:.cv^ ^* **f* 'M'^n4Un ^ .»<: /:< ?-:..:^ ■■■'■, ;:■'■'.. • ■.:•'':!!l'.Av•.v•';J••;,'. "''.- ?.:■■ '-.i. ,r;'-". ff&r:v":!«; r,;vi;: ^22- :-:-,:-_ /{? 7r~L*jf7' Destined for waste. ) Conveying the means ) of repair. The Arrangement of Organs according to their relative Functions. ( Brain and cerebral nerves. < Spinal cord and its nerves. ( Sympathetic ganglia and sympathetic nerve I' Heart and its Pericardium. Arteries. Veins. Lymphatics. Lymphatic glands Lacteals. Lacteal glands. Mouth, stomach, intestine. Salivary glands and pancreas. Liver. Spleen. Larynx and vocal system. Trachea. Lungs. Diaphragm. ^ Muscles of thorax and abdomen. 5. System of voluntary muscles. C Derma, or main portion. J Papillary tissue. ] Rete mucosum. [ Epidermis. f Kidneys. 7. Urinary System. J ^^ [ Urethra. 0 o • i a •«.• ( Organ of hearing. 8. Special Sensitive \ ° . , 6 o < Sight. bystem. ) ° ,, J { smell. i Bones. Cartilage. Ligaments. Synovial capsules. Testes. ^ Ductus deferens. Seminal vesicles Prostate gland. Penis. ) ~ , . Muscles of perineum. } C°Pulatlve Ovaries. ) Fallopian tubes. Uterus. Vagina. Hymen. Clitoris. Nymphae. Labia. Constrictor vaginae L Mammae,—accessory parts. 10. Genital System. < > Formative. Formative. > Copulative. Male. > Female. 58 INSTITUTES OF MEDICINE. 126. The organic and animal functions are also naturally subdivi- ded into, 1st. Those which operate from without inward, as in digestion ; and, 2d. Those which operate from within outward, as in circulation, se- cretion, &c. 127. There are generally two sets of organs for the animal func- tions, having a harmony of action in their natural and healthy states. 128. When the organs of organic life are in pairs, as the kidneys, concerted action is not necessary; and here one organ may supply the place of both (§ 109). 129, a. The whole assemblage of organic viscera act together in concert; but the animal organs, as a general system, act more or less independently of each other. 129, b. The mutual relations which subsist between the various or- gans and their several functions are of two principal kinds; namely, the vital, and the mechanical. 129, c: The first class of relations may be distributed into three dif- ferent orders. The .first order consists of the relations between the organs of sense. The second order embraces those between the brain and voluntary muscles. The third order comprises the relations which are especially maintained by sympathy. It is the last subdi- vision, mostly, which is relative to our present subject. It concerns, therefore, the organization by which organic life is carried on in ani- mals, and depends upon the nervous power in its function of sympa- thy, and upon a principle independent of the nervous power, called continuous sympathy, and which is probably also an important princi- ple in plants (§ 111-113, 222, 233, 495-500). 129, d. The vital relations of a general nature evince the highest order of Design. They refer to the mutual co-operation of distinct systems of organs in the production of particular results, and of these various systems in the maintenance of universal life; while the sev- eral individual organs possess distinct and specific offices that are more or less dependent upon the principle of sympathy (§ 222-233, 455). 129, e. The sympathetic relations are most strongly pronounced among organs which concur together in the performance of special functions, as the circulatory, the drgestive, the urinary, the sexual systems, &c. (§ 124). Other special relations subsist between the brain and the organs of animal life through the medium, in part, of the mental functions. Such is seen between the brain and voluntary muscles in the production of voluntary motion (§ 500, d). Thus, also, the senses aid each other; the sight being most independent. In this way, too, a concurrence is established between the teeth, mus- cles, eyes, nose, &c, in procuring food and supplying the stomach; each individual part having been also constituted with a reference to the nature of the food, and the mode of obtaining it (§ 323). 129,/ Plants are devoid of all that intimate association of parts which is determined by the nervous influence in animals, as well as by peculiarities of structure and special modifications of the common properties of life. But, a general relation of functions obtains to a certain extent in plants through the law of continuous sympathy, which as I have endeavored to show, depends upon the organic properties (§498). r ^ PHYSIOLOGY.--STRUCTURE. 59 129, g. The sympathetic relations in organic life are of the very highest moment in medicine. Disease is propagated, is maintained, and removed, very greatly, through these natural relations. 129, h. The sympathetic relations are variously modified by dis- ease, and are often more strongly pronounced than in health, though more or less diverted from their natural condition. Remedies also operate with greater effect through these modified relations, as well as through the greater susceptibility of the organic properties (§137, d). For the same reason, natural stimuli, as food, often prove morbific in diseased conditions (§ 152, b). The sympathies which grow out of morbific agents depend upon the natural principle, of which they are only modifications. And so of those which spring from remedial agents; these agents giving rise to greater influences in consequence of the morbid state of sympathy and of the organic properties, as well as in consequence of their own intrinsic virtues (§ 718, 901). 129, i. It appears, therefore, to be a most important law, that mor- bid states call into operation the function of sympathy among organs, which, in their natural state,,manifest but feeble, and perhaps no di- rect relations whatever; and that, in consequence of morbid changes, remedial agents will operate sympathetically through the stomach, &c, upon remote parts, when they would have no such effect in the healthy state of the organs. This principle is demonstrated in every case of disease, and constitutes our first position against the humoral pathology, and the doctrine of the operation of remedial agents by absorption (§ 819, &c). New vital relations being developed by disease, our remedies continue to operate through those acquired re- \ lations so long as they exist; while, also, the remedies themselves may institute analogous sympathetic relations, and thus simultane- ously induce sympathetic influences of a salubrious nature in organs not morbidly affected (§ 74, 117, 137, 143, 155, 156, 387, 422, 514 A, 524 d, 525, 528, 733 b, 905, 980). 129, k. The mechanical relations are equally common to plants and animals. They are maintained by the motion of matter from one or- gan, or part, to another; as the transmission of blood from the heart through the blood-vessels, sap from the roots to the leaves of plants, food through the intestinal canal, urine from the kidneys to the blad- der, and from the bladder through the urethra, &c. But, the move- ment of the matter is effected by the vital properties operating through the various organs. 130. Every part is a perfect labyrinth, anatomically considered. It is a labyrinth, also, of perfect designs; while the harmonious con- currence of these designs in the aggregate organs and tissues is too profoundly complex for any exact analysis. The deep intimacy of parts in each tissue corresponds with the union of the whole, with the dominion of common laws, and with that concerted action of all parts, which, in a popular sense, makes up the life of the organic being. 131. It has already been stated, that a knowledge of the minuteness of structure which is supplied by the microscope is practically use- less, while the deceptions of that instrument have led to many im- portant errors in physiology and pathology (§ 83). It cannot be de- pended upon, especially, in exploring soft structures. If it lead to unimportant facts, it is equally liable to betray us into error and fal- 60 INSTITUTES OF MKDICINE. lacious hypotheses. The whole history, of that instrument, so far as physiology is concerned, has gone to confirm the foregoing conclu- sions, which were originally advanced in another work, and has con- clusively sustained the opinion of one of the most profound observers of the present age. Thus: . . " Authors," says Bichat, " have been much occupied with the in- timate structure of glands. Let us neglect all these idle questions, in which neither inspection nor experiment can guide us. Let us begin the study of anatomy where the organs can be subjected to the senses." " No methodical mind will attend to the minute nature of the muscular fibre, upon which so much has been written. The ex- act progress of the sciences in this age is not accommodated to those hypotheses, which made general anatomy and physiology a frivolous romance in the last." Microscopical information, so far as correct, goes to the amount of human knowledge, and to the perfection of science, though it may not contribute to useful ends. But experience shows us, that we may not depend, as it respects the microscope, upon the vision of oth- ers, especially where a high magnifying power is required. Each must observe for himself; and, as allowed by Ehrenberg, long prac- tice, alone, can assure him of any general accuracy. The laborious student may attend to this accomplishment. But, vita brevis, ars longa; and he will be likely to live the subject of deluded sense rather than of enlightened understanding. "Enough is left besides to search and know. But knowledge is as food, and needs no less Her temperance over appetite, to know In measure what the mind may well contain; Oppresses else with surfeit, and soon turns Wisdom to folly, as nourishment to wind."—Milton. The following is another example in illustration of Milton's prin- ciple, and another instance* of the revolutionary spirit of the micro- scopic observers. I quote from Wagner's " Elements of Physiology for the Use of Students." " The study," he says, " of the varieties of form presented by the seminal animalcules ought not to be held as any trifling matter, or as tending to accumulate superfluous details. Most important phys- iological conclusions may be based on the information thus ac- quired" (§ 83, b). It is one of the few correct physiological conclusions to be found in the writings of Liebig, that " The most exact anatomical knowledge of the structure of tissues cannot teach us their uses ; and from the microscopical examination of the most minute reticulations of the vessels, we can learn no more as to their functions than we have learned concerning vision from counting the surfaces on the eye of a fly."—Liebig's Animal Chem- istry (§ 83 c, 699 c and d). When we consider, therefore, the constant deceptions of the micro- scope, especially in all explorations of soft substances, and the abso- lute uselessness of any knowledge it may convey as to the recesses of organization, it may be reasonably expected that the time is not * See article on the Microscope, in Medical and Physiological Commentaries vol i n 699-712; and my Examination of Reviews, p. 6, 89; also, this work, § 515, a. ' PHYSIOLOGY.--STRUCTURE. 61 distant when all this lumber will be excluded from practical works on physiology, and turned, at least, into a channel by itself. 132. Each simple texture, when united into compound organs, has as much its own specific function as the aggregate compound. It is even more important, in a pathological sense, to regard the individ- ual textures than the compound organ which they may form. 133, a. A consideration of the tissues in respect to their special character and functions, as well as their obvious anatomical differen- ces, being of the very highest importance to the physiologist and phy- sician, they can be only advantageously studied in these several as- pects. Much must, therefore, be now anticipated as to what will be subsequently stated more circumstantially in regard to the properties and functions of life. The student must be prepared with that anal- ysis before he can approach the tissues with any hope of enlightened knowledge. A simple statement of their apparent anatomical charac- teristics and relations, and of their products, would present a barren field. Nor is it alone their vital attributes which should most engage the attention of the medical- philosopher, but he should be equally and simultaneously employed in learning how these conditions are modified in disease. Such, therefore, is my projected plan in relation to the tissues (§ 83, c). 133, b. Every distinct tissue, and often the same tissue as it occurs in different places and connections, and even the different parts of one and the same continuous tissue, possess, respectively, special modifi- cations of the vital properties and functions. Upon these modifica- tions depend the variety of the natural vital phenomena, as, also, very greatly, those which are morbid. 133, c. But there would be no disease were there not another im- portant condition in the constitution of the vital properties; and this is their mutability. Its final cause is the well-being of organic nature ; since, as organization changes in the progress of the plant or of ani- mals to a state of maturity, so must there be an antecedent change in the properties which conduct the development of .organs, &c. The same principle is displayed in gestation, lactation, &c. It is this, in connection with the susceptibility of the properties of life to the action of blood and other vital agents, which renders them liable to morbid changes when other causes operate. Such, therefore, is a necessary consequence of the final cause of the adaptation of the properties of life to the influence of salutary agents, and to the varying exigencies of organic nature. Nor would there be any recoveiy from disease, but for the same mutability of the organic properties, and their liability to other chan- ges when yet other causes operate (§ 177, &c, 901). 134. Owing to the peculiarities in the vital constitution of the dif- ferent tissues, a common disease, as inflammation, is characterized by many peculiarities of symptoms, &c, in the several tissues, respect- ively. Differences also arise in their constitutional influences, and they may require corresponding variations of treatment (§ 717). This is even true of different parts of a continuous tissue, as the alimentary and pulmonary mucous membrane; where inflammation of this mem- brane in the nose, larynx, trachea, lungs, fauces, stomach, and intes- tines, is distinguished by almost as striking peculiarities in the vital signs, and in their constitutional influences, as are the physiological 62 INSTITUTES OF MEDICINE. functions of the different compound organs which it traverses (§ 740, 752-754, 780, 783). 135, a. The special modifications of the vital properties in differ- ent parts of one and the same continuous tissue is often strikingly de- noted by the character of the natural product of the several portions, respectively; as in the tissue last mentioned. Nothing, for example, can be more unique than the gastric juice, a product, no doubt, of all animals, while it can be generated by nothing but the mucous tissue of the stomach. Again, in the lungs we meet with this tissue per- forming the office of excretion; being the only example in which an organ eliminates truly effete matter from venous blood. And here an important analogy occurs to show that the elaboration of carbon is a vital process (§ 316, 419, 827 b). In the uterus, the same membrane appears as an organ of excretion in relation to the arterial blood, but for the uses of the uterus alone; nor is there any thing else in nature that is capable of generating a similar product. But, in all the cases, the analogy which is indicated by the coincidence of anatomical struc- ture is farther confirmed by the universal production of mucus by this remarkable tissue. 135, b. All the foregoing is delicately exemplified by the great variety of formations which are generated by the granulations that spring from ulcers; since, although in all the cases the granulations appear to be identical in character, we know from their production of parts analogous to such as had been removed by the ulcerative pro- cess, that, in every instance, the granulations must have been endow- ed, respectively, with specific modifications of the organic properties (§ 733, c). 136. In consequence, also, of the foregoing peculiarities of vital constitution, every tissue, and often continuous parts of a tissue (as in the last example), possess natural stimuli peculiar to each, and in cer- tain relative quantities. Each part, indeed, has as many stimuli as it possesses peculiarities of properties and functions. Owing, also, to the general coincidence in the vital constitution of all parts,°there are certain general stimuli adapted to the whole, especially the stimulus of heat. The blood has been regarded as a universal stimulus ; but, it is only so in relation to the sanguineous system. This fact, it may be now remarked, evinces, what is shown by diseases, a near identity in the vital constitution of all that part of the arterial system which conveys red blood; while, on the other hand, the difference between arterial and venous blood shows a difference in the organic proper- ties of the arterial and yenous systems. This has its deep foundation in the whole physiological condition of man and animals, and I may also add, in the whole vegetable tribe (§ 847, c). While every sur- face has some secreted product adapted to its own special modifi- cation of irritability, many of these products may be offensive to other parts. Again, the special irritability of one part may be exactlv suited to some product of another part, and this may or may not be a natural vital stimulus, and perfectly inoffensive, to the second nart while it may excoriate all other parts. Bile, for instance is the nat ural stimulus of the intestine, but will injure other parts Venous blood is harmless in the veins, and excites them, more or lesstoa contractile action; but is rapidly fatal within the arteries (i S4QN Urine is the natural stimulus of the bladder, but will exroriail I other parts (§ 74, 188* d, 650, 847 e). exconate most PHYSIOLOGY.--STRUCTURE. 63 137, a. In this relative sense the animal is filled with poisons; each one of which, however, in its proper place, is not only inoffen- sive, but indispensable. Here is the principle. 137, b. It is, also, upon the foregoing organic constitution of differ- ent parts, and which gives rise to a mutual relation of the different vital agents and products of organs and of the different parts of the or- ganism, that the differences in the effects of remedial as well as mor- bific agents upon different parts is essentially founded. Wine in- flames the mucous tissue of the bladder, &c, but may be good for the stomach. Tobacco smoke is inoffensive when inspired in the or- dinary mode; but it is a violent poison when introduced within the alimentary canal. Other agents affect the stomach, or intestines, or liver, or uterus, or bladder, &c, each organ more than the others, and more than other parts (§ 233|, 772 c, 838.) 137, c. From not duly regarding these important facts, or from an ignorance, or a disregard of physiology, many agents which have a specific relation to the vital constitution of some tissue in a particular part of the body, as the mucous, for example, are supposed to have the same relation to the tissue in all other parts. Hence the oil of turpentine, copaiva, naphtha, &c, have been abortively or injuriously employed in pulmonary catarrh, phthisis even, diarrhoea, dysentery, &c, mostly for the reason that they exert a specific effect upon the mucous tissue of the urinary organs. This great law of adaptation is so universal as to extend through- out the whole domain of medicine, reaching as fully into pathology and therapeutics, as it is conspicuous in physiology. If the blood be rendered morbid by morbid states of the solids, it never becomes morbific, since there is a progressive adaptation of the vital changes in the solids to such as the solids induce in the blood. And so of va- rious morbid secretions in relation to the parts by which they may be produced. These results, in which the vital properties of the solids are always concerned as the primary cause, are founded in an all- pervading law of the animal economy, and by which, and which alone, nature is enabled to throw off disease (§ 524 d, 944 c). 137, d. Again, it is one of the most important laws in medicine, that the susceptibility of tissues and organs to the action of remedial agents is more or less affected by disease. Many agents which oper- ate powerfully in certain morbid states, and in certain doses, both lo- cally and sympathetically, may be perfectly inert in the natural states of the same organs. And so of the natural agents of life. The great- ness of the effects, also, will depend very much upon the nature and intensity of disease. The same principle applies to the impressions which are made by many remedial agents upon existing states of dis- ease, or upon organs in their state of integrity ; by which the diseased or healthy parts are increased in their susceptibility to the subsequent action of the same or other remedies, or to morbific causes (§ 143, c). 137, c. It is, therefore, one harmonious system of laws throughout. Were it, indeed, otherwise, remedial agents could have no existence, and disease, of course, could receive no help from art. These, also, are the beginning of a long series of facts, which show us that the effects of all agents, whether morbific or remedial, may be traced to the peculiar impression which they exert upon parts with which they come in contact; and by which, also, we overthrow the whole system 64 INSTITUTES OF MEDICINE. of chemical physiology, the humoral pathology, and the doctrines of debility, and of cure by the absorption of remedies (§ 847, e). 138. The natural modifications of the vital properties and functions, or the special vital constitution, of any particular tissue, or parts of a continuous tissue, and, therefore, -their special modifications in any given disease, conform to the general nature of the complex organ of which the tissue may form a component part. Certain tissues of a compound organ are far more liable to disease than its other tissues. Thus, the mucous tissue of the stomach is quite liable, the serous rarely, and the muscular more rarely (§764, a) 139. Disease of any particular tissue, or parts of a tissue, is apt to be most severe, in its local and general character, according to tha importance of the functions of the compound organ of which it may form a component part. This, however, is less true of the constitu- tional influence, than of the local intensity of disease. 140. The sympathetic influences of disease are also greatly deter- mined by the nature of the affection, especially the constitutional ef- fects. Inflammation of the serous, venous, and ligamentous, tissues, disturb the constitution far more than the same degrees of inflamma- tion affecting the mucous, arterial, and muscular, tissues. But much, also, as already said, will depend upon the nature of the compound organ with which the tissue, or part of a continuous tissue, may be associated ; though sometimes, where the compound organ is compar- atively unimportant, inflammation of one of its tissues may give rise to great constitutional disturbances. Such, for example, is true of some inflammatory affections of the mucous tissue of the throat; and no disease is more intractable than laryngitis. Much, also, will often depend upon the special modification of disease; as in acute articular rheumatism (§ 525-530). .141, a. Tissues of the same organization are most allied in their vital properties, and hence are most liable to sympathize with each other in their diseases. • 141, b. When one tissue of a compound is diseased, the proper- ties and functions of the others are more or less disturbed ; though the primary disease is not apt to be propagated to them from the tis- sue first affected. It continues rather in the tissue first invaded. In- flammation, for example, beginning in the mucous tissue of the stom- ach, will extend along that tissue, so far at least as its connection relates to the stomach, without being often propagated to the other tissues of the compound organ. This principle has a broad founda- tion, and is owing to the general coincidence in the vital constitution of all parts of the same tissue, and to the differences between the vital states of that and the associated tissues. Exceptions, however, occur more frequently in some parts than in others; as in the lungs, where pleuro-pneumonia is not unfrequent. Nevertheless, in these cases, the simultaneous affection of two distinct tissues of a compound or- gan may be rather owing to a general predisposition effected by some remote cause, than to morbific influences exerted by one tissue upon the other. In other cases, especially of specific inflammation the dis- ease is propagated directly from one tissue to another, as in scrofula rheumatism, &c. 142. For reasons stated in § 133-136, morbific agents may readily excite disease in one part of a continuous tissue when it would have PHYSIOLOGY.--STRUCTURE. 65 no effect on another part of it; or may operate more profoundly on one part than on another. And this holds true of the action of reme- dial agents. The same is also true of the sympathetic influences which may be exerted by disease; and a like principle applies to cer- tain sympathies that fall upon special parts which are immediately continuous with each other, but which are determined, also, by cer- tain special vital relations of the different parts. Thus, the vital rela- tions of the tongue to the alimentary canal being far greater than to the lungs, and as the canal readily sympathizes with other chylopoi- etic viscera, the tongue is far more sensitive to abdominal than to pul- monary derangements (§ 129 c, i, 689 i). 143, a. Again, there may be varying susceptibilities of the differ- ent parts of a continuous tissue (arising from numerous causes not positively morbific), when the same morbific, or remedial, cause will affect one part or the other more in conformity with the acquired sus- ceptibilities, than with the natural modifications, of the vital proper- ties in the several parts, respectively. This is also more applicable to the tissue as it occurs in compound organs not anatomically con- nected, and to tissues which differ in their organization (§ 783). 143, b. Hence it follows, that, if all the organs be rendered preter- naturally susceptible, a general explosion of disease may follow the operation of some cause, which, in sounder health, would be harm- less. Under these circumstances, however, disease is most apt to spring up more or less sympathetically, and successively, in one part after another, till all parts may ultimately be brought into some, though variable, forms of disease (§514 h, 660, 666, 905). But, in these cases, it generally happens that some of the morbid states abate, oi subside, as new ones come forward, the new ones, perhaps, subduing sympathetically the older in the series (§ 804, 905). The system, therefore, is rarely universally invaded by disease, except in idiopathic fever (§ 148, 783). Nevertheless, it probably does not often, if ever happen, except in fever, that the primary is the efficient predisposing cause of universal disease, but that disease of one organ proves the predisposing of dis- ease in another; and as one organ after another becomes affected in this manner, they co-operate together in rendering other parts suscep- tible of disease (§ 644, &c). 143, c. In proportion, therefore, as the susceptibility of tke system at large is increased by morbid changes, or predisposed by morbific influences, so, in a general sense, will the alterative action of reme- dial agents be felt in a corresponding manner (§ 137 d, 152 b, 715). By the law of adaptation, as set forth in the Medical and Physiological Commentaries (vol. i., p. 649, 653-655, &c), and in various parts of the present work, the sympathetic influences of any local disease which is felt by distant organs modifies the vital states of those parts in a manner that institutes harmonious relations to the part more pro- foundly affected; and thus remedial agents will extend their salutary alterative action to such distant parts, and render them the source of salutary effects upon the essential seats of disease (§ 74, 80,117,129 i, 133-137, 143, 155,156,169/ 387, 399, 422, 514 h, 524 d, 525, ^28, 5 63S, 649 d, 811, 848, 902/, 905). When the whole system is inva- ded by disease, as in idiopathic fever, the alterative action of rem- edies is felt over the universal body (§ 148, 152 b, 222-232, 500, E 66 INSTITUTES OF MEDICINE. 904 d). It is owing, also, to the same law of adaptation, the same universal, however partial modifications of the vital states which local diseases often induce, that parts remote from the direct seat of dis- ease are protected against all morbific effects from any changes which the blood may undergo as a consequence of morbid action (§ 845, &c). Independently, however, of any increased susceptibility of organs, the action of numerous agents upon the stomach may determine influences upon distant parts whose natural state is unimpaired, and these influ- ences may become the source of other impressions upon other parts. Circles of sympathy may be thus established throughout the system, by which all parts shall concur in the relief of the gastric irritation which had given origin to the whole. In this manner a cathartic or an emetic may bring the whole organism to bear with favorable influences upon some slight inflammation of the throat which had exerted no mod- ifying effects upon other parts (§ 514 h, 692 a, 902 g). 143, d. Again, there are some remedial agents possessing general vital relations to the whole body, especially the several preparations of mercury, and others whose specific relations are more limited, like cantharides, which will affect profoundly the entire organization, oi certain individual parts, and alter the condition of their vital states, in the most healthy conditions. These agents, therefore, approach most nearly the truly morbific ones, while they possess the grand charac- teristic of the Materia Medica of instituting morbid changes which are of transient existence. 