IMPLE SOLUTION OK THE Mystery of Tubercles, AND OTHER IMPORTANT QUESTIONS. (ILLUSTRATED.) / By ROLLIN R. GREGG, M. D. BUFFALO, N. y. Nothing can be more fruitful of Disease to us, than the Celle Our Onto Body, when they become Diseased, or get Misplaced. Filtered, according to Act of Congress, in the year 1883, by Rollin K Grkug, M. D., in the office of the Librarian of Congress, at Washington, D. C. / «_ Haas St Klein, Prs. 136 Seneca St., Buffalo, N^Y. 1883. CHYLE-CORPUSCLES, RED BLOOD-CORPUSCLES. LEUCOCYTES, PUS-CORPUSCLES AND TUBERCULAR CORPUSCLES, SHOWN TO BE ALL ONE AND THE SAME: UNDER DIFFERENT CONDITIONS. Rollin R. Gregg, M. D., Buffalo, N. Y. A group of chyle- granules, as first made in the lacteals from the albumen and fatty- matters furnished to them as digestion pro- gresses. A group of Ic h y 1 e - granules compacted ready to receive cell- wall. A chyle-corpuscle after receiving cell- wall, but still show- ing i t s granular character. A chyle-corpuscle losing its granular appearance to be- j come a red blood-j corpuscle. A chyle-corpuscle i h aving lost its gran- ular appearance, J and assuming color to become a red j blood-corpuscle, as all chyle-corpus- cles do in health. All blood-corpuscles are made of chyle-corpuscles, and in the manner here illustrated. Disc face and edge of arterial blood-corpuscles. Disc face and edge of venous blood-corpuscles. A red blood-corpuscle losing color, as they all do while dying, or after their death,whether of old age or disease A natural white blood- corpuscle, the same as c h y 1 e-cor- p u s c 1 e on first receiv- ing cell-wall. A leucocyte, or red blood-corpus- cle, that has been fully decolorized and made trans- parent by circulat- ing in a too watery serum. A pus-corpuscle, or red blood-cor- puscle, that has been decolorized to yellow by in- flammation, and showing its gran- ules. A pus-corpuscle that has had its cell-wall dissolved away.or broken up. thus reducing it to a granular mass, the same as chyle-corpuscle just before receiving cell-wall. Pus granules, or a pus- corpuscle broken up in- to its granules,which are the identical granules that thecorpusclestarted with to become a chyle- corpuscle when first made. A transparent tuber- cular corpuscle, or red blood-corpuscle fully decolorized by circula- ting in the very watery serum of the last stage of consumption. It is these corpuscles decolorized to entire transparency, then congested in the cap- illaries, that make the gray or semi-trans- fiareni tubercles of Laennec. A globular tuber- cular corpuscle, showing granules; or the red blood-cor- puscle decolorized by chronic inflamma- tion, which brings it back to what it was as a chyle-corpuscle just after receiving cell-wall, and is then called a tubercular corpuscle. It is red blood-corpuscles, decol- orized to yellow by chronic inflam- mation that make yellow tubercles. A distorted tubercular cor- puscle, its dis- tortion owing to pressure in the tubercular mass They take various forms under such pressure. A tubercular corpuscle that has had its cell- wall dissolved away, thus showing the same granular mass and iden- tical granules that it had as a chylecorpuscle just before re- ceiving c e 11- wall to become a c h y 1 e-c o r- puscle. Tubercular granules, or a tubercular corpuscle broken up into its gran- ules, which are the same granules that the corpus- cle started with as a chyle-corpuscle, to be- come a red blood-corpus- cle. Chyle-granules and tubercular granules are all identically the same, the first at the beginning of |their healthy life, the last at its premature close by Ichronic or subacute dis ease. A. SIMPLE SOLUTION; MYSTERY OF TUBEECLES AND OTHER IMPORTANT QUESTIONS. ROLLIN' R. (IREOO, M. I)., BUFFALO, N. V. Nature is ever simple in what she does, as we find when we learn her met nods ; and she is even more simple, if possible, in her morbid, than in her healthy growths. To show that this is the case, even with that hitherto great- est mystery in disease, namely, the growth of tubercles, the accompanying illustrations are given, and supple- mented by the following explanation. The primary cells, or the so-called tubercular corpus- cles, of which all tubercles are constituted, are diseased blood corpuscles, or blood-corpuscles changed into tuber- cular corpuscles by disease, as the illustrations indicate, and as will more fully appear as we proceed. But before we can fully comprehend all the steps in this change, we must first understand more about blood-corpuscles, the process of their making, and their intimate structure; and also something of their demeanor under other and various circumstances, which we will now proceed to consider. To begin with, then, I will assert that all red blood- corpuscles are made of chyle-corpuscles. That is to say, the blood-corpuscles are made in, or by, the mesenteric glands, from the albumen, fatty matters, salts, etc., in the chyle, that is carried to those glands by the lacteals, from the small intestines, as digestion progresses. This is their formative stage, and in that stage they are without color, and are then called chyle-corpuscles. The illustrations, as will be