRICLES. The fornix is a medullary boily, flat, and of a triangular shape: its lower surface is towards the third ventricle : its lateral margins are in the lateral ventricle. On its upper sur- face it supports the septum lucidum, or partition of the two lateral ventricles, and under its most anterior part is the com- munication, betwixt the lateral ventricles and the third ven- tricle.* One of the angles is forward, and the other two towards the back part: it rests chiefly upon the thalami ner- vorum opticorum, but it is separated from them by a vascular membrane, which is continued from the external pia mater, and which stretches into the brain betwixt the posterior part of the corpus callosum and tubercula quadrigemina. This membrane connects the plexus of the lateral ventricle. The fornix leaves betwixt it and the convex faces of the anterior parts of the corpora striata, a triangular space, which is in part occupied by the septum lucidum. The extremities of this body are called crura. The poste- rior crura coalescing with the corpus callosum, (which is con- tinued downwards posteriorly,) are prolonged upon the edges of the hippocampi, and the anterior crura forming the anterior angle being close together bend downwards before the ante- rior commissure, and are connected with it: they then bend round the thalami, and may be traced into the crura cerebri;. or, according to others, they form the corpora albicantia.f Those pillars or crura of the fornix are fibrous in some slight * Of this communication see farther in the Anatomy of the Brain, illustrated by engraving + Two white bodies seen dti the base of the braiu behind the infundibulum. OF THE VENTRICLES OF THE BRAIN. 339 degree like a nerve. This is to be observed by cutting them either across or in their length.** Upon the lower surface of the fornix there are lines like those of the corpus callosum, and which are erroneously con- ceived by many to be the impression of the vessels of the ve- lum. It it this lower surface of the fornix which is called lyra, corpus psaloides, it being compared to a stringed in- strument.! OF the hippocampi, or cornua ammonis, and of the tenia HIPPOCAMPI. These are parts to be seen by following the posterior crura of the fornix. They are covered by a soft vascular substance, the plexus choroides. We have observed, that upon the back part, the fornix adheres to, or is continuous with, the corpus callosum. We shall find also that its posterior crus on each side divides into two lamina of medullary matter: the one of these is continued into the cornu ammonis, and the other (being the anterior of these portions) forms the tenia hippo- campi. The hippocampus is narrow at its commencement in the posterior crus of the fornix ;{ but it is enlarged as it descends, following the course of the inferior prolongation of the late- ral ventricle toward--, the base of the brain. It is, indeed. merely a relief or particular convexity of the floor of this lower horn of the ventricle, like a pad. The inferior extre- mities of the hippocampi on each side turn inwards, pointing to the crura cerebri, and taking thus a curve like a ram's horn.^ In its whole extent the hippocampus consists of an internal cineritious substance, and a superficial layer of white medullary matter. || * Vicq d'Azyr, Acad. Scien. 1781, p. 517. f The prevalent idea amongst the oldest authors regarding the use of the fornix way, that it acted like n ligament binding together the internal parts of the brain; or that it sup ported the incumbent weight of the upper parts - f the brain from pressing upon the lower. " Verum alter atque iste insignior fomicis usus rs" videtur quern modo inuimus; nempe ill " spiritus animales per ejus ductum ab altera cerebri extremitate ad alteram immediate tran- " seant, atque ita quasi per pelicani rostrum in sui ipsius ventrem intortum circulentur.""" Willis. X In speaking of the origin of the hippocampus as from the fornix, I mean simply that the student having gained the knowledge of one part of the brain may trace the others from their relation to it, and that, understanding the situation and the relation of the fornix, he traces its crura until he finds them terminating in the hippocampus. We might fully as well say that the hippocampi are formed from the posterior part of the corpus callosum, for they are the same medullary matter continued. J; Betwixt the extreme poiut of the hippocampi and the crura cerebri (when tlie base.of the brain is turned up) we can insinuate the probe into the inferior horn of the lateral ven Iricle without piercipe the substance of the brain, but merely tearing the pia mater. || " Vers la partie inferieure et postericuie du corps calleux, on tiouve, de chaquecote, • ■n petit boundet (V substanre pise qui se prolongs dans IVpaisseur de l'hypoeampedont 340 OF THE VENTRICLES OF THE BRAIN. The tenia hippocampi, or corpus fimbriatum, is the pro- longed margin of the fornix: it is merely the thin edge ofthe hippocampus, which follows in the whole of its circuit, and terminates in an acute point near its bulbous extremity in the inferior horn of tbe lateral ventricle. The lesser hippocampus or colliculus, is a relief or convexity in the floor of the posterior horn of the ventricles, which may be traced backwards from the crura of the fornix. It has the same relation to the fornix which the greater hippo- campus has, and lies in the posterior horn or prolongation, of the ventriele into the posterior lobe of the brain, in the same way in which the great hippocampus lies in the inferior horn or prolongation of the ventricle into the middle lobe of .the brain. The velum and plexus require to be taken away before we can fully understand the situation of the third ventricle, or of those tubercles which are but partially seen in the lateral ven- tricles. The velum vasculosum lies in the centre of the brain, and extends from the surface inward betwixt the posterior lobes of the cerebrum and the cerebellum, then betwixt the corpus callosum and nates and testes, and then under the fornix. It forms thus a great communication betwixt the external and in- ternal membranes of the brain. As it lies under the fornix, that medullary lamina adheres to it, while the velum again ad- heres to the thalami nervorum opticorum, which are beneath it. Its margin seems to be terminated laterally by the choroid plexus (when we view it after raising the fornix;) but it is not ' strictly so, for the choroid plexus is continued with tbe mem- brane of the ventricles, and has no where a termination. For the vascularity of" this membrane, turn to what has already been said in speaking of the internal veins of the brain. Seeing how the plexus choroides are formed and connected, they cannot be strictly said to have either beginning or termi- nation ; they are the connected folds and plicae of the inter- nal membrane of the ventricles loaded with vessels; but to de- scribe them intelligibly we must, notwithstanding, trace them in this manner. The plexus ofthe lateral ventricles rise from the bottom of the inferior horns of these ventricles (call- ed the digital cavity,) betwixt the pedunculi or crura cerebri and the termination of the hippocampi; they lie like fleshy bodies in that lower horn. As they rise into the superior level, they are at their greatest size (there they have often a diseas- ed appearance, being hard, and as if scirrhous or full of little " ii fait partie: ce bourrelet est recuvert dans son principe par une lame de substance " blanche." Vicq d'Azyr, loc. tit. OF THE VENTRICLES OF THE BRAIN.' 341 vesicles or hydatids;) they then pass forwards and inwards, diminishing in thickness, and approaching gradually until they coalesce under the fornix, and immediately behind the com- munication betwixt the ventricles. The plexus of the third ventricle, formed by the union of those of the lateral ventricles, turns back upon the lower surface of the velum, and is comparatively very small. If my reader has any diffi- culty in comprehending the relation and place of the telum interpositum, he has only to notice the place of the choroid plexus, lying the one in the left and the other in the right la- teral ventricle; then he is to lift the fornix, and he will disco- ver a vascular membrane passing betwixt the plexus of the right and left sides. This is the velum or diaphragma. The corpora striata are smooth, cineritious convexities in the forepart of the lateral ventricle. They are somewhat of the shape of a pear; they are obtuse forwards; they approach each other towards the forepart with a regular convexity, and they are narrow as they pass backwards, separating at the same time ; their posterior extremity being as it were pushed out by the thalami nervorum opticorum. These last lie more under the back part of the fornix, and are more concealed when the lateral ventricle only is laid open. The corpora striata are so called from the intermixture of the medullary matter in their substance, which gives the appearance of stria? when they are cut. They descend down to the base, and are intimately connected with the crura cerebri. The striae of medullary matter pass from above downwards, they therefore appear in the horizontal sections of this body like white points. A superficial horizontal section of the corpora striata shows those striae connected with the medullary matter of the middle and posterior lobe. A deeper incision brings into view a mass of cineritious substance betwixt those striae and the medullary matter of the middle lobe. Another incision shows the course of the striae altered, and brings into view the connection be- twixt the corpora striata of each side, by means of the ante- rior commissure.* The commissura anterior is a cylindrical medullary cord, which unites the fore and lower part ofthe corpora striata, and which spreads its connections for a full inch and a half into the middle lobe ofthe brain upon each side. We see it stretched transversely immediately under the anterior crura of the fornix. It is in figure like a bow; its extremities stretching (with a * " Hire pars commune sensorium est, quod sensibilium omnium ictus a nervis cujusque " organi dilatos accipit adeoque ornnis sensionis perceptionem officii; cujutmodi sensibilium " ictus, cum hinc ulteriiw in cerebrum trajiciuntur, smskmi statim imaginatio succedit; atque " insuper na?c corpora, uti sensuum omnium impetus, ita motuum localium spontar.eorum pri " mos instinctus suscipinnt." Willis, Edit. 4. p. 43. 342 OF THE VENTRICLES OF THE BRAIN. convexity forward) into the middle portion of the brain to- wards the extremity ofthe fossa silvii, where it terminates in the medullary matter of the middle lobe ofthe brain. The thalami nervorum opticorum are hid by the pos- terior angles of the fornix, and the plexus choroides: we do not see them fully until we have lifted the fornix and the velum or membrane which stretches under the fornix. They are somewhat of an irregular oval shape; they are whither than the corpora striata, their surface being chiefly of medullary matter. Internally they are cineritious; and the medullary and cineritious matter is blended in striae like the anterior tu- bercles ofthe ventricles or corpora striata. The thalami nervorum opticorum, having their convex sur- face towards each other, unite under the fornix by what is called the commissura mollis, in opposition to the commis- sura magna, which is the corpus callosum ; the commissura an- terior, which unites the forepart ofthe corpora striata; and the commissura posterior, which is yet to be described. This soft commissure of the brain, or the union of the optic thalami, is so soft that the slightest force will tear it, or in dis- section, the parts being unequally supported, the thalami will be separated and this connection lost.* After such separation of the tubercles there remains very little appearance of their having been united. Sabbatier, after the most careful dissec- tion, says expressly, that he could never observe this union, and he conceives, that in the smoothness of the contiguous sur- faces he has a proof of there never being such a union; but he goes on to say, " The fruits of my research were, that I con- " stantly found a soft cord of a cineritious colour, and about " a line or a line and a half in diameter passing betwixt them." I have seen, when the ventricles were distended in hydroce- phalus, and the communication betwixt the three ventricles enlarged to a square cavity of nearly an inch in diameter,f that this union was drawn out to some length, but still was above half an inch in diameter. The commissura mollis is exceedingly soft, of a cineritious colour, and vessels are some- times seen to cross upon its surface. It seems to be the con- tinuation of the grey or cineritious substance which covers the internal surface of the optic thalami.J Towards the forepart of the thalami we have to observe a peculiar eminence or convexity, viz. the antkrior tubercles of the optic thalami. In making a horizontal section of the thalami, we find that we cut across a medullary * Morgagni and Vicq d'Azyr say they have seen this commissure double. f In quadrupeds the adhesion is more extensive. X Mais il n'y a point de continuite, proprement dite, entre la substance intirae de crs couches etla commissure nrolle dont il s'agit. Vicq d'Azyr, Plane, p. 23. OT* THE VENTRICLES OF THE BRAIN. 343 streak or cord which descends from this tubercle to the mamil- lary processes, or corpora albicantia, in the base of the brain.* Its course is deep in the substance ofthe brain, and somewhat oblique. The limits of the thalami externally are contiguous to the corpus striatum, but betwixt them there intervenes a white medullary tract, which is continuous with the medullary striae, and which, as it marks the limits of the two great tuber- cles of the lateral ventricles, takes a course inwards towards the anterior pillars or crura of the fornix and middle of the anterior commissure. The surface of this tract, as seen in the lateral ventricle, is the tenia semicircularis geminum, which we shall presently more particularly describe. To understand the further connections and importance ofthe optic thalami we must dissect the base of the brain. There we find that it is through the corpora striata, and the thalami nervorum opticorum, that the crura cerebri establish their extensive connection with the internal mass of the brain ; par- ticularly we find that the crura shoot up into the back and lower part of the thalami. Here on the lower part also we may observe the tractus opticus, which we may trace backwards from the optic nerves. They surround the crura cerebri with a semicircular sweep, swelling out at the same time, and terminating in three con- siderable tuberosities : they are finally confounded with the lower part of the optic thalami ;f at the same time there runs up a division into the nates. The tenia semicircularis geminum is visible on the upper part of these convexities in prosecuting the dissection from above ; it is the tract of the medullary matter, which is betwixt the two great tubercles of the lateral ventricle, the corpus striatum and thalamus nervi optici. Towards the forepart of this tract its surface is covered with a layer of a semitransparent greyish matter, through which we see the veins which pass from the surface ofthe corpora striata to join the vena Galeni.f Sabbatier makes the anterior extremity of this medullary body join the anterior pillar of the fornix : Haller makes it join the anterior commissure: and Vicq d'Azyr says they separate ao-ain, where they seem to unite forwards and lose themselves * See Vicq d'Azyr, plate xii. Mem. de l'Acad Royale, 1781, p. 528. and plate 2. fig. 5 f Willis seeing the first and second pair of nerves so closely connected with these tubeiv des, and supposing, as we have mentioned in a former note, that the corpora striata were the common sensoriuin, concludes, " bine ratio patet, cur odores sine olfactus objecta " ipsum adeo cerebrum feriunt, et immediate amount; item cur*intervisionem et imagina- " tionem communicatio citissima habetur." P. 44. 1 " Quelquefois il se detache du taenia semicularis entre le corps strie et la couche op " tique un silet blanc, que faissant un angle, tres aigu2 soit en devant soit en arriere, monte '• a une certaine hauteur sur le corps caimele." Vicq d'Azyr, Mem. de l'Acad. Royale^ 17RI, p. sr.n 344 OF THE VENTRICLES OF THE BRAIN. on the corpora striata. Their posterior extremities are lost in the hippocampi; they thus form a kind of longitudinal com- missure which establishes a communication betwixt the fore and back part ofthe cerebrum. of the third ventricle. The third ventricle does not at all answer to the conception we form of the ventricles from the lateral ones. It is a mere sulcus, lying betwixt the thalami nervorum opticorum, and betwixt the crura cerebri, which are continued down from these tubercles. It is a longitudinal slit, rima, or gutter-like cavity, which is made irregular, and is divided by the union ofthe optic thalami: and finally, it is canopied by the fornix and vascular velum which stretches over the thalami.* Plan of the communication of the lateral and third Ventricles, represented by a perpendicular Section. The third ventricle opens forward and upwards into the two lateral ventricles, and under the common communication it opens into the infundibulum. Backwards it is continued by a canal which passes under the tubercula quadrigemina, or nates and testes, into the fourth ventricle. The bottom of the third ventricle is closed by a small stratum of cineritious matter, cloison pulpeuse du troisieme ventricule ; this fills up the space betwixt the junction of the optic nerves and the anterior * " Hanc caveam ventriculum tertium vulgo vocant, qua? et ipsa cum plena sint omnia : nihil est nisi contieuonim thalamomm limes." HalleT. OF THE VENTRICLES OF THE BRAIN. 345 commissure. We see it when dissecting the base of the brain. Lifting tbe optic nerves, we shall find it strengthened by the pia mater, and consisting of striae which pass obliquely back- wards and downwards, and some of which, while they adhere to the optic nerves, pass into them. As we have found that the pia mater could be traced into the lateral ventricles, and as by tearing with the probe the con- nections of those membranes we could penetrate into the lateral ventricle without piercing the substance of the brain; so here we can penetrate into the third ventricle, which is deepest of all; and also into the fourth, without lacerating the substance of the brain. Thus, after raising the vascular membrane of the base, we can pass a probe under the corpus callosum backwards into tbe third ventricle, and by raising the cerebellum from the medulla oblongata, and separating the adhesions of the pia mater, we get access to the fourth ven- tricle. We conclude, then, that the ventricles are not formed, as we should at first conceive, in the substance of the brain, but that they are formed by the replication and foldings of the convolutions of the brain. of the infundibulum. As I have explained in my tables of the brain, there is much confusion regarding the terms vulva and anus. Vulva is the space by which the three ventricles communicate, as seen when the fornix is lifted, in prosecuting the dissection from above downwards, viz. betwixt the thalami nervorum opticorum and before the commissura mollis. The anus is be- hind this commissure, and near the nates and testes; both these are mentioned as communications betwixt the ventricles; but we know that the union of the plexus choroides, of the two lateral ventricles, and of the termination of the velum under the anterior part of the fornix, leaves the vulva free. But the velum spreading over the thalami, and under the posterior part of the fornix, covers the anus ; and it appears as a communication similar to the other only when the velum is torn up. If we pass a probe gently downwards and forwards from the vulva or foramen commune anterius, or communication be- twixt the ventricles, we pass it into the infundibulum. The infundibulum is a funnel of a soft cineritious matter which leads from the bottom and forepart of the third ventricle to- wards the glandula pituitaria, which is seated in the sella tur- cica of thcsphenoid bone. vol. n. X x 346 OF THE VENTRICLES OF THE BRAIN. The infundibulum is formed of cineritious matter, which is continued from the bottom of the third ventricle, and which adheres to the back part of the optic nerves ; or, according to Warthon, of an external membrane with cineritious matter internally. Its cavity becomes contracted before it reaches the glandular pituitaria. Whether it be really capable of con- veying the fluids of the ventricles, or whether it be actually pervious, is likely to remain a disputed point. Tarin, and M. Adolphus Murray, and Haller, believe with the older writers that it is pervious. Soemmerring and Vicq d'Azyr have in their experiments found it shut.* But to the opinion that the infundibulum conveyed 'the superfluous moisture from the ventricles,-]- it did not seem necessary to Vieussens that we should find it to have a cavity in all its length. He conceived that where the apparent cavity terminated, less visible pores were continued towards the gland. infundibulum and pituitary gland. What is called the pituitary gland is a reddish body of a glandular-like structure,*! which is seated in the Sella Turcica * " Sed non ad apicem usque pervium." Soemmerring. t " ®tructura' s'tuque infundibuli spectatis, connectionis, & societatis, quam cum cere- bro, etglandula pituitaria habet, rationibus aequo iudicio perpensis, unicum illius usum esse, ut aquosuro, seu lymphaticum querodaem cerebro depluentem humorem, majoris, ad ' instar vasis lymphatici excipiat et pituitariam versus glandulam sensim transmittal, non 4 autumare non possumus: Etenim eum intertextarum plexibus choroidal glandularum * nsus sit, ut sanguinis calvariam subeuntis, spiritusque animalis materiam suppeditantis, aquosiorem partem, desinentibus in ipsas ab arteriis deposituni excipiant, quse deinceps ' per tnsensiles rarissinjae, qua obducuntur, membranae poros, sensim transfluit, et partim per ' vulvara partimve per anum, in tertium cerebri ventriculum delabitur; nullus esse videtur nmbigendi locus, qum aquosus omnis humore glandulis, quae plexuum choroidseorum vasis " interseruntur, sensim affluens, ad infundibulum deferatur." Vieussens p. 50 Such was the opinion regarding the economy of the brain, and now we have no theory, good or bad nor any explanation of this connection of the gland with the ventricles of the brain to offer. \ It perhaps has only the form ot a gland. Haller says " non acinosa quidam, nequ* OF THE VENTRICLES OF THE BRAIN. 347 of the sphenoid bone. It is plain upon its upper surface, or rather perhaps a little hollowed, of a globular shape below, and having a division into two lobes. The infundibulum ter- minates in it, piercing the dura mater, a thin lamina of which spreads over the gland. The gland, as is seen in the above plate, lies surrounded with the circular sinus, and has the ca- vernous sinus upon the sides; into these last, vessels have been seen to pass from the gland,* which, as Soemmerring observes, were probably veins. A distinction of substance has been observed in this gland, and it is by some considered as a part of the brain, or being like the cineritious substance, it has been supposed that it gave nerves to the fifth or sixth pair. It was conceived that the body receiving the superfluous moisture of the brain, conveyed it into the nose; or in- to the neighbouring sinuses.f To countenance this opi- nion, there was no want of cases proving the accumulation of the fluids of the ventricles, in consequence of the scirrhus of this gland, J while in truth dissection has shown no connec- tion betwixt the diseases of the ventricles and pituitary gland. M. Littre gave both a vascular structure and muscular fibres to this body, and conceived that its operations brought down the water and air from the ventricles of the brain.^ THE TUBERCULA O.UADRIGEM1UA. The tubercula quadrigemina, or nates and testes, are seen when we continue to lift back the posterior part of the fornix and corpus callosum, and when we have lifted back the velum with the vena Galeni. We find, in doing this, that the velum is connected with the pineal gland, which is seated upon these tubercles. The tubercula quadrigemina are not in the cavities or ven- tricles ofthe brain, but are seen upon lifting and turning for- ward the posterior lobes of the cerebrum from the cerebellum. These four tubercles are behind the third ventricle, and above the fourth. As they are immediately in the centre of " nullius alterius glandulae similes, quae iwtius cerebri quedam sit appendix." See also Bor- deu, Recherck. Anatomiq. sur les Glands. Pituet Glandulae Vitium, Sandift. Thes. Vol. III. * Adolph. Murray de Infiindib. ■J- Lower, Tract. deCorde. % Schneider (de Catar.) first opposed this theory; showed that there was no communica- tion betwixt the brain and the nose, and maintained that no fluid, not even the blood which flowed from the nose, had any connection with the brain : he was supported by other able anatomists. The old opinion was revived by M. Bouilld, Eltmens de Medecinc pratique. 