144. Many acquired conditions may be transmitted from parents to child, and they then form a constitutional predisposition to disease; being a permanent and more or less universal modification of the vital properties (though of some parts more than others), which does not properly belong to them; as in scrofula. Here, the absolute remote cause has operated upon the ancestor (§ 75-80, 563). 145. Subjects thus constituted (§ 144) are liable to morbific influ- ences which the more natural do not feel; and such causes as would produce in the natural subject common inflammation of the nose, trachea, &c, will excite scrofulous inflammation in the lungs of the acquired constitution (§ 650, 659). 146. Hereditary predisposition to disease manifests itself in certain tissues and organs more than in others, according to the nature of the transmitted constitution (^ 143, a). 147. Sympathetic diseases may spring up in unusual constitutions, when they would not in the more natural. Thus, in certain heredi- tary conditions, indigestion gives rise to scrofulous, rheumatic, and gouty inflammation of parts distant from the chylopoietic viscera. The same principle is also in operation when the vital constitution of parts is modified by habits, climate, age, the development of the gen- erative organs, &c. (§ 542). 148. Certain causes appear to be capable of affecting, directly and indirectly, all the tissues of the body, as in idiopathic fever; though, in these cases, the primary morbific effect is on particular parts, from which it is disseminated by sympathy over the entire body (§ 649 665, 666, 760). In these cases, however, it appears not to be a posi- tive state of disease in the part upon which the morbific agents may exert their primary effects, as on the mucous surfaces, which brings the rest of the system into a predisposition to disease; but a predis- PHYSIOLOGY.--STRUCTURE. 67 position being established in those primary parts, the impression is of such a nature as to be propagated sympathetically over the universal body; just as when many remedial agents acting upon the mucous surface of the stomach exert powerful influences upon remote organs, but without inducing disease in the gastric mucous membrane. It is, therefore, in idiopathic fever, as well as in numerous local affections, that the parts on which the morbific agents exert their direct effects may not manifest any signs of disease till the explosion of fever takes place ; or as when pneumonia, or catarrh, are induced by the action of cold upon the skin ; while it often happens that the parts thus origin- ally, but imperceptibly impressed, become sympathetically the seats of absolute disease by the reacting influence of the diseases which had been sympathetically produced through these parts. Very complex circles of sympathy may thus become established. These general af- fections may be also broken up by the action of a single remedy, as by an emetic, or mercury, &c. (557, 559, 712). 149. It is a great and important law, resulting from the physiolog- ical considerations now made (§ 133-148), that morbific causes, ex- ternal or internal, determine disease upon the tissues of one com- pound organ or another, according to the particular virtues of the morbific causes, and in accordance, also, with the natural modifica- tions of the vital properties in every part, and the susceptibilities which they may acquire from other causes (§ 642 b, 722 d, 725, 794, 795, 808). Hence it follows that many of the natural stimuli of life may become morbific. 150, a. It is a great fundamental law, that a general coincidence exists between the natural susceptibilities of the properties of life to their ordinary stimuli (§ 136), and to those of a morbific, and of a re- medial, nature, according to the natural modifications of the vital properties, whether in a general sense (§ 148), or in their relation to particular parts (§ 136) ; the influences produced conforming, of course, to the natural modifications of the properties of life and the special virtues of the several agents, though modified by the tran- sient or permanent influences which spring from other sources, espe- cially from disease (584, 644-674, 772 c, 826, &c, 847 e, 904). Such is the inevitable result of the constitution of the properties of life (§ 177). It is, as it were, the great focal point from which all di- verges that is embraced in medicine; the bond which unites every branch of the science. 150, b. All that is here said, and in § 149, is equally applicable to the nervous power, in all its modifications, as an agent in the produc- tion and cure of disease, as to agents of a physical nature (§ 222- 233^, &c). 151. It is through the foregoing law (§ 150) that the natural stim- uli of life maintain all parts in their precise conditions; through which, also, morbific agents alter those conditions in certain uniform ways, and through which remedial agents establish certain other changes which enable the properties and actions of every part to re- turn spontaneously to their natural states. The law involves an im- mense range of facts in physiology, pathology, and therapeutics, and groups many other fundamental principles. It should be the point of departure in all our medical researches and reasonings; for it is, as it were, the polar star which will guide us safely upon our difficult and dangerous voyage (§ 794, 795, &c). 68 INSTITUTES OF MEDICINE. 152, a. It follows, therefore, from § 150, 151, that the operation of all things upon the living organism, whether food, heat, cold, blood, poisons, the nervous power, or remedies for disease, is upon one com- mon principle, which is relative to the natural constitution of the or- ganic properties. Food stimulates the stomach, and throws a genial sympathetic influence over the whole organism, warming the cold surface as soon as it enters its appropriate receptacle;. blood main- tains, in the same way, the actions of all parts ; poisons and morbific agents, put into the stomach, affect the vital properties of that organ injuriously, when, unlike the case of food, pernicious sympathetic in- fluences are transmitted to other parts, or the same food, in excess, may do the same. We then introduce into the same organ another class of morbific agents that are less profound in their operation, and which prove remedial in certain doses, and therefore establish, through the same principle, a salutary change in the same properties which other poisons had affected injuriously (§ 638, 642 b). 152, b. It is also worthy of repetition, that such is the analogy be- tween morbific and remedial impressions, that the organs which sus- tain the former are thus rendered susceptible of the latter, when they might be otherwise insensible to the same remedial agents, in theii appropriate remedial doses. Such is the harmony of the laws of na- ture ; such their great final causes (§ 524, no. 3, d). For the same reason, also, many of the natural agents of life, such as the ordinary kinds of food, may be intensely morbific in most of the diseases of man (§ 849). Or, again, the agents which heal in their remedial dosea may establish severe forms of disease when administered in health. 153. Through the law of development, the tissues undergo natural modifications in their structure and vital endowments at many periods of life. In infancy, the organs are imperfectly developed, though the properties and functions of organic life, unlike those of animal life, are strongly pronounced in many of the viscera. A relation obtains, however, in organic life, between the properties and functions and the relative size Of organs (§ 159). In childhood, there is another well-marked change. In adoles- cence, another; when the organs become mature. In old age, an- other; when life is naturally on the decline. 154. The foregoing stages of development (§ 153) are not sudden, but gradually progressive. 155. The changes of organization (§ 153, 154) are preceded by corresponding changes in the vital properties, upon which the former depend (§ 445,/). This principle, too, like all others which relate to organic life, whether in health or disease, is universally true under any given combination of circumstances. It is true of the develop- ment of all tissues and all organs, and all other products, from the be- ginning of conception to the end of life. Hence, also, the variety in the remedial or morbific virtues of many plants, at different stages of their growth. _ As structure varies, the vital properties have under- gone modifications, in conformity with that order of Design which was instituted, that where one specific end is accomplished, and others are to be fulfilled, the powers by which these final causes are to be ac- complished shall have their necessary adaptations. And while also the vital properties, under all their natural modifications, are so con- stituted as to receive certain exact impressions from the natural stim- PHYSIOLOGY.--STRUCTURE. 69 uli of life, that vital actions may be determined according to the pur- poses ordained, so also will morbific and remedial agents be varied in their influences (§ 129 i, 387, 980). 156, a. The foregoing variations (§ 153-155), therefore, give rise to new dispositions to disease in many parts, and are productive of modifications of former diseases, or the latter disappear. This, as we have seen, is a necessary consequence of the physiological chan- ges, since the same properties which carry on nutrition and growth carry on all diseases. The relations of vital and morbific agents move on, pari passu, with the natural changes in the properties of life; and remedial agents undergo corresponding modifications of action. 156, b. The great law of adaptation is forever present to the eye of the naturalist; and when the same subjects are contemplated in a moral sense, the same evidences of Design meet him at every glance of the mind. Take an example of a compound nature, a universal physiologico-moral phenomenon in which our present topic is involv- ed. Thus, no sooner was man created than he was doomed to obtain his subsistence by the sweat of his brow. Roots, grains, fruits, &c, were, therefore, as far as the wants of animals would allow, created mostly in an unedible condition, but rendered susceptible of the re- quisite improvement by cultivation; and to carry out the great pur- pose, the nature of soils, air, water, &c, were made subservient (§ 74, 80, 117, 137, 143, 155, 169/ 266, 384, 385, 387, 399, 409/ 422, 514 h, 524 d, 525, 526 d, 528 c, 638, 733 b, 847 g). 157. Organs are softest and most fluid at the beginning of their de- velopment, and increase, progressively, in density through life. The animal ovum is scarcely more than an organic fluid. 158. Vascular action is promoted by the greater fluidity of or- gans, and vice versa (§ 142). Inflammation is in part, therefore, more intense and rapid in infancy and childhood than at later peri- ods, which, with other causes, gives rise to the necessity of great promptitude of remedies. Other causes attending the vital condi- tions of old age render equally important a decisive treatment of the severe diseases that may befall that age (§ 574, &c, 1009, &c). 159. The proportional size of organs varies at different stages of life. The cerebro-spinal system, for example, is largest in child- hood. Hence a greater development of the organic properties in those parts, and a greater consequent liability of the brain to inflammatory and congestive affections, and to hydrocephalus. The large propor- tional size of the nervous and arterial systems affects the physiolog- ical and pathological condition of all other parts; giving activity to nutrition, and susceptibility and intensity to disease. The glandular tissue of the liver has the largest proportional size in infancy ; but not so the venous system of the liver. Hence, again, the glandular function of that organ is especially liable to derange- ment in infancy, and its venous tissue to congestion at more advanced ages. It is also important to understand, that the veins, in a general sense, " have a real inferiority as it respects the arteries, during the first periods of life."—Bichat. There are some exceptions, espe- cially in the brain. 160. What has now been said of the modifications of the vital con- stitution of different tissues and organs may be illustrated by the rel- 70 INSTITUTES OF MEDICINE. ative liability of different tissues, and parts of common tissues, to some given disease, by the relative danger of that disease as it may affect the different parts, and by the effects of some remedial agent upon the various parts, respectively. The remedy may be loss of blood, and the supposed disease inflammation. The statement may be conveniently made in a tabular form, while, also, it may be con- verted to practical uses (§ 711). 161. The tables are intended in a general sense, and suppose the constitution to be naturally sound. If hereditary predispositions to disease exist, as in scrofula, or if the constitution be affected by in- temperance, or by previous diseases, &c, the order of liabilities to inflammation, &c, as marked in the first table, will be more or less affected. In the scrofulous constitution, for example, instead of the mucous, the lymphatic tissue may be most liable. 162. The tables will be more or less modified by age. Thus, the veins of the pia mater are more liable to congestion in infancy and childhood than any other part of the venous texture. This liability afterward decreases, and returns at the age of fifty and upward, re- sulting in cerebral hemorrhage (§ 805). PHYSIOLOGICAL AND PRACTICAL SUGGESTIONS. Tissues most liable to disease, especially to inflammation, in the order of arrangement: TABLE I. 1. Mucous. 2. Venous (venous congestion). 3. Cellular. 4. Serous. 5. Ligamentous and dermoid (fibrous). 6. Glandular. 7. Lymphatic. 8. Nervous. 9. Synovial. 10. Periosteum (fibrous). 11. Osseous. 12. Tendons, cartilage, dura mater, and pericardium (fibrous). 13. Muscular. 14. Arterial. TABLE II. 1" of the nose. " lungs, fauces. " eyes. ( Ilium, 1. Mucous texture ... J sma11 "destine, j Jejunum, ( Duodenum. " stomach. " large intestine. " uterus and vagina. i " bladder. PHYSIOLOGY.--STRUCTURE. 71 f ° Venous texture (form- ing, mostly, venous congestion)..... 3. Cellular texture 5. Glandular texture 4 Serous texture . . . .< t 6. Lymphatic texture . 7. Fibrous texture . . . 8. Nervous texture- . . 9. Synovial texture . . 10. Osseous texture . . . of pia mater, in infancy and childhood. " liver. " small intestine. " pia mater of adults. " rectum (piles). " uterus (phlebitis). " lungs (congestive asthma). " lower extremities (varix). " spermatic cord (circocele). sub-cutaneous. of the lungs. " pia mater. " voluntary muscles. of the lungs. " parietes of thorax. " parietes of abdomen. " liver. " small intestine. " large intestine. " heart and pericardium. " cerebral ventricles. " kidneys. " stomach. lymphatic glands. mammae (puerperal). salivary glands. liver. testis. lacteal glands. kidney. thyroid gland (goitre). thymus gland. pancreas. of the lower extremities. " upper extremities. " uterus (see Comm., vol. ii., p. 470). others rarely. ligaments. dermoid. periosteum. cartilage. tendons. pericardium. dura mater. brain. ganglia of sympathetic. spinal cord. of the knee-joints. " ankle. " joints of upper extremities. ( spongy bone. ( solid bone. 72 INSTITUTES OF MEDICINE. of the bram. H. Arterial .extare. } -h of aorta^^ rare in other parts. TABLE III. Relative danger of high inflammation affecting the tissues of dif- ferent organs, according to the order of arrangement: 1. All textures of the brain. 2. All textures of the heart and pericardium. 3. Venous and lymphatic textures of the womb, iliac and other veins. 4. Peritoneum of abdomen (puerperal women). 5. Serous membrane of small intestine. 6. Veins of the liver (venous congestion in congestive fevers). 7. Parenchyma of lungs. 8. Glandular texture of liver. 9. Mucous texture of small intestines. 10. Mucous texture of stomach. 11. Serous texture of large intestine. 12. Textures of kidney. 13. Mucous texture of large intestine. 14. Serous texture of lungs and thorax. 15. Serous texture of liver. 16. Serous texture of abdominal parietes (common inflammation). 17. Veins of lungs (low, or sub-active, forming congestive asthma See Comm., vol. ii., p. 494). 18. Textures of bladder. 19. Mucous texture of uterus. 20'. Ligaments. 21. Bone and cartilage. 22. Lymphatics of extremities. » TABLE IV. Tissues which require the greatest extent of general blood-letting, when affected with high inflammation,—-according to the organs in which they are associated, and in the order of arrangement. The remedy is supposed to be applied early. 1. All textures of the brain. 2. All textures of the heart and pericardium. 3. Serous texture of small intestine. 4. Peritoneum of abdomen (in puerperal women). 5. Parenchyma of lungs. 6. Serous texture of stomach. 7. Serous texture of large intestine. 8. Veins and lymphatics of uterus. (Early.) 9. Serous and glandular texture of liver. 10. Venous texture of liver. (Sub-acute, congestion in congestive fever. Often more largely.) 11. Mucous texture of small intestine. 12. Utems. 13. Textures of kidney. PHYSIOLOGY.--VITAL PROPERTIES. 73 14. Mucous texture of stomach. 15. Mucous texture of large intestine. 16. Serous texture of lungs and chest. 17. Serous texture of abdominal parietes. (Common inflammation.) 18. Ligaments. (Often more largely.) 19. Bladder. 20. Mucous texture of bronchiae. 21. Mamma, testis, parotid gland. 22. Absorbents of extremities. 163. In the treatment of disease, therefore, we should consider the precise pathology of each affected tissue, the natural vital peculiari- ties of the affected tissue in the compound organ, its general character as well as that of the compound organ in the animal economy, the in- fluences which its morbid state exerts upon the other tissues in a compound organ, its own morbific influences and the combined influ- ences of the compound organ upon other parts, and how the remote sympathizing parts may react, or shed an influence on yet other parts. And then follows not only the general plan of treatment, but all that nice discrimination of cathartics, emetics, alteratives, and other groups of agents possessing, in their individualities, respectively, analogous virtues, their combinations, alternations, precise dose, frequency of repetition, &c. (§ 675, 685, 686). The same variety of considerations are to be made when the condition of diseased parts may undergo changes, favorable or unfavorable, from the operation of remedial agents. We are mostly assisted in the foregoing inquiries by comparisons of the morbid with the natural vital phenomena and physical products of each part, and the whole collectively. We also acquire much of our knowledge of the natural constitution of individual parts by ob- serving the deviation of their phenomena when acted upon by mor- bific or remedial agents. The phenomena are then more strongly pronounced than in health, or new ones are developed. Indeed, it is sometimes through morbid conditions only that we acquire a knowl- edge of some of the important physiological conditions; as, for ex- ample, the existence of common sensibility in all parts. Hence a corollary, that none but an observer of disease can expound the nat- ural conditions and laws of life (§ 685, 686, 848). THIRD DIVISION OF PHYSIOLOGY. PROPERTIES OR POWERS OF LIFE. 164. A vital, or peculiar governing principle or power, in organic beings, has been recognized-by all the most distinguished medical philosophers at all ages of the science. It is the fundamental cause of growth, nutrition, and of all other phenomena of organic beings. It is, in all but the vulgar acceptation, synonymous with the term life ; and life, therefore, is a cause, and not an effect, as has been assumed by many distinguished physiologists. 74 INSTITUTES OF MEDICINE. 165, a. " Until it is proved," says Andral (the restorer of the hu- moral pathology), " that the forces which, in a living body, interrupt the play of the natural chemical affinities, maintain a proper temperature, and pieside over the various actions of organic and animal life, are analogous to those admitted by natural philosophy, we shall act con- sistently with the principles of that science, by giving distinct names to those two kinds of forces, and employing ourselves in calculating the different laws they obey."—Andkal's Pathological Anatomy. And, to the same effect, the distinguished organic chemist, Liebig, the chief of the school of pure chemistry (§ 4J): " There is nothing to prevent us from considering the vital force as a peculiar property, which is possessed by certain material bodies, and becomes sensible when their elementary particles are combined in a certain arrangement or form. This supposition takes from the vital phenomena nothing of their wonderful peculiarity. It may, therefore, be considered as a resting point from which an investi- gation into these phenomena, and the laws which regulate them, may be commenced; exactly as we consider the properties and laws of light to be dependent on a certain luminiferous matter or ether, which has no farther connection with the laws ascertained by investi- gation."—Liebig's Animal Chemistry. So, also, Carpenter, Roget, and other eminent chiefs of the physical school (§ 64). And thus, the eminent Muller, who leads in the school of chemico- physiology: " The only character that can be possibly compared in organic and inorganic bodies, is the mode in which symmetry is realized in each." " Whether the vital principle is to be regarded as imponderable mat- ter, or as a force or energy, is just as uncertain as the same question in reference to several phenomena in physics. Physiology, in this case, is not behind the other natural sciences ; for the properties of this principle in the functions of the nerves are nearly as well known as those of light, caloric, and electricity, in physics."—Muller's Physi- ology. Finally, we have the pure vitalist, teaching the same doctrine; though, with greater consistency. Thus : " Physiology," says Bichat, " would have made much greater prog- ress, if all those who studied it had set aside the notions which are borrowed from the accessory sciences, as they are termed. But, these sciences are not accessory ; they are wholly strangers to physiology, and should be banished from it wholly." " To say that physiology is made up of the physics of animals, is to give a very absurd idea of it. As well might we say that astronomy is the physiology of the stars."—Bichat's General Anatomy, fyc. Tiedemann, too, was right in saying that, " All the qualities of organic bodies should be looked upon as the effects of the vital powers. Even those phenomena seen in them, which they exhibit in common with inorganic bodies, undergo modifi- cations of their specific action, and should be considered subordinate to the vital powers."—Tiedemann's Physiology, 8fc. There is not, indeed, in the whole range of medical literature one author, however devoted to the physical and chemical views of life who does not evince the necessity of admitting a governing vital prin- PHYSIOLOGY.--VITAL PROPERTIES. 75 ciple as a distinct entity, distinct from all other things in nature. I say, there cannot be produced one author of any consideration, who does not summon to the aid of his discussion a vital principle whenever he touches upon the abstract phenomena of life. And this I have abun- dantly shown by an extensive range of quotations in my various pub- lications (Except 1034). 165, b. We are constantly asked, how we know the existence of the vital properties or powers 1 Again, I say, precisely by the same means as the advocates of the chemical and physical philosophy of life defend their knowledge of the forces which govern the inor- ganic world. The question is important, as implying that physiolo- gists either do not arrive at their knowledge of causes through their effects, or, that there is nothing different in the phenomena of organic and inorganic beings. What would the metaphysician say, were we to ask him for any other demonstration of mind than its manifesta- tions ; or the mechanical or chemical philosopher, should we demand any other evidence of gravitation, magnetism, chemical affinity, &c, than the effects which they supply? And do we not distinguish one from the other, and regard them as wholly distinct forces, by the dif- ference in their effects 1 The proof is clear and tangible, in all the cases. Where the results of power differ so materially from each other, it is as good a ground of argument, that the phenomena depend upon specific powers in one case as in the other; and, if it be " a cloak of ignorance" in either case to assume the existence of powers, it must surely appertain to him who attempts an explanation of the phenomena by assuming forces with which such phenomena have no known connection (§ 175, bb). 166. Many of the eminent ancient physicians considered the vital principle an intelligent agent; and even Hunter has been supposed, though erroneously, to have been of that opinion. Some distinguish- ed physiologists, of the present day, are inclined to regard the soul as that agent. Others confound it with the Deity ;* while yet others, confounding the Deity with Nature, fall into a labyrinth of absurdi- ties.t Others suppose the vital functions alone to constitute life 4 The ancient physicians generally distinguished the vital principle from the soul, and regarded both as immaterial (§ 175 d, 350| k). 167, a. The vital principle was early known underthe names of An- ima and Callidum Innatum. It was greatly lost sight of in the " dark ages," but reappeared among the earliest restorers of learning, when it took the name of Anima Vegetans, as significant of its organizing power in plants and animals. The eccentric philosopher, Paracelsus, substituted the name of Sidereal Spirit, to suit his dogmas of plane- tary and demoniac influence. Then came Van Helmont, with his in- novation of a Spiritus Archaus, an immaterial principle, which he lo- cated in the upper orifice of the stomach. It presided over the body in a general sense, and had under its command several subordinate spirits (one for each organ), to execute the orders of the great spirit. But, like Paracelsus, he expounded much of his physiological results upon chemical principles, and had no definite conceptions of the office of his Archaeus. Stahl followed Van Helmont with his Rational Soul, * See my article on the " Vital Powers," in Medical and Physiological Commentaries vol. i.; and my " Essays on the Philosophy of Vitality." t See my "Examination of Rcvieics," p. 43. J Comm., ut supra. 76 INSTITUTES OF MEDICINE. and Lord Bacon had entered the field in defense of a vital principle. Then came Haller, with his great philosophical and practical distinc- tion of the Vis Insita and Vis Nervea. Here we enter into the midst of the profound theories of irritability and sensibility, which had been suggested by Galen (§ 476, b). Glisson, too, had forced his way into the laws of irritability; and Baglivi had already dealt his fatal blows upon the humoral pathology. We may, therefore, date the progress- ive and substantial foundation of vitalism and solidism from Baglivi to Haller; a period of about one hundred years. 167, b. Whytt modified the Stahlian doctrine; and the visionary Des Cartes led the way in rejecting altogether, for awhile, the vital powers, in which he was aided -by the hypothesis of a nervous fluid, which appeared about his time. The doctrine then followed, as a consequence, that matter acquires vitality in virtue of a peculiar or- ganization, and this became an easy step to the atheistical doctrine of spontaneous generation. Then came up the view as set forth by Monro, Sir Humphrey Davy, and others, analogous to the Cartesian, that a living principle pervades the universe, and governs all things. Some of this school suppose the universal principle to be subordinate to the Deity; but a greater number, like Carpenter, Prichard, and especially many of our present geologists, as Lyell, &c, regard it as the Deity Himself, whereby the latter, either directly or by implica- tion, confound nature with God. The doctrine becomes, here, either atheistical or of a direct atheistical tendency; and we have, as a re- newed consequence, the assumption of spontaneous generation* 167, c. Those great luminaries, Hunter and Bichat, came forward in good time to rescue the philosophy of medicine from the degrada- tion with which it was threatened by chemistry and physics, and have left an impregnable shield to all future ages. 167, d. Tiedemann, too, soon after appeared with his " Physiology of Man," in which the doctrines Of life are ably expounded, and which must be ranked as one of the productions of an original mind. Tiede- mann could not believe that there was any sincerity in the absolute rejection of a peculiar governing principle of living beings. " How ever different," he says, " may be the names chosen by physiologists and physicians to designate this power, however various the ideas they attach to it, yet all must agree on the essential point, that of re- garding it as intended to maintain living bodies, vegetable and animal, and all their parts, during a certain space of time, in a state of integ- rity, in the composition, organization, and vital properties that are peculiar to them, and to render those bodies capable, at a certain pe- riod of their existence, of producing beings of the same species as themselves, which beings are confined to the same determinate mode of formation and development, and exhibit similar phenomena." " We are bound, therefore, to consider the principle which presides over those different acts, as a power inherent in all parts of living be- ings, and we cannot assume that, either in vegetables or animals it is limited to any one part or parts. All the parts of a plant, the roots, stem, branches, leaves, flowers, wood, and bark, are nourished. Nu- trition takes place in all the tissues and organs of animals. The con- * See Medical and Physiological Commentaries, vol. i., p. 25, and vol ii t, Ionian Also, "Examination of Reviews," p. 43 ; "Notice of Reviews," p. 4: "Ess'nv*™ v,-f«i ity," &c, p. 17. e ' ^ssays on Vital- PHVSIOLOGY.