seen, begin with a group of chyle granules, as first made, and follow them on through their more conspicuous stages of development, as, becoming more compact to receive their cell-wall, then, 2 after receiving their cell-wall and becoming a chyle-cor- puscle, next the chyle-corpuscle losing its granular appear- ance, then receiving color to become a red blood-corpuscle, and, finally, as a fully developed arterial or venous blood- corpuscle. As stated, these corpuscles are colorless when first made, but after passing from the mesenteric glands through the large lacteal trunks, to the thoracic duct, they begin to receive color, and also to flatten upon opposite sides from the globular form to more or less of the disc-shape, and are then called, or we then first begin to call them, blood- corpuscles ; which are perfected as they pass on through the thoracic duct into the left subclavian vein and general circulation. Thus it will be seen, that the chyle-corpuscles are but the formative stage of red blood-corpuscles ; and, accord- ing to what seem to be the most reliable calculations that can be entered upon, more than -five hundred millions of them are made, on an average, during every minute of adult healthy life. Being made so rapidly and in such enormous numbers, it will be seen that the manufacturing organs must be in immediate and direct connection with an unfailing source of supply of fresh material out of which they are made; and if so, what more natural ar- rangement than that they be made in and by the mesen- teric glands from the pure and fresh chyle brought to them directly and rapidly by four millions of lacteal vessels ? Instead of their being made by the liver out of stale and impure venous blood returned to it from the abdominal organs and the lower extremities, as some have taught; or by the spleen, from its indirect and deficient source of supply of the proper materials, as others teach. To judge properly on this point it must be borne in mind that the derangement to health would be great, and death speedy to all, if the blood-corpuscles were not made with great rapidity, and in sufficient numbers for the in- exorable demands of life upon them, to free the system of 3 the rapidly accumulating effete carbonic acid gas, and to supply oxygen freely to all organs and parts. Therefore, I repeat, the supply of material for their manufacture must be the most direct and certain of all nature’s provi- sions in nutrition. And what so well adapted to the pur- pose as the machinery pointed out ? It is one of the functions of the spleen and liver to decolorize the old and worn out blood-corpuscles and oth- erwise prepare them for excretion, but not to make new ones. Then, as all blood-corpuscles have a definite period of existence of but a few weeks assigned them, when they die of old age and must be removed from the circulation to avoid putridity, and to give place to those which are being so constantly and rapidly made ; and as it is clear that ample ways and means must have been provided for the excretion of the debris of their disintegration at the end of their natural life, and that only; it is equally cer tain that when disease destroys them faster than they would die a natural death from old age; or when, from any cause, they are brought into excess in the blood ; or when disease interferes with the excreting organs, so that the corpuscles, or their debris, cannot be cast out as fast as it should be; then it is certain, I repeat, that acute or chronic congestions must be produced by them, which are always more or less dangerous to life. And this brings us to consider one of the strange and unaccountable oversights in pathology, namely, that not the slightest attention has ever hitherto been given, or in- vestigation entered upon, by the profession, to see what becomes of the red blood-corpuscles when they are killed pr maturely by disease; or when they are brought into a relative excess to the other constituents in the blood, as they frequently are; or when disease assails or interferes with the excreting organs so that their debris cannot be cast out of the system, or circulation, as rapidly as they are brought to old age, and die a natural death. Of course, 4 if the blood-corpuscles are made as rapidly as stated, or not more than half or quarter so rapidly, they must die of age in the same ratio of rapidity as made, and be disinte- grated and excreted as fast as they die from that or other causes, else great danger might and does frequently arise to any organ in which they may become congested. It is, therefore, to show what disposition is made of the blood-globules, under the morbid conditions named, that the illustrations are given ; but we must first under- stand more fully than some do, how they are disposed of in health, when they reach the end of their usefulness, and can no longer serve the purposes of life, or of their creation. In health, the red blood-corpuscles are all first decol- orized as fast as they die of old age, then disintegrated, or broken down, into the granules that they started out in life with as chyle-granules, and then their refuse, or de- bris, that