6 See Littre, Mem. de l'Acad. des. Sciences, 1707 54b* OF THE VENTRICLES OF THE BRAIN. the brain, they form a kind of commissure, and they both com- municate with the tubercles, from which the tractus opticus emerge. The uppermost two are the nates, the lower are the testes ; the former are less white than the latter. A little under the inferior tubercle, we find a small tract of medullary matter which extends to the thalami nervorum opticorum, and the crura cerebri. And from the lower part of the testes there projects backwards, connecting itself with the crura cerebelli, a thin medullary lamina, which is the valvula " ieussenii, PROCESSUS a CEREBELLO AD TESTES, Or V •;! UM INTE: JECTUM. Behind the posterior tubercle, or from this medullary lamina itself, the fourth pair of nerves take their origin. Sometimes those four tubercles are ofthe same size ; sometimes the pos- terior, sometimes the anterior tubercles, are the larger: a per- pendicular section of them shows a mutual communication of stria; of medullary and cineritious matter; but those are seen faintly. THE PINEAL GLAND. Third Ventricle. Posterior Commissure. Peduncule of the P. G, Pineal Gland. Tubercula Quadrigemina. The pineal gland is a little glandular-like body, seated above the tubercula quadrigemina, and behind the thalami nervorum opticorum; it is fixed, says Winslow, like a button. It consists of cineritious matter covered with tbe pia mater; its base is surrounded with medullary matter; it adheres firmly to the velum vasculosum, and is apt to be displaced or torn from its pedunculi in lifting that membrane. It is a small soft greyish body, irregularly round, or of the figure of a pine apple; or, of all things, likest tbe heart of a frog* Its pedunculi, or foot- stalks, pass out from a transverse medullary base, which unites it to the posterior commissure. Those pedunculi pass on each * Ruysch considered the substance of this gland as different from that of the cerebrum c- cerebellum, and different also, from all other glands. OF THE VENTRICLES OF THE BRAIN. 349 side to the thalami nervorum opticorum (leaving a passage un- der and betwixt them to the fourth ventricle.) Their extremi- ties pass forward upon the internal surface of the thalami ner- vorum opticorum, and are united to the anterior crura of the fornix. Vicq d'Azyr remarks, that although the ideas of G.'en and Descartes,* and a crowd of others are remembered only with ridicule, there are still some peculiarities in the situations and connection of this body, which mark its importance. It is composed of cineritious substance ; it is in fact a prolongation of the substance of the brain, and by its pedunculi, which are like two nerves, it is connected with the thalami nervorum op- ticorum, with the fornix, and consequently with the corpus cal- losum, the hippocampus and corpora albicantia, which are themselves the centre of union to several medullary cords: therefore he concludes that the pineal gland must be an im- portant organ.f The pineal gland has often in it little peculiar grains and cal- culi, resembling bone in its constituent parts."}* It has a great variety of form and size ; sometimes hollow, and there is also a sinus found in it. 1 have found it surrounded with pus in an ideot boy, who was accustomed to wander about the Leith glass-houses. He died with symptoms of hydrocephalus, and in his ventricles, accordingly, there was found much fluid. Malacarne gives a case of its having degenerated into hydatids, like a cluster of grapes; I have also seen this appearance. In some cases it has not been found upon dissection. POSTERIOR COMMISSURE. The base of the pineal gland is connected with the poste- rior commissure of the brain. This commissure is seen like a cord, or like the anterior commissure, towards the back part * Alluding to their opinion of this being the seat ofthe soul; Willis imposed upon this part a lower office, " Ejusque munus non aliud omnino esse quam aliarum glandularum qua? juxta " vasorum sanguiferorum concursus dispqnuntnr : nempe ut humores serosos, a sanguine ar- " terioso depositos, excipiat, et in se retmeat; donee aut vence depletiores factae eosdem re- " sorbeant, aut lymphae ductus (si qui adfuerint) eos extra convehant." Willis, p. 46. f Mem. de l'Acad. Royal, An. 1781, p. 533. See Observ. par M. Mechel sur la Gland pineal, sur la cloison transparente, et sur l'origine du nerf de la septieme paire. L'Acad. gerlin, 1765. t " La parte anteriore della base n'e ordinan amente midollare, e qui appunto 1' ho mol- " nssime volte veduta gessata, ossoea, tartarosa e friabile, vizi, che ho trovati anche molte volte " nei piccinoli." Malacarne, part ii, p. 81. Acervulus: Meckel, Mem. de l'Acad. des Sciences a Berlin, 1755, fig. 1. b. b. Vicq d'Azyr, tab. xxvii. "• Super medullosum co- " narii vinculum vel in ipso vinculo, vel in ipso denique acervulo, plerumque vero ante " acervulum iam in fetibus inmaturis peculiares quidam lapilli, mox roaiorum acervulum, " mox vero duo vel tres minores acervulos constituentes, helui, semiperlucidi, iunioribus " semper pallidiores, annosioribus fusciores, infantibus ob coloris languorem et perlucidatem " dHBciles cognitn siccati albidiores etopaciores inveniuntur." Soemmerring, p. 6;?. 350 OF THE VENTRICLES OF THE BRAIN. ofthe third ventricle, before the tubercula quadrigemina, and above the iter ad quartum ventriculum. Betwixt this com- missure and the base of the pineal gland, we have to observe two or three medullary filaments, not passing from the gland, but lying parallel to the commissure. But this part of the brain whieh appears like a cord, does not deserve the name of commissure ; it does not pass on each side into the substance of the brain as the anterior one does; it is lost in the neigh- bouring border of the medullary matter, and is merely this matter reflected, so as to have a rounded edge. cerebellum* The cerebellum lies under the posterior part ofthe cere- brum. It weighs about a sixth or seventh part of the whole brain; it lodges in that part of the base of the cranium which belongs to the occipital bone, and has tbe tentorium stretched over it : and it is divided into a central or middle part {pars media,) and into great lateral portions Or lobes. The central, or middle part, is anterior to the lobes, and be- twixt them and the cerebrum : this is the part very common- ly called, from its appearance, the vermifokm process ; and upon the sides we have two portions, sometimes called lateral vermiform processes. The cineritious matter of the cerebellum is external, like that ofthe great mass of the cerebrum ; but the medullary in- ternal matter presents an appearance somewhat different, for. on a section being made it appears branching like a tree, and has been called arbor vita. The concentration of the medullary matter, from the two sides ofthe cerebellum, towards the nodus cerebri, form what are called the crura cerebelli. In dividing these crura we find in each of them the stain of yellowish matter, which is called corpus rhomboideum or corpus dentatum. OF THE FOURTH VENTRICLE. The fourth ventricle is the ventricle of the cerebellum ; it descends perpendicularly before the cerebellum ; it is inclosed on the upper and lateral part by the valvula Vieussenii; be- hind, by the pars media ; below, by the medulla spinalis and pia mater ; and on the right and left, by the crura cerebelli. When, from the third ventricle, we pass our probe obliquely OF THE VENTRICLES OF THE BRAIN. 351 backwards and downwards under the posterior commissure, it passes into the iter ad q_uartum ventriculum, or aqueduct of Silvius. This passage to the fourth ventricle, goes before the tubercula quadrigemina. The vaivula Vieussenii, it was supposed, prevented the falling down of the moisture of tbe other cavities into the fourth ventricle :* it is more proper- ly called the processus cerkbelli ad testes, being a me- dullary lamina spread over the ventricle and betwixt the crura cerebelli, as they rise from the arbor vitje, or the internal medullary part ofthe cerebellum. From the aqueduct there is continued down upon the fore- part ofthe fourth ventricle a kind of fissure, which Vesalius, conceiving it to have some resemblance to a writing quill, cal- led calamus scriptorius. The same fissure or furrow is continued down some way upon the spinal marrow. There pass up obliquely outwards, on each side of the cala- mus scriptorius, medullary lines, three or four in number, "but sometimes seven are observed.f One of these fibres ascends to the valvula Vieussenii; some are the origins of the auditory nerve, and one or two striae go to form part of the eighth. In the fourth ventricle, as in the others, are some convolu- tions ofthe plexus choroides; these are on each side at the termination of the vermis; they are continued out upon the base of the brain, and are seen exposed betwixt the seventh and eighth pairs of nerves. * Alveus Silvii. i Haller, Physiol, torn. iv. p. 78 352 OF THE VENTRICLES OF THE BRAIN. OF THE BASE OF THE BRAIN AND ORIGIN OF THE NERVES. Relation of the Brain and Skull-cap. We have anticipated much that might have fallen to be treated of in this division of our subject; but my intention here is to give a connected view of the parts, as seen when we have raised the brain from the skull, and when, having the base presented to us, we are about to enumerate the origins of the nerves. The first appearance which strikes us is the great propor- tion of the medullary matter in the base of tbe brain; the whole surface ofthe brain, while seen from above, was cineri- tious, but now the centrical medullary part ofthe brain is seen emerging from the envelopement of the cineritious matter, and, gathering together from the several internal medullary processes of the brain, it concentrates the essential properties of the encephalon, and is fitted to give out the several nerves. Those great medullary prolongations of the cerebrum and ce- rebellum are called the crura. The crura cerebri are composed of a white fibrous me- dullary matter, in which also there is a mixture of cineritious OF THE VENTRICLES OF THE BRAIN. 353 substance. They are formed from the whole central medullary part of the cerebrum ; or more immediately from the inferior and lateral part of the corpora striata, and from the superior and internal part of the thalami nervorum opticorum ; and, from the conflux of medullary matter, from the anterior and posterior lobes ofthe cerebrum. From all these various parts the medullary matter, passing downwards and backwards, and concentrating into a smaller space, forms the crura.* The crus of either side of the brain, contracting their diaraaters, unite at an acute angle, and are united to the pons Varolii, or nodus cerebri, formed by the crura cerebelli; they pass on, under the pons Varolii, to form the medulla oblongata, and, as they unite with it, they raise it into the eminences, called corpora pyramidalia. In those processes of the cerebrum, the cineritious and medullary substances mingle with some de- gree of confusion; so that when we make a- section of the crura cerebri near to their union with the pons Varolii we ob- serve a substance of a dark-brown colour, surrounded with white or medullary matter. Behind the union of the optic nerves, and nearer these crura, we perceive two white bodies, called the corpora albicantia. Anterior to these bodies, we see the infundibulum.—The tuber cincrius. In the angle ofthe union ofthe crura cerebri, behind the corpora albican- tia, and before the protuberance of the pons Varolii, we ob- serve a matter less perfectly white than the surrounding medullary substance, which forms a floor to the third ventricle. This part is perforated with a great many holes, and is the substance perforee of Vicq d'Azyr,f and gives origin to the third pair of nerves along with the crura themselves. CRURA CEREBELLI. The crura cerebelli are more exposed than those of the ce- rebrum ; the latter lie deeper, and are comparatively smaller., They are formed by the union of the internal medullary part of the cerebellum, or the arbor vitae. They are altogether composed of the medullary matter, except near the pons Va- rolii, where we observe a mixture of coloured striae. * I speak still of the relation of those to each other, according to their natural situation in the skull. + Vicq d'Azyr makes three divisions of this substance perforce—1st. At the roots of the tubercles, from whence the first pair of nerves emerge betwixt the roots of those nerves, and near the origin of the optic nerves. Id. Those I mention betwixt the crura cerebri. 3d. On the outer contour of the optic thalami. VOL. II. y v 354 OF THE VENTRICLES OB THE BRAIN. PONS VAROLII. The pons varolii, tuber annulare, or nodus cerebri, is formed by the union of tbe crura cerebri and cerebelli; those names are almost descriptive of its shape and relation to the other parts. Varolius, looking upon those parts inverted, compares the crura cerebri to a river passing under a bridge, and thence named it Pons. The nodus cerebri, again, is a a name well applied, since this medullary eminence has much the appearance of a knot cast upon the medullary processes of the cerebrum. On tbe surface, of this medullary protuberance there are many transverse fibres, which, uniting in a middle line, form a kind of rapha, which, upon a superficial section, shows a longi- tudinal medullary line. The fibres upon the surface of this body are uniform and parallel to each other in the most pro- jecting part; but upon tbe sides, they disperse to give place to the fifth pair of nerves and crura cerebelli. A deeper incision of the pons Varolii, while it shows the union of the crura cerebri, cerebelli, and pons Varolii, also shows the white medullary tracts which extend from the crura cerebri through the pons Varolii to the corpora pyramidaha \ part of these pass through the locus niger crurum cerebri, and can be traced backward to the corpora striata. We see also the transverse fibres of the medullary and cineritious sub- stance, which make a right angle with those longitudinal tracts. On the whole, though the pons Varolii differs in form and place from the comissura magna cerebri, yet, I think, the most likely conjecture is, that it stands in the same relation to the lateral portions of the cerebellum, that the corpus callo- sum does to the cerebrum. Anatomists have sought to explain a very curious phenome- non, by supposing that there is a decussation of the nervous filaments at this part. It has often happened that an injury to the one side of the braic, an ulcer or tumour on one side, caused a loss of power in the opposite sicfe of the body,* and tbe latest authority we havef proves that a tumour on the one side of the pons Varolii, will produce an effect on the other side of the body. But no decussation can be observed ; fibres, as I have said, run across like commissures, but the tract of matter is direct, not oblique. I am tempted to think there must remain much obscurity on this subject of the decussation of the fibres of the brain, or * The observation has descended from Hippocrates, and the explanation that '4 depends on a decussation of the roots of the nerves is from AreUeus. ■f Medico-Chirur. Transactions, VII. OF THE VENTRICLES OF THE BRAIN. 355 origin of nerves. I have found that the effect is not constant. An ulcer in the hemisphere of the cerebrum produced weak- ness in the same side; and in one well marked case of hydro- cephalus, when the brain on dissection was equally affected on both sides, the one side of the body was convulsed and drawn up, and the other side motionless. This is not a singu- lar occurrence; I have seen the eyes, face, and tongue in per- petual motion; but the action entirely on one side, the paraly- sis on the other, while both lateral ventricles were full of water, and the disorder of the brain equally affecting both sides of the organ. MEDULLA OBLONGATA. The medulla oblongata is the prolongation of the substance of the crura cerebri and cerebelli, from the pons Varolii; it is consequently the continuation of the encephalon, which, after giving off the nerves that pass through the foramina of the skull, enters the canal of the spine to supply the spinal nerves. The medulla oblongata is marked at its upper end by a deep sulcus dividing it from the pons Varolii; but towards the spinal cavity it decreases in thickness, and there is no natural distinc- tion or sulcus to mark the point where the medulla oblongata ends, and the medulla spinalis begins; nor perhaps is the me- dulla oblongata to be considered in any other light than as the beginning of the spinal marrow. When it passes the foramen magnum, it ceases to be called the medulla oblongata. We have to observe four eminences upon the medulla ob- longata, viz. two corpora pyramidalia, and two corpora oliva- ria. The corpora pyramidalia, so called from their shape, are thosein the middle. There is formed betwixt them and the pons Varolii (being three tubercles placed together) a lit- tle sulcus, which some have called the foramen c^cum. Be- twixt these eminences there is a longitudinal fissure, in the bot- tom of which there may be observed transverse little cords, which are like commissures connecting the two sides of the medulla oblongata, and the portion of the medullary cord, which is prolonged downwards from this body, twists to the other side, and forms with its fellow a decussation. The corpora olivaria lie upon the sides of the corpora pyramidalia. They are, in some degree, like them, limited by the sulcus which bounds the pons Varolii, rounded above and bulging, but gradually subsiding, at their lower part, into the level of the medulla spinalis; yet they are internally dif- ferent, for anatomists had observed a mixture of a yellow or cineritious-coloured matter in the corpora olivaria, but Vicq 356 OF THE VENTRICLES OF THE BRAIN. d'Azyr has observed a regular oval medullary substance, Or body surrounded with cineritious-coloured substance, like a miniature-representation of the cerebrum itself; he calls it CORPUS DENTATUM EMlNENTlffi OLIVARIS- The corpora restiformia are the projections or cords be- hind the corpora olivaria. MEDULLA SPINALIS. The medulla spinalis may be considered as an elongation of the brain. Its name implies its situation, that it is contained within the tube of the spine. Though chiefly composed of medullary matter, it is not entirely so; for there is an irregu- lar, central, cineritious substance, through its whole extent, having something of a crucial form when a section is made of it.* There are continued down from the calamus scriptorious behind, and the rima, formed by the corpora pyramidalia, be- fore, two fissures which divide the spinal marrow into lateral portions. On the back part, however, the fissure is less dis- tinguishable. Into the anterior one the little vessels penetrate to supply the cineritious matter with blood. The two lateral portions are divided into an anterior and posterior portion, so that this prolongation has four distinct portions. The spinal marrow diminishes in thickness as it descends in the neck; but below the giving off of the brachial plexus it again enlarges, then continues gradually to diminish. The tube of the vertebrae is connected by a strong ligamen- tous sheath, which runs down the whole length within the tube. The dura mater, after lining the internal surface of the cranium, goes out by the great foramen, and forms a kind of funnel; at the occipital foramen it is united firmly to the ligament. Further down, however, it forms a separate tube. The tunica arachnoides again adheres loosely, having a kind of secretion in it, while the pia mater closely embraces, and is intimately united to the medullary matter. From betwixt the ninth nerve and vertebral artery to the second and third lumbar nerve, there is a membranous connec- nection betwixt the lateral part ofthe spinal marrow and the dura mater ofthe spine. From the manner of its connection to the dura mater, by distinct slips irregular and pointed, it is called the Ligamentum Denticulatum, or Dentatum. * The surface of the spinal marrow has also been observed to be of a darker colour, and in large animals distinctly cioeritious. (Dr. Monro's Nervous System.) THE ORIGIN OF THE NERVES. 357 a HEME AND GENERAL DESCRIPTION OF THE ORIGIN OF THE NERVES OF THE ENCEPHALON AND SPINE. In enumerating the nerves which pass from tbe cranium, I shall keep to the old way of Willis, counting only nine nerves ofthe encephalon. I do not find that the sub-divisions of the nerves in this classification, and the description of the several fasciculi, of whicii the pairs of nerves are composed, cause intricacy. It rather, I am from experience convinced, con- nects some circumstances with many of the pairs of nerves thus enumerated, to which the memory of the student can at- tach. The common enumeration seems a natural one ; it serves well the purpose of dissection, and consequently will never be entirely exploded. The use of new classifications and arrangements, and names, whilst we must also retain the old, adds much to the "intricacy of demonstration. From the olfactory nerve to that which passes out betwixt the cranium and first vertebra, there are nine nerves. 1st pair—Olfactory nerves. 2d pair—Optic nerves. 3d pair—Motores oculorum. 4th pair—Trochlearis. 5th pair—Trigemini. rCarunculce mamillares Math. de Grad. Processus ad nares. < Conth d'Andernac. I 8,,m par Spigel. (^ I st. pair of Willis. C Nervus visivus, seu visorius. < Carpi. lm par antiquorwn. ( 2d pair of Willis. f'2 um par Fallop. et Vesal. J Nerfs moteurs communs des *S yeux.—Winslow. l^3d pair of Willis. rMinor propago 3,! Paris, id est 5'' recentiorum, Fallop. Gracilior radix 3" Paris, id est 5'1 recentiorum. Vesal. Nervus qui propenates oritur. Eustach. 9um par Cortes : et Columb. 4th pair; or, pathetic nerves of Willis. rNervus anonymus trigeminus multorum. \3U" par Fallop. et Vesal. 5th pair of Willis. Trijumeaax of Winslow. 358 THE ORIGIN OF THE NERVES. 6th pair—Abductores. rAuditory nerves. 'th pair< Nervicus eommu- nicans faciei. Glosso pharyn- geus. Sth pair-< Par vagum. Spinal accessory nerve. 4um par Fallop. Radix gracilior 5'' Paris, id est 7'' recentiorum Vesal. Par oculis prospiciens. 8um parCapp. Bauhini. j tith pair of Willis. I Nerfs oculo-musculaires, ou moteurs externes de Wins- l^ low. 2u,n par Alexand. Benedict. 4um par Carol. Stephan. 5nm par Vesal. et aliorum. 6'jm par V. Home. Portia mollis, ofthe Moderns. rDistinctus a molli nervus. Fallop. Portio ut prcecedens 5'' Paris, id est V recentiorum. Ve- sal. Portio dura, of the Moderns. Le petit sympathique, of Winslow. Facial nerve. rQui ad musculos lingua' etfau- cium tendet. Fallop. Le rameau lingual de la 8e paire of Winslow. 8th pair d'Andersch. Superior fasciculus of the 8th pair of Willis. ^Glosso Pharyngeus. Haller. rNervus sextus Galeni et alio- rum. 5" conjugatio Carol Stephan. rum par Alex. Benedict. 6U" par Casp Bauhini. 9dm par Bidloo et Andersch. 8th pair of Willis. I.e moyen sympathique of Winslow. < The spinal nerve. THE ORIGIN OF THE NERVES. 359 r7nm par Fallop. Vesal. etalio- rum. irm par Bidloo. ieum par Andersch. Par lingua le medium, vel ner- <■* vus lingualis medius.—Hal- ler. Soemmerring et alio- rum. The hypoglossal sub-lingual7 or gustatory. cThe 9th pair of Willis. fiOth pair of Willis. J I st spinal, or cervical nerve, | of Haller. I count this (_ the first cervical nerve. FIRST PAIR ; OR, OLFACTORY NERVES.* The olfactory nerve is soft and pulpy, and soon resolved by putrefaction; therefore, we should not be surprised that it was neglected by the ancients.f It adheres firmly to the lower surface of the anterior lobe of the brain, but it does not take its origin here : It is of a triangular shape, as if moulded to the sulcus in which it lies; by being sometimes sunk into the sulcus more or less on one side than the other, it has the appearance of being larger on one side than the other. It takes its origin by three medullary tracts ;J 1st, From the cor- pus striatum ; 2d, From the medullary matter of the anterior lobe ; 3d, From the fore and under part of the corpus callo- sum.^ When a section is made of it, we observe in it a cine- ritious portion. Towards the forepart, this nerve expands into a bulbous * In the present enumeration and description of the nerves, we attend chiefly to their re- lation to the brain. In the introduction to the next part of this volume, they will be found arranged and classed previous to the detail of their minute distribution. t The olfactory nerves are in brutes larjre prolongations of the substance of the brain, and are the proper mamillary processes. Their olfactory nerves have a cavity or ventricle in them, and it was natural for the ancients to imagine that the pituita of the brain was from this sti-ained through the cribriform plate into the nose. Ve*alius proved the absurdity of this opinion; it was, however, revived by Dulaurens. But Willis is not much better, when he describes the proper use of these nerves. He supposed the cribriform plate of the aeth- moid bone to prevent bodies from passing up into the brain (" ne quid asperi aut molesti " cum il lis unaadcerebrum feratur:") while the lymph in those nerves corrected the too pungent odours; " odorura species demulceie, easque sensorio quadantenus prseparare." X Or we ?ay that the external root generally splits, having two fasciculii. See Prochas- ka, tab. I. Scarpa Annot. Anat. p. 106. $ Vicq d'Azyr. M. de l'Acad Roy. 1781.—" Breviores fibrse mednllora cum lqngioribus " eiterioribus connexse nonnrmquam cinercam particulam excipiunt." Soemmerring. 9th pair—Lingual. 10th pair—Sub-occipital nerve. 360 THE ORIGIN OF THE NERVES. oval lobe, which consists of a semi-transparent cineritious sub- stance. This lies upon the cribriform plate, and from it are sent down the nerves which expand upon the membrane of the nose, and compose the organ of smelling.