--VITAL PROPERTIES. 77 tinual tendency of this power to preserve the individual and all its parts, forms the prominent character of individual life, and is present- ed to us as the most important internal condition of life. This power not only converts the alimentary matters, drawn from without, into nu- tritive fluids, endowed with special properties and assimilated by it, but it also introduces them into the solid organic form, determines and regulates the composition, the organization, and the vitality of parts. Every living body is exposed to external influences, which urge it to manifestations of activity. Every one, however, under certain exter- nal circumstances, retains its form, its composition, and activity. Cer- tain external impressions, however, of a mechanical or chemical na- ture, and divers organic matters, vegetable and animal poisons, are able to annihilate this power* and thus to cause the death of the living bodies on which they operate." 167, c. Next came the illustrious Muller to aid in arresting the al- most universal onslaugh, in Europe, that seemed to threaten the ex- tinction of every sage in medicine from Hippocrates to the exit of Bichat. Under the magic wand of Andral, the venerable doctrine of humoralism reared its portentous form; while Louis substituted mor- bid anatomy for the science of pathology, and Liebig, and his school, with fire and acids, overrun the whole domain of medicine. Although Muller employs the language of Stahl, in relation to a vital principle, I think it rather designed as a forcible mode of ex- pression, than as imputative of intelligence. Thus, "this rational cre- ative force," he says, " is exerted in every animal strictly in accordance with what the nature of each part requires." The fact is truly stated; but it reposes on great laws of organization, not upon intelligence. That such is Muller's view appears from another expression, that, " the formative or organizing principle is a creative power, modifying matter blindly and unconsciously•" The radical fault of this philoso- pher consists, like that of Van Helmont, Stahl, Hoffmann, and Para- celsus, in referring many vital results of organic beings equally to a "vital creative principle" and to chemical forces.—See Muller's Physiology. 167, f. So remarkably different, however, are all the results of life from those of dead matter, that some of the shrewdest physiologists, of our own day, can scarcely avoid the chimerical theory of Van Hel- mont. Thus, even Marshall Hall: " The principle of action in the cerebral system," he says, " is the tpvx^], or the immortal soul. Upon the cerebrum the soul sits en- throned, receiving the embassadors, as it were, from without, along the sentient nerves; deliberating and willing, and sending forth its emissaries and plenipotentiaries, which convey its sovereign mandates, along the voluntary nerves, to muscles subdued to volition."f—t(Hall * See "Examination of Reviews," p. 26-28 ; also, this work,§ 189 h, 350| b. t I have somewhere seen it suggested that the doctrines of vitalism may be applied in support of animal magnetism. But, while vitalism is fundamentally opposed, even to speculative theory, and rests alone on the absolute phenomena of organic beings, it is not less true that, with rare exceptions, the medical advocates of animal magnetism are, as in ancient times, among the physical theorists of life (§ 844). Dr. Elliotson is of that de- nomination. (See Med. and Phys. Comm., vol. ii„ p. 137, 138.) And, although I have, in the foregoing work (vol. i., p. 632), expressed my opinion of the countenance which has been given to this imposture by distinguished members of the medical profession, I will add my entire concurrence in the following sentiments by Hannah More. In a letter to Hor- ace Walpole, dated 1788, she remarks, " I give you leave to be as severe as you please on the demoniacal mummery which has been acting in this country; it was, as usual with 78 INSTITUTES OF MEDICINE. on the Nervous System.) Here I suppose the " emissaries and pleni- potentiaries" to be nothing more than the nervous power, a property prodigies, the operation of fraud upon folly. In vain do we boast of the enlightened eigh- teenth century, and conceitedly talk as if human reason had not a manacle left about her, but that philosophy had broken down all the strong-holds of prejudice, ignorance, and su- perstition ; and yet, at this very time, Mesmer has got a hundred thousand pounds by animal magnetism in Paris. Mamaduc is getting as much in London. There is a fortune- teller in Westminster who is making little less. The divining rod is still considered as oracular in many places. Devils are cast out by seven ministers. Poor human reason, when wilt thou come to years of discretion!" (§ 844.) I may also add the followiug extract from the New York Journal of Medicine for March 1845 : " New York, Feb. 14, 1845. "Mr. Editor, " Dear Sir—In a letter of the 11th inst., addressed to myself, you desire me to state what I witnessed of the firmness of a young gentleman, upon whom the operation of ex- section of the inferior maxillary bone was performed by Prof. Mott, 'and the reflections to which it gave rise, as bearing on the subject of alleged surgical operations without pain m the mesmeric state.' "The case to which you refer is briefly reported in the January number of the New York Journal of Medicine, by some person, who, like myself, was present at the opera- tion. The subject is there stated to have been ' a fine intelligent young man, whose he- roic deportment greatly facilitated the operation.' " Perhaps it is enough that I should have quoted the expres'sive languaee of one who appears to have looked on with the same admiration as myself; though these examples of 'heroic deportment' are common enough in the walks of sure-ery, especially amon~ females- and that, too, without mesmeric imposture. The same eminent surgeon, who operated in the case which is the subject of these remarks, will tell you that he has extirpated many breasts, rendered highly sensitive by carcinomatous disease, without observing any evi- dence of pain. But there was something in the case of Mr. Baker, which certainly better deserved the encomium of ' heroic,' than any thing I had ever before seen, or heard of or even imagined as within the compass of human fortitude. " This case, therefore, is interesting at this moment, as evincing a perfect capability of enduring the most intense, and sudden, and prolonged pain, without emotion, and as form- ing a test by which ' the subject of alleged surgical operations without pain in the mes- meric state, will receive the explanation which you seek. "The case is also physiologically interesting, and interprets the composure of those or- game movements, under similar conditions, which has been set forth in behalf of animal magnetism. "To appreciate properly the 'heroic deportment' of young Baker, you must imagine yourself to have been a spectator; follow the able surgeon in'all the capital steps, anil in all the minor details of the operation, and watch attentively the ' deportment' of the sub- 'f, H^ £as, lal,d at a convenient elevation upon a table, his feet crossed upon each other, and Ins hands lapped. I mention this position, because he did not move his feet nor displace his hands during the operation. "Now observe the operator; first, making a long and deep incision among the muscles of the neck, and then tearing his way down to the carotid artery, and throwin- and tvin- the ligature. It was, in itself, one of the most capital operations in surgery "but, owing to the dexterity with winch itwas performed, and with an operation still before us far ESTmnS f '■? i°U>' and danfrous'thi* g^nd step toward the exsection of the jaw lost much of its usual interest to the spectator. But it was not the less painful to the sufferer; who, however, sustained it without betraying the slightest evident of nain "Next came the circular incision, reaching all the lay from the joint of tLmaxniarv bone down along its lower edge, up to tliS middle of the chirTnis was oWbv oZ rwt£eSLSL3^ 5^5-—^tfe^7f)d section, in which it became necessary to eiamer»t/ri?» .' yi?lon£ed' tedious, painful dis- ing vessels; till, finally, the operatoT was• ready*fo%'sfw^S nnri™^ T7 "fe* pened to elicit a single manifestation that the natie^wf* \ • notJlmS had yet hap- ceptmg that his eye? were open, and ttt toSS^^tf*"* slumber' «" hand of a capable assistant. Another p^ll however brou<^ wuf^ ^l* 1° ^ neither attempt was there any more indLtion of sufk^LlntawSt a°n£i Sma " Then came the process of sawing, and this wax r-nlmiotoii tn r__..i from a slight accident which happened to the 7aw, and whicl°£to the P^1 operation. Still, however, the same 'heroic depoZen!' dUtiSSffi fe?* ??" bearance of the sufferer, the same unexampled complacency continued to mtE ' r '" region.1118 ^ *" ^ ^ *"*** "*&* ^V^trt^Z^ PHYSIOLOGY.--VITAL PROPERTIES. 79 of the vital principle of animals, and whose modus operandi in devel- oping voluntary motion I have endeavored to expound in sections 233, 243, 500 d. 167, g. For the proof of the existence of a vital principle, and of the government of organic beings by laws peculiar to themselves, as derived exclusively by myself from their composition, see that divis- ion of this work, and my Essays on the Philosophy of Vitality; and for the proof which I have offered as founded on the phenomena of life, sec Essay on the Vital Powers, in Medical and Physiological Commentaries, vol. i., p. 1-119. 168. It is practically useless to investigate the nature of the vital principle. That nature, however, may be as well inferred through the medium of its phenomena, as the nature of the most tangible ob- jects. The opinion of Muller commends itself to every right-thinking mind. " Whether the vital principle," he says, "is to be regarded as im- ponderable matter, or as a force or energy, is just as uncertain as the same question is in reference to several important phenomena in physics. Physiology, in this case, is not behind the other natural sci- ences ; for the properties of the vital principle are as well known in the functions of the nerves, as those of light, caloric, and electricity in physics." " But, without, in the remotest degree, wishing to com- pare the vital and mental principles with the imponderable agents, we must express our conviction that there is nothing in the facts of natural science which argues against the possibility of the existence of an immaterial principle independent of matter, though its powers be manifested in organic bodies—in matter."—Muller's Physiology. " The bone being separated at the chin, the dissection was resumed among the impor- tant parts, and though conducted with all possible skill and rapidity, it was necessarily tedious, as well as hopelessly painful, and, therefore, still calculated to try the firmness of the stoutest heart. A great extent of all kinds of tissues was divided, and, of course, no small proportion of nerves. Bleeding vessels continued to be secured, the difficult divis- ion of the articulating ligaments performed with as much facility as its difficulties would admit; and after the removal of the jaw, remaining portions of diseased muscle, &c, were cut away, and which tended not a little to embarrass that ' heroic deportment' which had marked every stage of this great and triumphant operation. From its beginning to its ending, which occupied one hour and a half after the first incision till the final extirpation of all the diseased mass, the sufferer did not manifest the slightest evidence of pain, or of impatience, or of fatigue, either by language, gesture, expression of countenance, winking, groaning, sighing, or any other imaginable method by which the mesrnerite might be dis- posed to evade the overwhelming rebuke which the recital of this case cannot fail to in- flict on his love of the marvelous, or his love of mischief, or his yet more culpable designs on human credulity. " I have said that there was something physiologically interesting in the foregoing case beyond its simple merit of an 'heroic deportment,' and that it goes to the very depths of mesmeric assurance and duplicity. It was this : " On feeling the pulse of the patient twice during the operation (the last time after the lapse of an hour), I found it calm, undisturbed, and with about the same frequency it had before the operation was begun. This proves to us what I have before expressed, that it is not pain, but the consequent mental emotions which affect the organs of circulation, whether the heart or blood-vessels. "Thus ended an operation, unequaled in the annals of surgery; alike triumphant to the surgeon, to American Genius, to the admirable subject, to the cause of truth, of moral- ity, and" of sound religion. '■ If you desire it, you may publish the foregoing statement, to which I should add some comments had I not already contributed my part, in a medical work, toward the sup- pression of one of the greatest nuisances that has yet infected the moral and reflecting part of the community. I have, however, some developments in reserve, which will prob- ably see the light when the parties interested may be beyond the reach of greater re- proof or mortification. " I remain, very truly, your friend and obedient servant, " Martyx Paine." 80 INSTITUTES OF MEDICINE. In the language of Liebig, " In regard to the nature and essence of the vital force, we can hardly deceive ourselves, when we reflect, that it behaves, in all its manifestations, exactly like other natural forces; that it is devoid of consciousness, or of volition, and is subject to the ac- tion of a blister" (§ 165, a). 169, a. We know, however, but little of the nature of the princi- ple of life, and as little of the most obvious material substances; but, while this proposition is sufficiently plain, it is extensively ar- gued that the vital principle, or organic force, has no existence, be- cause it is not obvious to the senses. Thus neglecting its infinite phenomena (our only knowledge of the most sensible existences), the age has run into a materialism that takes in its way the soul itself. Our great interest lies in the phenomena of nature. Through these phenomena their causes may be sought; their nature but very imperfectly. We can only describe matter by its manifestations; and so of the soul, and the principle of life. Of the nature of the soul, however, we have, as it respects its spirituality and some other important attributes, a special Revelation. 169, b. If organized beings possessed a principle of life that could, like light, be seen, they would then be allowed to be governed by this agent, and we should be relieved of the encumbrance of the phys- ical and chemical hypotheses. But, though no such principle ad- dress itself to the sight like electricity or light, its existence is far more variously attested by other phenomena, and more so than all the other powers of nature; and these phonomena being wholly dif- ferent from such as appear in the inorganic world, it is prima facie evident, that powers or properties which are predicated of them carry on the processes of health and disease; while the scrutiny of ages has never produced a fact in opposition. 169, c. Indeed, with so much light upon our subject, so much of fact to substantiate our conclusions, it would seem highly probable that all the facts which may be raised in opposition have no relative bearing, and that they are brought forward in the spirit of hypoth- esis. 169, d. The more comprehensive a law may be, the more readily is it known and determined, and the less likely is it that apparently conflicting facts will arise. Whenever such are produced, it is ow- ing to a proper want of investigation. The facts are examined su- perficially ; and the speculative or the credulous mind seizes upon some prominent characteristic, and pushes its opposition to nature under the spur of novelty, or the delight of discovery, or the goad of ambition. J ° Since, also, we seek, alone, for the existence and the nature of causes by means of their phenomena, he is no philosopher who refu- ses an inquiry into causes from want of other means of information. The objection has never been raised in any science excepting medi- cine; but here we are told by many, that we have no means of reaching even the existence of the properties of life as contradistin- guished from those of inorganic matter. It is this blindness, in part which refuses to apply to the science of life the universal fact that the phenomena are the only index to the forces which govern the i game world, that has embarrassed the progress of medicine and cumbered it with a spurious philosophy. ' mor- en- PHYSIOLOGY.--VITAL PROPERTIES. 81 169, e. Conscious, then, that I have taken my stand upon ground which true philosophy will recognize as her own, I shall go on with an investigation of the properties of life, as the source of all vital phenomena, of all morbid conditions, and which constitute life itself, and lie at the foundation of medicine. I shall enter far more exten- sively into an analysis of those properties than any other writer, shall set forth original views as to the character and office of the nervous power, and as to the mode in which this power participates in the operation of remedial and morbific agents, and endeavor to show, also, that, in proportion as philosophy may depart from the deduc- tions which are founded on the phenomena of living beings, so must all such philosophy be fundamentally false, and become the unavoid- able cause of practical errors of the highest moment. 169, f. Nor is it a small part of the proof that vitalism is founded in nature, that it is consistent throughout; seeking no multiplication of causes, but serving as an impregnable and universal foundation for every fact and every rational principle in physiology, pathology, and therapeutics; and, therefore, uniting all the principles relative to life, health, disease, and the art of medicine, into one consentane- ous, harmonious whole. What a contrast with the mechanical and chemical speculations, or those commingled with vitalism ! What a boundless source of stupendous philosophy for the votaries of one ; what unmitigated confusion, and corruption of knowledge, and mis- application of mind, for the disciples of the other! How truly, and with what sublimity on the one hand, and imbecility on the other, is here exemplified the great distinction between man and his Creator, that the former devises in parts that may have no congruity, while the latter perfects the whole and all together (§ 63, &c, 74, 80, 117, 137, 143, 155, 156, 266, 323-326, 387, 399, 514 A, 524 d, 526 d, 638)! 170, a. The vital principle is a whole, in respect to its substantial nature, and is common to vegetables and animals. Organic matter, or an organized substratum, is necessary to its existence; and, since the perpetuity of organic matter depends upon the vital principle, it is manifest that both were brought into being without the agency of each other. The vital properties cannot be generated by matter, since upon them the existence of organization depends, nor is there a single phenomenon that indicates their presence in inorganic sub- stances ; nor can they be produced by the forces of physics, since they are perfectly incapable of restoring the structure, or even its elementary composition, after the organized matter is decomposed; or, of reanimating the machine before decomposition has begun ; while, on the other hand, these are the forces which lay waste the structure, and only so, after the signs of the vital properties shall have totally disappeared. This unavoidable deduction goes far in confirming the Mosaic ac- count of the different steps observed by the Almighty in the creation of living beings; that the sensible structure was first produced, and the spiritual and vital existences superadded.* The rudiments of that organization have been perpetuated in connection with the prop- erties of life since they came from the hands of the Creator, and are the present source of all animated beings. Any doctrine adverse to " See Medical and Physiological Commentaries, vol. i., p. 86-92. 82 INSTITUTES OV MEDICINE. this is not only atheistical, but is opposed to all the suggestions of reason* (§ 74, 350| k). Nor is this all. The varieties in the differ- ent tissues of each animal, and of every plant, all the modifications of the vital properties in each species of animals and plants, in each tissue, and in every part, as already set forth (§ 133, &c), and to be yet expounded, all the various functions that correspond to the mod- ified structure and vital properties, all the secretions, even to the od- or of flowers, &c, are exactly the same now as at the day they were called into being. This shows us that the properties and laws by which organic beings are governed, though infinitely varied, are as precise as the principle and laws of gravitation, as the conditions of the solar beam and the laws which they obey. 170, b. Again, the moment inorganic matter is brought into a state to receive the vital principle, however low in degree or energy, it must be exalted to an organic condition. If chyle, blood, semen, the gastric juice, &c, possess life, so, also, must they possess an or- ganic state. This, indeed, is obvious from what we have seen of the manner in which their elements are united. 170, 6. The living principle appears, therefore, to be neither the result of organic compounds, as supposed by Hunter and others, nor, as stated by Prout, Millengen, and others, the primary cause of organic conditions. Both have coexisted since they were the prod- uct of Creative Power, both are necessary to the vivification of dead matter, and the co-operation of both to the farther development of each. 171. The vital principle appears entire in parts when separated from their connections, if such parts be constituted with the requisite structure for independent nutrition (§ 304). Hence the development of the egg, the germination of seeds and flower-buds, the growth of shoots, and the multiplication of polypi from portions of the animal. Muller, and others, suppose the vital principle to be divisible in such cases; but this construction regards the principle too much in the light of ordinary matter, and too little in that of a specific sub- stance endowed with a variety of properties. These properties, so far as necessary to organic life, are implanted m every part, and each part may be regarded as a whole as it respects its own organic con- dition. In simple beings, therefore, where no great complexity of organs is necessary to the great final cause, nutrition, many parts of such beings may be capable of carrying on the process independent- ly of the rest _(§ 299, 302, 304, 322). It is probable, therefore, that the vital principle, in the foregoing cases, is no more "divided" than the soul or instinct as implanted in the ovum.—Medical and Physio- logical Commentaries, vol. i., p. 85, 87. 172. The principle of life, or life itself, may be summarily defined as a cause, consisting of certain specific properties, appertaining to organic matter, capable of being acted upon by external and internal physical agents, by the nervous power, and by moral causes, and of thus being brought into a state of action itself, and in no other way. Its action is exerted upon the organism, and upon certain external sub- stances, as upon food. In the former case its action gives rise to mo- tion, upon which all the functions depend; in the latter its operation * See Med. and Physio. Comm., vol. ii., p. 123-140. Also, "Examination of Reviews p. 43; and "Notice of Reviews," p. 2, &c., in "Med. and Physiolog. Comm.," vol. iii. ' PHYSIOLOGY.--VITAL PROPERTIES. S3 is through the medium of the gastric juice in animals, but is more obscure in vegetables. The principle is creative so far as it combines she elements of matter in peculiar modes, and arranges the compound molecules into tissues and organs, and in modes identical with those which came originally from the Creative Energy of God, AVho thus far imparted to the principle of life a formative endowment. The principle is capable of protecting the matter which it endows against the decomposing influences of all the physical agents by which it is nat- urally surrounded, while the extinction of the principle exposes the or- ganic substance to an intestine chemical dissolution, and to the decom- posing action of surrounding agents, which proceeds with a rapidity without parallel in the natural state of the inorganic world. The principle is also susceptible of certain limited changes from the in- fluence of causes, moral and physical, which constitute the essence of disease; while other causes are capable of modifying the morbid changes in such wise that the principle of life takes on a restorative energy, through which it recovers its normal condition. The prop- erties of the vital principle are variously and naturally modified in different parts, and undergo natural modifications at certain stages of life, giving rise to changes of organization, &c. (§ 62, 64, 133, &c). These natural modifications will be farther explained in all the detail which is demanded by one of the most important topics in physiolo- gy ; and I now proceed to the various specifications relative to the principle of life. 173. It is the special province of the vital principle in plants to combine the elements of matter into organic compounds ; while in an- imals it can only appropriate compounds of an organic nature. This is a fundamental distinction between the two departments of the or- ganic kingdom; from which it appears that plants are indispensable to the existence of animals (§ 1052). 174. The vital principle is subject to extinction, and this consti- tutes death. When speaking of the composition of organic beings, I adverted to the manner in which they resist the decomposing effects of chemical agents, and how the seed and egg are capable of being converted into complex living beings, or the whole animal and vege- table kingdom of being resolved into their ultimate elements, by the action of heat, air, and moisture. The same structure remains in either case, when life is suddenly destroyed, and the exact difference which arises in the two cases, from the influence of the same causes, can be owing only to the presence of peculiar powers in one case which have disappeared in the other. The cessation of the phenom- ena of life is the consequence of death ; and, there is nothing to die (certainly not the forces of chemistry), but the principle of life upon which the phenomena depended, and which held the elements of structure in vital union (§ 584, 633). 175, a. As set forth in the Medical and Physiological Commentaries, 'I believe the vital principle, vital power, organic force, organic power, are one substance, whether material or immaterial; and they refer, with me, to a universal cause of animal and vegetable life, or, rather, as constituting life itself. I.believe, also, that this principle has vari- ous attributes, common or generic, and partial or specific ; or perhaps I should call the former distinct properties. Thus, of the generic, wo have irritability, mobility, sensibility, &c, and the modifications of 84 INSTITUTES OF MEDICINE. each of these in the same or different tissues form the specific or par- tial variations. These properties are also constantly varied m dis- ease, and these variations I call changes in kind. The partial modifi- cations in their natural state I designate as variations in kind" (§ 133- 163, 171). . . . . j 175, b. The vital principle has certain analogies with the mind or soul, and with the instinct of animals (§ 241). Each is inherent in or- ganic matter, and the operations of each are through the medium of that matter. Each, respectively, is one substance, and each possesses certain distinct attributes or properties. Each is not only capable of acting by means of organized structure, but of being acted upon, and modified in its nature, and only so in conjunction with that structure (§ 189, 191, 234/, 241, 566-568). Even in the inorganic world we meet with a substance which is not without its light in the way of analogy. This substance is light itself. It is apparently one homogeneous, imponderable, substance, yet has a multitude of distinct component parts, each of which is en- dowed with specific attributes. These component parts, however, are distinct entities, which I do not recognize in relation to the proper- ties of the vital principle, or of the soul. But the distinction is not im- portant to my present purpose. The materialists necessarily regard the properties of life and of the soul as so many separate existences, whether imaginary or real (§ d, 188^ d, 222, &c, 234 e). 175, bb. It has been well said by Professor Draper, that " Just in the same way that I am willing to admit the existence of forty different simple metals, so, upon similar evidence, I am free to admit the existence of fifty different imponderable agents, if need be. Is there any thing which should lead us to suppose that the imponder- ables are constituted by Nature on a plan that is elaborately simple, and the ponderables on one that is elaborately complex ] That the former are all modifications of one primordial ether, and the latter in- trinsically different bodies, more than a quarter of a hundred of which have been discovered during the present century ?" " We are thus forced to admit that rays of light, rays of heat, ti- thonic rays, phosphoric rays, and probably many other radiant forms, have an independent existence, and that they can be separated, by proper processes, from each other."