is, these granules are excreted through the bow- els as natural faecal matter ; while the haematin that is dis- solved out of them in the process of decolonization, is excreted in part through the kidneys, thus giving the nat ural color to the urine, in part through the bowels, giving normal color to the faeces, and it also furnishes the color- ing matter of the bile. It must be borne in mind, also, in this connection, and with reference to what is to follow, that the blood-globules break down after their death, in the exact inverse order of their original construction ; being first decolorized to show nothing but a mass of granules, with a cell wall holding them together, like chyle-corpuscles; then having their cell-walls dissolved away, and liberating their included granules, but leaving them at first more or less in a mass like a mass of chyle-granules, which are then carried along to and excreted through the bowels as so much refuse matter. 5 WHITE RLOOD-CORPUSCLES. This brings us to the consideration of the white, or colorless, blood-corpuscles of health—for there are healthy and unhealthy colorless blood globules. The white blood-globules of health, there are many reasons for believing, are nothing more nor less than red blood-corpuscles, dead of old age, then decolorized by the liver and spleen, ready to be disintegrated and cast off through the bowels—they being found in much greater numbers, or in much greater proportion to the red corpus- cles, in the splenic and hepatic veins, than elsewhere in the system, and no doubt preparatory to their excretion as refuse ; while a few of them stray off into the general cir- culation, or, perhaps, keep on going the rounds in this until they are there decolorized. But be they what they may, from this on through the balance of the illustrations our course is clear and steps certain. And it should be understood that up to this point we have been dealing >olely with healthy corpuscles, or those of healthy life; while from this out our concern will be as exclusively with unhealthy corpuscles, or those of diseased life. For in- stance : \I.L LEUCOCYTES, so-called, or the colorless blood-corpuscles of disease, are red blood-corpuscles which have been decolorized prema- turely (that is, before the time for their natural death and decolorization from old age), by circulating in a too watery serum, precisely as every other organic structure of color is faded or deprived of more or less of its color and finally dies prematurely, when compelled to live in a too watery medium. d'he law of emlosmosis, it must be borne in mind, is the absolutely governing law, or force, under all such cir- cumstances. That is, when, through disease, the serum is made too watery, as often happens, and especially if much too watery, then all or many of the red blood-corpuscles 6 past middle life, and those in middle life or younger, but of weak organization, absorb water from the too watery serum, are thereby distended from discs to globules, have their hsematin dissolved out of them, which, of course, leaves them colorless; and if the serum is very watery, as in leukaemia, many of them are made perfectly transpar- ent thereby, and many others ruptured by over-distension and thus wholly destroyed. Remember, that it is a law of nature that does all this, and that there is no possible escape from the mandates of the law under these circumstances; hence we can rely upon the facts being as claimed, with as absolute certainty as upon the best established fact in science. The middle-aged and all young blood-globules of strong organization, resist, for a time, what has destroyed their weaker comrades, and are held to perform the func- tions the red globules were created to perform, and with- out which the patient would speedily die; until they too, these stronger corpuscles, are more weakened by age, and then destroyed. But if the serum becomes excessively watery they are all destroyed rapidly, or quite so, and with them the life of the patient thus afflicted. PUS-C011PUSCLES. We come next in the order of our illustrations to pus- corpuscles. Here, too, we have a decolorization of red blood-globules, but by a different process, to make pus- corpuscles. The red globules, in this case, are first con- gested in the capillaries and smallest arteries and veins of a part, then decolorized by the resulting inflammation, and in that way brought to a yellow color, or to pus corpuscles so-called. We will take common boils to illustrate this impor- tant fact. These result from the smallest blood-vessels beneath the skin, or in the superficial muscles of a part, becoming greatly congested with red blood-globules. When the congestion is once fully established, no further 7 movement of tin* corpuscles therein takes place, at least in all the central portions of the congested mass, until they are let out at tin* end of suppuration as pus-corpus- cles. Lance the boil at any time before suppuration has commenced, and nothing but red blood-globules and a little serum is obtained as a discharge therefrom. Lance it at the close of completed suppuration, and what do we then get ? Nothing but’pus-corpuscles