* SECOND PAIR; OR, OPTIC NERVES.f The optic nerves arise from the posterior part of the optic thalami, and from the tubercula quadrigemina or nates. When we trace the optic nerves backwards into the tractus opticus, we find them adhering to the tuber cinerius, or layer of grey matter, then taking a circle round the crura cerebri, then en- larging, each forms a tubercle towards the back part of the thalamus opticus, and afterwards unites with the posterior tu- bercle of tbe thalamus opticus; at the same time a division stretches further backwards to the testes, while betwixt the posterior tubercle of the thalamus opticus and the nates, there is also a communication. When those tubercles are fairly ex- posed by separating the middle lobes of the brain, and dissect- ing away the tunica arachnoides and pia mater, they are seen smooth, and formed of medullary matter; which is uniformly continued from the one to the other, following their gentle con- vexities with an uninterrupted surface. Within those tuber- cles is a mixture of cineritious and medullary matter, and, es- pecially, there is a distinct streak which passes from the tractus opticus to the nates. J Thus there is a communication betwixt tbe nates and testes, and the optic nerve; but we must still consider the nerve as arising in a peculiar manner from the thalamus opticus, while at the same time it adheres to the crus cerebri. Tracing the optic nerves from their origin in the brain to- wards their exit from the skull, we find them approaching gradually, and uniting just before the corpora albicantia and the infundibulum. * Duverney has shewn us, that those nerves passing through the cribriform plate become iirm nerves, like those in the other parts of the body. They are to be seen by tearing the membrane of the nose from the bone. t The optic nerves were the first pair of Galen and many of the older anatomists, they being ignorant of the olfactory nerves. ! Santorini tab. Scarpa Anatom. Annotat. p. 106.. ■» THE ORIGIN OF THE NERVES. 361 Section of the Union of the Optic Nerve. Since the days of Galen it had been a disputed point, whether there is a union simply of the nerves, or a decussa- tion. Fishes have the nerve arising from one side of the brain passing to the eye of the other side : they cross, but they do not unite. Birds have but one optic nerve arising from the brain, which splits and forms the right and left optic nerves. Vesalius dissected a young man at Padua who had lost his eye a year before : at the same time he dissected a woman, whose eye had been lost a long while. In the latter he found the nerve of that side smaller, firmer, and of reddish colour, through all its extent. In the young man he observed.no ef- fect upon the nerve. He also gives a plate of an instance in which he found the optic nerves pass on to the eyes of the same side from which they take their origin, without adhering at all. Valverda, a physician of Spain, who travelled into Italy, and studied the works of Vesalius and Human Dissection, says, that at Venice he had frequent opportunities of assuring him- self that there was no decussation ; for robbers were punished for the first offence by losing one of their eyes; and for the second by death. Riolinus, Rolefinkius, and Santorini, give observations of the nerve of the injured eye being small and shrivelled, and of their having traced them past their union to the same side of the brain with the eye, to which they be- longed. Vicq d'Azyr, who, of all authors, I conceive to be the best authority upon such subjects, is decidedly of opinion that there is no decussation. Zin also agrees with the opinion of Galen, that there is an adhesion .and intimate union of sub- stance, but no crossing of the nerves. Soemerring deems it vol. 11. Z z 362 THE ORIGIN OF THE NERVES. sufficient to point out the authorities on both sides of the question, while he has no decided opinion whether there be a perfect decussation or not.* Porterfield, while he allows the intimate union of the optic nerves, has several observations, proving that they have no intersection or decussation. Sabbatier, encouraged by the authority of Morgagni, says, that he could trace the affection of the nerve of the injured eye no farther than to the union. He discredits the accounts of their having been traced to the same side of the brain, and believes the assertions to be the consequence of previous opi- nion and prejudice.—There are certain observations of Val- salva, Cheselden, and Petit, which seem to prove, that where the brain is injured, it is the eye of the opposite side that is affected.f After their union the optic nerves are much con- tracted in diameter; still the optic nerve is the largest of the head excepting the fifth pair. It is the firmest of all the nerves of the senses, but softer than the other nerves. J What remains to be said of the optic nerves, falls more naturally to be treated of when speaking of the organ of vision. THIRD PAIR OF NERVES ; MOTORES OCULORUM. The third pair of nerves arise from the internal margin of the crura cerebri, and the perforated medullary matter which is betwixt the crura. The delicate filaments of this nerve can- not be traced far into the substance of the brain, but still we may observe them spreading their filaments and traversing the dark-coloured spot which we have already mentioned to be vi- sible in the crura cerebri. Some anatomists have said, that the third pair of nerves had an origin also from the nates and testes. Ridley describes them as rising from the pons Varolii.^ In relation to the arteries, those nerves are betwixt the pos- terior artery of the cerebrum, arising from the division of the basilar artery and the anterior artery of the cerebellum.|j * " Ergo, utrum omnes nervorum fibrae, an quaedam tantum mutuo se secent, certe statui " nequit." + If Petit and others are proving that the optic nerves are affected in the side opposite to the injury of the brain, they are proving that they have no decussation ; for if they bad, it would counteract that effect, which from the structure of the brain, they must have iu common with the other nerves. X Soemmerring. § They seem to come from the angle betwixt the crura cerebri and pons Varolii. They are flat near their origin, but become round and firm. || " Cette disposition peut expliquer pourquoi on eprouve tant de pesanteur aux yeux " aux approches du sommeil, dans l'ivresse & dans certains especes de fievre." Sabbso- tier. This is a mechanical and a most improbable way of accounting for such an effect. THE ORIGIN OF THE NERVES. 368 They diverge from each other as they proceed forwards, and each penetrates under the anterior point of the tentorium by the side of the cavernous sinus, and passes through the fora- men lacerum. In the general description it is sufficient to say, that they are distibuted in common to all the muscles of the eye. THE FOURTH PAIR OF NERVES. The fourth pair of nerves, pathetici, or trochleares, are the smallest nerves of the encephalon, being not much larger than a sewing thread. This nerve comes out from betwixt the cerebrum and cerebellum, passes by the side of the pons Va- rolii, and after a long course pierces the dura mater behind the clynoid process, runs along for some way in a canal or sheath, formed by the dura mater; it then passes above the cavernous sinus, continues its course onwards through the foramen lace- rum to the orbit, and is finally appropriated to the superior ob- lique muscle of the eye. The origin of the fourth pair, if we take implicitly the des- criptions of authors, seems to have a much greater variety than any of the other nerves; so that it is common to say, the fourth pair of nerves arise about the region of the nates and testes.* The trochlearis arises sometimes by two filaments, but more commonly by one undivided root.f This root is seen to emerge from a point betwixt the medullary lamina of the cerebellum or valvula Vieussenii, and the lower part of the tubercula quadrigemina."]; From the connections of the parts whence this nerve arises with the rest of the brain, it is presumed, that this fourth pair of nerves has a very immediate and universal connection with the internal parts of the brain ; yet there is nothing in the final distribution of the nerve, which should incline us to believe that there should be any particular provision in its origins. * " Pone corpora bigemina posteriora mox paullo superius, mox paullo inferius, mox ma- " eis exteriora, mox magis iuteriora versus radice simplici, duplici, triplici, quin et quadru- " plici oritur.—Nonnunquam origo ejus in cerebri valvula, nonnunquam in ipso freuulo pa- " tet ut humore ventriculi qunrti alluatur." Soemmerring, vol. iv p. 209. + Santorini says, they have three roots or little fasciculi. Wrisberg following Vieussens, says the fourth pair arises from the valvula cerebri. Vicq d'Azyr. See Haller, fas. vu. tab 3. " Origo alius simplex est, alius duplex ; quando simplex est, a processu a cerebello " ad testes exterius prodit, quam est transversa stria, qua? eoa processus conjungit." Hal- ler Phys. vol. iv. p. 208. t " Et souvent ils se confondenl avec un tractus medullaire place transversalement au " dessus de la valvule du cerveau." Vicq d'Azyr. This nerve, says he, cannot be followed into the anterior part ofthe brain from its extreme delicacy, and because it is formed irom the medullary substance itself without the admixture of filaments to give it strength. He quotes those words of Soemaaerring; " Continua medulla oritur." 364 THE ORIGIN OF THE NERVES. FIFTH PAIR OF NERVES ; TRIGEMINI. / The fifth nerve of the brain arises from the fore and lowest part of the crura cerebelli, where they unite with the pons Varolii. The origin of this nerve may be divided into two portions; an anterior is small, and somewhat elevated above the other. The posterior part of this origin takes its rise a little lower than the anterior part. These two origins of the nerve are connected by a cellular membrane, and have betwixt them a little groove, in which not unfrequently an artery creeps. According to Santorini the anterior of these divisions is formed by the transverse fibres of the pons Varolii, and the posterior by the crura cerebelli.* Vicq d'Azyr could never, except in one dissection, perceive that any of its fibres arose from the pons Varolii.f The nerve of the right side has been observed sometimes larger than that of the left. This fifth nerve, the largest of the skull, passing forwards and downwards, slips in betwixt the lamina of the dura mater, opposite to the point of the pars petrosa of the temporal bone. It is here firmly attached to the dura mater, and forms a flat ir- regular plexus. From this plexus there pass out three great branches :—1st, One to the socket of the eye and forehead, through the foramen lacerum ; 2d, One to the upper jaw and face, through the foramen rotundum; and 3d, One to the lower jaw and tongue, passing through the foramen ovale. SIXTH PAIR OF NERVES J OR, ABDUCENTES.| The sixth nerve of the skull seems to arise from betwixt the pons Varolii and medulla oblongata. In the origin of its fibres, it has, however, much variety ; and authors differ very much in this point of the description.^ We may say, however, that the sixth pair of nerves arise from the corpora pyramidalia.— Sometimes the nerve rises in two branches, which do not unite until they are entering into the cavernous sinus.|| The sixth nerve is in size somewhat betwixt the third and fourth : it passes forward under the pons Varolii, until near the lateral * Santorinus. W'risberg de quinto p. Nervor. Scarpa Anat. Annotat. p. 107. f " Oritur e nodo cerebri, prope cerebellum duabus partibus, &c." Soemmerring. I Or, motores externi. tj Simple as the anatomy of the nerve is, Vieussens, Morgagni, Lieutaud, Winslow, Sab- batier—all diff»r in their account of the origin of this iitrve in some little circumstance ; and Vicq d'Azyr givps six varieties of it. '} S.iubatier. Scarpa loc. cit. THE ORIGIN OE THE NERVES. 365 and lower part of the body of the sphenoid bone: it thence continues its route forwards and downwards by the side of the carotid artery, through the cavernous sinus: here it seems in- creased in size.—It gives off that small twig which anato- mists account the beginning of the great sympathetic nerve. The sixth nerve, after giving off this delicate thread, passes on through the foramen lacerum to the abductor muscle of the eye. SEVENTH PAIR OF NERVES ; OR, AUDITORY. The seventh nerve arises from the posterior and lateral part of the pons Varolii, at the point where it is joined by the crura cerebelli. But this seventh pair of Willis consists of two parts; the facial nerve or portio dura, and the auditory or portio mollis; the last is the larger and posterior portion.* The portio dura comes out from the fossa formed betwixt the pons Varolii, corpus olivare, and crus cerebelli,f and upon a more careful examination we find it rising distinctly from the crus cerebelli. The origin of the portio mollis, of the seventh pair, is to be traced from the forepart of the fourth ventricle.f We ob- serve passing obliquely upwards from the calamus scriptorius several medullary striae; those vary in number from two to seven, and are sometimes not to be discerned.^ To these are added certain fibres arising from the pons Varolii, and as these fibres proceed from their origin, the/ become still more distinctly formed into fasciculi. The whole of this portio mollis is larger than the third nerve, firmer than the first, but less so than the second pair; it forms a kind of groove which receives the portio dura. The portio mollis and portio dura entering the meatus auditorius internus of the petrous bone, * And we may add a third portion ; the portio media of Wrisberg. f " Fosse de ('eminence olivaire," of Vicq d'Azyr. i Prochaska, speaking ofthe fourth ventricle, continues thus;—" Super has ultimas emi- 41 ncntias solent medullares candicantes quasi fibraedecurrere, a quibus proprie originempor- " tionis mollis nervorum auditoriorum saltern pro parte deducunt." (Ridley, Haller, Lob- stein, cum per antiquo auctore Piccolhoniini et etiam recentissimus Soemmerring.)—" E"o " postquam multoties in lineas illas medullares in quarto ventriculo inquisivissem, dkere 44 possum, non semper illas in originem nervi acustici mollis terminare; nonnunquam enim " paulo supra nonnunquam paulo infra desinunt, aliquando in uno latere, & baud raro utrin- 41 que desiderantur, ita ut ex his observationibus persuadear illas medullares quarti ventri- 44 culi strias ad originem portionis mollis nervi acustici niiuimc essentiajes esse." Pro- chaska, tab. iii. f. f. Scarp, loc. cit. § It is a curiouscircumstance, should future observation confirm it, which has been men- tioned by Santorini, that those origins of the auditory nerve have been observed particular'v strong in a blind nm*. whose hearing had been very acute. 366 THE ORIGIN OF THE NERVES. the former is divided into four portions, which pass to the se- veral parts of the internal ear. The latter traverses the petrous portion, and comes out by the stylo-mastoid foramen behind the ear, spreads upon the cheek, and forms the prin- cipal nerve of the face. EIGHTH PAIR OF NERVES. To understand a very intricate demonstration, it is neces- sary to recollect that the eighth pair of nerves, as they have a relation to the brain, consist of three distinct nerves.—These are, 1st, The glosso-pharyngeal nerve ; 2d, The par va- gum ; 3d, The spinal accessory.—Taken all together, they arise from tbe superior and lateral part of the medulla ob- longata. The glosso-pharyngeal nerve is only distinguished within the skull as a larger filament of the eighth pair; it is however distinct in its course from the origin to the point where it pierces the dura mater; it is the uppermost of the fibres of this pair of nerves.—Sometimes there is a very delicate fila- ment running parallel with its lower edge which belongs to it. It has the same origin with the fibres of the par vagum.* The par vagum is composed of ten or twelve very small filaments, which are sometimes united into three or four fasci- culi. These filaments arise from the outer border of the corpus olivare, or from the lateral part of the medulla oblon- gata, t Sometimes they arise in a double series like the nerves of the spine : a few fibres are to be traced from the side of tbe calamus scriptorius of the fourth ventricle. The spinal accessory nerve comes up from the spine to join the par vagum ; it begins by small twigs from the poste- rior roots of the fourth, fifth, sixth, and even the seventh cer- vical nerves. In the size, length, and origin of those little slips, there is much variety : as the nerve ascends to the top of the spine, it connects itself with the sub-occipital nerve ; it then passes behind the trunk of the vertebral artery, ap- proaches the par vagum, and receives some filaments from the medulla oblongata.—Those three nerves, the glosso-pharyn- * " Nervus glosso-pharyngeus fasciculo mox una, mox dnabus, quatuor, quinque fibru " composito oritur ex summa atqpe priore parte medulhe i>one corpora olivaria nervum fa- "•cialem inter atque nervum va^ura. nonnunquam etiam ex quarto ventriculo vel ex cruri- 44 bus cerebpjli ad spina? medullain. nonnunquam sub posteriori sulco nervi vagi, deductusab " eo vel distinctius, vel obseurius interposita arteria, vel vena, vel arteria et vena simul, vel 4i parte plexus choroidis, quid quod ipsa directions a nervo vago est distinctus." Soemmeriiug. 1 Some filaments, according to Vieu?scns, Santorini, and Soemmerring, are derived from he side of the 4th ventricle. THE ORIGIN OF THE NERVES. 367 geal, par vagum, and accessory nerves, in their passage out of the skull are connected in a very intricate way.* They there separate from each other. Tbe anterior branch, the glosso-pharyngeal nerve goes to the tongue and pharynx : the middle nerve, the par vagum, has an extensive course through the body, and finally terminates in the stomach ; the lowest nerve, the accessory, passing into the neck, perforates the mastoid muscle, and distributes its branches amongst the mus- cles of the shoulder. ninth pair of nerves ; or, lingual. The ninth nerve of tbe skull originates from betwixt the cor- pora pyramidalia, and olivaria. Like all the nerves of the spine, it is composed of several little filaments ; those unite into a fasciculus of a pyramidal shape : still those filaments do not forma nerve before perforating the dura mater, but pierce it severally ;f they then unite and pass out of the skull by the condyloid foramen of the occipital bone ; they are then con- nected with the eighth pair and ganglion of the sympathetic nerve. The final distribution of the nerve, is to the muscles of the tongue.f the tenth; or, sub-occipital nerve. From its origin, its manner of passing betwixt the skull and first vertebrae, and its distribution, it must be classed with the nerves of the spine. The nerves ofthe spine are divided into the eight cervical, twelve dorsal, five lumbar five, and sometimes six or seven, sa- cral nerves.^ Each of those twenty-five nerves arises in two fasciculi, one from the fore and the other from the back part of the spinal marrow. They are to be traced a great way in the length of the spinal marrow before they pass the membranes. * The minutiae of which will afterwards call for attention. f The ninth pair of nerves often differ very much in one side from the other, in regard to the origin and number of those fasciculi. Scarpa, after shewing that most ofthe nerves have double origin, describes this also ri- sing in two parts. Anat. Annotat. p. 108. X " Forsan etiam nimio sanguine plena arteria vertebrali pressus lasditur, ut hide haesi- 14 tantia atque resolutio linguae ebriorum, ex cerebri phlegmone ins»ni."ntium. attonitorum 44 explicari possit.—Collapsa veroeadem arteria ex nimio sanguinis profluvio lingua ob san- 14 guinis forsan defectum resolvitur.—Ex ejusdem nervi nexu cum nervis cervicsuibus voch 44 jacturam post laesam spinalis medulla partem quae in cervice est, explicarunt." t 44 Plerwmqne qn'mque sun", nonnunquam sex, raro tres vel quatuor." Soemmerring. 368 OF THE PARTICULAR SERVES. The posterior and anterior fasciculi penetrate the dura mater separately, and afterwards unite. The posterior fasciculi of the dorsal nerve before they unite with the other, swell into a little ganglion. The posterior fasciculi of the cervical nerves communicate with each other by intermediate filaments. CHAP. VI. OF THE PARTICULAR NERVES. THE FIRST PAIR OF NERVES ; OR, OLFACTORY NERVES. E have described the three roots of this pair of nerves: their triangular form, their bulbous extremities, and their man- ner of perforating the cribriform plate ofthe aethmoid bone. Where the soft and pulpy-like mass of the olfactory nerves perforate the aethmoid bone, the dura mater involves them, and gives them firm coats.* There are two sets of nerves thus formed. First, those which pass through the holes in the crib- riform plate, nearest the crista galli, run down upon the sep- tum of the nose, under the Schneiderian membrane, betwixt it and the periosteum ; they become extremely minute as they descend: and they, finally, pass into the soft substance of the membrane. The second class of filaments are those which pass down by tbe outer set of holes of the aethmoid plate, and which are distributed to the membrane investing the spongy bones. Although branches of the ophthalmic, pterygoid, palatine, and sub-orbital nerves pass to the membrane of the nose, there is reason to believe they have no power of conveying the im- pression of odours. These nerves are necessary that the mem- brane may possess the common properties bestowed by the nerves. Upon the question, whether those additional branches of nerves to the nose, assist in conveying the impression of odours, there has been much controversy. It is a subject upon which we might reason by analogy; but, certainly, litttle dependance * Duverney first observed this course and firmness of tbe olfactory nerves. w OF THE PARTICULAR NERVES. 369 can be placed upon those cases, brought by either party, of diseases affecting the one set of nerves without influencing the other. From the nature ofthe parts, ulceration or tumours, which destroy the bones of the nose, must press equally upon the branches of the olfactory nerve, and of the fifth pair. We find that there pass also to the other organs of sense, subordi- nate nerves : and we know that a nerve may be modified to much variety of function ; and this is evident from the nerve of taste being a branch of the fifth pair. But it is doubtful how far a nerve may be capable of receiving at one instant various impressions. Far from considering distinct nerves sent to the same organ, as affording an argument for these nerves receiving one uniform impression, and conveying one simple sensation, it would seem more rational to infer, that one indi- vidual nerve cannot perform two functions, and that two func- tions are often required in the organs of sense. I am inclined to believe, that the olfactory narve is incapable of bestowing common sensation on the membrane of the nose ; and that the other nerves which ramify on that membrane, do, on the other hand, contribute nothing to the sense of smell, as we find that the inflammation of the pituitary membrane, which raises the sensibility of the branches ofthe fifth pair of nerves, does in no degree make those ofthe olfactory nerve less acute. The mem- brane is painfully inflamed, but the sense of smell is deadened. In attending to the delicate sensibility of the nerves of the senses, we neglect to take into account the less prominent, but no less curious peculiarities in the sensations, and sympathies of the common nerves. The senses of taste or smell are not more distinct form each other, or from common sensation, than are the peculiar sensations which belong the sensibility of the several viscera. The stomach and intestinal canal possess as great a discriminating power as the organ of taste, although the sensations are less perfectly conveyed to the sensorium. There is a variety in the susceptibility ofthe several organs and visce- ra, a distinct sensation and proportioned action and election which is essential to the order and economy of the general system. This is conspicuous in the variety of the affections in remote parts, when food, medicine, or poison is received into the body. These peculiarities in the impression of which each organ is susceptible, are so far distinct as to be essential to the due excitement of that organ ; and are yet so general, as to connect, in one combined action, the whole system, and to occasion sympathies in remote parts, which perplex us, and give that decree of intricacy to the living actions, which renders medicine an uncertain art. vol. ii. A a a 370 Of THE PARTICULAR NERVES. ARRANGEMENT OF THE NERVES PROCEEDING FROM THE CRANIUM. The first nerve we have seen passing to the nose. The second, third, fourth, part of the fifth and sixth, pass to the eye, or through the orbit. The seventh nerve is that which becomes the organ of hearing. Part of the fifth, seventh, eighth, ninth, and sub-occipital nerves pass to the bones of the face, the integuments and muscles of the face, the jaw, and throat. From the sixth pair of nerves is derived the great sympa- thetic ; from the eighth is sent downwards tbe par vagum. The extreme branches, of the fifth pair, of the seventh, of the eighth, ninth, and first cervical nerves, form a chain of connections, surrounding the head, face and neck. second pair; or, optic nerves. Iv this part ofthe work there is no occasion to deliver any thing 'urther concerning the optic nerves, than has been al- ready said of their origin, and final expansion in the retina of the eye. It will be more proper to consider them fully when treating of the eye in particular. THIRD PAIR OF NERVES ; OR, MOTORES OCULORUM. These nerves have the name of motores oculorum, be- cause they are distributed to the muscles which move the eye balls. They pass upwards from their origin; and then diverging, they penetrate tbe dura mater under the extreme point of the tentorium ; they descend again by the side of the carvernous sinus, and pass out of the cranium by the foramen lacerum ofthe sphenoid bone. The nervus motor oculi having come into the socket divides into two branches: The inferior branch passes forward along the outside of the optic nerve; it then divides into these branches: 1. To the adductor muscle. 