—Draper's Treatise on the For- ces which produce the Organization of Plants, p. 70, 71. Organic life, however, needs only a single principle, or " imponder- able," till it be shown that its supposed properties are individual ex- istences (§ 165, b). 175, c. I have presented in the Commentaries, in the Essays "on the Vital Powers," and " Spontaneous Generation," and my " Notice of Reviews," certain facts which go to the conclusion that the mind or soul is a distinct immaterial substance, and that the instinctive principle of animals is equally a distinct substance from the brain. I will now add a few words, physiologically, in respect to the main ar- gument of the materialists, drawn from analogy, that the mind, like the gastric juice, the urine, &c, is only a product of the functions of the brain (§ 1076, c). The analogy is fictitious. Both the mind and instinct are entirely wanting in every known attribute of the product of other organs, and are sui generis in all their characteristics. This is sufficiently obvi- PHYSIOLOGY.--VITAL PROPERTIES. 85 ous. But there are other considerations which establish the distinc- tion more fully, though they appear not to have engaged the attention of physiologists. What, for example, is the efficient cause of the pro- duction of bile, urine, &c. 1 Certainly the blood, in connection with organic structure and organic actions, and while these actions go on, bile, urine, &c, are uninterruptedly secreted ; or, if arrested, it is from the failure of the organic processes. But, it is just otherwise in re- spect to the mind and the instinctive principle. These are completely suspended in all their manifestations during sleep, and often so with great instantaneousness. And yet there is every reason to believe that the organic functions of the brain continue to move on as per- fectly as those of the liver, the kidneys, &c.; especially when it is con- sidered that sleep may happen in almost the twinkling of an eye. Indeed, were any change to befall the brain, it should be more or less manifested by some consequent modification of all the organic actions ; particularly as those of animal life undergo complete suspension. Again, other peculiarities which contradistinguish the mind and instinct from every organic product are the quick transitions from sleeping to waking, and the occurrence of the change without any change in the organic functions of the brain. Take in connection the act of sleeping and the act of waking,—the instant suspension and the instant reproduction of the intellectual operations, and in all their isolated aspects, and the most obtuse understanding must concede not only the entire want of analogy with any other phenomena of nature, but that there must be a unique cause for such perfectly unique effects. But, again, suppose some change in the organic condition of the brain as the cause of sleep; what is it, I say, that so instantly rein- states its functions when we pass from the sleeping to the waking state ] What rouses the organ to its wonted secretion of mind 1 Are there any analogies supplied by the liver, the kidneys, &c. (§ 241) 1 What is it, I say, that brings the great nervous centre into operation in all the acts of volition, in all the acts of intellection 1 This ques- tion must be answered consistently, or in some conformity with the argument drawn from analogy. If that can be done, then it must be conceded that the analogy is irresistible, and the argument in favor ot materialism incontrovertible. So, on the other hand, should the ar- gument fail in this indispensable requisite, materialism must stand convicted of sophistry, insincerity, and a leaning to infidelity (§ 14, c). The premises are perfectly simple. They are also sound so far as it respects all organic actions and results. The blood, as with all other organs, is the natural stimulus of the brain, and here as there all the organic phenomena are distinctly pronounced. They proceed, in all parts, with uniformity, and without interruption. Nothing can suspend them or modify them in the brain, or elsewhere, during their natural condition. So far the analogy is complete. Now, as it can- not be the blood, according to the analogy, which rouses the brain to action in willing, reflecting, &c, I ask the materialist the nature of the stimulus which operates upon the brain in eliciting the phenomena of mind 1 And again, I say, if he can sustain his answer by analogy, such is the consistency of Nature in organic philosophy, such the har- mony of Design, that it would be in vain to oppose Revelation itself to what is so fundamental in Nature. 175, d. It is assumed by many late physiologists, as Drs. Carpen- 86 INSTITUTES OF MEDICINE. ter, Prichard, &c, after admitting and denying the existence of vital properties, and contending for their existence in the elements of matter, and the organizing agency of the forces of chemistry, that, nevertheless, all the results of organic beings are owing to the im- mediate acts of the Almighty (§ 64, h). This, therefore, as with the author of the " Vestiges of Creation," is only a circuitous method of confounding nature with God (§ 350f 7i-350| I). Let us, how- ever, suppose that there is a Supreme Being in their opinion, who is the Author of nature, and that He is the Power who presides in or- ganic beings, and regulates all their processes, and we shall see that the doctrine abounds with absurdities. Its advocates generally carry this sophistry so far as to affirm that the particles of matter are con- stantly maintained in union by Almighty Power, that chemical affini- ties are nothing but manifestations of that Power, that gravitation is only a constant emanation of the Deity, that digestion, circulation, secretion, excretion, &c, are only immediate acts of God. It is plain, therefore, that they can allow no other God than nature. But, let us now look physiologically at this hypothesis. Organic beings are made up of matter, which, it will be conceded, is distinct from God, if we allow his existence as distinct from matter. It is therefore perfectly consistent to suppose that this,matter is endowed with distinct forces for its own government (§ 14, c). If we regard next, the results of vital stimuli, we have a palpable proof that they elicit actions and physical results through principles which possess the power of acting, or we must take up the absurdity of supposing that they act on God himself. The same may be affirmed of the poisons medicinal agents, &c. But this will not hold either in religion or philosophy. Nevertheless, it is evident that some active agent is op- erated upon. If stimulants are applied to the nose, the heart may be thrown, on the instant, into increased action. Of course, it cannot be entertained that God is the agent acted upon in such a case, any more than when prussic acid destroys life with the same instantaneousness • and, therefore, He cannot be assumed as the cause of the healthy and natural functions (64 h, 241 d, 350| #-350£ o, 3764, 733 d) ,L T1^7! "N?tlc'°f ^views" (in Comm., vol. iii.) I have shown hat the doctrine of » the properties of 'life in the elements of matter" is thoroughly material as it respects the soul (§ 14 c, 189 i 3503 I m) 176. Besides an organized substratum and a principle of life there is something still beyond not less important to all the great purposes oi lite. I his consists of the actions and various results of life If all animated beings existed in the state of the seed and ovum the whole universe would be nearly without any other apparenlarima Slsst :otrC:fofhpeotarnly bodies would be the *™d^de- Although therefore, the actions and phenomena of organic beino-s like the motions of the heavenly orbs, are merely the effects of a le culiar power which we call life, they are, nevertheless, the tmlv*" endants of life hat interest our senses beyond the physical stUc Lure. Hence, it is not remarkable, considering how liable S, are to take the lead of the understanding: thatTven tL "T68 minds have supposed that life consists ^HoST eThave overlooked the great efficient cause or power upon which the results PHYSIOLOGY.--VITAL PROPERTIES. 87 depend (§ 234 g, 247). Had they considered for a moment, however, the analogy which subsists between the motions of organic beings and those of the heavenly orbs, and that the latter depends upon a power which is called gravitation, and without which all the orbs would suffer the stillness of death, the conclusion would have been unavoidable that celestial motion is merely an effect, and, therefore, that all organic motions and their results depend upon moving pow- ers. They should have seen, too, that when a drop of prussic acid, or of the spirituous extract of nux vomica, is applied to the tongue, all the phenomena of life are instantly extinguished, that nothing can reproduce them although the organized structure remains unimpair- ed, and that the whole being is immediately resolved into its ultimate elements (§ 1042). 177. The properties of life are the fundamental cause of all healthy and morbid phenomena. They are liable to be more or less diverted from their natural state by a variety of causes, and these new condi- tions constitute the most essential part' of disease. This instability of the properties of life is at the foundation of all disease, and even of therapeutics (§ 642, b). Other causes, acting upon these morbid conditions, alter them in yet other ways, and contribute to their res- toration to the natural standard. This is the aim of all our remedies ; and the recuperative tendency of the properties of life (the vis medi- catrix natures), when they are driven by morbific causes from their healthy state, enables them to recover spontaneously from the artifi- cial conditions which are substituted by remedial agents for the more intensely morbid (§ 172, 893, 1041). 178. Notwithstanding the natural instability of the properties of life, they have a definite character in every part of the body, accord- ing to the nature of each part, at every hour of existence (§ 153-156). 179. The exact nature of disease depends mostly upon the forego- ing definite conditions (§ 178), and upon the particular virtues of the morbific agents. The salutary changes produced by remedial agents involve the same principles. But, these definite changes, and the ac- tion of morbific and remedial agents, are liable to contingent influen- ces from habits, &c.; as set forth under the fifth division of Physiol- ogy. Our calculation of results is thus embarrassed according to the nature and extent of the contingent influences (§ 756, b). 180. The vital properties are without renovation, or mutation in health, except as they are liable to certain natural modifications at different periods of life, or during gestation, or from the slow opera- tion of external agents, as in the artificial temperaments. They must remain without renewal, to be forever ready for the work of nutri- tion, &c. (§ 237). 181. The permanency of the vital properties enables us to under- stand the nature of predisposition to disease, artificial temperaments, and hereditary diseases, which many refer to the ever-changing blood (§ 238, 666). 1S2, a. According as the vital properties may be modified, either in the foregoing manner (§ 181), or as in disease (§ 177), so will be the condition of the elementary combinations, and other physical products. 182, h. Nevertheless, the properties of life never undergo any rad- ical change till they shall have passed the limit of their recuperative 88 INSTITUTES OF MEDICINE. power (§ 177), and are therefore approaching a state of extinction. Hence, essentially, in connection with the nature of the remote causes, the analogies among diseases (§ 670, 855). 183. In their highest development, the properties of the vital prin- ciple are six; namely, irritability, mobility, vital affinity, vivification, sensibility, and the nervous power (§ 175). They are called vital prop- erties, vital powers, and vital forces; but are clearly attributes of a common principle, just as judgment, perception, the will, &c, are properties of the soul. They will be examined according to their nearest relations to each other in the most perfect beings, and their practical application. 184, a. The first four properties (§ 183) are common to plants and animals, and reside in all the tissues. They may be properly called organic properties, as they carry on the organic processes (§ 476-492, 516 a). The last two are peculiar to animals. This multiplication of vital properties in the animal kingdom harmonizes with the intro- duction of tissues and organs which have no existence in plants (§ 201, 222, 232, 450, &c, 500). 184, b. The nervous power has been considered a principle by itself, and often regarded by eminent physiologists as the galvanic fluid, generated by the brain, or other organs, and conducted by the nerves (Med. and Phys. Comm., vol. i., p. 65-68, 107-119). Its phe- nomena, however, declare it to be entirely distinct in its nature from all things else; while its analogies to the other properties of life show it to be an element of the vital principle (§ 227-232). If it be diffi- cult for the limited comprehension of man to surmise how this prop- erty should prove an agent to others with which it is associated, the difficulty is no greater than the admitted fact that the will may con- trol other properties of the mind, and the passions. Nevertheless, it is unimportant.in a practical sense, and in the institution of principles, whether the nervous power be considered an element of the vital principle, or a principle by itself (§ 175 bb, 186, 226, 1072 b). 185. Although the organic properties which are common to plants and animals are essentially the same, they possess greater modifica- tions throughout than will have been seen to appertain to the same properties in the different parts of animals. But all the variations in the two organic kingdoms are intimately connected by close analo- gies ; just as they are in the different animal tissues (§ 133, &c.). Much of the difference in the general vital constitution of the two kingdoms is owing to the presence in one, and the absence in the oth- er, of the nervous system, and those corresponding properties which play so important a part in the animal tribes (§ 733, f). In both de- partments of organic nature, however, there is, essentially, the same principle of life, its great organic elements, and the same great func- tions over which they preside. Here, too, in the vegetable kingdom, in the modifications of structure and of the organic properties and functions, and of the laws which they obey, we witness the greatest simplification of life. The vegetable tribes, being also exempt from most of those secondary influences which so constantly embarrass our inquiries in more complex organization, especially from the compli- cations that arise from nervous influence, are better subjects for the experimental researches which concern the philosophy of life ; and the facts, therefore, which they supply may be carried up, for the PHYSIOLOGY.--VITAL PROPERTIES. 89 same general purpose, as sound analogies, to more complex beings (§ 191 a, 409, 733, 853,1052). 186. The mental property, perception, is necessary to the exercise of specific and common sensibility, and the will to that of mobility as modified in the function of voluntary motion (§ 194, &c, 226, 241, 243, 500 e). Here we have not only other analogies between the in- tellectual and vital principles, but each is brought into direct action with the other (§ 175, 184 b). 187. The vital properties co-operate together in their functions, more or less, as they exist in any given being. I875. The conditions now mentioned as to the principle of life, as well as all those to be hereafter stated, and the phenomena of which they are predicated, form other groups of facts, which, individually and collectively, contradistinguish the principle of life from all the forces of inorganic nature (fy 1041). irritability. 188, a. Irritability belongs to all tissues, and is the property upon which all vital agents, external and internal, physical and moral, nat- ural, morbific, and remedial, produce impressions in organic life ; ex- cept as sensibility is concerned in the function of sympathy (§ 201-203, 226). If motion follow, the impressions are transmitted to mobility, by which that property is roused into action, when motion ensues as a consequence. All actions or motions, in animal as well as organic life, are brought about by impressions on irritability (§ 205, 233, 257, 486, 500). This may be either by the direct action of the agent, or by the indirect action of the nervous power (§ 222, &c). When vital agents affect the organic functions in a direct manner, it is by direct action upon the irritability of the parts which perform the functions. This is true, in part, of the natural excitants of organs; as blood acts directly upon the irritability of the heart and blood-ves- sels, bile upon that of the intestines, food upon that of the stomach, &c. In these cases, however, influences are also transmitted through sympathetic sensibility to the nervous centres, and thence propagated to the muscular tissue of the organs (§ 201, 514 f). So, also, reme- dial agents operate upon the irritability of parts to which they are ap- plied, and thus affect their functions in a direct manner. But their influences are commonly more extensive, and then they call into op- eration the nervous power by their action upon sensibility (§ 201), thus giving rise to the function of sympathy (§ 222, &c, 500). When mental emotions affect the organic functions, it is by deter- mining the nervous power upon the irritability of the parts (§ 226, 227). And, although sensibility receives the primary impressions in the function of sympathy, the resulting influences upon organic actions are brought about by a determination of the nervous power upon the irritability of the affected organs (§ 201, 226, 227, 1041). 188, b. When vital agents act upon specific sensibility, the results of their impressions are merely their propagation to the nervous centres, and a consequent action upon those parts (§ 194-204, 222-234). 188, c. I shall endeavor to show that the doGtrine is entirely unfound- ed which supposes that vital agents produce their effects in organic life by direct impressions upon the nervous system, excepting so far as sympathy is concerned. This demonstration, indeed, was made in 90 INSTITUTES OF MEDICINE. the Commentaries, but mainly by other processes than will be present- ed in the Institutes. The fact alone, however, should be adequate, that plants have no nervous system, yet carry on all the essential or- ganic processes that exist in animals; while they are alike liable to corresponding results from the operation of morbific and remedial agents. . . . . 188^, a. Every thing which is capable of affecting irritability, and sensibility, is a vital agent. These agents are either natural to the body, as blood, heat, bile, &c, or external, as food, air, heat, light, electricity, &c. Irritability is perpetually alive to the stimulus of blood in all parts of the sanguiferous system, as it is to that of the sap wherever it circulates (§ 136). This shows the exquisite suscep- tibility of the property. 188|, b. Many vital agents, those just mentioned, are indispensable to the maintenance of organic processes, either in animals or plants. Hence, from maintaining the organic powers in constant action, they are called vital stimuli. Those of a morbific or remedial nature are known by these epithets, though, in a philosophical sense, they are vital agents. They are distinguished by very different characteristics from the natural agents of life ; even all those which are stimulant to the organic processes; for they not only excite the properties of life, but are capable, also, of affecting their intrinsic nature. But, there are others, whose effect, in certain degrees of intensity, is directly the reverse of the foregoing, as hydrocyanic acid, tobacco, &c.; and these, when thus operating, are vital depressants (§ 441 d, 650, 743). 188|r, c. Some of the vital stimuli which are natural to the body, as blood, and bile, and also food, subserve other purposes than that alone of rousing the action of organs. They are also acted upon and appropriated to the uses of the system. This is more extensively true of animals than of plants. In the latter case there are certain external stimuli which are indispensable to vegetation, and whose only operation is that of excitants, but which are comparatively un- important to animals. These agents are particularly light and heat, and perhaps electricity. The heat which is most important to animals is generated by the living organism. 188£, d. An important error has prevailed among chemists, from their necessary want of physiological knowledge, in regarding the imponderable agents as the causes of life, and not as mere stimuli to those real causes which are implanted in the organization itself, and by which, of course, all the actions and results are determined. This vitiation of philosophy has beset, especially, the functions of animals as it regards their assumed dependence on electricity, and the func- tions of plants in their obvious dependence upon light. The fallacy of the former hypothesis is shown extensively in the Medical and Physiological Commentaries (Essay on the Vital Powers and its Ap- pendix). Of the latter I will now say, that in all the relations of light to plants, we have the most distinct analogies, with other vital stimuli to guide us to the same certain conclusion, that, like other stimuli, it does but rouse the properties of life to certain special modes of ac- tion, by which they decompose carbonic acid gas, carry on the work of appropriation, &c. But, thanks to my colleague, Professor Draper, whose name in early life glows, upon the sunbeam, organic science is supplied with PHYSIOLOGY.--VITAL PROPERTIES. 91 an adornment which vies in delicacy, yet sublimity, with the attri- butes of the nervous power (§ 222, &c, 234 e). The professor has obligingly furnished me with the following state- ment of the progress, and nature, of the discoveries in relation to the solar beam. Thus : " Until the time of Sir Isaac Newton, it was universally supposed that light was a simple elementary body, and therefore incapable of decomposition. '• The great optical discovery of Newton consisted in proving that the white light of the sun, or of day, is in reality made up of many colored varieties. He fixed the number at seven: red, orange, yel- low, green, blue, indigo, violet. He indisputably established that that which we commonly call light is made up of, and therefore con- tains, the seven prismatic rays. They differ not only by impressing the organ of vision with different sensations, but also in intrinsic brill- iancy or illuminating power. It is to be remarked that of these the yellow is the brightest. " It was the opinion of Newton, and his followers, that when light falls upon bodies and disappears, it is converted into heat; or, in oth- er words, that heat is extinguished light. Sir W. Herschel, the as- tronomer, proved the separate and distinct nature of these principles. The proof chiefly depends on the fact that the brightest ray is not the hottest, and that in the sunbeams there exist rays in abundance which are wholly invisible, but which can rapidly raise a thermometer. That which we cannot see we should scarcely call light. Moreover, a vessel of hot water in the darkest place is invisible; yet common observation shows it is emitting calorific emanations. The independ- ence of light and heat may therefore be considered as established. " Some of the alchemists discovered that certain of the white salts of silver (the chloride) turned black under the influence of the sun- shine. Toward the dose of the last century it was shown that the rays which produced this effect were invisible, and therefore could not be regarded as rays of light. At a later period I showed that they could not disturb a thermometer, or communicate to our organs the impression of warmth, and therefore must be distinct from heat. From the circumstance that they are always accompanied by light, I gave them the provisional name of Tithonic rays, from the fable of Tithonus and Aurora. " The same species of modification which light exhibits (as colors) has been traced by Melloni for the rays of heat, and by me for the Tithonic rays. But, as both these classes of rays are invisible, their coloration must be necessarily so too, and is known to us only by in- direct facts. We speak of it, therefore, as ideal or imaginary. There are seven colors for heat and the chemical rays, as there are seven for light. " It is worth remarking how complex the constitution of light is now understood to be, when contrasted with the opinion held by the predecessors of Newton (§ 183, &c). " I have established, as respects some of these rays, that they dis- charge extraordinary functions. It is the yellow ray of light which has control of the evolution of plants. Under its influence their leaves effect the decomposition of carbonic acid gas in the atmosphere, set- ting free its oxygen and fixing its carbon. This wonderful phenom- 92 INSTITUTES OF MEDICINE. enon is unquestionably the first step in the production of organized matter, such as starch, woody fibre, &c, from inorganic gases. The carbon is first fixed under the form of chlorophyll in the leaf. Chloro- phyll occurs under remarkable circumstances as the coloring matter of bile. " Extended investigations have shown that each particular ray of these principles exerts specific powers. The compounds in which silver enters are affected by those of a violet color; chlorine is most acted on by the indigo; and carbon by the yellow. It is for this rea- son, as I have shown, that to the animal eye the yellow ray is bright- est. If nature could have formed a retina of which silver was the basis, the indigo would have been the most brilliant ray. All our conceptions of beauty in colors depend, therefore, on the physical pe- culiarities of the carbon atom. And it is a beautiful and interesting fact, that the ray which evokes from atmospheric air the multitude of forms composing the vegetable world has charge of the process of vision in all animals. " Dr. Gardner discovered that the movements of plants are chiefly directed by the indigo rays of light. They grow in the direction in which it falls upon them; and the blue color of the sky is one of the causes of the upright growth of stems. " Besides the three classes of rays which I have mentioned, there is a fourth, of which much less is known; the phosphorogenic rays. These take their name from the fact that when they fall on certain bodies, such as the diamond, Canton's phosphorus, &c, they cause them to glow with a pale or splendid light. The extraordinary pecu- liarity they possess is, that glass is opaque to them. " The advance of chemical optics has sufficiently proved that each of the constituent rays of the sunbeam, or of light derived from arti- ficial sources, has capabilities of its own. Thus, each of the seven rays of light impresses our minds with special sensations. The yel- low, moreover, controls the growth of plants, the indigo their move- ments. Of the Tithonic rays, the blue is the one concerned in Da- guerreotype portrait taking, and the red can bleach paper blacked with oxide of silver. The same peculiarities will undoubtedly be discovered as respects the rays of heat." Professor Draper's analysis of the sunbeam, by subjecting plants to the various elements of the solar spectrum, demonstrates, what was still conjectural, the individuality of its component parts, and estab- lishes their rank as distinct physical and vital agents. Analogy justi- fied this demonstration; and had the professor proceeded upon the basis of analogy, and applied the spectrum to the philosophy of life, it would have been one of the most splendid achievements of the hu- man mind. But, like Philip and Muller, in respect to the nervous power, he lost the opportunity; but in losing it, he reared another beacon upon the quicksands of chemistry (§ 476, 493, 528). The chemical properties of the solar spectrum having been an- nounced by other philosophers, it only remained to infer that, like all other things, the integral parts of the spectrum which had manifested peculiar agencies in the physical world would probably, if each were specifically distinct, exhibit greater diversities in organic life (§ 52, 136, &c). It is this which settles the individuality of the numerous rays. The results of sensation, the test of the thermometer, and even PHYSIOLOGY.--VITAL PROPERTIES. 