and a little serum, besides some natural cells from the dissolved tissues. What, then, has taken place to cause the change? Why, nothing but a decolorization bv inflammation of the red corpuscles congested there, and through which they are changed into pus-corpuscles. Every pathologist knows that there are no movements in the red blood globules of an inflamed part after con- gestion is once fully established therein, until resolution, or suppuration, removes them ; hence, in the case of sup- puration, there is no other possible scientific explanation of the result, excepting that the red corpuscles are decol- orized and thus changed into pus-corpuscles by the inflam- mation. This does fully explain the matter, and furnishes another of the strangest oversights in pathology, viz.: that this only true explanation of the suppurative process was not seen as soon as the microscope revealed the existence of pus-corpuscles in the discharges from all abscesses. Of course,.the process of the formation of pus-corpuscles is precisely the same in all acute and chronic abscesses, not tubercular, whether internal or external, and in all ulcer- ations, whether deep or superficial, as it is in boils. The next step with the pus-corpuscle, if it shrivel from partially drying under the heat of the inflammation, or from other causes, is that it then becomes granular in ap- pearance, and exhibits the identical granules that it started in life with as a chyle-corpuscle, just after receiving its cell-wall; only of a more yellow color, from having had haematin developed in it. and this not being fully dissolved 8 out, as is done with many or most leucocytes. Or, if its cell-wall is ruptured under suppuration and its granules thereby released, these tlow out in a less compact mass, much as they were as chyle-granules just after first made, and before receiving the cell-wall; but now they are dead and disorganizing bodies, instead of living and progress- ively organizing structures for higher purposes, as in the first instance. Here, too, we have a breaking down of the corpuscles in a manner similar to their disintegration after their death of old age, in health; for it is a law of all organic, bodies to disintegrate, or break down, under various pro- cesses, into their primitive elements, when undergoing dis- solution, in the inverse order ol their original construction. Hence the red blood-globules, when changed to leucocytes, or pus-corpuscles, are first distended from the disc to the globular form, then lose their color in further retrograde metamorphosis, then show their granular structure, then the cell-wall is ruptured and-the included granules liber- ated in clusters, precisely as they wrere originally as chyle granules, only now dead instead of living bodies, as just stated. All this, too, shows why leucocytes and pus-cor- puscles are globular, instead of disc-shaped like the red blood-globules, if any question should be raised on that point. TUBERCULAR CORPUSCLES, AND HOW MADE. Next, and finally, in the order of our illustrations, come the tubercular corpuscles and their explanation. They, too, as all the facts and philosophy bearing upon them show (when properly collated and exam ined), are nothing more nor less, in any case, than red blood-corpuscles, decolorized by chronic or sub-acute dis- ease ; and through this and subsequent shriveling, changed into what have been so long mis named tubercular corpus- cles. If this be true, the important question next arises : How is it all brought about, and why are they different from pus-corpuscles and leucocytes ? Let us see. 9 All, even tlie laity, know that the blood of tlie con- sumptive is “poor” and “ thin,”—that is, too watery. This is patent to the most casual observation, and it is a scientific fact as well. We will, therefore, enter upon a little further inquiry to see what must be some of the effects of this too watery serum upon the blood-corpuscles, and why different from leukaemia ; also to see if we do not lind some of the most important facts in this direction, to be found in pathology, upon which to base a true science of tubercles. In every department of healthy nature means are ex- actly adapted to ends, and all associated things to each other and to their environment. This exact, or nearly ex- act, adaptation is what ensures health to all living things, and nothing else does. The salt-water fish, for instance, is made to live in salt water, and dies if compelled to remain long in fresh water. Why 1 Because the latter is too di- lute a medium for the nature of that fish to exist in. Here, too, that important law of nature, viz., endosmosis, gov- erns and compels the result, and there is no possible escape in any case from its mandates, when violated. The fish is constructed to live in a medium of a fixed 6r nearly fixed density; but if it be placed in a medium of less density, that is, too watery, or which contains less than the normal quantity of salt required by its nature, then successive portions of water are absorbed into its body, which bloat it and render it dropsical, take away more or less of its color, and finally its