2. To the rectus inferior. 3. To the external oblique and to the lenticular ganglion. But the branch ofthe third nerve, which, with the fifth, forms OF THE PARTICULAR NERVES. 371 this little ganglion, is, by no means, constantly derived from this branch. The lesser and superior branch ofthe third, is distributed to the rectus superior oculi and levator palpebral superioris. fourth pair of nerves ; trochleares ; or, pathetici. These nerves are very small. Their origin, from about the tubercula quadrigemina, and their long course under the base ofthe brain, have been already described ; after pro- ceeding a considerable way, incased in the duplicature of the dura mater, where it forms the extreme point of the tento- rium, they pass amongst tbe lamellae of the dura mater, where it forms the cavernous sinus. They pass by the. outside of the third pair of nerves; turn round so as to be above them, and make their egress through the foramen lacerum of the sphenoid bone. They pass forward in the orbit, undiminish- ed by the giving off of branches ; and are each finally distri- buted to the superior oblique muscle or trochlearis. Some- times, however, in their course, they send branches to unite with those ofthe fifth pair, which pass to the nose, or even to the frontal nerve; but this is very rare.* My pupils have traced these connections betwixt the fourth and fifth nerves. As this nerve is derived very far back from the brain, and as the parts from which it originates are less affected by the distention ofthe ventricles than almost any other part ofthe brain, this has been given as a reason why in hydrocephalus we so frequently see the eyes turned obliquely towards the nose. The origin of these nerves being affected, they will give a com- paratively greater power to the superior oblique muscle. It has been observed also, that in death the power of the supe- rior oblique muscle is greater than the other muscles of the eye-ball. I account differently for these phenomena. THE FIFTH PAIR J OR, TRIGEMINI. The tracing of the branches ofthe fifth pair, by dissection, is a difficult task, for those branches are distributed among the bones of the face, to the eyes, nose, mouth, tongue, antl throat. From this extensive distribution the fifth nerve is neces- sarily the largest of those that pass out ofthe cranium. It is of a flattened form ;f it penetrates the dura mater at Soemmerring. ' So it is said, by Mickel, to resemble the flat worm, or taenia. 372 OF THE PARTICULAR NERVES. the anterior point of the petrous bone, and spreads flat under it. Here under the dura mater, it is matted into one irregular ganglion; viz. the semilunar or Gasserian ganglion. This gang- lion lies on the anterior point ofthe temporal, and on the sphe- noidal bone. It is not alike in structure to the proper ganglion, and has indeed more resemblance to a plexus. In their pas- sage from the brain, the filaments, composing the fifth nerve, are loose, or easily separated ; at this place, they are all found so subdivided and entangled, as to resist further division. The nerve here swells out into a greater size ; it seems to be incorporated with the dense fibres ofthe dura mater; it be- comes of a dark red, or mixed colour, having a semilunar mass of matter of the same appearance as ganglion stretching across it; all which circumstances have, by no means, been unobserved by anatomists. Vieussens supposed, that the use of this ganglion, of the fifth pair, before it perforates the cra- nium, was to strengthen the nerve, and enable it to withstand the motion of the jaws! But it would rather seem to be a ganglion connecting in sympathy all those parts to which the nerve is finally distributed.* The connection of the Gasserian ganglion with the dura mater, is so firm, that it yet remains undecided whether there are sent off here any nerves to that membrane j but I conceive that there are none, and that the connection of the ganglion with the' fibrous membrane, or sheath which covers it, has been mistaken for nerves passing from the ganglion to the dura mater. From the semilunar or Gasserian ganglion, the fifth nerve divides into three great branches: whence the name of tri- geminus : 1st. The ophthalmic branch of Willis, which passes through the foramen lacerum into the orbit. 2d, The superior maxillary nerve, which passes through the foramen rotundum. , 3d, The inferior maxillary nerve, which passes to the lower jaw, through the foramen ovale. The OpLhalmic Branch of the fifth Pair. This nerve enters the orbit in three divisions, these are, the frontal, the nasal, and the lachrymal nerves. 1st, The first of these runs under the periosteum of the up- per part of the orbit, and above the levator palpebral superi- * " Et affectum an'mi indicia in faciei partibus depingere adjuvet." Hirsch. Sand. The«. Jliserta. p. 491. OF THE PARTICULAR NERVES. 373 •ris. Upon entering the orbit it gives off a small branch, which passes to the frontal sinus ; the nerve then divides into the su- per trochlearis, and the proper frontal nerve. The first of these passes to the inner part of the orbicularis oculi and fron- tal muscle. The other, the outermost, and the proper frontal nerve, passes through the hole, or notch, in the margin of the Orbit, and mounts upon the muscles and integuments of the forehead. These superficial branches communicate tritb the ex- treme branches ofthe portio dura, or nervus communicansfaciei. Cases are on record of wounds of the frontal nerve occa- sioning a great variety of nervous symptoms, and especially loss of sight; and it certainly marks a very particular connec- tion and sympathy betwixt this branch and the common nerves which pass to the eye-ball and iris, and the retina, that blindness is actually occasioned by the pricking of the frontal nerve. Morgagni supposes this to be occasioned by the spasmodic action of the recti muscles pressing the globe of the eye down against the optic nerve. find, The nasal branch of the ophthalmic nerve sends off a slip or twig to form with a branch of the third pair, the lenticular, or, ophthalmic ganglion; while the trunk of the nerve passes obliquely forwards and inward through the or- bit, and gives off one or two extremely small twigs, which join the fasciculi of ciliary nerves. The nasal branch then con- tinues its course betwixt the superior oblique and adductor muscles; before piercing the orbital plate, it sends forward a branch, which passing under the pulley ofthe superior oblique muscle, joins that division of the frontal nerve which passes over the pulley. This branch supplies the caruncula lachry- malis, and sends a twig down to the lachrymal sac and duct. The nasal nerve then passing through the internal orbital fora- men, enters the skull again, and runs under the dura mater, which covers the aethmoid bone, to pass through the cribriform plate of that bone, and again to escape from the cranium. It is finally distributed to the upper spongy bones, and to the frontal sinuses. We thus observe such a connection ofthe nerves ofthe eye and nose, and of those distributed to the inner angle ofthe eye, and muscles of tbe eye-lids, as sufficiently accounts for the sympathy existing among those parts. We see the necessity of this connection, since the excitement of the glands which se- crete the tears, the action of the muscles, and the absorption of the tears into the nose, must constitute one action- The lenticular, or, ophthalmic ganglion, comes natu- rally to be considered under this division of the fifth pair. The lenticular ganglion is formed by a twig from the nasal branch 374 OF THE PARTICULAR NERVES. of the fifth pair, after being united to that branch of the third pair of nerves, which goes to the levator palpebrae and the rectus superior muscles. The ganglion is of a square form, and is situated upon the outside ofthe optic nerve. The cili- ary nerves pass out from this ganglion in two fasciculi; they are ten or twelve in number; they are joined by branches of -the continued nasal nerve. Tbe ciliary nerves run forward amongst^tje fat of the orbit, to the sclerotic coat of the eye, and pierce it very obliquely in conjunction with the ciliary ar- teries. The ciliary nerves and arteries then pass forward be- twixt she sclerotic and choroid coats ofthe eye to the iris. The iris is considered as the part the most plentifully supplied with nerves (as it certainly is also with arteries) of any part in the body. It follows, indeed, from what we formerly said, that a profuse circulation of blood is necessary to an accumulated nervous power. The fine sensibility enjoyed by the iris is owing to those nerves; but it must be observed, that the na- ture of this sensibility is quite peculiar. Thus when the iris is touched with the needle it does not contract, although it be sensible to the slightest variation of the impression of light on the retina. This is a subject of very peculiar interest, and has engaged some of my pupils in a suite of experiments. From the connection of these ciliary nerves with those passing to the nose, Soemmering accounts for sneezing being the consequence of a strong light upon the eye. This may perhaps be true; but, certainly, the temporary loss of light, from sneezing, does not depend upon this connection of the nerves, but upon the immediate affection of the optic nerve and retina, from tbe concussion and interruption to the circula- tion, or upon the accumulation of blood in the eye. 2. The lachrvmal nerve is the least of the three divisions ofthe ophthalmic nerve ; it divides into several branches be- fore it enters the gland. Several of these branches pass on to the tunica conjunctiva, being joined by twigs of the first branch of the superior maxillary nerve. Others connect them- themselves with the extremities of the portio dura of the seventh pair, and with the superior maxillary nerves. By these the flow ofthe tears is commanded by the degree of ir- ritation of the surface ofthe eye, so that the tears flowing wash away the offending matter. THE SECOND BRANCH OF THE FIFTH PAIR; VIZ. THE SUPERIOR MAXILLARY NERVES. The superior maxillary nerve, having passed the foramen rotandum, emerges behind the antrum Highmorianum, at the OF THE PARTICULAR NERVES. 375 back part of the orbit, at tbe root of the pterygoid process of the sphenoid bone. The infra-orbital canal lies directly oppo- site, and ready to receive one branch, while the spheno-maxil- lary opening is ready to receive another. The chief part, or trunk of the nerve, may be said to be seated, and to give out its divisions in the pterygo-palatine fossa. Through the spheno-maxillary fissure, a branch of the superior nerve is sent into the socket of the eye. This twig unites with branches ofthe lachrymal nerve, and in general supplies the periosteum of the orbit. It then sends, through the foramen in the os malae, a branch, which is distributed to the orbicularis muscle of the eye-lid, and communicates with the branches of the portio dura of the seventh pair, or nervus communis facialis. Another branch of this first division passes upward from the zygomatic fossa, in a groove of the wing of tbe sphenoid bone, to the temporal muscle, and getting superficial, it accompanies the branches of the temporal artery. The superior maxillary nerve, after sending off the small branches which I have described to enter the orbit, having fairly emerged out of the cranium, sends down two small branches which, uniting, form a small ganglion of a reddish colour, and of a triangular shape, like a heart. This, the spheno-palatine ganglion, or ganglion of Mickel, is exact- ly opposite to the spheno-palatine hole; and those nerves, and this ganglion are immersed in the soft fat which fills up the space betwixt the sphenoid palatine and superior maxil- lary bones. From this ganglion are sent out several lesser nerves, and particularly the nasal, vidian, and palatine nerves. The superior nasal branches pass to the membrane on the back part of the nose, and to the cells of tbe sphenoid bone. . The vidian nerve comes off from the back part of the ganglion, and passes into the foramen pterygoideum back- wards. It first gives off some small branches to the nose (the superior and posterior nasal nerves of Mickel;) these perfo- rating the bone laterally, are distributed on the pituitary mem- brane, covering the vomer. The vidian nerve, continuing its course backwards, splits; one branch, after a long retrograde course through the petrous part of the temporal bone, forms a connection with the portio dura,* while the other forms one of the roots of the great sympathetic nerve, by joining the branch of the sixth pair, which passes down with the carotid artery. * In the faHus, the foramen innominatum or vidian hole is so short that the union of the vidian nerve and portio dura may be seen. In the adult it is seldom necessary to cut more \*g* tV tenth e>f an in<-h to expose clearly the union of the nerves. 376 OF THE PARTICULAR NERVES. From the distribution of this branch of the fifth pair to the membrane of the nose, and its connection with the sympathe- tic, some physiologists account for the effects of odours in causing fainting, as the chief nerves of the heart are received from the sympathetic. They also account thus for the ex- citement of the heart, in deliquium, by stimulant applications to the nose. The palatine nerve is the largest of the branches sent out from the ganglion. We have to recollect, that there are two canals in the bone conveying nerves to the palate ; one ante- rior and larger; and another running nearly parallel to it, a posterior and smaller one. The division of the palatine nerve, which descends through the anterior palatine hole, is of course the larger branch; as it passes through the canal, it gives branches which enter the nose, to be distributed upon the pituitary membrane. This larger branch, in its further pro- gress through the bone, divides, and having emerged from its hole, is distributed all along on tbe soft palate. The poste- rior division of the palatine branch, passing down by the poste- rior palatine foramen, is distributed to the velum pendulum palati and its muscles. There is yet a third branch of the palatine nerve; viz. the external palatine nerve. It is the least of all the branches; and, sometimes, instead of coming from the ganglion, is de- rived immediately from the superior maxillary nerve. This branch descends before the pterygoid processes, and on the convex surface of the upper maxillary bone, and js distributed to the velum palati and uvula. The superior maxillary nerve, after sending off the branches which form the spheno-palatine ganglion, passes obliquely downward to the infra-orbital canal. In this course it gives off the posterior nerve to the teeth of the upper jaw; and this again gives off a twig, which takes a course on the outside of • the maxillary bone, and supplies the gums and alveoli, and buc- cinator muscle. While passing in its canal, the infra-orbital nerve gives off the anterior nerve to the teeth ; and when it emerges from the infra-orbital foramen, it spreads widely to the muscles of the face, connecting itself with the extremities of the portio dura of the seventh pair or nervus communicans facialis. The " tic douloureux," and the " tic convulsif," of the French authors, are diseases attributed to the affection of this nerve. The seat of the tic douloureux is the side of the face, the nostril, the cheek-bone, and root of the alveoli. Sauvage calls it the trismus dolorificus, or maxillaris. But it is a disease not absolutely fixed to this point of the cheek-bone; but on OF THE PARTICULAR NERVES. 377 the contrary, from the universal connection betwixt the nerves of the fate, it takes, sometimes, a wide range ; and the dis- ease, I have no doubt, is sometimes seated in the portio dura of the seventh pair. Sauvage has given to one species of it, the name of occipitalis. It is a disease attended with extreme pain, which forces the patient to cry out in great agony. The patient has described it to me as like a flash of lightning through the head, so sud- den is it in its attack; And as to its violence, it is sufficient to say, that it throws the same patient into the most violent con- tortions of pain, who will sit unmoved and suffer the nerves to be deliberately cut across. The pain is felt deep rooted in the bones of the face, and seems to spread upon the expanded extremities of the nerve ; it is sudden, violent, and reiterated in its attack, and it varies in the length and repetition of its accession. It is confined chiefly to those advanced in years, and is as violent in the day as during the night. The disease is apt to be confounded with the affection of the antrum Highmorianum, the tooth-ach, rheumatism, and clavis hystericus, or even with venereal pains. It has been cured by dividing the infra-orbital nerve, but this is an uncer- tain remedy. It has not succeeded with me. In hemicrania, the affection of the three branches of the fifth nerve, is such as to mark their distributions. There is swelling and pain of the face, pain of the upper maxillary bone, pains in the ear and in the teeth, difficulty of swallow- ing, and lastly, stiffness in moving-the lower jaw, in conse- quence of the affection of those branches which pass up to the temporal muscle. There are cases spoken of by Sabbatier, where this infra- orbital nerve being wounded, unusual nervous affections, and even death, were the consequence: but it would rather appear, that, independently altogether of the affection of the nerves of the face, inflammation spreading from the wound to the brain, had, in the examples which he gives, been the occasion of the unusual symptoms, and of the death of the patients. third branch of the fifth pair; or, lower maxillary NERVE. This, the last of the three great divisions of the fifth pair of nerves, the largest but the shortest branch within the skull, passes out by the foramen ovale. It is distributed to the mus- cles of the lower jaw, tongue, and' glands. The trunk of the nerve having escaped from the cranium, lies covered by the vol. n. B b b 378 OF THE PARTICULAR NERVES. external pterygoid muscle; and is at this point divided into two great branches, which again subdivide into numerous small branches; many of which it would be superfluous to describe. It is sufficient to mention them as going, 1. to the masseter muscle ; 2. to the zygomatic fossa and temporal muscles; 3. to the buccinator muscle. We regard as tbe two greater divisions of this nerve, the proper maxillary nerve which passes into tbe lower jaw; and the gustatory or lingual nerve; the division into these two great branches is formed, after the nerve has passed the ptery- goid muscles. The gustatory nerve, immediately after its separation from the nerve of the lower jaw, is joined by the chorda tym- pani; or, perhaps we should rather say, a branch of this nerve, by traversing the petrous portion of the temporal bone in a retrograde direction, unites itself with the portio dura of the seventh pair, as it is passing through the ear. This nerve being seen passing across the tympanum, is the reason of its being called chorda tympani. The gustatory nerve, pro- ceeding obliquely downward, sends off twigs to the salivary glands and muscles, situated betwixt the jaw-bone and tongue. Where it is passing by the side of the maxillary gland, it gives out some filaments which form a small ganglion, from which branches penetrate the gland. The trunk then proceeding on- ward betwixt the sub-lingual gland and the musculus hyo- glossus, several twigs are sent off, which form a kind of plexus amongst the muscles and salivary glands ; and communicating with the ninth pair of nerves, are distributed, finally, to the gums and membrane ofthe mouth. These nerves account for the flow of saliva from these glands, excited by the sapid foot affecting the gustatory extremities. The gustatory nerve terminates in a lash of nerves, which sink deep into the substance of the tongue, betwixt the inser- tion of the stylo and genio-glossal muscles. These pass to the papillae on the surface of tbe tongue. The sense of taste, the impression of which is received upon this nerve, is seated in the edge and anterior part of the tongue: the action of the tongue against the palate forces the sapid juice of the morsel to extend to the edge of the tongue. The proper lower maxillary nerver which enters into the lower jaw-bone, sometimes called mandibulo labralis, passes downward in an oblique direction to the groove of the lower jaw-bone. Before this nerve enters the canal of the bone, it gives off branches to the mylo-hyoideus and digastri- cus, to the sub-maxillary glands and to the fat. The nerve then entering the bone, runs its course all the length of the lower jaw within the bone, and comes out at the mental hole. OF THE PARTICULAR NERVES. 379 In this course it gives' branches which enter the roots of the teeth, and accompany the branches ofthe arteries. When this lower maxillary nerve has escaped from the mental hole, it divides into two branches upon the chin ; one of these is distributed to the orbicularis and depressor anguli oris, and to the skin and glands of the lips ; the other to the depressor labii inferioris and integuments, and forms a kind of plexus, which surrounds the lips. These nerves are also connected with the wide-spreading branches of the portio dura of the seventh pair; and they are the lowest branches of the facial nerves, and the last enumerated of the intricate branches of the fifth pair. the sixth pair of nerves ; abducentes, or motores EXTERNI. The sixth pair of nerves, as we have seen, arises betwixt the tuber annulare and the corpus pyramidale. Advancing forwards and upwards, sometimes above and sometimes be- neath the branches of the basilar artery, it penetrates the dura mater by the side of the basilar sinuses. It then passes by the side of the carotid artery, and through the cavernous sinus. Here it gives off filaments, which, clinging to the carotid artery, descend with it until they are joined by a branch of the vidian nerve. These together form the origin of the great sympathetic nerve. It is a disputed point, how- ever, whether this be a branch given out from, or received into, the sixth pair; and in the description of the sixth pair, we might say, with equal show of reason, that as it passes the carotid artery, it receives one or more nerves which come up through the carotid hole, and encircle the artery. The sixth nerve enters .the orbit by the foramen lacerum, with the third and fourth nerves and first branch of the fifth. It pierces the abductor muscle of the eye before it is finally distributed to its substance. It has been presumed, that the sixth nerve does not give off the sympathetic nerve, but receives those branches from it, because tbe sixth nerve is larger betwixt this point and its dis- tribution in the orbit, than betwixt the same point and its ori- gin from the brain. But I conceive, that this enlargement of the sixth pair is not owing to such a junction ; but that, on the contrary, the nerve naturally swells out when it enters the sinus, not from being soaked in th.p blood ofthe sinus, but from its having additional investing coats, or from the coats being strengthened in order to pr< pare the nerve for its pas- sage through the blood of the sinus. 380 OF THE PARTICULAR NERVES. Again, that the sympathetic nerve sends up those branches to join the sixth, has been presumed from the effects of experi- ments on brutes in which the sympathetic nerve has been cut or bruised. But I should not be apt to give implicit credit to the result of these experiments. Supposing that the sympathetic in the neck gave an origin to the sixth pair, should not paraly- sis of the abductor muscle of the eye, and in consequence of this, the turning of the eye towards the nose, be the effect of cutting the sympathetic? On the contrary, inflammation and heaviness ofthe eye has been observed. We shall probably cease to dispute this point, when we con- sider the relations and use of the sympathetic nerve. The sympathetic nerve may be defined, a tract of medullary matter, passing through and connecting the head and neck, the viscera of the thorax, abdomen, and pelvis, into one whole. The sympathetic nerve is singular in this, that it takes no particular origin, but has innumerable origins, and a universal connection with the other nerves through all the trunks ofthe body. Those viscera to which it is distributed are entirely independent of the will, and have functions to perform too essential to life to be left under the influence of the will. The sympathetic nerve is thus, as it were, a system within itself, having operations to perform of which the mind is never conscious; whilst the extent of its connections occa- sion, during disease, sympathetic affections not easily traced. It is impossible seriously to consider the sixth nerve as giv- ing the origin to the sympathetic in any other light, than as such an expression may be subservient to arrangement, de- scription, and general enumeration of the nerves;—a thing most necessary in so intricate a piece of anatomy. The cha- racter of the sympathetic nerve (or, I believe I should say, sympathetic system of nerves,) is that of having ganglions form- ed upon it;—and thus the ganglions in the sockets of the eyes, in the fossa of the jaws, and every where, whether within-or without the head, are to me proof of the sympathetic nerve extending its connections to such parts. OF THE SEVENTH PAIR OF NERVES. The nerves ofthe seventh pair consist each of two fasciculi, which arise together, and pass into the foramen auditorium internum.