93 of chemistry, with their united force, established only probabilities. Nature alone had supplied the unerring, the "indisputable" requisite, the Vital Principle. And, although discovery is probably only begun, the principles of individuality, and of organic relations, are as well determined by the properties of one ray as by those of a dozen. That others, than such as are known, belong to the class of vital agents, there can be little doubt. The physical capabilities of other rays supply a strong analogy for this conclusion. It only remains, therefore, for the experimenter to follow the path marked out by Draper; and if it do not conduct him to equal glory, he will increase that of the projector, and multiply facts for the great principles in- volved (fy 1072, a, note). It will be now observed that every tangible substance yields an overwhelming analogy in corroboration of the doctrine which I ad- vance as to the vital relations of the solar spectrum; while the coin- cidence in the specific influences of its component parts upon organic life with every other distinct agent, equally in its own turn, surrounds the spectrum with a vital philosophy. Nor is this alone the importance to organic philosophy of the rich discovery. The individual parts of the spectrum not only affect sen- sibility and irritability in modes peculiar to each, but, in beautiful harmony with all tangible substances, each part, respectively, affects certain organs only, according to their special modifications of irrita- bility or sensibility, and according to its own peculiar virtues (§ 133 b, 136, 137 b, 150 a, 188 a, 190, 194, 199, 203). Here, also, it will be seen, is another analogical proof of the vital nature of the influences of light upon organic beings (§ 74 a, 303 e). Much, also, may be found in Professor Draper's own conclusions to show the vital nature of the agency of light. Take, for example, the statement that the " indigo ray controls the movements of plants," and that. " the blue color of the sky is one of the causes of the upright growth of plants." Now what intelligible explanation can chemistry offer of those phenomena in their undoubted relation to light 1 The unavoidable answer supplies an indisputable analogy for the vital in- fluences of the yellow ray, &c. As to the decomposition of carbonic acid gas, it is the only phenomenon in organic life, and I may add animal, which Liebig abstracted, unequivocally, from chemical agen- cies (§ 350, nos. 66, 68). If we now carry the foregoing analogies along in comparing the effects of heat and electricity with those of light upon vegetable or- ganization, we shall readily see that a common philosophy attends the operation of the whole, and that light, in its relation to vegetable life, is nothing but a vital stimulus, adapted to the peculiarly modified vital properties of the leaf, as blood is to the sanguiferous system, sap to the circulatory system of plants, bile to the intestine, semen to the ovum, pollen to the germen, &c. (§ 133, &c). Consider, too, the analogy which is supplied, in the foregoing aspect, by the action of light upon the retina (§ 234, e), and how it contributes to the produc- tion of various hues of the skin, and how, on the other hand, the skin becomes blanched, like the plant, by the exclusion of light. And the analogy may be extended to the motions produced in the iris by the action of light upon the " carbon atom" of the retina (§ 514, k). Nay, more, the action of light, as I have shown, by its absence, at 94 INSTITUTES OF MEDICINE. least, reaches far beyond the peculiarly modified sensibility of the retina (§ 199); since, by its long privation, the entire organ of vision ceases to be developed (§ 74). Again, by what chemical philosophy shall we interpret not only the painful effect of light upon an inflamed eye, but its aggravation of the disease ] And here, by-the-way, its simultaneous action upon the sensibility of animal life and the irri- tability of Organic life concur together in the demonstration. And now to continue the analogies with electricity and galvanism. Either will promote the growth of plants which no degree or modifi- cation of light can exert. So will they, also, promote nutrition in muscles that are wasted in paralysis; and if the pneumogastric nerve be divided, the transmission of galvanism through the inferior portion will rouse the stomach to the production of the true gastric juice and partially restore digestion. And here I may stop to say, that the co- incidence in the effects of galvanism upon vegetable and animal organ- ization is one of the many facts which establish the general identity of the properties of life in both departments of the animated king- dom, while it proves that galvanism and the nervous power are per- fectly distinct, though each be a vital agent (§ 73 b, 74, 185, 226). Again, also, galvanism is a remedial agent, affecting morbid functions after the manner of other remedies, which, with its analogy to light in promoting the growth of plants, shows farther that the latter is, in the same sense, only a peculiar stimulus to organic functions (§ 74, 303). What is said by Professor Draper in the foregoing abstract on the subject of the yellow ray in its connection with sensation deserves a critical inquiry, not only for the sake of the facts, but as contributing light upon organic philosophy. The chemical doctrine of vision is so clearly fallacious, that any specific relations which may be shown between particular rays of light and the sensibility of the retina, may advance our knowledge, analogically, of the connection of the rays with organic functions, through irritability. But I see not how it is shown that the yellow ray " has charge of the process of vision in all animals," since " each of the seven rays of light impresses our minds with special sensations." Moreover, if the yellow ray give rise to sensation by its action on the carbon atom, or by any chemical influence, then, also, do each of the remaining six, and each one in modes peculiar to itself, and in all the cases upon distinct bases. Nay, more, when the retina feels the united rays, each of the seven must simultaneously exert their specific chemical actions. Besides, how are those invisible rays employed which operate chemically upon inorganic compounds 1 In whatever aspect, therefore, we may regard the chemical doc- trine of vision, it is every where shown to be untenable. But, from the close analogies between the relation of physical agents to sensi- bility m animal life and irritability in organic life, if their action in the former case be not chemical, but vital, so is it equally in the latter, and vice versa. It is either vital throughout, or chemical altogether.' But, organic philosophy, through its analogies, should be able to explain what chemistry cannot as to the resulting sensation when the united rays of the sunbeam fall upon the retina. One example will do it. Thus, every distinct agent of positive virtues produces distinct impressions in organic life. But, by uniting two or more too-ether either mechanically or chemically, a new agent is created, winch op- PHYSIOLOGY.--VITAL PROPERTIES. 95 erates either in an individual sense, or if by several virtues, as an en- tire whole. So, in respect to vision, the united virtues of the numer- ous rays of the sunbeam acting upon the sensibility of the retina give rise to sensation attended by a white light (§ 136, 188, 193, 199, 650, 872 a, 1054). The intelligent reader may now test the foregoing philosophy by what is perpetually observed within himself, and bring to its illustration the exact analogies which I have indicated as being supplied by the different passions of the mind; how anger stimulates the whole vascu- lar system,—how fear depresses it,—how shame acts upon the capilla- ries of the face alone,—how joy acts upon the heart and kindles the eyes in its own peculiar way, or its antagonist, grief, seeks the lachry- mal gland, or expectation of food the parotids,—how fear, again, rouses the kidneys, or bathes the skin with perspiration,—how love poises its aim at the genital organs (§ 227, 234 g, 509, 512, &c). If, therefore, light do not affect organic actions, and influence organic results according to the foregoing moral causes, and according, also, to all vital agents, but, on the contrary, its operations upon plants, and therefore upon animals, be of a chemical nature, then, by the clear- est analogy, all other agents of life, the mind and its passions, every act of intellection, every voluntary movement, belong equally to the same category (§ 175 c, 349 c, 1072). 189, a. Where physical views of life obtain, their advocates sup- pose that vital agents operate directly upon the structure. This is one of the first steps in materialism. Many of the chemical school imagine, as Liebig expresses it, that " every motion, every manifesta-' tion of force, is the result of a transformation of the structure, or of the substance of parts ;" that " every thought, every mental affection, is the result of a change in the composition of the substance of the brain." And so of every pulsation of the heart (§ 350). Others, again, who belong to the school of vitalism, to accommodate their lan- guage to the physical conceptions of the day, speak of the action of vital agents " upon the structure through the medium of the vital properties." This difference among vitalists is only verbal; since, by admission, the structure can only be affected " through the medi- um of its vital properties," upon which, therefore, the impression must be made. Hence, distinguished vitalists, Professor Caldwell, for example, who defend the semi-physical mode of expression, often fall into the simple realities of their philosophy. Thus the professor, in his " Outlines of a Course of Lectures," observes that "irritability and sensibility can be acted on by stimulants alone." " Purgative medicines act chiefly on our irritability," &c. (p. 185, 187). And so it ever happens with inquirers after truth. They cannot adhere even to ambiguities of language; and others who see the truth, but build upon hypotheses, are often betrayed into fatal contradictions (§ 64, 236, 345-350, 350f n, 699 c, 740, 819 b). 189, b. But, what is more remarkable, the most absolute physical phi- losophers of life, they who deride the existence of the " vital proper- ties," and speak of their " destruction" as an absurdity, not only fall into the language of the vitalists, but unavoidably contradict their whole system of materialism, whenever they approach the realities of life. This is true even of Dr. Carpenter, who, in his review of my Com- mentaries , attempted their overthrow by satirizing the supposed exist- 96 INSTITUTES OF MEDICINE. ence of "vital properties," and particularly the supposition that prop- erties could be "destroyed." Thus, then, Dr. Carpenter, at a subse- quent time, and in a work of great professional popularity. The cap- itals and italics are mine : " It is a fact of some importance, in relation to the disputed question of the connection of muscular irritability with the nervous system that when, by the application of narcotic substances to the nerves their vital properties are destroyed, the irritability of the muscle may remain for some time longer; and the latter must, therefore, be independent of the former. Hence we should conclude that contrac- tility [mobility, of these Institutes, § 205] must be a property really inherent in muscular tissue, which may be called into action by va- rious stimuli applied to itself, and which may be weakened by vari- ous depressing agents applied to itself ; and that the nerves have the power of conveying the stimuli which call the property into action, but have little or no other influence on it."—Carpenter's Human Physiology, Section 376.—See, also, this work, § 175 d, 167 d, 291, 350f b; and Examination of Reviews, p. 8-12, 26-43. It is important to the great objects of medicine, that I should now say, that the foregoing is only an example of numerous palpable con- tradictions of the physical views which form the fundamental philoso- phy of life in the foregoing work, and, I may add, of most others which are devoted to the propagation of medical materialism. It will be seen that enough is admitted in the preceding quotation to substantiate every doctrine advanced in these Institutes. There are the vital prop- erties, in all their individuality, called into action by stimuli, and " act- ing" of themselves even beyond the doctrine of vitalists, or, again, "weakened by various depressing agents," and liable to be "de- stroyed;" though I do not allow, as affirmed in the quotation, that "irritability remains" after it is "destroyed." Finally, we have ad- mitted, " that the nerves have the power of conveying the stimuli which call the property [contractility, or mobility] into action;" and which is all that is necessary to the whole doctrine which I have propounded as to the nervous power (§ 222-233f, 500, &c, 512, &c, 893-905). 189, c. The impressions which are made on the vital properties be- come the causation of the changes which may ensue in the actions, or structure, of the solids, where the impression is made. No vital agents elicit actions, or a single phenomenon of life, when applied to an in- organic compound, not even from an organic being just dead from in- stant destruction by hydrocyanic acid, or by a pin thrust into the me- dulla oblongata. On the contrary, indeed, all the agents which had before contributed to the maintenance of life, now carry out the work of destruction, and more speedily resolve the organic fabric into its ultimate elements, than any inorganic compound (445, e) It follows therefore, that agents do not elicit the actions of life by operating upon the organized structure; but upon those properties which hydrocy- anic acid, &c., may extinguish in an instant of time ; nor do thev op- erate upon the functions, since those are merely effects ($> 176^ And is it not a greater paradox that hydrocyanic acid, or aconite &c should destroy life in a second of time by its action uponthmere structure than upon that living principle which imparts to the orLic kingdom all its peculiar characteristics 1 Or, as the blood or inv or anger, rouses the heart, or as fear brings on perspiration, micturition PHYSIOLOGY.--VITAL PROPERTIES. 97 &c, or as the want of air throws into action the respiratory muscles, or as odors, light, &c, produce their sensations 1 By facts of the foregoing nature, and by all those considerations which have been made in relation to the differences in the vital con- stitution of the different tissues, and of different parts of one and the same continuous tissue (as of the alimentary and pulmonary mucous membrane, § 133, &c), it becomes perfectly obvious that the proper- ties of life are something per se, something besides organization itself, or organic functions, and upon which the agents of life exert their im- mediate impressions (§ 1029, 1030, 1034, 1041). There can, therefore, be no appreciation of the laws of organic be- ings, of the modus operandi of natural, morbific, or remedial agents, of healthy or morbid processes, of voluntary or involuntary muscular motion, of the results of the operation of the nervous power and sen- sibility, or even of perception, without a critical reference to the prop- erties of life as the efficient causes, and as receiving the impressions which may be created by external and internal agents (§ 872). 190, a. Irritability, and other vital properties, are naturally modi- fied, in kind and degree, in the different tissues, in tissues of the same order, and in different parts of one and the same continuous tissue (§ 133, &c., 199, 203, 227-232, 441). These natural modifications are shown in all parts by the peculiar action of the natural stimuli of life; as blood upon the heart and blood-vessels, food on the stomach, bile on the intestines, urine on the bladder, the will, through the nervous power, upon the voluntary muscles (§ 215, 227, 486), and by the differences that arise from their action on parts to which they are not peculiar. And so of the diversi- fied effects of external agents on different parts. 190, b. There are remarkable modifications of irritability in the ova of oviparous and viviparous animals, and in seeds. Semen is the only natural stimulus of the former, in their absolute state of ova; while in the ova of viviparous animals, the actions, after being roused by the stimulus of semen, must go on to a full development of the organ- ic beinp;, and in undisturbed connection with the parent; but, in the oviparous, when the ovum has acquired a certain development, the actions cease spontaneously, the properties of life no longer obeying the vital stimuli as in the other case. These properties then become dormant (and in the seed, also), and nature, having fulfilled her final cause, the ovum is expelled from the body, and the seed cast off, that they may be subjected to new agents. Semen will not now act upon the ego;, but heat and atmospheric air become necessary to restore the actions, and carry out the process originally instituted by the spe- cific stimulus of semen. There are certain oviparous animals that present other peculiarities, and other changing modifications, of irritability in respect to their ova. At certain seasons their ova undergo a partial development from the influence of season, and from the stimuli supplied by the female pa- rent. These influences, however, finally cease to operate, and the ovum is expelled to undergo the action of semen in the external world. This action again modifies irritability, and adapts it to other vital stimuli. Again, it may be affirmed of many oviparous animals, at least, that a partial development of the cvum takes place, though imperfectly, G 98 INSTITUTES OF MEDICINE. through stimuli supplied by the female parent, and the ovum is ulti- mately expelled as when incipient development is brought about by the stimulus of semen. But these ova are insusceptible of renewed actions, either from the stimulus of semen, or other vital agents (§ 71-73, 1051). . 191, a. The variations in kind and degree of irritability (§ 190) adapt each part to be acted upon by peculiar natural agents, while the same agents may have a pernicious effect on other parts, in the great plan of organic life (§ 133, &c). The same principle governs the operation of morbific, and, more or less, of remedial agents, and is one of the main causes of disease, and of the determination of dis- ease upon one part in preference to another (§ 149-151). The prin- ciple is, therefore, very comprehensive, and refers as well to the kind, energy, and degree of the operating causes or agents, as to the kind and degree of irritability (§ 150). And so, also, of sensibility (§ 194). The principle is not only seen in all parts of the organic being, but every distinct species of animal and plant has, in a collective sense, its own special modification of irritability, through which its organic habits as to food, composition, nutrition, &c, are specifically regula- ted. It is this which renders what is poisonous to one animal or plant salubrious or inoffensive to another. And this lets us into a knowledge of the reason why certain atmospheric influences induce the "milk-sickness" in the kine of the Western States, and probably in no other animal. It reveals to us how it is that the stately plata- nus occidentalis and the common peach tree have been dying out over extensive regions of country, and why the potato-crop is cut off, year after year, in vast regions of Europe and America, while every other tree and herb escape the epidemics (§ 150). These very facts de- monstrate, also, the principle as to the natural modifications of the properties of life, and establish, alone, the fundamental identity of the vital properties in the two departments of the organic kingdom (§ 185). 191, b. Again, more remarkable modifications of irritability, or changes in kind, are artificially effected by morbific and remedial in- fluences, external and internal, physical and moral; and these, far more than a mere increase and depression of this property, constitute an essential part of disease. These affections of irritability give rise to new series of influences, from every variety of agent, and often very different from such as are exerted under circumstances of health (§ 542). Hence it is that ordinary food, &c, becomes morbific in diseased conditions, remedial agents operative, either for good or for evil, when otherwise they might fail of any effect (§ 226), and, upon this mutability, and varying susceptibility of the property now under consideration, is greatly founded the art of medicine. It is, especial- ly, these varying conditions of irritability which demand so much critical reference to the exact nature of remedial agents, their doses, &c. (§ 49£, 871, 878), and to the mutability of the property is partic- ularly due the salubrious influences which are exerted (§ 901). 191, c. And here we have striking analogies in the manner in which the properties of the mind are modified, in their character and again restored to their integrity when the organic properties of the brain become affected in the foregoing manner ('§ 175). 191, d. Remote analogies probably exist even in the inorganic kingdom; though we have apparently nothing there in this respect PHYSIOLOGY.--VITAL PROPERTIES. 99 which transcends other affinities between the two great kingdoms of nature. Wo do not find that dead matter is endowed with proper- ties as specifically distinct from the matter itself as the living being and the properties by which it is governed. And, so far as this analogy extends to dead matter, its properties do not appear to be liable to any mutations in kind, but only in degree ; and here it would seem that the analogy should end, since we do not find that instability in the mineral world which, in the organic, grows out of the mutability of the properties of life. What 1 have thus said of the analogies between the properties of living and dead matter is sustained by the late researches of chemists. Thus, on the allotropism of simple bodies, it is said by Prof. Draper, thai, "to a certain extent, the views of M. Berzelius coincide with those which have offered themselves to me from the study of the prop- erties of chlorine. They are not, however, altogether the same. M. Berzelius infers that elementary bodies can assume, under varying cir- cumstances, dfferent qualities. The idea which it is attempted to communicate in this memoir is simply this,—that a given substance, such as chlorine, can pass from a state of high activity; in which it possesses all its well-known properties, to a state of complete inac- tivity, in which even its most energetic affinities disappear. And that, between these extremes there arc innumerable intermediate points. Be- tween the two views there is, therefore, this essential difference: From the former, it does not appear what the nature of the newly-assumed properties may be ; from the latter, they must obviously be of the same character, and differ only in intensity or degree, diminishing from stage to stage until complete inactivity results."—Draper, on Allotropism of Chlorine as Connected with the Theory of Substitutions. 1845. 192. Irritability stands as a sentinel at all the openings and pores of the body, and between the capillary and extreme vessels of the ar- terial system; admitting and excluding according to its natural mod- ifications in different parts. Thus, all but chyme is excluded from the duodenum by the pyloric orifice of the stomach, and all but atmo- spheric air by the glottis. The globules of blood are vastly smaller than the visible capillaries which carry only white blood, from which they are excluded by the peculiar irritability of these vessels. When admitted, as in inflammation, it arises from a morbid alteration of irri- tability. And so when the lacteals absorb deleterious agents, or the pylorus allows the escape of undigested food. There is no analogy between a set of inert tubes and the living ducts. And yet are we presented with tubular instruments of glass, &c, to demonstrate the laws which govern the circulation of the blood and of sap, and sponges and lamp-wick to exemplify the process of absorption as carried on by the lymphatics and lacteals (§ 289, 291). 193. Bichat confounded irritability with sensibility, by calling the former organic sensibility, and the latter animal sensibility. He made, also, a greater mistake in supposing that irritability and sensibility are only different degrees of one property. This fact derives its impor- tance from the high authority of the French philosopher, and the er- rors into which he has thus led a multitude of others. The coincident functions between plants and animals, and organic actions being carried on in parts of animals after the greatest possible destruction of the nervous communications, evince the clearest distinc- 100 INSTITUTES OF MEDICINE. tion between irritability and sensibility, however close their analogies in respect to the operation of physical agents. When nux vomica rouses spasmodic actions in a paralyzed limb, it is by its action on irrita- bility, for sensibility may be extinguished, and not reproduced (§500, d). 2. SENSIBILITY. 194. Sensibility, which is peculiar to the vital principle of animals, resides exclusively in the nervous system. That which gives rise to true sensation is mainly limited to the cerebro-spinal system (§ 184, 523). 195. Through sensibility we learn the existence and nature of ex- ternal objects. These objects make their impressions upon this prop- erty as we have seen of other agents in respect to irritability (§ 188, &c). Another important function is also performed by sensibility, which consists in the transmission of impressions to the cerebro-spinal axis, as a part of the great function of sympathy. All the modifications of sensibility are designed for the transmission of impressions from the circumference to the nervous centres (S 437. 438). 196. The nerves are the organs of sensibility, and the brain and spinal cord the recipients of impressions transmitted by this property through the medium of the nerves. Perception is also necessary to the recognized modifications of sensation ; and, therefore, the perfect exercise of the power, in its function of true sensation, requires a healthy state of the foregoing elements (§ 523, no. 3). 197. Sensibility is said to be of two kinds, common and specific. I shall distinguish it into a third kind, which may be called sympathetic sensibility ($ 1037, b). 198. Common sensibility is the source of pain, and resides in all the nerves. It is generally dormant in the organs of organic life, but may be greatly roused by disease. The best examples of this latent state occur in the ligaments and bones. Its development by disease is a clear illustration of the light which is reflected upon natural phys- iological conditions by their morbid changes (§ 137, d). 199. Specific sensibility is peculiar to the senses, where it mani- fests very striking peculiarities. Light, alone, will affect the specific sensibility of the retina, the intrinsic virtues, only, of various substan- ces give rise to tasting and smelling, certain mechanical impressions to hearing^ &c. This proves a difference, or modification, of specific sensibility in the several organs of sense, by which, as in the case of irritability (§ 190, 191 , it is adapted, in various parts, to the action of special stimuli, according to the predetermined uses of each part 199*. The impressions transmitted by common and specific sensi- bility are received by the brain alone, or its equivalent. The spinal cord is only a medium of communication. These, also, are the kinds of sensibility which require for their operation the exercise of ner ception (§ 451, 523 nos. 1, 2); and it is these upon which true sen- sation depends. Whenever brought into operation, the mind takes cognizance of the transmitted impressions 200 The foregoing (§197-199) are coincident with what we have seen of differences in irritability (§ 133, &c, 190, 191), though more strongly pronounced, and are clear examples of what is rrTeant by PHYSIOLOGY.--VITAL PROPERTIES. 101 natural modifications of the vital properties; and illustrate those mod- ifications which constitute the essence of disease (§ 133, &c, 191). The three principal kinds of sensibility, and the several modifica- tions of the specific kind, as shown by the special causes which, re- spectively, give rise to seeing, tasting, smelling, &c, also illustrate the principle which governs the special relations of different agents, natural, morbific, and remedial, to irritability as modified in different parts ; and this, also, reciprocally illustrates the characteristics of sen- sibility. A harmony of laws prevails universally (§ 133-138). Like irritability, sensibility is also liable to artificial modifications from the action of external and internal causes; and, as will be seen, the ner- vous power is susceptible of even more remarkable influences (§ 226- 232, 725). 201, a. The last section leads me to consider the third kind of sen- sibility, or what I have denominated sympathetic sensibility (§ 197). Its office will explain the qualifying term sympathetic, which appears to be necessary to avoid the confusion which prevails in the applica- tion of the general term to the distinct offices of exciting acts of in- tellection and of influencing organic motions, and of producing invol- untary motion in animal life. There was a radical objection to Bi- chat's designation of irritability as organic sensibility (§ 193); but in the present term there seems to be a peculiar advantage (§ 451, d). " Impressions," says Muller, " conveyed by the sensitive nerves to the central organs are either reflected by them upon the origin of the motor nerves, without giving rise to true sensations, or are conducted to the sensorium, the seat of consciousness." When light produces vision, or odors give rise to agreeable sensa- tions, it is due to specific sensibility. The mind perceives, and the effect goes no farther; there is no extension of the impressions be- yond the sensitive nerves. Again, the light or mechanical irritants are productive of pain, and the effect is limited in the same manner. But here there is no specific sensation. It is the same in all the or- gans of sense. This, therefore, is due to common sensibility. At another time, however, the light induces a paroxysm of sneezing, or the odor syncope or disease. Here is a perfectly new train of re- sults, the principal of which are in parts distant from the direct seat of the impressions. The primary influences have been propagated upon various organs by the nervous centres through the system of motor nerves. These influences, therefore, have called into action another modification of sensibility, and that is the sympathetic (§ 450, &c, 464, 514 k-m, 902). 201, b. This variety of the common property, like specific sensi- bility, belongs to certain parts only of the nervous system, and is the medium through which impressions upon all parts are transmitted to the cerebro-spinal axis, in the function of sympathy. Perception, and true sensation, therefore, which is rarely an attendant phenomenon, are not necessary to the office of this modification of sensibility, nor is a continuity of the nerves with the brain. Reflected motion may be as readily excited through the spinal cord as through the brain; " and we are in possession," says Muller, " of no facts which prove that the spinal cord, when separated from the brain and medulla ob- longata, can be the seat of true sensation. The reflected motions ex- cited by the irritation of the surface in decapitated frogs are no proof of this." 102 INSTITUTES OF MEDICINE. 