life. Well, our blood-corpuscles are also constructed to live in a medium, healthy serum, of a fixed, or nearly fixed, density. Very probably moderate deviations either way, for a few lipurs, or possibly for a few days, may be toler- ated by the corpuscles, as the salt-water fish might live a few days in water somewhat less salt than natural, witliout serious injury. But, when the blood becomes much too watery and continues so, as with all consumptives, and their blood-globules are thus compelled to live continu- 10 ously in this too watery medium, very similar results are wrought upon them as upon the salt-water fish living con- tinuously in water which does not contain sufficient saline ingredients. That is to say, many, or all (according to the degree of dilution of the serum), of the older and weaker cor- puscles, and also many of the middle-aged and young globules as well, not possessed of marked vigor of life, be- gin at once, or soon, to absorb portions of water from this dilute serum, which distend them gradually at the sides from the disc to the full globular form, and dissolve their haematin out of them, thus bringing them directly back to the appearance of white blood, or chyle-corpuscles. By this process, too, the globules are made viscid, or sticky, upon their surface, so that when they reach the capillaries in their onward circulation, the smaller or smallest of these vessels that will admit them, in any or- gan, will not allow such changed corpuscles (being now of full globular form and sticky) to pass on through them, but they stop them, and are blocked up by them. Then the force ol the circulation from behind drives other cor- puscles (both those not decolorized as well as those that are, and generally many more of the former than of the latter, in the earlier stages of the disease), into all such obstructed capillaries, where they remain permanently congested. The walls of each and every capillary so con- gested are then gradually distended by the congestion, (and under the continued pressure from behind), from a vessel of parallel sides and uniformity of size throughout its whole length, as are all capillaries in health, into a bulging or protuberant sac, which is filled at first partly with decolorized and partly with colored blood-corpuscles under the congestive action described—but with many more of the latter in the early stages of consumption, and more with the former in its last stage, when the blood be- comes very watery, and a much larger proportion of its corpuscles are rapidly decolorized. But all the colored 11 corpuscles thus stopped and held in congested capillaries are also decolorized soon, or finally, by the dilute serum percolating among and through them, or by the inflamma- tion they excite, as effectually as were the others before being congested therein. The blood - corpuscles cannot escape these conse- quences upon them when compelled to live in a too wat- ery serum,* as they are in every consumptive's blood, any more than we could escape bloating, and losing color if compelled to live in a continual fog, or in very damp cel- lars; or any more than the salt-water fish could escape similar results if kept in fresh or nearly fresh water. The protuberant sac named, or the congested capillary of decolorized corpuscles, then becomes the nucleus of a tubercle. That is to say, the distension of the one, or of several contiguous capillaries, presses upon all surrounding and adjoining capillaries to the extent of obstructing them and preventing the free passage of corpuscles through them, when they also become congested with both colored and decolorized blood-globules—the former being all final- ly decolorized as already described—and thus the mass becomes gradually developed into a tubercle, which grows from the first one or few of them obstructed, as a center, or focus, outwardly from capillary to capillary, to any known size that tubercles ever attain. These knots of congested capillaries holding decolor- orized blood-corpuscles, are the “ knots,” foci,” or u tu- bercle granules” of Virchow, which he says “never * If the reurter should suppose from what precedes that leukaemia should furnish the most conspicuous examples of tuberculosis, he has only to re- member that, In leuksemia, the blood is so very watery and the capillaries are all so relaxed by it, that the corpuscles are washed on through them ; or If they do lodge therein, they are then destroyed in situ, by this very dilute serutn percolating through them and dissolving away or bursting their cell- walla, when their granules are liberated, washed on and finally excreted as refuse. Besides, the corpuscles are much more rapidly distended to burst- ing, and thus destroyed, while yet circulating, in leukaemia, Ilian they are In the less watery serum of the consumptive, excepting, perhaps, in the very last stages of the latter disease, when the serum becomes excessively Watery. 