* But these portions do not pass through the bone * The intermediate filament* of Wrisbere, which is betwixt those two portions of the seventh nerve, is afterwards united to the porSu dura, and must he considerX" one of iU OF THE PARTICULAR NERVES. 381 in union ; for the anterior and lesser fasciculus, is a common nerve, which passes through to the face, and is invested, like. the common nerves ofthe body, with strong coats. It is there- fore called the portio dura.* The more posterior fasciculus is the auditory nerve, and is distributed to the organ within the pars petrosa of the temporal bone; and in distinction it is call- ed the PORTIO MOLLIS. The port'O dura, or nerves communicans facialis, in passing from the brain to the internal auditory foramen, is lodg- ed in the forepart of the auditory nerve, as in a groove. When it leaves the auditory nerve, it passes on through the bone, and emerges on the side of the face through the stylo-mastoid foramen at the root of the styloid process, so as to come out betwixt the lower jaw and the ear, covered, of course, by "die parotid gland. The portio dura, while passing through the canal of the temporal bone (which is the aqueduct of Fallo- pius,) gives off a branch whicii unites with the vidian nerve of the fifth pair ; or rather, we may conclude with the best au- thors, that it receives a branch which comes retrograde from the vidian nerve, passing through the small hole on the an- terior surface ofthe petrous part ofthe temporal bone. The portto dura, when it has proceeded onwards by the side of the tympanum, gives off one or more very minute branches to the muscles within the tympanum, which give tension to the small bones of the ear. A little further on, this nerve gives off a more remarkable branch, which, passing across the tym- panum, is called chorda tympani. This is the branch which, as we formerly mentioned, joins the gustatory branch of the lower maxillary nerve. The chorda tympani passes into the tympanum by the hole in the pyramid; it takes its course on the membrane betwixt the long process of the incus and the handle of the maleus; then, received into a groove of the bone, it passes by the side of the Eustachian tube, and after enlarging considerably, it is united with the gustatory nerve. When the portio dura, or nervus communicans facialis, has escaped from the stylo-mastoid foramen, but is yet behind the condyle of the lower jaw, and under the parotid gland, it gives off, 1st, The posterior auris. This has connection with the first cervical nerve, and passing up behind the ear, it is con- nected with the occipital branches of the third cervical nerve. 2d, The nervus stylo-hyoideus to the styloid muscles, and to unite with the sympathetic. 3d, A branch which supplies some of the deep muscles, and joins the laryngeal branch of the eighth pair. * Galen divided all the nerves of the brain into those two classesj mollis and dura: of which the first were those of the sense?, the latter the motores corporis. 382 OF THE PARTICULAR NERVES. The portio dura, rising through the parotid gland, spreads out in three great divisions, and where it divides, the mem- branes connecting the divisions are like webs betwixt them, and this has acquired to this division the name pes anserinus. 1. An ascending branch, which divides into three tempo- ral or jugal nerves; so called, because they ascend upon the jugum, or zygomatic process. Two orbitary nerves, which, passing up to the orbicularis muscle, branch upon it, and inos- culate with the extremities of the fifth pair. 2. The facial nerves. The superior facial nerve passes out from the upper part of the parotid gland, across the face to the cheek and orbicularis muscle of the eye. The middle facial nerve passes from under the risorius Santorini; it goes under the zygomatic muscle, and encircles the facial vein; it sends branches forward to the lips, and upwards to the eye- lids, and to unite with the infra-orbital nerve. There is an in- ferior facial nerve, which comes out from the lower part of the parotid gland, passes over the angle of the jaw, and is dis- tributed to those fibres of the platysma myoides which stretch up upon the face, and to the risorius Santorini: it passes on to the angle of the lips, and is distributed to their depressor mus- cle. Betwixt those facial nerves there are frequent commu- nications, while they are at the same time united with the ex- tremities of several branches of the fifth pair. 3. The descending branches pass along the margin of the jaw, down upon the neck, and backward upon the occiput, Thus we see that the communicating nerve of the face is well named.—It is distributed to the side of the face, head, and upper part of the neck: it unites its extreme branches with those of the three great divisions of the fifth pair, with the eighth and ninth, with the accessory of the eighth pair, with the second and third cervical nerves, and with the sympathe- tic. From those various connections the portio dura has been called the lesser sympathetic. The connection of the nerves of the face, throat, and neck, with the nerves of respiration, affords one of the most curious subjects of inquiry as connect- ed with expression. The portio mollis of the seventh pair of nerves is the acoustic or auditory nerve; which shall be considered in a more distinct and particular manner, when we describe the other parts of the organ of hearing. ^ The nerves which we have now described are connected with the anatomy of the head, and circulate chiefly around the bones of the face. Those we are next to consider extend their branches to the neck, and form there a very intricate OF THE PARTICULAR NERVES. 383 piece of anatomy, while a class of them still more important, pass down to the viscera of the breast and belly. THE EIGHTH PAIR OF NERVES. The fasciculus, which, proceeding from the medulla oblon- gata, passes out of the cranium by the side of the great late- ral sinus, and which, in the view we have of the neives upon raising the brain from the cranium, is properly enough con- sidered as the eighth pair, consists in truth of three distinct nerves. These are the glosso-pharyngeal nerve, the par vagum, and tne spinal accessory nerve of Willis. THE GLOSSO-PHARYNGEAL NERVE. This nerve, parting from its connection with the par vagum and accessory nerves, perforates the dura mater separately from these, and in many subjects, passes through an osseous canal distinct from the par vagum. When it escapes from the cranium, it lies deep under the angle of the jaw, and passes across the internal carotid artery upon its outer side. It is to be seen by lifting the styloid muscles, at which point it sends small branches to the styloid and digastric muscles, and to join the par vagum. It sends also some very small twigs down upon the internal carotid artery; some of which join that pharyngeal branch* which is formed from the par vagum and accessory nerve. These branches united form a small irregular ganglion, from which again pass off numerous branches to the constrictor muscles of the pharynx. The trunk of the glosso-pharyngeal nerve, after giving off those nerves which pass in the direction of the internal carotid artery, continues its course attached to the stylo-glossal and stylo-pharyngeal muscles, to which of course it gives more branches, and also to the upper division of the constrictor pha- ryngis. A division of the extreme branches of this nerve termi- nates in the tongue, under the denomination of rami linguales PROFUNDI, RAMI LINGUALES LATERALES, NERVI GLOSSO-PHA- RYNGEI.f It appears to me that these branches are distributed amongst tbe short muscles of tbe tongue, and perhaps to the large pa- pillae upon the most posterior part of the tongue. Amongst the * This is a branch to the pharynx which is formed by the par vagum and the spinal acces- sory of Willis. After this nerve is formed, it again forms connection with the par vagum.— Pain in the throat having been observed by Galen to extend to the back, Scarpa explains it on the ground of this connection with the spinal accessory nerve. f Scarpa. 384 OF THE PARTICULAR NERVES. branches of the pharyngeal nerve is to be enumerated that which turns back to join the ninth pair in its distribution to the tongue.* The remaining branches of the glosso-pharyngeal nerve are distributed in innumerable filaments upon the pha- rynx, in which they are assisted by branches from the ganglion of the sympathetic nerve. THE PAR VAGDM. The par vagum is the great and important division of the eighth pair. It is the middle fasciculus of the three nerves as they lie within the skull. In its exit, it is separated from the internal jugular vein by a thin bony plate ; and sometimes two or three fibres of the nerve pass the bone distinct from the others, and afterwards unite into the proper trunk of the par vagum. Deep under the lower jaw and the mastoid process, the glosso-pharyngeal nerve, the par vagum, the spinal acces- sory, the sympathetic nerve, the portio dura of the seventh, and the upper cervical nerves are entangled in a way wnlch will fatigue the dissector, and may account for many sympa- thies. The par vagum, lying behind the internal carotid arte- ry, and as it were, escaping from the confusion of the ninth accessory and glosso-pharyngeal nerves, descends and swells out into a kind of ganglion.f We now observe three branches to be sent off: The first and second pharyngeal nerve's, which pass to the constrictor pharyngis muscle, and the inter- nal laryngeal nerve. This last mentioned nerve is even larger than the glosso-pharyngeal nerve. It is behind the ca- rotid artery, and passes obliquely downward and forward. In its progress the principal branch passes under the hyo-thyroi- deus muscle, and betwixt the os hyoides and the thyroid car- tilage ; while others, more superficial, pass down and are con- nected with the external larvngeal, or pharyngo-laryn- geus ; which is a nerve formed by the sympathetic and par vagum conjointly. The principal branch of the internal la- ryngeal nerve, which runs under the hyo-thyroideus, is distri- buted to the small muscles moving the cartilages. The mi- nute extremities of this nerve pass also to the apex of the epiglottis, and the glandular membrane covering the glottis. We have at the same time to remark a very particular com- municating nerve betwixt this internal laryngeal nerve, and the recurrent branch of the par vagum. This branch is described by Galen. The par vagum continues its uninterrupted course * Sabattier. t Truncus gangliformis octavt, tumidulum, corpus olivare Fallopii; but it is suspected that in this he meant the ganglion of the sympathetic nerve. OF THE PARTICULAR NERVES. 385 betwixt the carotid artery and jugular vein, and is involved in the same sheath with these vessels. In this course down the neck, it sometimes sends back a twig which unites with the ninth pair, and when near the lower part of the neck, it sends forward twigs to unite with those from the sympathetic nerve, which pass down to the great vessels of the heart, to form the superior cardiac plexus. On the right side, those nerves to the great vessels are in general given off by the recurrent nerve. The par vagum now penetrates into the thorax by passing before the subclavian artery ; it then splits into two. The main nerve passes on by the side of the trachea, and behind the root ofthe lungs; while the branch on the right side turns round under the subclavian artery, and on the left, under the arch of the aorta, and ascends behind the trachea to the la- rynx. This ascending branch of the par vagum is the recurrent nerve. On the right side it is sometimes double. It ascends behind the carotid artery, and sometimes is thrown round the root of the thyroid artery. On the left side, this nerve, from its turning round the arch of the aorta, is much lower than on the right; it gives off filaments which go to the lower cardiac plexus, after having united with the branches ofthe sympa- thetic. Under the subsclavian of the right side, also, there are sent branches from the recurrent to the cardiac plexus; and on both sides there pass branches of communication be- twixt the sympathetic nerve and the recurrent. When the re- current nerve has turned round the artery, it ascends in a di- rection to get behind the trachea, and here it lies betwixt the trachea and oesophagus. . It now sends off many branches to the back and membranous part of the trachea which pierce this posterior part, to supply the internal membrane. It gives also branches to the oesophagus and th)roid gland. The final distribution of this nerve is to the larynx. It pierces betwixt the thyroid and cricoid cartilages, and separates into many fila- ments, which terminate in the crico-arytenoideus, lateralis and posticus, and thyro-arytenoideus, and in the membrane of the larynx. We have already mentioned the branch of communi- cation betwixt the recurrent and internal laryngeal nerves,* and Sabbatier describes a branch of the recurrent, which some- times ascends and joins the sympathetic high in the neck. Two cases, mentioned by Galen, of scrophulous tumours in the neck opened, where the consequence was loss of voice, have tempted many anatomists to institute experiments on the * There is a double communication betwixt those nerves; in the first place by this more superficial branch, and again by several internal and more minute branches. VOL. II. , C e r $86 OF THE PARTICULAR NERVES- recurrent and internal laryngeal nerves* Notwithstanding the deep situation of those recurrent nerves, Galen says, they were cut in these cases, and he believed that the branch ot communication betwixt the laryngeal and recurrent restored the voice after some time had elapsed. Both the internal la- ryngeal and recurrent nerves are necessary to the formation of the voice. Experiments have been made upon them in dogs, and the result is curious; although tbe lesser changes of the strength, acuteness, and modulation of the voice could not be well observed in the lower animals. When the laryngeal nerve is cut, the voice is feeble but acute ; when the recurrent nerve is cut, there is a relaxation of those muscles moving the arytenoid cartilages which command the opening ofthe glottis, and in consequence the voice is flatter or graver, or more raucous. The par vagum, after sending off the recurrent nerve, de- scends by the side of the trachea. Before it passes behind the vessels and branch of the trachea going to tbe lungs, it sends minute branches which form'the anterior pulmonic PLExus.f This plexus is entangled in the connections of the pericardium, and is dissected with difficulty. The branches of this plexus throw themselves round the pulmonic arteries and veins, and follow them into the lungs. The par vagum, passing on behind the root of the lungs, forms the posterior pulmonic plexus. From this also the nerves proceed info the lungs, by attaching themselves to the pulmonic arteries and veins, and bronchial arteries, and the branches ofthe trachea.J The trunks of the nerve continuing their course upon each side of the oesophagus, unite and split into branches, and again unite so as to form a netting upon the cesophagus; these * Martin, in the Edinburgh Essays, Professor Sue of Paris, Dr. Haighton, in the Memoirs of the Medical Society of London; Cruikshanks, Professor Scarpa, Arnemann, &c. f I do not conceive that this plexus admits of any useful division, or requires any dislinc- iion of name. X JVcrves of the Lungs.—Galen, Vesalius, and others, conceived that there were very few nerves sent to the lungs, and that those which were, went only to the membranes, and uot to the substance of the lungs. They believed also that the discharge of blood from the lungs and the existence of vomicae without pain, while there was great pain in peripneumony, tvas a confirmation of this opinion. Fallopius corrected this idea, and showed that the bron- ehiaewere also attended through their course with nerves. There often exists vomica? and effusions of blood in the lungs; and Haller says, the lungs can be lanced without the ani- mal feeling pnin, but still the bronchia" are extremely sensible.—Water accumulated in the interlobular cellular membrane, or the infraction of blood into it, gives no acute pain, but only a stn«e of weight and difficulty of breathing. It is an oppression in a great measure depending; upon the return of the blood from the lungs, unchanged in consequence of the compression of the cells. —The sensibility of the bronchia?, and the existence of their nerves, appear in asthma ; andalso from the pain excited by calculi, and from their irritability ex- cited by recent ulceration, or when vomica; are discharged into them. The connection hetwfat the stomach and bronchiae, through the medium of the par vagum and pulmonic plexus, is evident from those asthmatic attacks whicii depend upon foulness "n the stomach. OF THE PARTICULAR NERVES. 387 Me the anterior and posterior plexus gul.e, or oesopha- geal plexus. The par vagum, thus attached to the oesopha- gus, pierces the diaphragm with it, the anterior plexus unite? again into a considerable trunk, is attached to the lesser arch of the stomach. It stretches even to the pylorus, and sends its branches to the upper side of the stomach, and to the lesser omentum; at the same time it unites with the left hepatic plexus, some of its branches terminate in the solar -plexus. which surrounds the root of the caeliac artery. The posterior oesophageal plexus, likewise uniting again into a considerable chord when it has come into the abdomen, sends branches to encircle the cardiac orifice of the stomach; it branches also to the inferior side and great arch of the stomach ; it sends also branches to the splenic plexus and solar ganglion. Thus we see that the par vagum has a most appropriate name, and that it is nearly as extensive in its connections as the sympathetic itself. It is distributed " to the oesophagus, pharynx, and larynx; to the thyroid gland, vessels of the neck and heart, to the lungs, liver, and spleen, stomach, duo- denum, and sometimes to the diaphragm." The recollection of this distribution will explain to us many sympathies; for example, the hysterical affection of the throat when the sto- mach is distended with flatus; the exciting of vomiting by tickling the throat; the effect which vomiting has in dimin- ishing the sense of suffocation; that state of the stomach which is found upon dissection to accompany hydrophobia, whether spontaneous, or from tbe bite of a dog. All the parts to which this nerve is distributed, are also sup- plied by the branches of the sympathetic. But in order to connect certain organs with the sensorium, and to combine these organs together, the par vagum takes a course from the head to the throat, larynx, heart, lungs, and stomach; and it is of the first consequence for the physician to observe the sympathies produced among these organs by means of this communication. OF THE ACCESSORY NERVE ; OR THIRD DIVISION OF THE EIGHTH PAIR OF NERVES. The spinal accessory nerve of Willis is that which, taking its origins like the cervical nerves from the spinal marrow, ascends through the spine and foramen magnum of the occipi- tal bone, and passes again from the skull like one of the nerves of the brain. It passes out with the par vagum, is attached to it in its passage, but again separates from it when it has esca- 388 OF THE PARTICULAR NERVES. ped from the skull. Under the base of the cranium it is attach- ed to the ninth pair also. Commonly this attachment is firm ; sometimes, it is by a short filament. This parasitical nerve then passes behind the internal jugular vein, and goes < obliquely downward and backward. It then perforates the mastoid muscle, and passes in a direction across the neck to the shoulder. While it pierces it gives nerves to the mastoid muscle ; and after piercing, it entangles its branches with those of the third and fourth cervical nerves. It then passes under the trapezius muscle, and is distributed to it, where it is on the back of the neck and shoulder. From the distribution of this nerve, says a Frenchman, we discover that the shrug of the shoulders is very natural: and " pourquoi les grandes pas- sions de l'ame nous portent a gesticuler, pour ainsi dire, malgrenous!"-* OF THE NINTH PAIR, LINGUALIS MEDIUS ; OR HYPO-GLOSSUS. After passing out from the skull by the anterior condyloid foramen, the ninth nerve adheres to the eighth pair, by cel- lular filaments and the interchange of nerves. It receives also branches from the first cervical nerve, or from the branch of union ofthe first and second cervical nerves. When dissect- ing in the neck, we find the ninth nerve lying by the side of the internal jugular vein under the styloid muscles, and com- ing out from under the occipital branch ofthe carotid artery. The nerve here divides, or it may rather be said to give off that branch which is called the descendens noni. The con- tinued trunk of the nerve passes before the external carotid artery, and forwards under the larger branches of veins in a direction tending towards the os hyoides. Here it turns up- wards under the stylo-hyoideus and digastricus muscles, and betwixt the stylo-glossus and hyo-glossus. Where the nerve is near the os hyoides, and passing under the stylo-glossus muscle, it sends down a twig which passes to the forepart of the throat, and chiefly to the sterno-hyoideus and thyro-hyoideus. Tbe continued nerve is distributed to the muscles of the tongue and lower jaw, and glands under the jaw ; and it termi- nates by numerous filaments, which form a net-work amongst the muscles of the tongue ; to which is united part of that branch of the fifth pair which goes to the tongue.f The ramus descendens noni passes downward, and ob- liquely over the trunk of the carotid artery, and under the * Sabbatier. f This has been called plexus ccrafo-basio-stylo-ghssus'. OP THE PARTICULAR NERVES. 389 thyroid vein. In the superficial dissection of the muscles of the neck, two slender twigs of nerves will be seen to come from the side of the neck, and crossing the jugular vein, unite to this descending branch. Those twigs come from the second and third cervical nerves ;* and a little ganglion or plexus is formed by their union with the descendens noni. From this centre are sent out many delicate and superficial nerves to the omo-hyoideus and sterno-thyroideus muscles. Thus we find that the ninth nerve has connections with the eighth pair of nerves, with the spinal accessory, the sympa- thetic, the cervical, and phrenic nerves. When this nerve is injured, the motion of the tongue is lost, but the sense of taste remains unimpaired. On the contrary, when the branch of the fifth nerve going to the tongue is hurt, the sense of taste is lost, while the mobility of the tongue remains.f Columbus knew a man who had no sense of taste and who ate indiffer- ently every thing presented to him. When he died, Colum- bus was curious to know the cause of this, and he found that he altogether wanted the gustatory nerve or lingual branch of the inferior maxillary nerve. Cases detailed by Professor Scarpa still further illustrate this fact. A woman, subject to epileptic attacks in an early age, was seized in her pregnancy with an hemiplegia and loss of speech. From this attack, by tbe use of medicines, she recovered; but in a future labour the disease recurred. Now the cure was less complete: for, though she regained the use of her arms, she never recovered the faculty of speech, or was only capable of articulating with great dissonance the monosyllables, affirming or denying. Up- on making her exert herself to speak, they observed no mo- tion in the tongue ; and, upon applying the hand under the jaw, they could,feel no motion in the muscles of the tongue ; yet she relished her food and drink, and had an acute sense of taste, and could swallow easily. He mentions another case, where the patient was attacked with a sense of weight at the root of the tongue, a difficulty of speaking, and copious flow of saliva. In a short time he entirely lost the power of articu- lating, but retained acutely the sense of taste.J From the extensive connection of this nerve, particularly with the eighth and sympathetic nerves, we see why tremors of the tongue and aphonia may be occasioned by hysteria, hypochondriasis, colics, or worms in the intestines.^ * In some instances those twigs are found to be derived from the first origin ofthe phrenic nerve. + Soemmerring de Cerebro & Nervis. t Tabula? Neurologies, Auctore Anton. Scarpa. b J. F. Will. Bachmer Comment. deOno. pare Nervorum. 