201, c. Sympathetic sensibility appertains to what arc denominated the sensitive nerves, and the sensitive fibres of compound nerves, which are also, in part, the instruments of common sensibility. But, a remarkable anatomical distinction, and which goes far to sustain the variety of sensibility which is here indicated, is found in the sen- sitive fibres of the sympathetic and pneumogastric nerves; which possess, in the most exalted degree, the power of transmitting organic impressions to the nervous centres, but which are nearly destitute of common sensibility. Indeed, it is through this system of sensitive fibres that the whole organic department maintains the specific rela- tions of its several parts (§ 129, 523, nos. 1, 2, 3, 6, 1037, b). 201, d. The impressions transmitted through sympathetic sensibility may be received either by the brain, spinal cord, or certain parts of the ganglionic system (§ 520); and either connectedly or independ- ently of each other. When thus received by the nervous centres, they give rise tO a development and transmission of the nervous pow- er through what are called the motor nerves, and terminate in those influences which complete the function of sympathy, by giving rise to sensible or insensible motions, or modifying such as had existed. 202, a. The manner in which sympathies are brought about through the medium, in part, of sensibility, and the failure of impressions upon common and specific sensibility to generate sympathy, or to excite the influence of the motor nerves, and the absence of sensation in the former case, and the admissible absence of the brain, as well as other peculiarities, prove, abundantly, the existence of this third kind of sensibility. Besides, also, the prominent demonstrations to the fore- going effect, which occur in disease, this modification of sensibility is in universal operation in healthy states of the body; as manifested in respiration, and in the concerted action with which the various organs carry on their respective functions. Through this modification, all parts transmit to the cerebro-spinal axis special influences that are relative to their existing conditions, and these influences are propa- gated through motor nerves, and maintain a harmony of movements (§ 129, 464, &c). The special function of this kind of sensibility, and its co-operation with the nervous power in the function of sympathy, will be farther considered along with that function, and the function of motion, and again under the laws of sympathy, and the modus operandi of reme- dial agents (§ 1037, b). 202, b. It may be now said, however, that when sympathetic sen- sibility gives rise to motion, whether in organic or animal life, or whether sensible or insensible, it is through impressions received and iransmitted by this property to the cerebro-spinal axis (unless the ganglia of the sympathetic be also a medium of reflex action), and- a consequent development of the nervous power, which power then op- erates, through motor nerves, upon the organic irritability of parts which are brought into motion. 203. Like specific sensibility (§ 199), and the organic property, ir- ritability (§ 190-192), sympathetic sensibility is variously modified in different parts, by which it is adapted to the reception of impressions from agents of particular virtues, and for their transmission to the cerebro-spinal axis, and for the ultimate generation of true sympathy- while the same agents fail of these effects in other parts (§ 133, &c.)' PHYSIOLOGY.--VITAL PROPERTIES. 103 204. Another manifest contradistinction between sympathetic, and common and specific sensibility, is seen in the general failure of im- pressions made on sympathetic sensibility to act upon the mind, and therefore in the ordinary absence of all sensation. If sensation be an attendant phenomenon, it then arises from impressions simultaneously made upon common sensibility (§ 445, 464-467, 473, no. 5, 474, no. 4, 542, 1037, b). 3. MOBILITY. 205, a. Mobility is the property by which all motions are carried on in animals and plants. It is peculiar to the solids, though some late physiologists have ascribed it to the globules of blood, while oth- ers have mistaken the globules for entozoa (§ 233, 253, &c). 205, b. Sensible and insensible contractility, as employed by Bichat, and muscular power, are bad substitutes for the name mobility. They lead to erroneous conclusions ; since the heart, blood-vessels, and other muscular organs dilate or elongate, as well as contract, through the same vital property; and motion occurs in various tissues.—(Med. and Physiolog. Comm., vol. i., p. 150, 379-391.) The terms sensible and insensible contractility limit the'law of mo- tion to simple contraction, while there must be always a correspond- ing active dilatation, or the part would always remain in a state of tonic spasm. Elasticity will never explain the dilatation of the heart, of the veins, &c.—(Med. and Physiolog. Comm., vol. ii., p. 147-156, 175, 176, 399-402). 206. The philosophical Macbride remarks that, " as irritability ne- cessarily implies mobility of the animal fibres, this does not require to be considered a distinct property." If, then, the existence of mo- bility be thus implied, it is a distinct property; and when the phenom- ena of irritability and mobility are duly considered, it will be seen that they should be regarded in a separate sense. Irritability is cer- tainly necessary to the exercise of mobility; but the former may be greatly exalted without a corresponding increase of motion. The distinctions are numerous and of great practical importance (§ 500, d). 207. The existence of mobility in plants is abundantly shown by the motion of their fluids, which no mechanical principle can inter- pret, by their secretions, and by other results analogous to those which depend, in part, on this property in animals. It is also manifested by the sensible movements of the leaves, blossoms, stamina, &c.; and from these wo may reason analogically, and infer insensible motions of the sap-vessels, the secretory apparatus, &c, as is also done in an- imals (§ 1054). Mobility, therefore, gives rise to sensible and insensible motions. They are generally sensible in animal life, and of either kind in or- ganic (§ 476-492, 516, no. 2 ; also, Medical and Physiological Com- mentaries, vol. ii., p. 150, 379-391). 208. Mobility is brought into operation through impressions made on irritability, whether by vital stimuli in organic life, or by the ner- vous power in either organic or animal life (§ 188). The philosophy of this will be considered along with the attributes of the nervous power, the function of sympathy, and the laws of sympathy. 209. If sensation apparently give rise to motion, it may be occa- sioned by the action of external or internal causes upon sensibility; 104 INSTITUTES OF MEDICINE. but this impression is imparted to irritability and then to mobility, before motion can follow (§ 195); or, from the intimate associations and analogies between irritability and sensibility, the two properties may be simultaneously affected by the same agents. Where, how- ever, sensation is accompanied by motion as an apparent effect of im- pressions upon common sensibility, it probably arises in all cases from a simultaneous impression upon sympathetic sensibility (§ 198, 201, 202). 210. Irritability may be increased through an exalted state of sym- pathetic sensibility, and organic motions may be thus increased through sensibility; which is nearly the same as the foregoing law (§ 209). 211. It is doubtful whether parts may be irritated without exciting mobility (§ 202); but it is otherwise with common and specific sensi- bility, as in seeing, tasting, &c, and in pain. 212. Mobility, like irritability and sensibility, may be in a passive or dormant state, as in the ovum and seed, or as sensibility exists in the organic life of animals. All are roused by appropriate agents, and could not be roused were they not already present. Certain an- imals, such as the wheel, and the sloth animalcula, may have all appa- rent traces of life extinguished, maybe completely exsiccated, and be speedily revived by heat and moisture.* The first impression of semen, or of heat, &c, upon the ovum, or seed, is made on irritability, through which, as the next step in the process, mobility is roused into action. Then follows the new ele- mentary combinations. We thus learn, in part, that life is a cause, not an effect.—(Med. and Physiolog. Comm., vol. i., p. 9, et seq.) 213. Sensible mobility is especially manifested in the compound organs, taken as a whole (§ 205). Insensible mobility occurs in the small vessels (§ 207). But, the palpable evidences of a special law of motion in the small vessels are apt to be sacrificed to the negative fact that the motion itself is not of a visible nature. As well might we deny the existence of microscopical animals. 214. The insensible motions in organic life are the most important that occur, especially such as take place in the extreme capillary ves- sels ; since these are the instruments of all the most essential actions and phenomena of life, and of disease. 215. Voluntary motion is brought into exercise by' the will and nervous power, as will be set forth under my consideration of the lat- ter property and the function of motion (§ 222-233^, 500 d). The essential difference, therefore, between the motions in animal and or- ganic life, lies in the nature of the stimuli; voluntary motion requiring the exercise of the will, while the organs of organic life do not obey the stimulus of the nervous power when excited by the will (§ 486). It is probable, also, that mobility has a peculiar modification in the muscular tissue of animal life. Notwithstanding mobility, in animal life, is always subject to the nervous power, motion is here, as in organic life, independent of the nervous system (§ 483, 486). * See SrALLANZA-Nis Experiments in Opusndi di Fisca Animate, Overe r vi n 482-556. y ' c* ™-' v' PHYSIOLOGY.--VITAL PROPERTIES. 105 4. VITAL AFFINITY. 216. It has been seen that the elements of organic compounds are very differently combined from those of inorganic (§ 32, &c). Hence has arisen the term vital affinity, as denoting a property peculiar to plants and animals, by which all their elements are united and main- tained in combination. When death takes place, chemical affinities operate, and resolve the organic into inorganic compounds, or into their simple elements (§ 174). 217. Vital affinity exists in modified states in the two departments of organic nature ; since, in plants, it unites the simple elements into organic compounds, while in animals, it can only operate upon com- pounds of this complexity. Vegetable organization is, therefore, more of a creative nature than animal (§ 13). 5. VIVIFICATION. 218. By vivification, in conjunction with vital affinity, life is bestow- ed upon dead matter. The elements of matter are, essentially,.com- bined into organic compounds by vital affinity; but there is a pro- gressive vitalization of the organic compounds till they become united with the solids. This shows that vital affinity must have an associate power of vivification. 219. Vivification belongs, particularly, to the assimilating organs, though its energy must be great in the gastric juice. It has natural modifications in all parts, and presents distinctions between plants and animals. 220, a. Vital affinity and vivification, like the other properties of life, are susceptible of morbid changes. This gives rise to changes in the general vital character, and in the composition, of the solids and fluids. These changes in composition are inferred upon principle, as well as from observation (§ 665, b). No chemical analysis can detect them, unless it be an alkalescence or an acidity of the secreted fluids, or changes in the urine; and even these imperfect results are often sur- rounded by objections (§ 5jr b, 53). 220, b. Changes in some of the secretions, or in the milk, may be brought about by temporary influences, and independently of disease, as by emotions of the mind, the action of cathartics, &c. These also affect the condition of organs and their products in the various states of disease; and upon this depends the art of medicine (§ 852, &c). 220, c, The alterations which take place in the solids and fluids are always the same in any given condition of the affected properties of life. They are, therefore, constantly liable to variations during the progress of disease, and are various in different diseases, and accord- ing, also, to the nature of remedial influences, and of those other causes by which they are affected independently of disease (§ 672). 221. The changes which arise in the solids and fluids from morbid conditions never approximate the condition of dead matter (§ 674). There is no " putrescency," though otherwise averred in the late re- production of the humoral pathology. Living matter cannot generate dead organic compounds; nor can remedial agents reconvert the pu- trid into living solids and fluids (§ 17, 847, 901). 106 INSTITUTES OF MEDICINE. 6. THE NERVOUS POWER. 222, a. The analysis which I shall make of sympathy establishes so clearly its functional character, that I shall remove it from among the properties peculiar to animals, where it has been hitherto placed. In the room of this function, generally regarded as a property, I shall substitute the nervous power, upon which, in connection with sensi- bility, the former depends (§ 201). 222, b. The philosophy of the operation of the nervous power in producing motion, under all its various aspects, as manifested in its natural regulation of organic actions (§ 202), in the phenomena of sympathy induced by morbific and remedial agents, or by the influ- ences of disease, in the motions which are generated in the organs of organic life by the passions and analogous affections of the mind, in the movements of the voluntary muscles, in the production of sudden death from all causes, as well as the solution of other relative prob- lems, and the physiological interpretation of the recognized laws of sympathy and their general introduction into pathology and thera- peutics, were originally attempted by myself in the Medical and Physiological Commentaries, and subsequently, and more extensively, in my Essay on the Modus Operandi of Remedial Agents. Should the exposition there and now set forth prove to be well founded, it must necessarily result, sooner or later, in the overthrow of all the mechanical and chemical hypotheses in physiology, consign to its well-merited oblivion the humoral pathology, and place upon its true foundation the operation of remedial agents. 223. The nervous power appertains to the vital principle, resides exclusively in the nervous systems, and is, therefore, peculiar to ani- mals (§ 184, b). It gives rise, however, to results in organic as well as animal life. These results, also, are far more numerous and impor- tant in the organic than the animal mechanism, while sensibility is es- pecially designed for the latter. Unlike sensibility, also, in its func- tion of sensation, perception is not necessary to the operations of the nervous power, nor does the latter, like sensibility in its office of pro- ducing sensation, require a continuity of the nerves with the brain for the function of sympathy, especially in organic life (§ 209). The nervous power is constantly, though, for the most part, in in- sensible operation throughout the organic mechanism, and is the pow- er which maintains all parts in harmonious action. For this special reason I have endeavored to show that the nervous power is super- added to the vital principle of animals, and that the complexity of or- gans and functions which it is designed to subserve, and the absence of its phenomena in plants, afford a substantial proof that the proper- ty belongs to animals alone (§ 1041.) 224. The nervous power is exerted, especially, through what are denominated the motor nerves and the motor fibres of compound nerves, or " nerves of motion ;" these nerves, however, being mainly dependent for the nervous power upon the brain and spinal cord (§201). . ^ Nevertheless, there is reason to suppose that the nervous power is implanted in the motor nerves, as well as in the brain and spinal cord. The phenomena of contiguous sympathy, as when inflammation of the liver, the lungs, &c, is relieved by blisters, over the region of the PHYSIOLOGY.--VITAL PROPERTIES. 107 affected organs, can hardly be traced through the mechanism of the cerebro-spinal system, though they may, perhaps, through the gangli- onic nerve. Again, also, the very division of a nerve will produce inflammation of the part to which it is distributed. In this case a shock of the nervous power must be determined by the nerve itself (§ 226). The experiment is precisely analogous to those in which Wilson Philip influenced the functions of various parts by irritants, &c, applied to the brain and to the spinal cord (§ 474 b, 480, &c). It is evident, however, that the nervous power is much less strongly pronounced in the nerves than in the brain and spinal cord ; just as sensibility is less in the brain and spinal cord than in the nerves of sensation, and less in the trunk of a nerve than in its ramifications ; or, as irritability and sensibility exist in very various degrees in numer- ous parts. 225. Like irritability, sensibility, and the other properties of life, the nervous power is capable of being acted upon by external and internal causes, both moral and physical, of being increased, or di- minished, or altered in kind, according to the nature of the causes (§200,203, 258). 226. The nervous power possesses the remarkable characteristic of being a vital agent to the property irritability (§ 184, b). It is also liable to artificial modifications from the operation of physical and moral causes upon the nervous system ; and its influences upon irritability will correspond with the nature of its modifications ; be- ing thus rendered a vital stimulus, or a vital depressant, or a vital alterative (§ 150). When, therefore, this power operates in any un- usual manner, organic and animal motions, whether sensible or insen- sible, will be variously modified, or produced, by calling mobility into exercise, according to the nature of the influences exerted upon the power (§ 188, 205, 216, 492, no. 5). These facts are known by the endless variety of phenomena which are relative to the nervous pow- er (§ 165, 1881 d, 480, Exp. 12, 13, and 14, 503-505, 891'a k). 227'. The nervous power is brought into unusual operation very va- riously, according to the seat of the exciting cause (§ 951). 1st. Its operation is excited in a direct manner by irritants, &c, ap- plied to the brain, to the spinal cord, and to the motor nerves. It is also excited directly by cerebral or spinal disease, by the passions, men- tal emotions, imagination, intense reflection, and by the will (§ 226, 486, 500 d, 940-951, 969 a, 974-977). In all the cases, the nervous pow- er will be rendered stimulant, or depressant, or alterative to the or- ganic properties and functions; and variously energetic accordino- to the nature of the operating cause, and the intensity and suddenness with which it may operate (§ 480, 743, 951). In blushing, the pow- er is rendered stimulant; by fear, depressant; by grief, anger, hope, ike, alterative (§ 844). These effects are also commonly very sud- den, especially the physiological. Even such as are morbific are oft- en almost instantaneous ; and this rapidity of change ceases to be re- markable when we regard their near coincidence with the natural results, and that the same principle is involved in voluntary motion. A close analogy subsists between all the foregoing direct causes and all the physical agents of life, whether natural, morbific, or reme- dial, as the latter may develop the nervous power sympathetically (§ 500). These analogies will have been variously illustrated. They 108 INSTITUTES OF MEDICINE. evince the simplicity of fundamental principles and the relationship and perfect harmony which prevail among the whole, even those which are especially relative to mind and instinct as superadded to the simple condition of the vegetable kingdom (§ 323-325). 2d. The operation of the nervous power is excited through the medium of sympathetic sensibility (§ 201-203). This complex process results in the true function of sympathy. Impressions are made by physical and moral causes, by disease, &c, upon the foregoing varie- ty of sensibility, and according, also, to its different modifications in different parts, and the nature of the operating causes. The impres- sions are then communicated to the cerebro-spinal axis, or to other central parts of the nervous system, and there bring into operation, and variously modify, the nervous power (§ 224). The power, thus developed, thus influenced, or so modified in kind that it partakes of the nature of the transmitted impressions, which are more or less co- incident with the virtues of the remote causes, is then exerted, through the motor system of nerves, upon the organic properties of distant parts, or of the nervous system itself (§ 208, 209, 462-469), by which those properties, and their resulting functions and products, are vari- ously affected according to the foregoing circumstances. From this fact it also results, that the modified conditions which are brought about by the nervous power, when the preternatural operation of this power depends upon external causes, whether morbific or remedial, are more or less analogous to those changes in the organic conditions which are wrought in parts by the direct operation of the same causes (§ 188, 657 b, 503-505, 898J k 893 e, 902 g, 904 a). 228, a. It thence follows, that there is imparted to the nervous power, by the foregoing means (§ 227), more or less of the charac- teristic virtues of the remote causes, but under the influence of its own nature, by which the nervous power is substituted for those causes, and thus reaches, with its acquired attributes, and their various effects, every part Of the organization, and, often, with great instantaneous- ness. It appears, therefore, that this constitution of the nervous pow- er is wonderfully suited to the various exigencies of life ; while, as will be seen in section 232, it grows out of its physiological nature as a regulator of organic actions (§ 1057, 1075). 228, b. It is also an important law that the nervous power is vari- ously influenced in its morbific and remedial action by slight vari- ations in the intensity of the operating causes, whether moral or phys- ical ; though a determination is simultaneously given to its action by the numerous other conditions already mentioned, and which may happen to be present. Thus, an impression from cold, as a blast of air, or a drop of cold water, upon the skin in syncope, will rouse the respiratory organs. Another impression from the same, and under other circumstances, will excite catarrh, or pneumonia, or articular rheumatism. One degree of impression upon the stomach by tartar- ized antimony will determine the nervous power upon the respiratory muscles (as will cantharides upon the bladder, or mercury upon the salivary glands), and vomiting is the consequence; while it simul- taneously reflects the same power upon the skin, and other organs, and of which perspiration, &c, is a consequence. In smaller dosesi the respiratory movements are not affected, but only the condition of the skin, &c, and in lesser degrees. But, these examples embrace PHYSIOLOGY.--VITAL IROPLRTIES. 109 only certain parts of the influences in each case; while in others they are far more complex, one sympathetic result becoming the cause of others, till, through a single impression upon the skin, various circles of morbific or remedial sympathies may be instituted (§ 743). 229. When disease operates in the foregoing manner in exciting the nervous power, and determining it with alterative effects upon re- mote parts, or upon the nervous system itself, it often imparts to it a modification by which a similar condition of disease is generated in the parts upon which the power is thus determined. Hence the con- secutive inflammations which are often springing up, sympathetically, in various parts. But, this depends, more or less, upon the nature of the organs secondarily affected, upon their precise condition as divert- ed more or less from their healthy states by other causes, upon tem- perament, age, sex, &c. When, therefore, the nervous power is de- veloped by disease, other conditions varying more or less from the primary affection are observed among the common effects. For the same reasons, also, when morbific and remedial agents operate through the medium of the nervous power, the results may be very various. 230. If the nervous power be brought into preternatural operation in a direct manner (§ 227), as when impressions are made upon the brain, or spinal cord, or the trunks of nerves, or by cerebral disease, or when the mind or passions develop its operation, it is also liable to modifications, and corresponding effects, as when the impressions are communicated through the medium of sympathetic sensibility. Thus alcohol, applied to the brain or spinal cord, increases the action of the heart and capillary blood-vessels, and so do anger, joy, hope, love, imagination. But, a watery infusion of opium or of tobacco, applied in like manner, depresses those actions, and so do fear, grief, and anx- iety. We see, also, various other organic functions affected in a cor- responding manner (§ 480-485, 489-492, 943, 945). In these cases, the nervous power is often determined, with more or less effect, di- rectly upon the organic properties of the brain, and may extinguish them instantly. A sudden explosion of anger may, in this manner, induce apoplexy, while in other cases the destructive influence of the nervous power is expended mainly upon the heart. Inflammation of the brain determines the nervous power directly upon the cerebral vessels which carry on the morbid process, and thus increases its force and obstinacy. So with many morbific and remedial agents of a physical nature, which, when applied to the stomach, excite the ner- vous power indirectly, or through the medium of the sensitive fibres of the pneumogastric and sympathetic nerves, but in which cases the nervous power is determined upon the organic properties of the brain, or of the spinal cord, or of the individual nerves, as well as upon those of other parts. Such is the case with all the narcotics, strych- nine and analogous substances, prussic acid, aconite, &c, which bear specific relations to the nervous system; either exciting or removing morbid states of the brain or nerves (§ 487 g, 526 d). 231. It is not alone the general functions of tissues and of com- pound organs which are affected by the nervous power in the fore- going manner (§ 227-230), but equally, also, those of the intimate or- ganization af all parts, upon which nutrition, vital decomposition, &c, depend (SS 395, 1040). 232. The modifications of the nervous power now described (§ 110 INSTITUTES OF MEDICINE. 227-230) are analogous to those which we have seen to be exerted upon irritability and sensibility (§ 191, 200), and they spring from that physiological constitution of the nervous power which is design- ed for treat natural purposes in the animal economy. This power is manifestly associated with the vital principle of animals (§ 184, b) as a regulator of their multifarious parts, by which the whole are main- tained in harmonious action, or by which the varying changes and failures of some shall institute vital changes in other parts that shall contribute to the restoration of the former, or exempt the general or- ganism from the evils which would otherwise arise (§ 184). Volun- tary motion (§ 215, 486), respiration, a permanent contraction of the sphincters, are also other final causes of the institution of the nervous power. The power is in perpetual operation in every part of the animal organization, though more obviously pronounced in some of its results than in others, as in the function of respiration, the perma- nent contraction of the sphincters, the motions of the iris, &c. It is, however, not less constantly operative, though with less intensity, in all organic processes, whether the general functions of a compound organ, or those of its individual economy, and forever stretches its universal sway, as a harmonizing power, over the whole organic mechanism. This power, therefore, is rendered exquisitely suscepti- ble to the most astonishing variety of physical, vital, and moral causes; and, that it may feel and transmit the influences of the vital changes that may befall one part or another to other parts, for the maintenance of the great balance of functions, and to fulfill the office of restoration as well as of conservation, there is imparted to it, as to the other prop- erties of life, a partial mutability in its nature, conformable to the va- rious impressions exerted upon it, and by which it is rendered vari- ously and usefully alterative to morbid conditions; and since, also, such alterative effects as are demanded by morbid states could not be exerted by a natural vital agent in its unmodified condition. Thus we have, in the obvious constitution of the nervous power, as manifest in its common functions, a principle of interpretation for all the vari- ety of changes that are not less obviously exerted upon it by morbific and remedial agents (§ 1075). 