12 attain any considerable size,” as, of course, they individ- ually could not, beyond the distension of each capillary’s walls into a protuberant sac, as described ; and which he wrongly says are nests of proliferated connective tissue cells, though how such proliferation is brought about he entirely fails to give a satisfactory account. lie further says: “ You will generally lind the tuber- cles in (he brain described as being solitary, but they are not simple bodies; every such mass (tuber) which is as large as an apple, or even not larger than a walnut, con- tains many thousands of tubercles; it is quite a nest of them which enlarges, not by the growth of the original focus (gfanule), but rather by the continual formation and adjunction of new foci (granules), at its circumference;” which is precisely the way, and the only way, tubercles can grow, being, as they are, an aggregation of great num- bers of contiguous capillaries filled with decolorized blood globules. While thus forming, fibrin is poured out through the capillary walls into the interstitial spaces between them, from the excess of it in the blood in all such cases, where it, the fibrin, organizes and makes the firm and partially fibrous mass that slowly-organizing tubercles generally are in their first stage, or before the changes that lead to their softening. When inflammation is aroused by the tubercle, and goes on to suppuration, then—that is, during the inflam- matory period—a portion of this excess of fibrin in the blood is poured out all around the tubercular mass, where it organizes into the firm and dense fibrinous wall that outlines every tubercular abscess, or cavity; and which separates the tubercle from the surrounding healthy tis- sue, and confines its suppurative and destructive processes to itself and the immediate tissues in which imbedded. But for this wise provision a small tubercle in the apex of either lung, for instance, might, and often, if not always, would, rapidly destroy that entire lung, by the more fluid 13 portion of its poisonous pus percolating down through the interstices to all parts of the lung, carrying inflammation, suppuration and destruction everywhere in its course. Sometimes tubercles grow rapidly, as we see in acute tuberculosis, but generally they are of slow growth, grad- ually extending outwardly from capillary to capillary as delineated. This affords time for the corpuscles to give up to the surrounding tissues the water that has distended and decolorized them, and especially under the heat of the inflammation they finally excite, when they shrivel into the “angular,” “jagged,” “elongated” and other dis- torted shapes that tubercular corpuscles are found in, and which both shriveling and the pressure of the gathering mass contribute to bring about. This drying down of the corpuscles, and the absorp- tion of the capillary walls and tissues between, under the pressure, are what lead to the tubercle becoming “cheesy” ; and generally the older the tubercle, or the longer it is growing, other things being equal, the myre cheesy it be- comes ; unless, indeed, it is so slow in its growth, as some- times happens, that all, or nearly all, the constituent ele- ments of (lie corpuscles are absorbed, leaving the fibrin of the mass organized and occupying the space, as a harmless fibroma. Or, again, the distinctively organic, or animal, elements of the corpuscles are sometimes all absorbed when “ cretification” of the tubercle is the result; that is, the inorganic elements or salts of ; he corpuscles are left as a chalky deposit and remnant of the tubercle. When the tubercle, on the contrary, excites inflamma- tion and suppuration, as is almost always the case, all the tissues between the capillaries,and their walls as well, are broken down, the corpuscles flow together, in mass, and then slough their way through into some natural passage like the bronchi, if in the lungs, when they are coughed up and thus secure their exit from the body. But for the diseased conditions behind, or the active continuance of the causes thereof, that go right on organizing more and 14 more tubercles to destroy more and more of the lungs, re- covery from any ordinarily large tubercle, or from several small ones would be complete even without medication. But the causes and process go on when once begun, and more rapidly the more tubercles form, until the organ or organs are sufficiently destroyed to take life, unless stop- ped by stopping the cause. In this process, too, many of the tubercular-corpuscles have their cell-walls destroyed, or ruptured, which.releases their inclosed and constituent granules in clusters, and which are the same granules, again, that the corpuscles started in life with as chyle-corpuscles, but now dead and undergoing retrograde mstaniorphosis. In other words, here, again, the blood-corpuscles, as tubercular-corpuscles, go to pieces under the softening of the tubercle, precisely as they disintegrate after their death of old age, in health, and as they do as pus-corpuscles under suppuration; in this instance also, making good our illustrations and making this hitherto terribly complicated subject and great- est mystery in pathology, the tubercle, one of the most simple in all science. • . Here comes up another important fact. Ever since the. time of Lsennec, at least, it has been wed known that two kinds of tubercles are developed in all, or nearly all, cases of consumption, viz.: the gray or semi-transparent and the yellow-tubercle. Of the former Gross says: “In several cases of chronic inflammation of this membrane,” (peritoneum), he has “ discovered tubercles in every possible stage of development some of them— evidently deposited only a day or two before the individ- uals expired—being of a soft viscid consistence and per- fectly transparent appearance, others semi concrete, yel- lowish, and consequently more or less opaque, and lastly, another set perfectly dense and firm, like fibro-cartilage, organized and covered by an accidental serous membrane of the most delicate texture.” 