390 OF THE PARTICULAR NERVES. of the cervical nerves. First cervical nerve. Tenth pair of the skull. Sub-occipital nerve. This is the least of all the nerves of the spine ; it arises by two roots from the medulla spinalis. Some difference has been observed in the manner in which those roots collect their filaments; and only the anterior root or fasciculus is described by some authors. The posterior fasciculus is indeed the larger, and comes in a direction dif- ferent from the general direction of the roots of the other cervical nerves. The root of the sub-occipital nerve are con- nected with the spinal accessory nerve, but seldom form a gan- glion with it; and frequently they form a union with the pos- terior roots of the second cervical nerve. The fibres of the sub-occipital nerve passing transversely and a little obliquely upwards, go out under the vertebral artery, and betwixt it and the first vertebra of the neck. The little trunk of the sub- occipital nerve, thus formed, and having escaped from the spine, rises for a little way upwards, swells into a kind of gan- glion, and then divides into two branches. The anterior of these branches is the smaller. It passes down upon the inside of the vertebral artery; its filaments unite with the hypo-glossal nerve, or ninth pair, and with the superior cervical ganglion of the sympathetic, and with the first branch of the second cervical nerve.* The larger and posterior branch divides into eight twigs, which are chiefly distributed to the muscles moving the head—to the obliquus superior and inferior, the recti postici and laterales, complexus, and splenius. Some of those muscular branches unite with that branch of the second cervical nerve which ascends upon the occiput. Second cervical nerve.—This nerve, arising by a double origin from the spinal marrow, like the other nerves of the spine, passes betwixt the first and second vertebra?. It is larger than the last; and, after forming a little ganglion by the side of the transverse process of the first vertebra, divides into two branches. The superior branch sends up a considerable division be- hind tbe projection of the transverse process of the first verte- bra, to be united to the sub-occipital or first cervical nerve. Several twigs pass forward to unite with the superior cervical ganglion of the sympathetic nerve, and with some of the more _* A very small nerve is described by some authors as passing from the anterior division of this nerve, into the canal of the vertebral artery. OF THE PARTICULAR NERVES. 391 interior branches of the third cervical nerve, and with the ninth and spinal accessory nerves. Besides these intri' ate connections, irregular branches of this nerve proceed to tiie small muscles, moving the head and lying on the forepart of the spine. The posterior branch of the second pair of cervi- cal nerves is chiefly a muscular nerve. It rises up by the side of the complexus, gives branches to that muscle and to the splenius, and communicates With the branches of the first Ltr- vical. Its branches are also distributed to the upper part of the trapezius muscle, from which they extend along the inte- guments, covering tbe occiput even to the summit of the head. The thihd cervical nerve, in the first place, communi- cates with the second and fourth cervical nerves, with the sym- pathetic and lingual nerves, and sends down a twig to unite with the origin of the phrenic nerve from the fourth cervical nerve. From the anterior division of the third cervical nerve, branches pass to the splenius and complexus, and trapezius, and upwards to the ear. We may observe also a cutaneous nerve which accompanies the external jugular vein, viz. ner- vus superficiai is colli ; the distribution of which is chiefly to the angle and margin of the lower jaw, while some of its branches enter the parotid gland, and unite with the extremi- ties of the portio dura and other facial nerves. The small posterior division- of the nerve passes to the complexus, spinalis cervicis, and multifidus spina?, while at the same time it unites to the branches of the second cervical nerve. The fourth cervical nerve, coming out from betwixt the third and fourth cervical vertebra?, divides into its anterior and posterior branches like the other cervical nerves. t The first goes to form, with the third and fift% cervical nerves, tbe phrenic nerve. It sends also a branch to the sympathetic, to the integuments of tbe neck and shoulder, and to the supra and infra spinatus muscles. These are call- ed by Soemmerring superclaviculares anteriores, medii, and POSTERIORES. The great postkrior division of the fourth cervical nerve, passes to the muscles of the spine and shoulder, in conjunc- tion with the branches of the third cervical nerve. Fifth cervical nerve —This nerve comes of course from betwixt the fourth and fifth vertebra?, and from betwixt the scaleni muscles. It divides also into two branches. The superior of these passes backwards to the muscles of the back and shoulder, and a branch formed by it; and the sixth passes down under the scapula and serratus major. 392 OF THE PARTICULAR NER\ Es. This nerve I call the external respiratory nerve. It .has the same source with the phrenic nerve ; it is connected with that internal nerve ; at its origin it is separated from the phrenic by a very small portion of the scalenus. Its course is through the axilla, passing across the nerves of the arm; it is distributed to the muscles on the side of the chest, and com- bines them into a class with the internal respiratory muscles. The superior division of the nerve sends up also two small twigs of communication with the fourth cervical nerve. The inferior division of the fifth cervical nerve sends down upon the side of the neck a considerable branch to the formation of the phrenic nerve. It communicates with the root of the sixth nerve, and sends muscular branches back- ward. The sixth cervical nerve.—The muscular branches of this nerve are large, and extensive in their course. They pass into the levator scapula?, extend under the trapezius, and unite with the extreme branches of the spinal accessory nerve. They are prolonged to the latissimus dorsi and serratus mag- nus. Branches also extend down behind the clavicle, and un- der the pectoral muscle. . Besides these branches, this nerve communicates with the fifth, and gives out an origin to the phrenic nerve ; and lastly, uniting to the seventh, it passes into the axillary plexus. The seventh cervical nerve.—This nerve goes almost entirely to form the axillary plexus. There is a communica- ting nerve from the last to this, and from that communica- ting branch generally there passes off a filament to the phre- nic nerve ; and from the very root of the nerve there passes off a branch to the lower cervical ganglion of the sympathetic. Irregular tvwgs also descend from this nerve under the clavicle to the pdfctoralis minor and major. The eighth cervical nerve.—The greater part of this nerve passes to the axillary plexus. It sends small branches to the lower cervical ganglion of the sympathetic, and to the muscles of the breast; which last descend behind the cla- vicle. recapitulation of the distribution of the cervical NERVES. Upon reviewing the description of these nerves, we find that the general tendency of their branches is backwards over the side of the neck, to the muscles moving the head and shoulders. We find also that they are connected in a very intricate manner with the most important nerves of the era- OF THE PARTICULAR NERVES. 393 nium. High in the neck and under under the jaw, they are connected with the portio dura, with the fifth pair, with the eighth and ninth pairs, and with the sympathetic. Towards the middle of the neck they are still throwing their connecting branches to the descendens noni, and sympathetic, and eighth pair. The lower cervical nerves again are still supporting their connections with the lower ganglion of tbe sympathetic. Further, we find the phrenic nerve derived principally from the third and fourth, and branch of communication betwixt the fourth and fifth. The axillary plexus is formed by the fifth, sixth, seventh, and eighth cervical nerves, and first of the back. OF THE DORSAL NERVES. There are twelve dorsal nerves. These, as we have de- scribed, are formed by two fasciculi of fibres; one from the fore, and the other from the back part of the spinal marrow. These filaments run for some way superficially in the length of the spinal marrow before they pierce the dura mater. They pierce it separately; the posterior branch first forms a gang- lion, and then the two fasciculi are united. They are now be- twixt the heads of the ribs. We must here recollect, that the trunk of the sympathetic nerve, which passes along the cavity of the thorax, runs down behind the pleura, and passes before the heads of the ribs through all the length of the back. It receives, as it passes the interstices of the several ribs, at each interval, a communicating nerve from the spinal marrow, that is, a branch from the intercostal nerve. It is in a manner thus made up of roots, from the intercostal nerves, hence the sym- pathetic is sometimes called intercostal. The proper intercostal nerve sends its greater branch for- wards betwixt the ribs; some lesser branches pierce back- wards to the muscles of the back; opposite to this there goes out from each nerve the first branch of union with the sympa- thetic, and this union forms a firm ganglion. Sometimes there run out in this direction two short branches from the spinal nerve, to unite with the ganglion of the sympathetic; but more commonly there passes in a retrogade direction from the intercostal nerve, where it is about to take its course between the ribs, another branch of communication which joins the sympathetic. The intercostal nerves pass on betwixt the ribs, in company with the intercostal arteries^ and reach even to the sternum. vol. j i. D d d 394 OF THE PARTICULAR SERVES- In this course they supply the intercostal muscles and trian- gularis sterni, while they are at the same time sending out branches, which, piercing the intercostal muscles and fascia of the thorax, are distributed to the muscles on the outside ofthe chest.—Those branches which we mentioned as passing be- twixt the heads of the ribs, and which are sent off immediately upon the trunk escaping from tbe vertebral opening, supply the multifidus spinas and levatores costarum, and other exten- sor muscles of the spine. Slips proceeding from the second, third, fourth, and fifth intercostal nerves, send branches to the pectoral muscles, the serratus anticus, and serratus posticus su- perior, trapezius, and rhomboides. The sixth, and all the lower nerves of the back, send branches from betwixt the ribs to the latissimus dorsi, serratus inferior, and abdominal muscles. The eleventh and. twelfth are distributed to the diaphragm. quadratus lumborum, psoas magnus, and iliacus internus. LUMBAR NERVES. The lumbar nerves are five in number. They arise like the other spinal nerves. The first comes out under the first lumbar vertebra, and the others in succession. Their trunks are covered by the psoas magnus. They pass very obliquely downward, and the lowest are of remarkable size. In the general distribution, we may first remark the posterior branches, which go backwards to the muscles which support and extend the spine. Again, the anterior branches; which give, 1st, additional branches to the sympathetic nerve as it passes over the vertebra? of the loins, and by which it is sup- ported and reinforced till it terminates in the pelvis ; 2dly, they have frequent connection with each other, and with the last nerve ofthe back, and first of the sacrum ; 3dly, they send out branches, delicate but of great extent, to the muscles of the loins and back, and to the abdominal muscles and integu- ments of the groin and scrotum ; 4thly, the principal anterior branches ofthe lumbar nerves pass down to form (along with the great nerves of the sacrum) the anterior crural nerve, the obturator, and tbe great ischiatic nerve. SACRAL NERVES. The nerves which come out from the extremity of the me- dulla spinalis, or cauda equina, through the sacrum, are in gene- ral five in number. Sometimes there is one more or less. OF THE PARTICULAR NERVES. 395 The first division of each sacral nerve is into those branches which pass out by the posterior foramina of the sacrum, and those which, by the anterior foramina, come into the pelvis. The posterior branches are very small, and pass to the mus- cles supporting tbe spine ; while the anterior ones are particu- larly large, especially the first and second, which, with the lowest of the loins, go to form the largest nerve of the body, the ischiatic nerve. It is difficult to recollect the distribution of the several "branches of the lumbar and sacral nerves, when taken thus to- gether; but when we deliver the description of the nerves of the thigh and leg, we count them, and hold them in remem- brance with comparative ease. At present we are best pre- pared to follow the sympathetic nerve in its course. OF THE GREAT SYMPATHETIC NERVE, OR INTERCOSTAL NERVE. Notwithstanding the idea of this nerve, which I have endeavoured to convey, viz. that it is a distinct system of nerves, I conceive that we must still continue to speak of its origins in the usual way, for the sake of simplicity and arrange- ment. Tbe sympathetic nerve is in general considered as originally derived from the sixth pair ; or, we may say, it takes its origin from the sixth, where it passes by the side of the carotid arte- ry, and from the vidian branch of the fifth pair. It appears without the skull, sometimes behind and sometimes before the carotid artery, and sometimes it is double in its exit from the base of the skull. Almost immediately after it has escaped from the skull, it forms its first ganglion; which is very large and remarkable, and has the name of the superior cervical ganglion of the sympathetic nerve. It is of a soft consistence and reddish colour, and it extends from the skull to the trans- verse process ofthe third vertebra. It gradually tapers down- wards until it becomes a very slender nerve. This ganglion has much variety of shape in different subjects, and may be said in general to receive twigs of nerves upon the back part. whilst it gives them out upon the forepart. The superior cervical ganglion of the sympathetic nerve re- ceives nerves from the second, third, and fourth cervical nerves, and even sometimes from the root of the phrenic nerve. It has also connections with the hypo-glossal, par va- gum, and glosso-pharyngeal nerves. It sends out branches to unite with the glosso-pharyngeal, and which follow that nerve in its distribution to the tongue and pharynx. Many of ite 396 OF THE PARTtGULAR NERVES. branches surrounding the carotid artery form connections with the internal and external laryngeal nerves, and proceed in meshes, or form plexus along with the branches of the artery. These may be followed to great minuteness. To be more particular in the description of these anterior branches of the sympathetic nerve, they are called the nervi molles, or nervi vasohum. They are nerves peculiarly soft, with a greater proportion of cellular membrane ; they spread in net-works along the arteries, and form frequent connections by little knots like small ganglions. Classed with these nervi vasorum, are branches which pass forward from the upper ganglion of the sympathetic, to unite with filaments from the internal laryngeal nerve of the par vagum, and which form the external laryngeal nerve. It is remarked, that none of these branches of the sympathetic nerve are distributed to the larynx and pharynx without being mingled and associated with the glosso-pharyngeal nerve, or with the pharyngeal branch of tbe par vagum* Of the nervi molles some form a plexus upon the internal carotid artery. These are extremely soft and pulpy, and are united with branches which descend from the glosso pharyngeal nerve. A net-work is also formed, which covers the beginning of the external carotid artery. From this, as from a centre, branches are sent out with the arteries to the neck, and face, and glands under the jaw; and these last, with a mesh which passes up upon the temporal artery, unite with the portio dura of the seventh pair. It has been often observed, that the branches of the carotid artery have a peculiar provision of nerves, and that these nerves are more numerous and minutely distributed than in any other part of the body. There are indeed no nerves in any part of the body which have so extensive and intricate connections with important vital nerves as the cutaneous nerves of the face and neck. This distribution of the nerves is, I conceive, a provision tor that power possessed by the imagination, or rather that un- controlable connection which exists betwixt the feelings and the action of the vessels in blushing, and in the expression of the passions. r The lowest of the nervi vasorum or molles, sent off from he superior ganglion of the sympathetic nerve, descends in the course ofthe trunk of the nerve, and forms, with other branches, the superior cardiac nerve. Tins nerve, generally called nervus chordis superfichlis passing down in the direction of the trunk of the^sympathetic * Scarpa. OP THE PARTICULAR NERVES. 397 nerve, and near the longus colli muscle, is for some length, a very slender branch; but in its course it receives two, three, or four additional twigs from the sympathetic, and branches which come under the carotid artery from the pharyngeal nerves. When this superior cardiac nerve is within an inch or two of the subclavian artery, branches of union pass betwixt it and the recurrent nerve of the par vagum ; and branches of the nerves passing to the heart from the lower cervical gang- lion, also join it. It then, attaching itself to the investing mem- branes and sheaths of the carotid and subclavian arteries, forms with others, a plexus of nerves, which run along the great ves- sels to the heart. The continued trunk of the sympathetic, where it emerges from the superior cervical ganglion, is extremely small. It de- scends behind the carotid artery, and lies near to the spine. When opposite to the fifth and sixth cervical vertebra?, the in- ferior cervical ganglion of the sympathetic is formed. In this course, twigs of communication pass betwixt it and the cer- vical nerves, or join it with the beginning of the phrenic nerve. But not unfrequently there are three cervical ganglions formed by the sympathetic nerve ; the superior, middle, and inferior ganglions.: or it happens that we find the sympathetic nerve split into two branches in the neck ; one of which forms the middle, and the other the lower ganglion. There are received by the middle cervical ganglion, or thyroiii ganglion, branches of nerves from the third, fourth, fifth, and sixth cervical nerves, and also sometimes from the phrenic nerve. The ganglion is by no means constantly found, and it is irregular in its size and shape. When large, and in what may be considered as its most perfect state, it gives off some considerable branches. Of these, part unite with the superior cardiac nerve already mentioned; others form the great or deep cardiac nerve, while lesser ones play round the subclavian artery, and unite with the lower cervical ganglion, or the upper thoracic ganglion. The deeper cardiac branch of the sympathetic, splitting and again uniting so as to form rings, runs outwards, attached to the arteria innominata and arch of the aorta, to the heart. In this course, while it passes before tbe trachea, it forms con- nections with the recurrent branch and trunk of the par va- gum. Under the arch of the aorta, we find this branch con- centrated to form the ganglion cardiacum of Wrisberg, or ganglion molle et pellucidum of Scarpa. This ganglion is like a mere enlargement or swelling of the nerve. From this, four or five branches may be enumerated ; 1st, A branch 398 OF THE PARTICULAR NERVES. passing behind the pulmonary artery to the back of the heart, and following the left coronary artery; 2dly, A small division to the anterior pulmonary plexus of the par vagum; 3dly, A pretty considerable branch which, passing behind the aorta, and betwixt it and the pulmonary artery, is distributed with the right coronary artery to tbe anterior part of the heart. On the left side of the neck, the sympathetic, receiving on tbe one side branches from the cervical nerves, and on the other giv- ing off branches, which descend behind the carotid arte- ry to the heart, (viz. the superior cardiac,) often splits be- fore it forms the middle or thyroid ganglion, and sometimes throws its branches over tbe thyroid artery, and the ganglion lies upon that artery. Again, from the ganglion there de- scend two series of numerous lesser filaments, which form meshes upon the thyroid and subclavian arteries to the heart. Others proceed downward behind the arteries to the lower cervical ganglion. Those branches which descend upon the arteries, entangle the roots of the thyroid, transversalis colli, and internal mammary arteries, in their plexus ; these uniting, follow the subclavian artery, and form again a plexus upon the arch of the aorta. This is joined by branches from the par vagum and recurrent. The principal branches of this plexus terminate in the cardiac ganglion under tbe arch of the aorta.* The lower cervical ganglion of the sympathetic nerve is placed upon the limits betwixt the neck and thorax upon the head of the first rib, and by the side of the musculus longus colli j and it is in part covered by the root of the vertebral ar- tery. The ganglion is of an irregular cushion-like shape. It lies close to the cervical nerves which go to the brachial plex- us, and it receives branches from them.f Branches also pass from this ganglion to the par vagum and recurrent, and also pass on to the cardiac and pulmonic plexus. That nerve, which must be considered as the continued sympathetic, throws a ring round the root of the vertebral artery, and sending out branches upon the subclavian, terminates in the first dorsal or thoracic ganglion. the superior thoracic ganglion. This ganglion surpasses the other thoracic ganglions in size. * This description of the sympathetic nerve on the left side follows the more usual distri- bution, but is not peculiar to the left side. f And even it receives sometimes from the fifth and sixth, more rarely the seventh and eighth, from the first and second of the back j and lastly, from the phrenic nerve.--. Sometimes these connections are wanting. OF THE PARTICULAR NERVES. 399 It is, indeed, frequently composed of many branches of the nerve in the neck, coming both before and behind the subcla- vion artery. It receives also nerves from the three or four lowest cervical nerves, and first dorsal nerve. It is of a very irregular figure, or rather it varies exceedingly in its shape; so that by various anatomists it is described as round, oval, trian- gular, quadrangular, cylindrical!—Filaments proceed from this ganglion into the canal of the vertebral artery, and to the cellular coat of the subclavian artery, and to the cardiac plex us, and also to the pulmonic plexus ; or to supply the posterior surface of the lungs. sympathetic nerve in the thorax. The sympathetic nerve (as we have explained in describing the dorsal nerves) through all its course in the thorax, has ad- ditional branches from the dorsal or intercostal nerves. It forms also, while it is lying on the side of the vertebra?, a divi- sion in the thorax, which it will be important to recollect. This nerve is sent more forwards upon the body of the verte- bra?, and passes into the abdomen betwixt the crura of the dia- phragm ; while the trunk of the sympathetic continues its course by the heads of the ribs, passes under the ligamentum arcuatum, and downwards upon the lumbar vertebrae. The splanchnic nerve, then, is this anterior branch of the sympathetic in the thorax. It is the great nerve of the viscera ofthe abdomen. It generally has two or four roots from the trunk of the sympathetic nerve, where it is opposite to the sixth, seventh, and eighth intercostal nerves. It is seen lying under the pleura, and passing obliquely over the bodies of the lumbar vertebrae, from the seventh to the tenth. It then passes be- twixt the crura of the diaphragm, enters the abdomen, and forms the great semilunar ganglion. One or more branches are sent forward from the sympa- thetic, commonly from the ganglions, opposite to the interstice betwixt the ninth and tenth, or tenth and eleventh ribs. These also pass the diaphragm, and unite with the semilunar gan- glion. There is, however, a considerable variety to be ob- served both in the origins of the splanchnic nerve, and in the number of these subsidiary branches. A larger branch, going off betwixt the tenth and eleventh ribs, is so common, that it has the name of splanciinicus minor, or accessorius. This nerve as frequently terminates in tbe renal plexus, as in the semilunar ganglion : or sometimes it sends branches to both. 400 OF THE PARTICULAR NERVES. semilunar ganglion and celiac plexus. The ganglion which is called the semilunar ganglion, has no regular shape—and least of all when it is fully dissected. It is formed by the splanchnic nerve, and by branches which come from the lumbar nerves. It lies by the side of the ca?lic arte- ry, and consists of many lesser ganglions, (sometimes to the number of eleven or twelve,) matted together into a glandular- like shape. Tbe semilunar ganglions of the splanchnic nerves lie on each side of the root of the ca?lic artery; their connection with each other is frequent and intricate ; so that they throw a mesh of nerves round the root and branches of this artery, which is the great source of vessels to the stomach, liver, and spleen.