233. The nervous power does not. generate motion either in animal or organic life (§ 476-492, 516, nos. 2, 7). It only influences the or- ganic property mobility, upon which all motion depends, through the medium of irritability (§ 188, 205, 208, 209, 226). Even voluntary motion is entirely independent of the nervous system, excepting as the nervous power is a stimulus to irritability. In the production of this complex function several elements are concerned : 1st. The will, operating as a stimulus upon the brain, develops the nervous power; 2d. This power is then transmitted to the voluntary muscles, where it acts as a stimulus upon irritability (§ 226); 3d. Mobility is thus called into exercise, the immediate result of which is voluntary motion (§ 205, 206, 208, 209, 245, 256, 476 c, 486, 487, 492, no. 7, 500 d). However complex, and destitute of analogies in the world of mere physics, this phenomenon may be, I have no doubt that the solution which I have offered will be received by every philosophical mind Which may attentively consider the nervous power in its connections with the motor nerves, and the experiments of Wilson Philip (% 464, &c, 476, &c, 1041). v vs PHYSIOLOGY.--VITAL PROPERTIES. Ill Since, also, the nervous power has no existence in plants, their ac- tions are alone influenced by the physical agents of life; and, having no sympathetic relation of parts, the diseases of one part are felt by other parts only through the common laws of nutrition, while, also, remedial agents are curative by their local action alone. 233 £. The nervous power, in a manner analogous to its determina- tion upon the sphincter of the bladder after the evacuation of the urine, may be propagated upon distant parts, with morbific or curative effects, long after the removal of the agent by which it was originally excited. This is owing to the continued change, or impression, wrought upon the part to which the agent was applied (§ 514 g, 516, no. 6). 233^. One of the most remarkable laws of the nervous power is that of its determination through particular nerves upon certain parts, according to the nature of the exciting cause, whether moral or phys- ical, whether natural, morbific, or remedial, and equally so in animal and organic life; passing over, in the fulfillment of this law, various intermediate nerves of more direct anatomical connection. This is remarkably exemplified in many musical performances and feats of agility. This special determination of the nervous power is most in conformity with the special influences that may bring it into operation, in healthy conditions of the body ; but in diseased states, or where or- gans are but partially diverted from their natural state, a direction is more or less given to the determination of the power by these acquired susceptibilities (§ 500 j, k, 903). This peculiar attribute of the ner- vous power distinguishes it from the direct action of remedial and morbific agents, which, if taken into the circulation in efficient quan- tities, would often derange the universal body. But the same physi- ological constitution of the nervous power which renders it obedient to the will in its transmissions to particular muscles, or to the passions in its effects on special organs in organic life, renders the power, when modified by remedial or morbific agents, and according to its pre- cise modification and susceptibility of parts, equally determinate and circumscribed in its operation (§ 150-152, 838, 844). There is noth- ing in Nature more wonderful and paradoxical than this attribute of the nervous power; and while the facts which it supplies in connec- tion with the operation of the will and the passions bear with the strongest analogical force upon the philosophy which respects the in- fluences of morbific and remedial agents upon all parts distant from the seat of their application, that analogy is corroborated by the limitation of the morbific or remedial effects to certain parts of the organism. The fact may be regarded as fatal, in itself, to the doctrine of the op- eration of morbific and remedial agents by absorption, and to the hy- pothesis which identifies the nervous power with galvanism. GENERAL REMARKS UPON THE PHILOSOPHY OF LIFE. 234, a. Notwithstanding all the laws of sympathy, that are neces- sary to the full interpretation of the remote effects of morbific and re- medial agents, are as well established as any laws in physics, they have not been applied to these important objects ; but, on the contra- ry, those philosophers who have contributed most to their critical ex- position, overlook their pathological and therapeutical bearings, and cling to the doctrines of humoralism, and of the operation of remedial agents by absorption ; nor have they applied, in the least, the nervous 112 INSTITUTES OF MEDICINE. power in a philosophical manner to an exploration of the natural phe- nomena of sympathy. The oscillations of Newton, the contractions of Darwin, the vibrations of Hartley, the secretions of Galen, the gal- vanism of Galvani, the destructive forces of the chemist, and the caloric and the magnetism of wilder imaginations, continue to be adopted, and show as well by their great incongruity as by their failure, that the hypotheses are founded on imaginary data, and that each has neglected the phenomena of life (§ 189 b, 785). 234, b. I say nothing of those who still refuse their assent to the well-ascertained laws of sympathy, as manifested in the natural states of the body. These they have yet to study and to learn; but it may be well objected that their ignorance shall prove an obstacle to the progress of knowledge. He, indeed, must have been a very imperfect spectator of human events, who anticipates the acquiescence of ignorance or prejudice, or the ready concurrence of inferior minds, in the intricate problems which relate to the laws of the vital functions. The demonstrations of Philip have become obsolete, in all but their abstract nature; and the discoveries of Prochasca, Sir Charles Bell, Muller, Hall, Valentin, and others, in the functions of the nerves, are either unknown, or un- appreciated, by all but the erudite student or such as aim at erudition; and the very anatomical medium of sympathies, through which the operations of the nervous power and the phenomena of sympathy ap- peal, as it were, to the senses as well as to the understanding, is apt to be regarded as an accidental or as a superfluous appendage of the body, or thrown in to embarrass inquiry by multiplying the complex- ities of organic beings (fy 1039). Coming to the different kinds of irritability and sensibility, or as these are modified by morbific and remedial agents, or by other phys- ical causes, as well as the analogous modifications of the nervous power, and its remarkable attributes as a vital agent, its direct action as such when developed by causes acting directly upon the nervous system, or when brought into operation indirectly through the medi- um of sympathetic sensibility (§ 227), and other analogous facts which are equally substantiated by an endless variety of phenomena, they are pronounced by a no small number of the profession, even by wri- ters who appear in the character of expounders of medical philosophy, as metaphysical speculations, or as imaginary hypotheses. Even life itself is regarded as a subtlety of the schools, or as a phantom of less reputable claims. " For my part," says Magendie, " I declare boldly that I look upon these ideas about vitality, and the rest of it, as noth- ing more than a cloak for ignorance and laziness"* (\ 1034). 234, c. If, then, you object to the existence of a principle of life, why not to the existence of mind, to the imponderables, or to tangible matter itself (§168, 169, 175 bb) 1 Do you deny its several well- attested properties 1 Then why not deny the properties of the mind 1 Have you not, for the aid of the senses, a tangible analogy in the solar beam (§ 18Si d, 234 e) 1 Do you cast aside all the phenomena of irritability and sensibility, and maintain that the action of internal and external causes, the mind and its passions, is exerted upon the struc- ture alone, because you cannot see the properties (§ 169, 189) 1 Can * See Medical and Physiological Commentaries, vol. i., p. 397, 511, 512, 514 515 as to Magendie. PHYSIOLOGY.--VITAL PROPERTIES. 118 you see the Maker of the eye, or did the eye make itself (§ 74) 1 Do the muscles move without a moving power? Are you not amazed at what you cannot deny, that the mutual co-operation of the mind and the brain, which results in willing, is limited in its action upon the body to exactly those parts where its operation can be alone useful to the animal, namely, the voluntary muscles ; nay, more, that the will elects of these muscles such only as are precisely necessary to its present purpose, and bestows every imaginable degree of force with- in the limit of its power, and variously, also, on the several muscles which it may throw into simultaneous action (§ 233|, 349 e, 500 i) 1 [s there nothing as improbable in all this as in the propositions of the vitalist 1 Consider how, on the other hand, those other acts of the mind, called the passions, so near akin to the will, judgment, reflec- tion, are clearly ordained to operate in organic life for the moral and physical good of the being; or, if they be also the causes of pain and disease, the analogy of Nature shines out even here in placing them on a par with the remedial agents of the external world. If this be so, or a single fact conceded, how will you disregard the multitudi- nous phenomena of irritability and sensibility, or their various natu- ral and artificial modifications (§ 64,/*) 1 Will you consider an ar- gumentum ad hominem ? Do you, then, deny that you possess judg- ment, reflection, and the ability to discover truth ] If you object not to this, you must concede the philosophy of these Institutes as to the foregoing properties of life, and by the Same demonstration upon which that philosophy rests you must admit the imputed attributes of the nervous power, which are far more clearly and variously attested than judgment, reflection, or the ability to discover truth. Look at the experiments by Wilson Philip, Hall, Muller, Bell (§ 464, &c, 476, &c). Look at the nervous system, and there you shall absolutely see. Or, do you require other aid for your senses, look, again, at the analo- gies which are supplied by the solar beam, by electricity, by galvan- ism, by magnetism. Consider how they astonish you in their over- powering influences upon all things but the living being. And yet you can not see how these destructive effects are exerted. You give up your senses when the needle traverses the compass, and stand in mute astonishment, gazmg at the north for some sign that shall help the un- derstanding as to the nature of the mysterious agent. But you see and feel nothing. Nor is this all; for the dismay of sense becomes inexpressible, when imagination surveys the interval of thousands of miles, through which the unseen force exerts its mystic sway. And so of gravitation. But the effects are strongly pronounced upon the sense of vision, and their frequent repetition begets an acknowledg- ment that there is something besides the tangible and visible qualities of matter which, operating through vast distances, maintains the nee- dle in one everlasting direction, and the heavenly orbs in their unde- viating rounds. And here, in the perpetual operation of magnetism, there is something to aid your conception of an equally unintermit- ting exercise of the nervous power (§ 1034). 234, d. Do you object to what I have propounded as to the artifi- cial and temporary modifications of the nervous power (§ 227-232) 1 Can you state an objection, farther than that which has been just con- sidered 1 Do not the infinite phenomena of sympathy mutually con- spire together without a contradictory fact, in proving the occurrence 114 INSTITUTES OF MEDICINE. of such modifications; and is there a single effect of morbific and remedial agents, operating through the nervous systems, which cannot be clearly, perfectly, explained by the doctrines which I have pro- pounded in relation to the nervous power 1 Can a like affirmation be made of any other thing 1 But, you cannot see the modifications of the nervous power. Neither can you see the modifications of the electric fluid, as manifested under the conditions of electricity and galvanism ; but, the effects of the latter make a strong impression upon sense, which "grows into the belief that physical causes do, in re- ality, alter the conditions of electricity and turn it to galvanism, and those effects have actually engendered the expression of " modification of electricity." Here, then, is something for the senses, to aid them in their survey of the less tangible, but not less precise, and infinitely diversified, phenomena, that mark the artificial modifications of irrita- bility, sensibility, and the nervous power. And, should you require a like assistance as to the natural modifications of irritability and sen- sibility, or even the existence of the different properties which apper- tain to the vital principle, you have only to regard the solar beam, and the solar prism, and try experiments with each prismatic color (§ 188|-, d). 234, c. Do you marvel at the rapidity with which the nervous power moves in its operations'? Consider, then, the incomprehensi- ble velocity of light,—200,000 miles in a second of time ; or the more rapid apparent motion of the electric fluid. Or, take the more prob- able doctrine of the undulations of light, and this will be yet more con- formable to what is probably true of the nervous power. Of the un dulations, then, we have not less than 458,000,000,000,000, for the red ray ; 535,000,000,000,000, for the yellow ray ; 727,000,000,000,000, for the violet ray, in a second of time. I say, when we think of the physical effects of electricity, galvan- ism, magnetism, and of light, and more especially when we attempt to think of the inconceivable rapidity with which the undulations of light are propagated, we shall have no difficulty with what I have attrib- uted to the nervous power in resolving the phenomena of sympathy, voluntary motion, &c. > and when, also, we reflect that those very un- dulations, according to their variety, produce on the retina all the im- pressions that are requisite for every phenomenon of vision, and that every impression, which is thus produced, must be transmitted to the brain, before the sense of vision can be excited (§ 188^ d, 500 k). If, also, the retina be thus sensitive to the undulations of a substance which is so imponderable that it is doubted by many whether the sub- stratum of light be actually material, we shall have no difficulty, I say, by the aid of this plain analogy, in making the same philosophical use of the vastly more numerous and unique facts that are supplied by an- imal life, or in apprehending that the virtues of more substantial agents, whether morbific or remedial, may, in like manner, exert pow- erful impressions upon the properties of every part, both nervous and organic, and that such influences may, equally with the impressions of light, be transmitted to the brain and spinal cord, and establish im- pressions upon the parts in conformity with the virtues of each agent (§ 503). . _ & The undulations of light are excited by the various objects from which they proceed. And so of the nervous power. It is not in tran- PHYSIOLOGY.--VITAL PROPERTIES. 115 situ, a movable substance, but, like the principle of light, is every where diffused through its appropriate medium, and, like that princi- ple, is brought into operation by exciting causes. Is it difficult, how- ever, to imagine how the nervous power can move with the velocity of light in parts so dense as the nerves % It is less difficult than the comprehension of the admitted fact that light traverses the diamond as rapidly as it does ethereal space (§ 175 b, 188| d). Do you still marvel as to how the nervous power should induce or subvert diseases'? Were you not equally in the dark as to the modus operandi of the so- lar beam in its various agencies upon inorganic compounds, till a few obscure phenomena led to the hypothesis of undulations 1 But, what have you gained by the undulations ? Can you tell us how these in- conceivably small motions operate, without a resort to absolute as- sumptions I Are you any more convinced than before, that the phe- nomena of light are realities, or have you been aided a whit, by these discoveries, as to your former knowledge of the laws of light 1 You tell us that not only the well-known colors of the solar spectrum possess, individually, specific properties, but that " each of these com- prises rays differing in constitution, and differing in refrangibility, and that, doubtless, to each one specific effects are due."* You show the physiologist a few positive results, and he believes the analysis, and the existence of the several rays; though he may greatly dis- credit your philosophy of the effects as manifested in a department of nature which you only study under influences supplied by the labora- tory (§ 188£, d). But, you tell him, also, that the solar ray embraces " other principles which are invisible," and you call upon him to ad- mit the existence of these, notwithstanding he cannot see them (§ 175, bb). ' The physiologist, however, readily admits their existence upon the strength of the few facts which imply the operation of an in- visible agent; and he does so because he is a physiologist. But, ta- king your own rule of judgment as to a vital principle and its several properties, you were doubtful whether he might demand more tangi- ble proof; and, accordingly, you prepare him for an admission of your premises by a mode of reasoning which you reject, contemptu- ously, when the physiologist sets forth his endless series of facts which prove, each one, the existence of properties peculiar to living beings. You prejudge the case, as it were, by impugning his understanding, unless the induction be conceded. You tell him, that, "just in the same way that I am willing to admit the existence of forty simple metals, so, upon similar evidence, I am free to admit the existence of fifty different imponderable agents, if need be" (§ 188£, d). The phys- iologist requires you to admit but one, and, with this one he explains, with perfect consistency, all the processes of living beings, all the phenomena in physiology, in pathology, and therapeutics, while no one of them can be interpreted without the agency of such a principle. 234, f. But again, I say, what have we gained in a practical sense, or as to the modus operandi, or the laws of light and heat, or of the constituents of the solar ray, by the discovery of the undulations, or by any supposed decision of the question as to distinct rays or modi- fications of a common ray, or even by the prismatic colors ] Nothing whatever ; no more than has been gained, in a useful sense, by mi- croscopic explorations in physiology, but with the greater advantage * Draper's Treatise on The Forces which produce the Organization of Plants, p. 103. 116 INSTITUTES OF MEDICINE. of more precision, and more accomplishment to science, and without the pernicious hypotheses of the latter. And can the same affirma- tion be made of our knowledge of the properties of the vital princi- ples, and of their natural modifications in different parts, and those which are induced by morbific and remedial agents 1 On the contrary, we see this knowledge every where converted to the most important uses of organic beings, not only in a direct practical sense, but in un- folding the great laws by which they are governed. This knowledge, indeed, is the great foundation of physiology and of the healing art. Do you object to the relation which sympathetic sensibility bears to the nervous power (§ 201), and the relation of the nervous power to irritability (§ 226), in the phenomena of motion? Have you any better data for your conceptions of the relation of the magnetic pole to the needle; and to explain that relation, do you not admit a pecu- liar imponderable, invisible agent, which acts upon the properties of the needle 1 Do you understand any better, or have you any better facts respecting, the relation of physical agents to the mind, in the phe- nomena of sensation 1 You obtain your ideas of matter through the operation of physical agents upon the intellectual part; and how will you explain the access of those physical means to the spiritual sub- stance unless you also admit the physiological property, sensibility1? What intelligible connection is there, between the properties of mind and the motions of the brain'? What intelligible connection between the stimulus of the blood and the motions of the heart, or those mo- tions which attend the generation of bile and all other organic products, unless you admit a principle of life ? The forces of life are concerned about sensation in a peculiar manner, and there would be a violent interruption of the law of analogy were there not something interme- diate between mind and matter, a bond of union, as it were, through which impressions upon the senses should reach the spiritual existence. We may fancy it to be electricity, or the chemical forces; but, this no more aids our comprehension, through the known phenomena sup- plied by these causes, as to the communications from matter to the immaterial, thinking existence, than if we regard the nerves, per se, as the only medium. We therefore turn our reason to the special phenomena, and find a property in universal operation throughout the body, as the medium through which certain kinds of impressions from physical agents are transmitted to the mind. But, we find, also, an- other analogous series of phenomena which force us to'the conclusion that these depend, also, upon a certain modification of the,same prop- erty as that through which impressions are made upon the mind by external objects. We see, also, that these transmitted impressions give rise to another endless series of peculiar results, which have their point of departure in the nervous centres; and we see, too, that each one corresponds with, and confirms the others, in the several series respectively. We learn, besides, that those of the last series are anal- ogous to the direct effects of vital agents, healthy, morbific, and re- medial, upon the organs which' are the immediate seat of their opera- tion. Hence, we conclude, inevitably, that there exists what is de- nominated the nervous power, with all the attributes which I have as- cribed to it, and that it is brought into operation through the same channel of sympathy as the mind when sensible objects exert their effects. The mind, and the nervous power are, therefore, so far on a PHYSIOLOGY.--VITAL PROPERTIES. 117 par. Each is an agent, each gives rise to sensible and insensible mo- tions, and modifies variously the ordinary results when themselves are affected in an unusual manner, and each is brought into opera- tion by analogous causes. The mind, through the properties of life, forms a special bond of union between itself and certain parts of the organization; the nervous power, another special bond between the same properties of the vital principle, and other parts of the organi- zation, and by which, and by the perpetual operation of that power, the whole organic mechanism of animals moves on in a well-balanced, concerted action. Thus are the properties of the mind, the proper- ties of the vital principle, and the sensible mechanism, all mutually related to each other, and bound together by laws as precise as those more simple ones which rule in the inorganic world. 234, g. We need not, therefore, inquire into the intrinsic nature of the nervous power, or of the organic properties. It would be as ab- surd as to interrogate the nature of gravitation, or of any other prop- erty of mere matter, or even matter itself; though we may well say what the nervous and organic powers are not, and thus save much speculation and its resulting practice. It is enough that we know their existence and the laws they obey. This is all that can be philo- sophically or practically useful. With these we are about as well acquainted as we are with the laws of gravitation, or of light. An ignorance of the nature of the principles or causes affects in no respect our study of their laws, of their modes of operating, or of the influ- ences to which they may be liable. Their laws, like the laws of gal- vanism, or of optics, must remain the same, whatever theory may be adopted as to the nature of the causes. Inquiries, therefore, so obviously beyond our reach as the absolute nature of the vital principle, or any of its properties, should never raise our curiosity, much less receive our attention. Their pursuit vitiates the judgment, diverts the mind from practical and useful in- quiries, and renders it prone to speculation. But again, I say, we know enough of the whole of this subject for the purposes of philosophy, and for the good of mankind, by the phe- nomena alone; and since the phenomena of organic beings are far more diversified than those which relate to inorganic matter, so also should we be as contented with the former as with the latter, and ap- ply them in the same philosophical and practical manner. We also know enough of physics to marvel at nothing in organic beings which may be utterly different from the constitution, the phenomena, and the laws of inorganic matter; and, if it seem mysterious that such an agent as the nervous power should exist, with the characteristics which I have assigned, it will become less wonderful when we reflect upon the phenomena of the immaterial mind in its connection with organization, as in muscular motion, blushing, palpitation, syncope, apoplexy, &c, or even upon the velocity of light, the inconceivable rapidity of its undulations, its laws, its effects, &c. All that we can know of the nature of any substance, material or immaterial, is by the phenomena it manifests. Where these are the same, or closely allied, as in electricity and galvanism, we may be sure that the essential causes are the same. But, where great and striking differences exist, and more especially where there are no analogies in the phenomena, as between the nervous power, or the 118 INSTITUTES OF MEDICINE. organic properties, and all inorganic agents, substances, or causes, We may be equally certain that the agents, substances, causes, or powers, are as different from each other, in their essence, as in their phe- nomena. It follows, therefore, that the nervous power, and the organic prop- erties, are, respectively, sui generis ; having no analogies in the inor- ganic world. The phenomena which different agents, powers, or causes, manifest, are so unlike each other, that different modes of investigation must be pursued to arrive at a knowledge of each; and the phenomena will be just as conclusive of the nature of one substance or power as of another. A stone, for instance, affects the sight, and touch; it ap- pears of a certain size, shape, color, &c, or it is hard or soft; if an- alyzed, it is found to be composed of several distinct substances, each of which manifest other phenomena; and this is all we know of the nature of a stone. And so of magnetism, galvanism, light, heat, and whatever else appertains to the inorganic world. We examine their manifestations, and compare them together, and distinguish different things from each other by the.manifestations or phenomena of each. But, there are groups of phenomena which have certain general re- semblances, and these we arrange into genera or families, as the sev- eral earths, metals, gases, &c.; but the specific distinctions always remain, so that by the phenomena peculiar to each species we can always distinguish one from another. Just so it is in respect to the physical and chemical powers. The means of knowledge are of the same nature in all the cases, and the proof is as good in one case as in another. Coming to plants and animals, a general survey of their phenomena shows us that they have no other analogies, of any importance, with the inorganic world, than in the elements of which they are composed. These are derived from the inorganic kingdom; and here the simili- tude ends. If we investigate the phenomena analytically, they come upon us in a profusion wholly surpassing those of inorganic beings, and without the most remote resemblance. Here, therefore, we ap- ply the same rule as to inorganic beings, and we learn by the same process of observation, as much of the nature and powers of one class of beings as of the other, and the proof is as good in one case as in the other, though more conclusive in respect to organic beings, in- asmuch as their phenomena are more various. By the same rule, also, we attain all the knowledge we possess of the soul, and, beyond that of Revelation, all that is relative to a Supreme Being; and we distin- guish each from all the others, or bring them into relationship, in the same way. The same mode of reasoning is, of course, applicable to what I have said of the modifications of the nervous power (§ 227-229), and of the organic properties (§ 133-156, 188-215). 234, h. We are, however, so much the creatures of sense, that the majority will probably still go on explaining every thing appertaining to life by some tangible or visible cause, or by some laws with which we fancy ourselves to be better acquainted. I have already cited sev- eral examples ; and if we take up any writer, indifferently, it is more than an equal chance that the authorities will be increased. Thus here is Sir Gilbert Blane's excellent work on "Medical Lo^icl' PHYSIOLOGY.--VITAL PROPERTIES. 