15 Now, there has never been any satisfactory explana- tion of this difference in tubercles ; but it would neverthe- less appear to be a very simple matter. The “ perfectly transparent” tubercles are made of blood-corpuscles that have been lirst decolorized to entire transparency by cir- culating in the very watery serum of the last stage of tu- berculosis, then congested in contiguous capillaries, bulg- ing these out at the sides into protuberent sacs, until a mass, or tuber, is formed of perfect transparency, and as otherwise described. Those that are ** dense and firm, like fibro-cartilage,” are such us have had a good deal of fibrin extravasated (from its excess in the blood) into and around them, and there organized to make a firm structure of the whole mass. The semi-', mcivte and yellowish tubercles, in this case, were probably such as had been organized some days or weeks, or long enough to have the transparent corpuscles give up by endosmosis, to the surrounding tissues, much of the water that had decolorized them, when they would shrivel and bepome yellowish. Whereas, yellow tubercles generally, at least those of much size, are caused by the blood-corpuscles being con- gested in a mass without first losing their color and then being decolorized by chronic or sub-acute inflammation, which does not take the color out of them so completely as does their circulating in a very watery serum. Let it hereafter be remembered, then, that semi-transparent tu- bercles are made of red blood-globules decolorized to en- tire transparency before their deposit, by circulating in the serum, whenever this becomes very watery; while the yel- low tubercles are made of red corpuscles first congested in mass, then decolorized by the resulting inflammation. It is a curious fact, too, and equally susceptible of the simplest scientific explanation, that the various organs of the body are ravaged by tubercles in almost the exact ra- tio of the nearness to each other of their capillary blood 16 vessels. Thus, the lungs are more frequently destroyed by tubercles than any other Organ, or organs of the human body, and their apices more frequently than any other part of either lung. And it is in their apices that the meshes between the capillaries are the smallest, conse- quently the latter lie the closest together there of any or- gan or part of the body, excepting the choroid coat of the eye. While from the lungs outwardly, the frequency, or, rather, the rareness of tubercles, is in almost exact proportion, as already said, to the distance between the capillary vessels; the farther these are placed apart, the less frequently is the organ disturbed by tubercles, un- til we come to the bones, which show the greatest distance between their capillaries, and the least frequency of tuber- cles of any vascular tissue; and, finally, to the cartilages, which have no capillaries and never develop tubercles. This fact of no capillaries and no tubercles in cartil- ages, while all the other tissues containing capillaries suf- fer from tubercles, and in the ratio of the profusion of those vessels therein, is the strongest evidence that can be adduced of the direct relation of capillary blood vessels to tubercles; and that the former must be the channel to carry the tuberculous matter, decolorized blood corpuscles, into a part to make the latter. Where the capillaries lie closest together will be the very parts where the conges tion of one, or a few of them, will press upon and obstruct the free passage of corpuscles through the greatest num- ber of adjoining capillaries, and these be the parts that will show the most frequent destruction by tubercles; thus showing an unmistakable and indisputable physical fact at the foundation of this question of the frequency or infrequency of the tubercular destruction of various organs. THE CONSTITUENT ELEMENTS OF TUBERCLE. Wood says of the tubercle and its microscopic consti- tution : 17 “ Tlie constituents, before the softening of the tubercle, are first, a hyaline formless substance; second, molecules or mole- cular granules in great numbers; and, third, peculiar and char- acteristic corpuscles; the two latter being held together by the translucent material first mentioned. The corpuscles are quite distinct from all others. They are seldom perfectly round, but are irregularly polyhedral with rounded angles, approaching sometimes the spherical and sometimes the oval form. Their diameter varies from about 5