—This plexus, formed by the semilunar ganglions round the caeliac artery, is the solar or caeliac plexus. CiELlAC PLEXUS. The caeliac plexus is the great source of nerves to the higher viscera ofthe abdomen. The splanchnic nerves are the prin- cipal, not the only nerves which form this plexus. The par vagum sends branches down from the stomach which join it; £nd »ven the phrenic nerve, which is the nerve of the dia- phragm, sends down twigs to unite to the branches of the splanchnic and par vagum. We shall find also small nerves which come from the seat of the kidney, and which are de- rived from the superior lumbar nerves.—These pass across the crura ofthe diaphragm, and enter into the caeliac plexus—In pursuing the nerves ofthe viscera further, we have itno longer in our power to follow individual branches, but must rather mark the course, and enumerate the various sources of the plexus, and net-work of nerves which follow the great vessels. From the caeliac plexus, there pass out, 1. Nerves which accompany the phrenic arteries upon the lower surface ofthe diaphragm. 2. Nerrestothe liver:—and of these there are two plexus, the right and left hepatic plexus; one passes along the vena portae, biliary ducts, and right hepatic artery, to the right side of the liver, the gall bladder and ducts; this of course is the right hepatic plexus: the left hepatic plexus passes along the left hepatic artery ; and this has con- nection with the cardiac nerves, branches of the par vagum. 3. That plexus, which runs upon the lesser curve of the sto- mach, while it is formed in a great measure by the par vagum. OF THE PARTICULAR NERVES. 401 has also connection with the solar or caeliac plexus. 4. The plexus of nerves which pass to the lower orifice of the stomach and duodenum is chiefly a division ofthe right hepatic plexus. These nerves, to the liver, stomach, and duodenum, are attach- ed to the branches of the caeliac artery. Along the great sple- nic artery, which is also derived from the caeliac artery, there passes out a plexus of nerves to the spleen. From this splenic plexus there pass nerves to the great omentum ; and they even unite with those passing out upon the duodenum, and which attach themselves to the right epiploic artery, and take a course upon the great curvature of the stomach. Thus the solar or caeliac plexus is a great central net-work of nerves, which pass out in divisions to the liver, spleen, pan- creas, stomach, duodenum, and omentum. SUPERIOR MESENTERIC PLEXUS. The place and connections of the superior mesenteric plex- us is at once known, when it is considered that it is formed upon the root ofthe superior mesenteric artery.—It is formed by a division of the caeliac plexus continued down upon the aorta so as to involve the root of the mesenteric artery, and by nerves coming over the side of the vertebrae of the loins from the lumbar nerves. This plexus spreads betwixt the membranes of the mesentery, and extends upon the branches ofthe artery, and is distributed to the small intestines and part of the colon. It consequently supplies the mesenteric glands, and it sends nerves also to the" pancreas, that join those which it receives from the splenic plexus. inferior mesenteric plexus. The same mesh of nerves, being continued down upon the face of the aorta, surround the lower mesenteric artery, and fol- low its branches. This is the lower mesenteric plexus, or me- socolic plexus ; and it is formed in a great measure from the branches of the continued trunk of the sympathetic nerve.—As this plexus spreads upon the branches of the lower mesenteric artery, it passes to the left side of the colon, and rectum.— While the lower mesenteric plexus is continued from the upper one, on the side of the lumbar vertebra it is continuous with the renal and spermatic plexus ; and towards the pelvis, with the hypogastric plexus. Before considering the other lesser plexus of nerve* m thf vol. u. F e e 402 OF THE PARTICULAR NERVES. abdomen, it is necessary to follow the continued trunk of the sympathetic nerve which we had described as following closely the lateral part of the dorsal and lumbar vertebrae, whilst the splanchnic nerves pass obliquely over them to the viscera of the upper part of the belly. The continued trunk of the sympathetic nerve, after it has given off the splanchnic nerve in the thorax, sends several small nerves forward over the vertebrae to the mediastinum and sheath of the aorta. It then passes the diaphragm, keeping close to the transverse process of the vertebrae. When, how- ever, it comes lower upon the lumbar vertebrae, it lies more upon the side of their bodies, and the connections with the lum- bar nerves are by small and numerous twigs which stretch over the side of the vertebrae. In this course, it is giving off upon the forepart numerous irregular twigs to the several plexus which have been described. Where it lies under the vessels which pass to the kidney, it sends up some branches to the re- nal plexus. The renal plexus, however, is not entirely formed of these branches of the continued sympathetic, but is rather a continu- ation from the caeliac and superior mesenteric plexus; while the lesser splanchnic nerve, which was sent off in the thorax, also terminates in it. This plexus is thrown over the vessels of the kidney, and forms several little ganglions. From the renal plexus descends the spermatic plexus with the vessels to the testicle. This plexus of nerves in woman follows the spermatic artery in its distribution to the ovaria and uterus. In passing down upon the loins, the sympathetic nerve forms five or six ganglions with the branches from the lumbar nerves. These are oblong, angular, stellated—irregular in their form, as in their number, situation, and size, or the twigs which, by their union with the sympathetic, form them. Betwixt these ganglions or connections with the lumbar nerves, the sympa- thetic is not always one nerve, but is sometimes split into seve- ral smaller nerves, which unite again. From the sympathetic nerves of both sides we have to observe frequent interchange of branches, which sometimes attach themselves to the lumbar nerves, sometimes creep under the aorta, or unite to the plex- us covering the face of the aorta.—There are several little gan- * glions formed by these nerves upon the face of the lumbar ver- tebra?: they have the name of ganglia accessoria. Before the sympathetic nerve descends into the pelvis, it has become extremely delicate. In many subjects it seems to terminate in the last lumbar, or first sacral nerve ; but, upon more minute dissection, lesser branches will be found to de- OF THE PARTICULAR NERVES. 403 scend amongst the loose cellular substance of the pelvis.— When regular, or perhaps we may say with truth when regu- larly and fully dissected, the sympathetic nerves of each side are seen to descend upon the forepart of the sacrum, and form connections with the sacral nerves similar to those with the dorsal nerves.—As they descend, they of course approach, and finally unite in an acute point on the os coccygis. At the points of union of these extreme branches of the sympathe- tic nerves with the branches of the sacral nerves, small gan- glions are formed ; and there pass out branches from them, which cover the intermediate surface of the sacrum with an extensive plexus. The ultimate ganglion, formed by the union of the two sympathetic nerves, is the coccygeal ganglion, and from it there pass three or four nerves to the extremity of the rectum. HYPOGASTRIC PLEXUS. This is a plexus which lies on the side of the pelvis, and involves the hypogastric artery. It consists of the nerves passing to the parts contained in the pelvis: which do not, however, pass in distinct branches, but like those of the abdo- men, are formed into a minute interwoven net-work. The hypogastric plexus takes no determinate origin, but is continu- ous with, or formed by, the extreme branches of the sympa- thetic nerves, the extremity of the spermatic plexus, the sacral nerves, (and particularly the third sacral nerve,) and by the branches ofthe accessory ganglions on the sacrum. of the phrenic nerve.* The phrenic or diaphragmatic nerve arises from the cervi- cal nerves, passes obliquely down the neck, enters the thorax, and is distributed to the diaphragm.—-This nerve has much variety in its derivation. It comes chiefly from the third cer- vical nerve, deriving also some twigs from the fourth and se- cond. But it also takes an origin very high in the neck, from "■ the par vagum, from the ninth nerve, and from the portio du- ra ofthe seventh; and it has connection with the superior cer- vical ganglion ofthe sympathetic. Lower in the neck it will be found in some subjects to derive very small additional twigs from the fifth or sixth cervical nerves, and from the » E. Kruger de Nervo Plirenico. Sandifort Thesaur. VqI Hf. 404 OF THE PARTICULAR NERVES. lower ganglion of the sympathetic ; where the phrenic nerve takes its principal roots from the third cervical nerve, it holds communication with that I have called the external respi- ratory nerve, a nerve which has nearly tbe same origin with this, but is distributed to the muscles on the side of tire chest. The phrenic nerve, thus connected with the nerves of the face, tongue, side of the neck, and the vital nerves, descends into the thorax betwixt the subclavian artery and vein. In the chest it proceeds downward and forward, attached to tbe me- diastinum, and passes before the root of the lungs.* It takes its course upon the outside of the pericardium, and from tbe pericardium slips off to the surface of the diaphragm. From the position ofthe heart, the left phrenic nerve differs a little in its course from the right; and it passes over the pericar- dium, covering the apex ofthe heart. The phrenic nerve of the right side, besides supplying the diaphragm, sends down through the diaphragm (to tbe right side of the vena cava) the ramus anastomoticus. This communicates with the semilunar ganglion of the sympathetic, or with the division of the solar or caeliac plexus which passes along the phrenic arteries. From the phrenic artery of the left side, there pass down with the oesophagus small nerves which appearing in the abdomen, unite with the caeliac ganglion, or some of its divisions ; and both phrenic nerves will be found by some minute branches to unite to the par vagum. These, however, are but minute branches. Tbe great destination of the phrenic nerve is to the diaphragm. The branches strike out upon the diaphragm like roots from a centre ; they pass some way only covered by the pleura, and then pierce into the substance of the muscle. There are innumerable experiments upon living animals, which show the connection of this nerve with the action of the diaphragm. When the nerve is stimulated, the diaphragm is excited to contraction ; when cut, pressed, or tied, the muscle becomes relaxed and inactive, and there is difficulty of respi- ration ; when the spinal marrow is injured low in the vertebrae ofthe neck, or in the vertebrae ofthe back, the external mus- cles of respiration cease to act, but the diaphragm still con- * Ludwig. Martin, in the Edinburgh Essays, and others, explain the action of the dia- * fihragm upon the supposition of the mechanical pressure of the lungs upon the phrenic nerve. t is a piece of doctrine inconsistent with knowledge of the general laws of the economy. It is repugnant to comparative anatomy, and it is evident that the soft and elastic distention of the lungs could not compress the firm uerve. Moreover, the lungs, when distended, do not press upon the mediastinum, for it is the dilatation of the thorax which causes the lungs to inhale the atmospheric air. See Wrisberg de Nemo Phrenico. Sandif. Thes. vol. ii. p. 260. It is betwixt the heart and muscles of respiration that the strict relation and sym- pathy exists. When in turning the child in utero, and, when the cord has been pressed, I have felt the strong convulsive fetches of the muscles of respiration endeavouring, by th* play of the lungs, to compensate for the loss of the placenta. OF THE PARTICULAR NERVES. 405 tifiues its function; and in this case, as observed by Mr. Hun- ter, the patient lives for some days, breathing by the dia- phragm. If the phrenic nerves be divided in a living animal, the diaphragm ceases to act, and the abdominal muscles lose their opponent muscles, and remain as in expiration ; but still the respiration is continued by the motion ofthe ribs. If af- ter this the spine be divided, the motion of the lungs ceases entirely, and the animal dies suddenly.—The injury ofthe spi- nal marrow above the origin of the phrenic nerves is of course suddenly fatal, because it destroys at once the function ofthe diaphragm and muscles moving the chest. From the connec- tion of the phrenic nerve with the par vagum, we may explain the sympathy betwixt the trachea and the diaphragm, how the irritation of the trachea occasions coughing and the con- vulsive action of the diaphragm ; in the same manner in the affection ofthe stomach, singultus, from the sudden action of the diaphragm and abdominal muscles, (which usually alter- nate in their action,) may be explained. Again, a connection of nerves might be followed from the origins of the phrenic to the sympathetic nerve, and branches of the fifth pair to the nose : which accounts for that sympathy of action which oc- casions sneezing from irritation of the membrane of the nose. The connections of the phrenic nerve form a most interest- ing subject of enquiry, which is followed out in my lectures, 1. on respiration, 2. on expression, 3. on the action of the stomach, and in treating of vomiting. NERVES OF THE ARM; AXILLARY, OR BRACHIAL PLEXUs. The nerves which proceed from the spine, and go to supply the arm, are formed into an intricate plexus before they divide into the several nerves ofthe arm. This brachial, or axillary plexus, is formed of five of the spinal nerves ; viz. the fifth, sixth, seventh, and eighth cervi- cal nerves * and the first dorsal nerve. The highest of these nerves, proceed from betwixt the fourth and fifth cervical vertebrae ; the last from betwixt the first and second dorsal ver- tebrae. They pass out betwixt the middle, and anterior division of the scaleni muscles; and even while covered by these mus- cles, and before they have proceeded far from their foramina, the last nerve of the neck and first of the back unite.f—The •r This is of course counting the sub-occipital as the first cervical nerve. - Before the nerves which form the plexus intermix their filaments, or are connected together they xend off small branches to the scaleni muscles, to the muscles of the spine .md to the levator scapular.—The branches wliich they give to the sympathetic nerve, we Mave already noticed. 406 OF THE PARTICULAR NERVES. plexus extends from above the clavicle to the edge of the ten- don ofthe latissimus dorsi. It allows of no natural division.* The axillary artery passes for some way close under it, and then perforates betwixt the divisions which form the radial nerve. Use of the brachial Plexus.—In the plexus of the axilla, the nerves ofthe arm make that interchange of branches which combines the muscles of the arm into classes, and which con- sequently orders the action of the muscles in the several mo- tions of the arm and hand. From the axillary plexus proceed these nerves : 1. The thoracic nerves. 2. The supra and infra scapular nerves. 3. The circumflex, or articular nerve. 4. The perforans Casserii, or external cutaneous nerve. 5. The radial nerve, (better named median.) 6. The ulnar nerve. 7. The muscular spiral nerve. 8. The internal cutaneous nerves. 9. The nerve of Wrisberg. 1. The thoracic nerves. Although the nerves which supply the muscles ofthe chest are derived from the intercos- tal nerves, as we have seen, yet there also pass off branches from the axillary plexus to the great and little pectoral mus- cles, to the latissimus dorsi, to the skin and mammae. These thoracic branches proceed from the upper division ofthe plex- us, or that which gives out the external cutaneous, and from «one of the roots of the radial nerve. 2. The supra-scapular nerve comes off from the upper edge of the plexus, and is the highest of the branches. It runs towards the root ofthe coracoid process, it passes through the notch of the scapula, and goes to supply the supra and in- fra spinatus muscles, the teres minor, and the sub-scapularis. The sub-scapular nerves come out from the posterior part ofthe plexus along with the articular nerve. They are attach- ed to tbe sub-scapular muscle, they turn round the fleshy edge ofthe muscle, and insinuate their branahes betwixt the'tendon of the latissimus dorsi and the teres major. 3. The circumflex, or articular nerve, or axillaris, lies very deep. It comes from tbe back part of the plexus, passes behind the neck of the humerus, and above the tendon of the latissimus dorsi, and teres major. One of its branches * I mean that it admits of no division useful in the arrangement of the demonstration. See Monro's Nervous System, and the Latin work of Anton. Scarpa. Scarpa describes the oonnection of filaments betwixt the ulnar and radial nerve at their separation from the great njexus, Plexus brachialis minor. Vide tab. ii. fig. ii. h. OF THE PARTICULAR NERVES. 407 we trace into the teres major, while another passes round the bone, and is distributed to the under surface of the deltoid muscle, the joint, and the cellular membrane. 4. Perforans Casserii, or the external cutaneous nerve. This nerve passes through the coraco-brachialis mus- cle before the os humeri, to gain the outside of the arm. From its perforating this muscle, and being described by Cas- serius, it is called the nervus perforans Casserii. Before pass- ing through the coraco-brachialis muscle, it sends a nerve into the substance of that muscle. Here it also sends down a branch of communication with the radial nerve ; and in many sub- jects it will be found to be like a branch from one of the ori- gins ofthe radial nerve. Where the nervus perforans lies be- twixtthe brachialis internus muscle and biceps, (and, of course, after it has perforated the coraco-brachialis muscle,) a branch or two are sent up to the heads of the biceps muscle ; another branch turns inward to the belly of that muscle; another is given to the brachialis internus; and, finally, twigs pass in- ward to the cellular membrane, which involves the brachial artery. The continued nerve passes obliquely across the arm, and under the biceps. When approaching the outside of the arm, it divides into three small branches; one to the integuments which are upon the supinator longus, another to the integu- ments on the inside of the fore-arm, and a third, which con- tinues its course along the edge ofthe supinator longus to the wrist. Of this prolonged branch of the perforans Casserii, a minute twig is lost on the ligament of the wrist, another passes to the ball of the thumb, and a third goes round to the integu- ments of the back of the thumb. 5. The radial or median nerve. This nerve is formed by those divisions of the plexus, which surround the brachial ar- tery, and sometimes by a division from the perforans Casserii. It takes its course by the side of the brachial artery, and gives off no branches until it has sunk under the aponeurotic expan- sion of the biceps muscle. When the median nerve has come to the bend of the arm, it gives off three branches. The first belongs to the pronator teres, flexor radialis, palmaris longus, and flexor digitorum; a second passes to the pronator teres ; a third to the deep mus- cles of the fore-arm, to the flexors of the thumb particularly, and from this a fine branch attaches itself to the interosseous membrane, and is distributed to the pronator quadratus mus- cle. Tbe median nerve, continuing its course down the fore- arm betwixt the flexor sublimis and profundus digitorum, sends off branches to those muscles ; and in this part of its course 4-08 OF THE PARTICULAR NERVES. we see why the name median is more applicable than radial. Before passing under the ligament ofthe wrist., it gives out a branch which emerges from the tendons, and passes to the in- teguments, short flexor, and abductor muscles ofthe thumb. The trunk of the median nerve passes with the tendons of the flexor muscles of the fingers under the ligament of the wrist. In the palm of the hand it divides into five branches;— the first passes to the abductor and flexor pollicis brevis; a se- cond goes to the adductor pollicis, and side ofthe thumb next the fore-finger; the third passes to the fore-finger, and to the lumbricalis muscle ; the fourth to the side ofthe fore and mid- dle fingers ; and the fifth to the sides of the middle and ring finger. All these nerves, while in the palm ofthe hand, send off branches to the lumbricales muscles. 6. The ulnar nerve comes off from the lower part ofthe plexus in union with the internal cutaneous nerve. It descends upon the inside of the arm, and is tied down by the fascia, and then passes behind the internal condyle of the humerus. While above the bend ofthe arm, it gives off a superficial branch to the integuments on the inside ofthe arm, and the ulnar side of the fore-arm ; at the same time it sends a muscular branch through the triceps muscle, along with the arteria profunda in- ferior. Immediately above the elbow-joint, twigs are sentoff, some of which accompany the ramus anastomoticus major of the brachial artery. After passing the condyle of the humerus, it sends a branch to the flexor carpi ulnaris, and to the head of the flexor digitorum profundus. It then sinks deeper betwixt the flexor ulnaris and flexor digitorum sublimis; it is here con- nected with the ulnar artery, and descends along with it to the wrist. In this course, along the fore-arm, the ulnar nerve gives branches to the flexor digitorum sublimis. Often it sends a branch of communication to the median nerve, while some few lesser muscular nerves are sent off, and accompany the branches of tbe ulnar artery. When arrived near the wrist, the ulnar nerve divides into two branches. The continued trunk passes on under the pro- tection of the tendon of the flexor ulnaris, and then under the annular ligament into the palm of the hand ; while a branch, the ramus posticus, takes a turn under the flexor ulnaris, and over the edge ofthe flexor digitorum profundus;—it passes then over the lower end of the ulna to the back ofthe hand; on the back of the hand it is found branching over the ex- panded tendons and under the veins, and is finally distributed to the back of the little and ring fingers. The continued ulnar nerve passes under the palmaris brevis muscle and palmar aponeurosis, and above the flexor brevi= OF THE PARTICULAR NERVES. 409 and adductor minimi digiti. Here it divides into two, viz. the sublimis and profundus of Camper. Tbe superficial branch passes by the side of the abductor minimi digiti to the integu- ments on the ulnar edge of the hand, and adductor minimi digiti—to the outer edge of the little finger,—to the side of the little and ring fingers, and a branch communicates with the median nerve. Albinus, Monro, and Camper, differ in their description of the nerves to the lumbricales muscles, which only proves that the twigs passing to those little muscles are irregular. They come from the deep branch of the ulnar nerve. The deep branch [profundus] forms a deep palmar arch, and is sent to the lumbricales, to the adductor and flexor pollicis. 7. The muscular spiral nerve. We find the external cutaneous nerve, or perforans Casserii, passing before the arm- bone. The muscular spiral nerve, on the contrary, passes behind the bone, and takes a spiral turn under it to get to the outside of the arm. It perforates the flesh ofthe arm betwixt the middle and the short head ofthe triceps muscle. Before it perforates the triceps muscle, the muscular spiral sends off branches which pass over the tendon of the latissimus dorsi; and before it enters the triceps muscle, it may be observed to divide into several branches. Three of these may be men- tioned : a branch to the middle head, and one to the short head of the triceps muscle, and a third and larger nerve which pierces betwixt the muscles, along with the trunk of the nerve. . . This last nerve does not follow the trunk of the nerve in its course, but perforating the triceps more directly across, it comes out behind the supinator longus, where it takes its ori- gin from the os humeri. This is a cutaneous branch, and might be considered as the external cutaneous nerve with as much propriety as the perforans Casserii. Often we shall find some lesser branches of the muscular spiral nerve piercing th« fibres ofthe triceps muscle, and terminating in the skin. The great division of the nerve, after piercing the triceps muscle, lies betwixt the brachialis internus and the inner edge of the supinator longus ; and here it sends a branch in upon the bend of the arm, and on the edge of the triceps muscle. Where it is near the elbow-joint it divides into the nervus pro- fundus and superficialis; the profundus gives branches to tin- extensor carpi radialis, then perforates the supinator radii brevis, twists round the radius, and here divides amongst the extensor muscles, sending branches to the extensor carpi ulnaris, to the extensor pollicis, primus secundus pollicis, the extended nerve keeping still under the extensor tendons passe? VOL. 11. ' ' ' 410 OF THE PARTICULAR NERVES, to the back of the wrist, and is lost under the insertions of the extensores radiales. But the great superficial division of the muscular spiral nerve comes out betwixt the head of the supinator longus muscle and the joint. This branch then lies betwixt the supi- nator longus and pronator teres. Continuing its course by the side of the supinator longus and flexor radialis, it passes under the tendon of the former, it then becomes superficial, on the radial edge of the wrist, and is distributed to the integuments ofthe back ofthe hand, back ofthe thumb, fore, middle, and ring finger. This branch is sometimes called radial. 8. The internal cutaneous nerves. Of those we may describe three :— 1. The great internal cutaneous nerve. This nerve is deri- ved from the ulnar at its root, or comes off from the plexus along with it, passes down the arm, giving off no considerable branches, accompanies the basilic vein and twists its branches over it, divides into four branches upon the fascia of the fore- arm, and running betwixt the fascia and veins of the fore-arm, it is finally distributed to the cellular membrane and integu- ments, while one of its branches reaches to the ligaments of the wrist. 2. The cutaneous nerve of Wrisberg comes sometimes from the axillary plexus, as a distinct nerve ; sometimes it is a branch of the great internal cutaneous nerve ; sometimes it is derived, or a nerve which takes its place is derived from the intercostal nerves. This nerve of Wrisberg is distributed to the integuments of the arm, and terminates near the internal condyle. 3. The upper and internal cutaneous nerve comes from the first intercostal nerve, or from the second, and passes out betwixt the first and second ribs. It supplies the integuments-" of tbe arm, and the glands and fat of the axilla.* There are besides several nerves derived from the intercos- tal nerves, which cross the axilla, and supply the arm-pit and side. nerves of the thigh, leg, and foot. In tracing the^ nerves of the lower extremity, we find no difficulty in the arrangement at least, for they fall into a very simple and natural order. They are all derived from the lum- bar and sacral nerves. The great nerves are three in number. One passes out under Poupart's ligament to the extensor mus- * See System of Dissections, vol. ii. plate 1. g. OF THE PARTICULAR NERVES. 411 files of the Teg, viz. those which lie on the fore-part of the thigh. This of course is called the anterior crural nerve. The second nerve is the obturator nerve, so called because it passes out from the pelvis by tbe thyroid hole. This nerve lies amongst the deep muscles of the thigh, and distributes its branches chiefly to the adductor muscles. The third nerve is the greatest nerve of the body, viz. the ischiatic nerve. It passes 011% from the back part of the pelvis, through the sacro- sciatic notch, and takes its course down the back ofthe thigh into the ham. In this course it supplies the muscles lying on the back of the thigh, but its chief destination is to the leg and foot. nerves about the pelvis- The cutaneous branches of nerves which have their source internal, are always important, because the internal affection, as in the present instance of the kidney, the intestine, the uterus, are attended with external pains or pains felt to be external, which will often guide us to the real source of the disease. There are three divisions of nerves which deserve attention for this reason ; first, those cutaneous nerves which coming off from those of the loins, drop over the spine of the ilium upon the integuments of the hip and thigh ; and how many are the instances of sensanon here which have their source in the kidney or the colon ? secondly, there are a class of nerves which course from the loins round in the spermatic passage, and go to the scrotum and membranes ofthe testicle, or turning up from the groin pass to the integuments of the pubes. These are nerves which give occasion to many sym- pathetic pains, in affection of the sigmoid flexure of the colon, in disease of the uterus, bladder, he. In the third class are those nerves which go down upon the integuments of the thigh. These cutaneous nerves of the thigh come from the lumbar nerves, or more immediately from the anterior crural nerve. They pierce the tendon of the oblique muscle of the abdomen, or pass under Poupart's ligament, and are distributed to the groin, scrotum, and betwixt the fascia and integuments of the forepart of the thigh. There may be described five cutane- ous nerves on the forepart of the thigh, viz. the external cutaneous, the middle cutaneous, the anterior cutaneous, the internal cutaneous, and those ofthe groin and scrotum. The external cutaneous nerve is that which comes out from the belly near the superior spinous process of the ilium. It divides almost immediately into two great branches. ?v:] ;r \\'Z OF THE PARTICULAR NERVES. the front view of the thigh the anterior branch alone is to be seen. It takes a course above the fascia in the direction of the line which divides the vastus externus from the rectus femoris, and terminates near the knee, while the posterior branch passes over the tensor vagina: femoris, and down upon the outside and back of the thigh. It is derived from the third lumbar nerve. The middle cutaneous nerve is seen amongst the inte- guments ofthe groin, and emerges from under the fascia near the upper edge of the Sartorius muscle. It passes down upon the rectus muscle, and is distributed to the integuments in three or-four divisions. The anterior cutaneous nerve comes out to the integu- ments very high up, in the middle of the groin betwixt the pubes and spine of the os ilii. It passes down the thigh along the surfaces of the Sartorius and vastus internus muscles. This, like all the other cutaneous nerves, runs above the fascia, and immediately under the skin. The internal cutaneous nerve is the least regular. It does not pierce the fascia in one trunk, but sends three, four, or five branches through the fascia, which are distributed to the integuments on the inside of the thigh. Some 0f these, after running a considerable way under the. fascia, emerge and en- circle the inside of the knee. the pudic nerve. The pudic nerve comes off from the third, fourth, and fifth of the sacrum, holding connection with the roots of the great ischiatic nerve. It runs towards the outlet of the pelvis, and to the side ofthe tuber ischii. In the female it sends branches to the anus, vulva, and clitoris. In the male it accompanies the common pudic artery in its course, and it consequently runs to the muscles of the anus, and of the perineum, to the caput gallinaginis, to the penis, and to the glands in many branches: and here it is the organ of a peculiar sense. NERVES OF THE LOWER EXTREMITY. ANTERIOR. CRURAL NERVE.* This nerve arises from the union of the second, third, and fourth of tbe lumbar nerves, or the second and third lumbar f Crural nen:, truncus lumbnum, femoralis magnus. OF THE PARTICULAR NERVES. 413 nerves uniting into one trunk, are afterwards joined by a divi- sion of the fourth,* or the anterior crural, is formed by the anterior branch of the third and the first branch of the second lumbar nerve,f or by the four first lumbar nerves; and the first sacral nerve. At its origin, it lies under the psoas magnus, and, as it descends, it holds its course between the psoas mag- nus and iliacus internus. It then descends towards the thigh, and passes out under Poupart's ligament; and in its course along the brim of the pelvis, it is for some way covered by the external iliac artery. Here, while within the pelvis, it gives off several small nerves, which pass into the iliacus inter- nus, and to the psoas magnus muscles. These form a kind of small plexus. As the anterior crural nerve passes under Poupart's liga- ment, it splits into its numerous branches which supply the muscles and integuments on the forepart of the thigh. From the forepart of the nerve there is sent out a musculo-cutaneous branch, which, while it descends and supplies several of the muscles of the thigh, gives out the middle cutaneous nerve. The anterior cutaneous nerve is sent off lower down. But almost immediately after it has passed under foupart's liga- ment, the internal cutaneous nerve is sent off from some oi those branches which run under the internal articular artery. The last of the cutaneous branches of the anterior crural nerve, and the most important, is the nervus saphenus, or cutaneus longus. This is the chief cutaneous nerve of the leg ; but it is to be distinguished as a particular nerve, so high as under the external articular or circumflex artery, being a division of what is called the nervus longus. This nerve is joined by a branch of the obturator nerve; and about the same place muscular branches are given off to the vastus internus. When we are dissecting in the course of the femoral artery, we have to observe two nerves running parallel to, and con- nected with the sheath of the artery. That which is on the inside is the largest, the course of which we shall prosecute. It follows the artery through the tendon of the triceps muscle, but it does not descend into the ham with the popliteal artery. It comes out again through the tendon with the perforating branches of the popliteal artery, or with the upper and internal articular artery. It then becomes a superficial nerve, and descends upon the inside of the leg with the saphena vein, to the inner ankle and foot. . Those two nerves, which are so closely connected with the * Fischer-^Walter. f Sabatticr and Haller. 414 OF THE PARTICULAR NERVES. femoral artery in the middle of the thigh, are very often taken up with the extremity of the artery in amputation. This occasions twitching in the stump and a good deal of distress. Where the continued nerve descends upon the inside of the leg, it sends out many-twigs to the integuments, and is entan- gled with the saphena vein. Here it has been pricked in bleeding in the ankle.—Sabbatier gives us an instance of this. The patient had been previously subject to nervous affections. She felt in the instant of the operation an acute pain, which was succeeded by convulsive motions, first of the limb and then of the whole body. These attacks returned from time to time, she lost her health, and for many years was still in suffer- ing almost continual. He relates to us another instance ofthe injury of this nerve accompanying the saphena vein, in the case of a young man who received a wound with the small sword in the inside of the knee. There came on much fever and swelling of the^ part, with great pain of the limb. This sub- siding, there followed slight trembling of the limb, which gra- dually increased to an extreme degree. The caustic was pro- posed, but the patient had not resolution to let it be applied. After long suffering with exhausted strength, he was at last re- lieved by nature, and his health gradually returned. When the nerve passes over the tibia, it is subject to be bruised, and I have seen tetanus proceed from such an injury. These branches we have mentioned are only the cutaneous or superficial branches ofthe anterior crural. The larger and more numerous set of branches are those to tbe muscles lying on the forepart of the thigh. These diverge suddenly into innumerable twigs, and are entangled with the branches of the arteries, and follow them in their distribution. There can be no excuse for bestowing particular names on these branches ; —to say that one is the branch to the pectinalis, another the branch to the Sartorius, another to the rectus, &c. is sufficient. obturator nerve. This nerve arises in common with the anterior crural, from the third and fourth lumbar nerves, or we say it arises by fas- ciculi from the second and third lumbar nerves, and some- times by a small twig from the fourth. It lies under the in- ternal border of the psoas magnus. It descends into the pel- vis, and goes obliquely downwards to pass through the liga- mentous membrane which fills up the thyroid hole. The ob- turator nerve, before it escapes from the pelvis, sends off a branch which, accompanying the parent nerve, is given to OF THE PARTICULAR NERVES. 415 the external obturator muscle. When it has escaped from the pelvis, this nerve lies in the middle of the flesh of the thigh : here it divides into a deeper and more superficial branch ; the more superficial lies betwixt the adductor longus and brevis, and here it divides into three branches. These divisions pass to the adductor longus, adductor brevis, and the gracilis. The branch which passes to the adductor longus, sends a small nerve under the inner edge of that muscle, and down through the tendon of the triceps to the inside of the vastus internus, and there it unites with the nervus saphenus, and then passes betwixt the adductor longus and brevis. The posterior division of the obturator goes down betwixt the adductor magnus and brevis, sends branches to the obturator externus and adductor brevis, and continues its course down- ward before the great fleshy partition of the adductor muscles, and parrallel which the crural vessels, to the fat above the in- ner condyle of the femur. the origin of the ischiatic nerve. The ischiatic nerve is formed by the two last nerves of the loins, and the three first ofthe sacrum : or we may describe its origin more particularly thus; the anterior branch ofthe fourth lumbar nerve and the trunk of the fifth uniting, form a strong cord of about two inches in length: this root is joined to another nearly as large, formed by the first and second sacral nerves; and again, a third division joins it from the inferior branch of the second sacral nerve and from the third.* The ischiatic is thus formed of three great roots matted together into a kind of plexus. It is flat to escape from pressure; it passes backwards betwixt the pyriformis muscle and the gemi- ni, and thus escapes from the back part of the pelvis by the great ischiatic notch. But before following this great nerve into the thigh, we must take notice of some lesser nerves sent out from the sacral nerve, and from the trunk of the ischiatic nerve. These nerves pass to the muscles and integuments ofthe nates and back of the thigh to the perineum and private parts. There passes off one or two very small nerves from the body of the ischiatic nerve, while yet within the pelvis, or from the middle divisions of its origins, which go to the pyriformis and gluteus medius muscles. * This third.and lowest origin, before uniting with the others to form the ischiatic nervp. i,ive?> out many small branches to the hypogastric plexus and viscera of the pelvis, tc :!i* perineum and private pnrt< 416 OF THE PARTICULAR NERVES. Just where the great nerve passes over the posterior liga- ments of the pelvis, there goes off a twig to the obturator ex- ternus, gemini, and quadratus femoris. While these nerves are sent off upon the anterior face of the nerve, there goes backward a large fasciculus of nerves to the glutei muscles, and to the integuments of the nates.* When the integuments are dissected off from the nates and back ofthe thigh, we see two sources ofthe cutaneous nerves; first from the lumbar nerves, which give out many small nerves which pass over the spine of the os ilii, and the branches of the anterior and outer cutaneous nerve; and secondly, from under the lower margin of the great gluteus muscle, there come many extensive cutaneous nerves of which, that last de- scribed is the principal. A little further down, the ischiatic nerve gives off small nerves to the muscles surrounding the hip joint; and, whilst the sci- atic nerve is passing over the quadratus femoris, the inferior and internal cutaneous nerve is given off. This nerve runs down even to the inside ofthe calf of the leg.—The exter- nal and posterior cutaneous nerve is a branch sent off from the ischiatic nerve, after it'has descended from under the gluteus maximus and just before its division into two fasciculi, viz. the tibial and peroneal nerves. This external and poste- rior cutaneous nerve passes down upon the integuments of the back part and outside of the leg. OF THE TRUNK OF THE ISCHIATIC NERVE IN THE THIGH. But we must not allow these lesser branches to distract our attention from the general course of the great nerve, which passes over the gemini muscles, betwixt the tuberosity of the ischium and the trochanter major, then runs deep under the bellies of the ham-string muscles, and is lodged immediately in the great cavity behind the knee-joint, in company with the popliteal artery and vein. In this course the sacro-sciatic gives off branches to the quadratus femoris, the biceps cruris. semi-tendinosus and semi-membranosus and triceps. A little below the middle of the thigh, the great ischiatic nerve divides into the internal and greater, and the lesser and external popliteal nerves. But as this is really the division into the two great nerves ofthe leg, we take the more deter- minate names of tibial and fibular nerves. •■ Tii.> posterior. cutantous nerve arises within the pelvis from the sacral nerves, and con- nerttiu •i-df with the sciatic as it escapes, it afterwards descends upon the integuments on Hie back of the thigh ; it sends branches also to the skin about the anus and to the bad part of the scrotum; pains are felt iu the course of this nerve from disorder in the rectum OF THE PARTICULAR NERVES. 41? TIBIAL NERVE. The greater and more internal of these divisions ofthe pop- liteal nerve is the tibial nerve. Whilst it is yet in the hollow behind the joint formed by the ham-string tendons, it gives off a nerve which comes out from the ham, and descends su- perficially on the back ofthe leg. This has been called ramus communicans tibialis. When this nerve has arrived op- posite to the beginning ofthe tendon Achillis, it turns a little to the outer side, passing upon the outer margin ofthe Achil- lis tendon, over the outer side of the heel-bone, and is finally distributed on the outside and forepart of the foot. Upon the back of the leg, this nerve unites with a branch descending from the fibular nerve, nearly in the same course, and with the same destination. After giving off this superficial branch, the tibial nerve sends branches to the back of the knee-joint, and popliteua muscle, to the plantaris muscle, and to both heads of the gas- trocnemius. It then descends behind the articulation, and be- hind the head of the tibia. It then passes under the origins of the soleus, and betwixt the soleus and flexor longus digito- rum pedis, and tibialis posticus, and descends to the inner ankle. In this course it furnishes many branches to the lower part of the popliteal muscle, to the tibialis posticus, to the flexor communis digitorum, and to the flexor pollicis longus, and many of these branches end in cutaneous twigs. We have also to observe a particular branch which the tibial nerve de- taches, which passes betwixt the heads of the tibia and fibula, and goes to supply the muscles arising from the forepart of the interosseous ligament. Further down, two or more small branches of the nerve also perforate the interosseous ligament, to supply the muscles lying on the outside of the tibia. The tibial nerve, in its course amongst those posterior muscles, ac- companies the posterior tibial artery. When it has arrived behind the inner ankle, it sends off a branch to the integu- ments of the inside of the foot, and to the abductor muscle of the great toe. Continuing its course by the side of the heel- bone, and under tbe ligament, it begins to split into those branches which- are naturally called the plantar nerves, because of their lying in the sole of the foot. TnE plantar nerves. The internal plantar nerve passes over the abductor mus- vol. n Ggg 418 OF THE PARTICULAR NERVES. cle of the great toe, and by the inside of the short flexor to the first metacarpal bone ; and in this course it gives out seve- ral twigs to the muscles ofthe sole of the foot. It now di- vides into three branches. These are distributed io the great toe, to the second, the third, and one side of the fourth toes ; and these nerves in their course give branches to the lumbri- cales and interossii muscles. The external plantar nerve is the lesser of the two. It gives branches to the short flexor and adductor of the little toe, and to the massa carnea Jacobi Silvii. It gives also a deep branch to the third and fourth interosseous muscle and adductor mus- cle ofthe toe. Another of its branches makes the arch with the internal plantar nerve, while its extreme distribution is to the little toe, and to one side ofthe fourth toe. These nerves ofthe sole ofthe foot are connected with the internal and ex- ternal plantar arteries, and are protected like them by the plan- tar aponeurosis. the fibular nerve. The fibular nerve is the more external division of the pop- liteal nerve. It separates from the tibial branch about four inches above the knee-joint; it does not pass down under the gastrocnemius, like the tibial nerve, but turns towards the out- side of the joint, and passes round the head ofthe fibula, and under the origin of the peroneus longus.—Before the fibular nerve passes from behind the joint, it gives off several branches. There are sent down two branches to the integuments. One of these branches unites with the communicans tibialis, and de- scends with it to the outer ankle. Sometimes this anastomo- sis is formed high in the leg upon the heads of the gastrocne- mius. More generally there is a double communication form- ed by these nerves, about the termination of the belly of the gastrocnemius muscle in the Achilles tendon. This prolong- ed branch of the fibular nerve terminates upon the side and upper part of the foot, and upon the little toe. There are al- so no me nerves sent off from the fibular, which are distributed about the back and sides ofthe knee-joint. When the fiisular nerve has turned over the head of the fibu- la, it divides into two great branches. The deeper seated of these branches, though it is not the largest of them, may be considered as the continued trunk. It passes deep amongst the muscles, lying betwixt the tibia and fibula, and supplies tbe tibialis anticus, the extensor communis digitorum, ex- tensor longus pollicis, and the peroneus brevis. Thus the deeper division of the fibular nerve, taking its course OF THE PARTICULAR NERVES. 419 between the tibialis anticus, and the peroneus longus mus- cles, and lower down betwixt the tibia and extensor pol- licis longus, continues giving off branches in rapid succes- sion, and when it arrives at the annular ligament, it is much diminished. Here it divides into the ramus dorsalis pedis pro- fundus, and superficialis.:—This division is made after the nerve has crossed under the tendon of the tibialis anticus muscle, and, while it lies betwixt the lower heads of the tibia and fibu- la.—Although they are distinguished by the name of deep and superficial branches, they are both deep compared with the extremities of the great and outer division of the peroneal nerve. The branch which lies most towards the outside of the foot, passes under the extensor digitorum brevis muscle, and on the outside of the tarsus. It distributes its branches to the extensor digitorum brevis, and interossii muscles. That branch which is more towards the inside of the foot, although distinguished by the term superficialis, goes forward not only under the fascia which covers the foot, but also under the ten- dons ; and after dividing and again uniting, and after sending off some small branches, it comes out betwixt the great toe and the second toe, and sends numerous branches to their con- tiguous surfaces. The great superficial division of the fieular nerve is sometimes double, or immediately splits into two. Its first branches are to the peroneus tertius, extensor longus digito- rum, and to the peroneus brevis and secundus. The trunk or principal division runs down under the head ofthe peroneus longus, and then coming out from under it, continues its course beneath the strong aponeurosis, which covers the muscles on the fore part ofthe leg. It then pierces the aponeurosis and becomes cutaneous, and runs obliquely down to the convexity of the foot, giving off in its course a nerve which passes over the outer ankle. THE METATARSAL NERVES. When the superficial branch of the peroneal nerve descends before the ankle-joint, it divides into the metatarsal nerves, or the rami dorsales pedis. The external of those branches passes above the tendons, and above the tendinous expansion on the dorsum pedis ; is united to the extreme branches ofthe ramus communicans tibiae, and is finally distributed to the out- side of the third toe, to the fourth, and to the inside of the lit- tle toe.—The internal branch is again subdivided; one branch extends over the middle of the foot to the second and third 420 OF THE PARTICULAR NERVES. toes, while the other passes straight along the metatarsal bone of the great toe (above the tendons;) sends many branches over the inside of the foot, and terminates on the inside and dorsum of the great toe. The nerves of the lower extremity have the same connec- tion with the visceral nerves, or the system of the sympathetic, that the nerves of the arm have, and this connection is further proved by various sympathies ; the influence of cold feet on the bowels, the effect of cold water dashed on the legs to pro- mote a purgative, the spasms of the legs in cholera, pains in the knee preceding a fit ofthe bile. end of the second volume. \ * V • •"* » C^tsi-