119 " The changes," he says, " accomplished by the actions of life may be conceived to be effected through the agency of some imponderable fluid; such as electricity, light, or magnetism. We may conceive, for instance, that each gland may be furnished with a sort of voltaic apparatus for effecting its specific change." The same doctrine has been adopted by a host of medical philosophers of our own times. But, did any of the foregoing agents ever produce, out of the organic being, a single one of the phenomena of life ] Did they ever give rise to one of those phenomena in a dead subject, although the organ- ized structure remain unimpaired; as in cases of instant death from hydrocyanic acid, nux vomica, or from a needle thrust into the medul- la oblongata ? Is not the whole hypothesis contradicted by all that is known of the effects of those agents 1 It is the merest assumption to sustain an unintelligible and absurd hypothesis, to affirm that struc- tural derangement is necessary to death. If galvanism, the chemical forces, &c, be the immediate cause of the deposition which constitutes the interstitial growth, what bestows vitality (or life, if it be preferred) on the new-formed matter? Or, if this vitality be imparted by spe- cific powers of the formative instruments, why should not those pow- ers be adequate to the entire work (§ 64) "? Why so great a violation of the most common rule in philosophy, as to introduce other forces, whose great office is to pull down, and whose results are confusion ] 234, /. The whole art of medicine consists in producing certain im- pressions upon properties or powers that are wholly unlike those which rule in the inorganic world. It will not answer to talk of mod- ifying the operation of galvanism, magnetism, gravitation, light, chem- ical affinity, &c, by an emetic or cathartic. It must, however, come to this, if you will have it that those forces preside over organized beings, or even if they be allowed to have a subordinate agency (§ 175, d). 235. Finally, the phenomena of life are as easily comprehended as those of inorganic matter, and denote as clearly, and even more so, the nature of the causes. Who will demonstrate the nature of those physical properties by which foreign agents produce their impression on the properties of life ] And yet so accurate is our discrimination among them, as prompted by the vital signs which they produce, that it is one of the most important objects of the physician to select from the multitude of cathartics, emetics, &c, a certain species whose properties shall correspond with the modified signs of the properties of life ; and, it is no unusual phenomenon, that, of the whole range before him, he decides with accuracy that there is only one medicine which is well suited to the case. And his conceptions of the specific properties of the agent, and of those of the organization, even in the modified state of the latter, are so comprehensive, that he may foretell their united result. He knows as much of the properties of life as of the remedial agent. He knows them far better; and that he admits their existence and specific nature is manifest from his deliberate ac- tion. Wlroever prescribes for disease upon any other ground is a mere charlatan. Who, again, will define the nature of cohesion, gravitation, chem- ical affinities, &c. ] Like the properties of life and of spirit, and their relations to matter, their existence is only inferred from certain uni- form phenomena, and from such, alone, we deduce their relations to 120 INSTITUTES OF MEDICINE. objects of more sensible demonstration; and this is all we know of the sensible objects themselves. We reach the connection between common matter and its properties, between the vital properties and organized structure, between the intellectual and moral faculties and the nervous system, the concurrence between them in the production of certain effects, and the differences in the nature of the several prop- erties, by a common process of observation. There are mysteries at- tending the same conditions of the whole which must be left to the sole comprehension of the Author Who intended the whole to sub- serve the purposes in which we are alone interested; Who has wise- ly secured to Himself the nature and control of primary causes; and Who has thereby restricted our inquiries to the only useful end of knowledge, the existence of the causes, and their various phenomena and laws. These may be so employed, as to answer the wants, the conveniences, and the various exigencies of intelligent beings. Those are the springs of action which it might be unsafe for man to under- stand. 236. From what I have hitherto said on the subject of life, it must evidently be regarded, in a philosophical sense, as a cause, not as an effect. The functions and other phenomena are the effects. This con- struction, which I have also set forth in my Essay on the " Vital Pow- ers" in other demonstrative aspects, is indispensable to any sound principles in medicine. All effects have their causes; and this simple principle obliges us to look for a cause of the phenomena of life. It is with the conditions of that cause, ascertained through the medium of its effects, that all physiology and medicine are concerned. 237. The powers by which living beings are governed, ceteris par- ibus, are always as precise in their operation, and bring about results as precise, as gravitation itself. But the properties of life are con- stantly liable to variations, and, therefore, there will be correspond- ing variations in their phenomena. Gravitation, and other physical forces, on the other hand, are immutable, and there are, therefore, no variations in the results of their operation. But it is also equally true that any given condition of the properties of life, connected with any given influences, is equivalent to the unvarying state of the physical forces. That particular condition, in conjunction with the supposed influences, always determines the same results, whether in health or disease. Every power in nature, when operating under given circum- stances, always terminates in uniform effects. The uncertainties, therefore, to which the science of medicine is liable, or any other which has nature for its foundation, are owing to our inability to understand all the facts. If any remedial agent produce an effect at one time which it does not at another, it is because the properties of life have been differently affected in the different cases ; and there may have been, also, a concurrence of many other different influences. Never- theless, in each case, the medicine operates according to established laws, and the modifications depend upon the difference of circumstan- ces. Each combination of circumstances, however, always gives a uniform determination to the laws which govern the effects. Where the conditions are the same, the remedy in a certain dose will always produce the same results. Although gravitation is immutable in its nature, we yet see some- thing analogous to the foregoing influences upon the properties of PHYSIOLOGY.--VITAL PROPERTIES. 121 life, in the manner in which the revolution of the heavenly bodies may be affected by their interference, in relation to each other, with the power as exercised by the sun ; as seen in the erratic movement of comets. In either case the incidental influences may be calculated, and the results foretold,—conforming, in one case, to the laws of grav- itation, and in the other to those of the vital force. The stability of the physiological conditions enables us to calculate not only what will happen to-day, but through all future time. But, the vital conditions are subject to precise modifications at the several great eras or stages of life ; but, being marked by uniformity, the results are forever the same, at each era respectively. The fundamental changes enable us, also, to foresee how the modified properties of life will be differ- ently affected by vital stimuli, the new sympathies that will spring up, the different relations of sensibility to the faculties of the mind, the difference in the acquisition of knowledge, &c, at the several eras. From these natural and uniform modifications of the vital states, we may turn to those of a fluctuating and accidental nature, which grow out of the influence of climate, habits, employments, &c, and which may be not only as lasting as the individual, but may be transmitted to his posterity. As at the different eras of life, we here find, also, variable influences from the natural, the morbific, and the remedial agents, variable sympathies, &c, among organs, according to the arti- ficially-modified condition of the properties of life. These conditions, however, are rarely exactly the same in any two individuals; but, they are strictly analogous in principle to the natural ones which dis- tinguish the several stages of life, and, so far as they may be known in any given case, we may calculate, with great approximation to the truth, what will be the special characteristic phenomena that will mark the organic, the animal, and the intellectual existence of that in- dividual (§ 153-156, 535, &c, 574, &c). Thus we have a series of analogies, in respect to the mutability of the properties of life, and corresponding results, which bring us upon the confines of disease ; which consists, also, in certain modifications of the vital properties, but more profound, more various, and more tran- sient (§ 176-182). Here lie the difficulties of medicine ; difficulties attending our knowledge of the modifying causes, the influences they produce, the complications of sympathy, and other contingent circum- stances. All these conditions must be known in any given case, to foresee, with certainty, any immediate or more remote result either of disease or of the action of any medicine, or of any natural vital agent. But, the properties of life being never very greatly varied from their natural character, we may come, by a careful observation of their varying phenomena, to a knowledge of their conditions, and to foresee the results, or such as may spring from the operation of medicine, from the different kinds of food, &c, with sufficient accura- cy for all useful purposes. With this knowledge, we get at the most important laws of disease, general and specific, and build up princi- ples which are more valuable in practice than ages of disconnected experience (§ 149, 150). 23S. I have said, that although instability is a prominent character- istic of the properties of life, and lies at the foundaton of disease and therapeutics, these properties never undergo any radical change till they shall have lost their recuperative tendency. They are the only 122 INSTITUTES OF MEDICINE. attributes of organic beings that do not undergo absolute change and renewal. These properties must be forever present, without essential change of their nature, to carry on the work of decay and renewal, which are in perpetual progress in all the solids and fluids over which the properties preside. Hence an important law, that all hereditary predispositions to dis- ease, and all impressions from morbific agents, which do not produce their manifest effects till the blood shall have undergone a renewal (as in hydrophobia, fevers, &c), must be primarily exerted upon the properties of life, and that all the subsequent changes in the fluids and solids must be due to that original modification of the vital prop- erties. To perpetuate the primary influences, something of a perma- nent nature must receive the impression. Analogy, alone, would as sure us that this must be also equally true of the effects of all mor- bific and remedial agents. 239. There is nothing more important to be known and appreci- ated, than the endowment of the properties of life with a tendency to return from diseased to their natural states. This is the vis medica- trix natures, and is the immediate foundation of therapeutics. This, and this alone, has given rise to the art of medicine ; since, by no ar- tificial means can the diseased properties and functions of life be con- verted into their healthy state. It is also remarkable that the most efficient remedial agents institute their favorable effects by establish- ing new pathological conditions ; which farther shows that it is nature alone which cures, and through the foregoing principle. That prin- ciple is one of the most remarkable exemplifications of Design, since, without it, the human race would become extinct. 240. Connected with the foregoing law is another not less funda- mental, and which shows the fallacy of reasoning from the effects of remedial agents upon healthy to morbid conditions. It is, that the susceptibility of all parts to the action of remedies, physical or moral, is very different in disease from what it is in health, and the nature and the results of the influences are greatly different in the two con- ditions. Take many of the most powerful agents, arsenic, tartarized antimony, iodine, &c, and when administered in certain small and repeated alterative doses, they bring about the cure of the most ob- stinate and formidable conditions of disease; while the same doses may not manifest any action upon the system, or on any part of it, un- der circumstances of health. This manifestly depends upon an in- creased susceptibility of the organic properties, in their diseased con- ditions, to the action of foreign agents, and upon an increased dispo- sition to undergo changes. And here we have opened a grand dis- play of infinite Design, Wisdom, and Goodness, to mitigate the pen- alties of disease, and to preserve the human race. This law, which unfolds a principle latent in health, and by which morbid organic properties acquire susceptibilities to salutary influences from agents which in health would either produce no effects, or lead to untoward results, and its ally, the great recuperative principle (§ 239), impose the highest obligation on physicians to become medical philosophers. 7. THE MIND AND ITS PROPERTIES. 241, a. Reason and instinct belong to man; instinct alone to ani- mals. Mind is commonly regarded as synonymous with reason and PHYSIOLOGY.--MENTAL PROPERTIES. 123 instinct a principle by itself. The latter is undoubtedly true of ani- mals ; but I would consider instinct, in relation to man, as a property of the soul; while in animals it is shorn of the great distinguishing attribute of man, the rational, immortal,faculty. Independently of the specific facts which go to this conclusion, it has the strong ground of analogy in the more complex condition of the principle of life as it exists in animals than in plants (§ 184, 185). 211, b. To simplify the discussion of this intricate subject, the word mind, with the foregoing explanation, and mental properties, so far as perception, the will, and the understanding, are concerned, may be applied indiscriminately to man and animals. Judgment and reflec- tion are the great characteristics of reason ; but, contrary to the usual representation, the understanding belongs as well to the instinct of animals as to the human mind. Many, again, may be disposed to consider the understanding a function, rather than a property; but this construction would suppose the operation of judgment and reflec- tion, which do not belong to animals. The term is also employed in other acceptations than the present. 241, c. The abstract manner in which metaphysicians have consid- ered all the operations of the mind, while no one of them is performed without the co-operation of the brain, or a principal nervous centre, and originally elicited through the corporeal senses, proves to us that physiologists are best qualified to analyze the phenomena of the soul and of instinct, and to indicate their relations to the body, and the laws which they observe. There is also a mysterious affinity between the soul of man and the instinct of animals, of which metaphysicians take but little or no cognizance. This alliance is shown by the cor- responding manifestations of perception, of understanding, and of the will in animals-; by the amazing precision with which their habits are regulated ; by the evidence of common passions ; by the coincidence in the external senses of man and animals, through which they alike acquire a knowledge of external things; by the parallel in the ana- tomical structure of the brain of man and of animals which stand high in the scale; and by other analogies, which denote an affinity between the soul and instinct So great and various, indeed, are the evidences of the foregoing nature, that the special attributes of instinct are as- sociated with the human mind; thus forming a connecting link, through the moral faculties, between rational and irrational beings. Nevertheless, the phenomena of the human mind are infinitely su- perior to those of instinct, while the operations of instinct in animals greatly surpass any of its manifestations in man. Many special pecu- liarities concur, also, in demonstrating an absolute distinction between the rational mind and instinct. The latter, for instance, always moves, in each individual species of animal, in a particular, unvarying path, but differently in each species of animal.* It never diverges to im- prove its original endowments, or to add a gain which it did not pos- sess in its infant condition. It is then nearly as perfect in its opera- tions as at mature ago ; nor does one generation of animals gain upon its predecessors. How different with reason, and with the instinct of man ! He passes through early infancy without a trace of the for- mer, and with only that helpless development of the latter which ena- * Hi-re I may say that analogy proves that there is but one species of mankind, since the manifestations of reason and instinct are the same in all. 124 INSTITUTES OF MKDICINE. bles him, with the foreign aid of reason, to imbibe the sustenance re- quired by organic life. Unlike the instinct of animals, however, the corresponding manifestations become greatly multiplied as age ad- vances ; but it remains always far more circumscribed and imperfect, and often plunging itself, and leading reason, into violations of their natural functions. And what a contrast between the limitations of in- stinct and the progress and grasp of the human mind; the latter for- ever tanging through all the labyrinths of nature, investigating their phenomena, developing their powers, their subsidiary causes, and their laws, turning in upon itself and multiplying its knowledge, and en- larging its powers by its own independent efforts, laying up the gains of the past as a fruitful source of present good and of farther acquisi- tions, distinguishing good from evil, from which results the sense of moral responsibility, investigating its own attributes, and attempting even its own nature, and tracing up its existence to a Higher Power, as the Author of the Universe which was made for the contemplation and the enjoyment of mind (§ 175). 241, d. It is not an object, however, of the Institutes to investigate the philosophy of mind beyond those physiological considerations which are relative to the properties and functions of life, however it may have been important to their interests to contradistinguish the Maker from His works (§ 14 c, 175, 350f h-l). Perception and the will are the only mental properties which concur, more or less, in the phenomena of animal life. 242. Perception is always necessary to true sensation, and therefore to the exercise of all the senses. The mind, or instinct, must per- ceive an impression made upon sense, and consciousness must operate before the impression can be realized. The phenomena of sympa- thy in their connection with sensibility, in the ordinary processes of life, are not relative to sensation, but depend on a special modification of sensibility and on the nervous power. 243. The to ill, another property of the mind, upon which volition lepends, exemplifies yet farther the complexity of the principles which obtain in the animal kingdom; and its phenomena admonish us to pause over that materialism which sees nothing but the demon- strations of physical and chemical power in the equally unique mani- festations of irritability, sensibility, mobility, the nervous power,—the entire organic force (§ 215). The will presides in animal life. It governs the movements not only of the voluntary muscles, but even the operations of the other mental faculties. In producing muscular motion, the operations of judgment and perception are often associated, and even bring the will into action. All muscular movements with which the mind, or in- stinct, is not connected, depend upon other causes than the will. Vol- untary motion is, therefore, as dependent on the will, as true sensation is upon perception (§ 1072, b). The will has little or no operation in organic life (§ 500, e); though the passions operate with power upon the heart, the abdominal viscera, &c. This peculiarity is founded in consummate Design ; since great- er latitude to the will would be incompatible with animal existence; while, on the other hand, other elements of the mind are allowed, for useful purposes, to stretch their influences to the deep recesses of life. 244. The will, a property of the mind, like the nervous power a PHYSIOLOGY.--FUNCTIONS. 125 property of the vital principle, is, therefore, a vital stimulus to the brain, whose chief office is the production of voluntary motion, by bringing into action the nervous power. 245. When the will gives rise to voluntary motion, the philosophy is the same as when motion is developed in the organs of organic life by the nervous power (§ 205-215). The latter may take place through impressions transmitted to the nervous centres (§ 227, 500), or by impressions exerted in a direct manner upon these centres (§ 227, 230, 477). The will operates in the direct manner, develops the nervous power, and transmits it to the irritability of the voluntary muscles, by which mobility is brought into operation (§ 233). When the passions affect the movements in organic life, it is exactly in the same way as with the will in animal life (§ 500 h, 1040). 216. Thus it appears that the unity in the great plan of the ner- vous power, in its relations to both organic and animal life, to mind as well as to matter, and the perfect concurrence of all the facts, and the obvious nature of the whole, which declare a harmony of principles and laws throughout all the immense variety relative to the nervous power, continue to unfold a grandeur of the subject which invites an unprejudiced attention to the expositions I have made of this brilliant institution of Nature (§ 1069-1082). FOURTH DIVISION OF PHYSIOLOGY. FUNCTIONS. 247. Our fourth grand division of Physiology comprehends the functions of organic beings. They are carried on by the properties of life in their connection with organized structure (§ 170, 175, 177), and of which the functions are the great final causes, or effects (§ 176). They are, indeed, the only useful ends of life; since, otherwise, all organic beings Would exist in the condition of the seed and egg (§ 235, 236). The terminating series of the capillary vessels are the im- mediate instruments of all the essential processes in organic life, and therefore, also, of all diseases (§ 109, 668, 679). 248. The functions are common and peculiar. 249. The common functions belong to all organic beings. They consist of, 1st. Motion; 2d. Absorption; 3d. Assimilation; 4th. Dis- tribution ; 5th. Appropriation, or nutrition and secretion; 6th. Excre- tion ; 7th. Calorification; 8th. Generation. The first seven are in- dispensable to animals and plants. The eighth appertains only to the species, and has no essential part in the organic economy (§ 97, 11S-123). ' 250. The peculiar functions belong to animals only. They are, I. Functions of relation ; comprehending, 1st. Sensation; 2d. Sym- pathy. II. Voluntary motion, and functions by which the mind and instinct act on external objects. III. Other mental and instinctive functions. 126 INSTITUTES OF MEDICINE. I. COMMON, OR ORGANIC FUNCTIONS. 251 Organs which perform similar functions are very variable in structure in different orders of animals. The liver, for example, " is represented in one case by simple caeca, or blind sacs; in another by tufts of ca?ca; in a third by bunches of cells ; in a fourth by a spongy mass; in a fifth by branched ducts ending in feather-like terminal twins';" and so on, up to the complication of the most perfect animals. Nevertheless, they all secrete a very analogous fluid. And so of oth- er organs and functions. A due regard for the preceding facts must unavoidably reconcile every mind to what I have said as to microscopical explorations of the minuteness of structure (§ 131, 304, 306, 409, I). 252. Though structure be very various, there is a great analogy in the vital functions and their immediate products,—even between plants and animals. This is remarkably true of every individual part in the different races of animals, whatever its simplicity or complexi- ty (§ 251). Hence, it becomes more and more manifest that the properties of life have a greater agency in the formation of organic products than the structure itself (§ 67-69). 1. MOTION. 253. Motion is the immediate result of the action of mobility or contractility, and was necessarily explained in describing that prop- erty (§ 205-215). It is the function by which all things acquire their movement in organic beings. 254. Motion may be remotely mechanical, as the movement of the blood, ingesta, &c.; but the power and the actions of parts which gen- erate the mechanical movements are purely vital. 255. Motion belongs, of course, to every tissue in which its mani- festations occur; and it is therefore an error, however common, to limit this function to the muscular tissue. 256. The great offices of motion in organic life are to supply the system with useful materials, and to remove such as are useless. 257. In animal life, this function appears under the aspect of loco- motion or some analogous result, and I have associated the considera- tion of this modification of the function with that which is common to the organic life of animals and plants, on account of their common na- ture. 258. Voluntary motion proceeds from the action of the will upon the great nervous centre, by which the nervous power is developed and transmitted to the irritability of the voluntary muscles (§ 188,208, 233, 476 c). Here the excitation of the nervous power is direct, as in the experiments by Wilson Philip (§ 486, 487). If the motion be involuntary, as in the ordinary movements of respiration, the develop- ment of the nervous power is indirect, according to the usual process when organic actions are influenced by the nervous power (§ 222, &c, 500). When other involuntary motions affect the muscles of animal life, as convulsions, &c, the development of the nervous power may be direct, as in diseases, and concussions, of the brain, or indirect, as in teething, and intestinal irritation. The philosophy, however, re- specting the production of motion in all these cases, is exactly the same. Whether the movements be voluntary or involuntary, the PHYSIOLOGY.--FUNCTIONS. 127 movements depend upon the action of the nervous influence upon mo- bility through the property irritability. The mind _does not, as has been supposed, leave the brain to enter the muscles in voluntary mo- tion. The difficulties of explanation are not only multiplied by this supposition, but it is shown to be erroneous by the analogous move- ments which may be excited through the spinal cord, or through the nerves, after the soul and instinctive principle are separated from the body by the removal of the head. This philosophy is also coincident with that which I have propounded as to influences of the nervous power in organic life. Each illustrates and sustains the other (§ 500). 259. It is now important to repeat, that the nervous power never generates motion, per se (§ 222-232). The function always depends immediately upon the organic property mobility, which is brought into action through impressions made upon irritability (§ 188). The ner- vous power is only a stimulus to irritability. But, it is much more im- portant to motion in animal than organic life; since it is the only nat- ural stimulus of the voluntary muscles, while blood, and other agents, arc the natural stimuli in organic life. Indeed, the nervous power is not a natural stimulus to the viscera of organic life, but only super- added, in animals, for an incidental purpose (§ 215, 223, 226, 232, 455,1034,1051). 260. Very important laws grow out of the foregoing distinction be- tween the relation of the nervous power to the function of motion in animal and organic life, and its essential independence of that power in either life (§ 476, &c). 261. That motion does not depend upon the nerves, is shown by the sensible and insensible motions of plants ; by that of their leaves, stems, stamens, by their absorption, nutrition, secretion, &c. (§ 455, c). The analogies in results prove this independence of the nerves, and the near identity of the function in plants and animals. Indeed, the chemists will have it that all the essential compounds of the animal are formed by vegetable organization (§ 18, 409). Such analogies are always sound, being based on great fundamental laws. But there may be great variety of mechanism. The same independence is shown by the organic actions which continue in parts from which all the nerves are severed; by the regular action of the heart and intestines after their removal from the body, &c. 262. " The heart of a frog continues to beat with its ordinary rhythm even when the entire base of the organ, when the ventricles, as far as their juncture with the auricles, are cut away." In the same way, "the peristaltic movements of the intestinal canal continue not only when the intestine is removed from the trunk to- gether with the mesentery and ganglionic plexus, but also when the intestine itself is isolated from the plexus by being separated from the mesentery at the line of its insertion."—Muller's Physiology. 263. Dr. M. Hall tied a ligature around the root of the heart and lungs, and then separated them from the body. " The action of the heart was still such as to carry on, in a slight degree, and for a short period, the circulation of the blood through the pulmonary artery, and a few of the capillary vessels." He adds his belief, " that the actual circulation of the blood has not been before seen proceeding entirely and independently of the sympathetic system."—Hall, 264. It seems also to have been shown by the case of the monster 128 INSTITUTES OF MEDICINE. recorded by Dr. Clark, that while the foetus exists in utero, the nerves are no more necessary to its growth and maturity than are the glan- dular organs; simple nutrition being alone in progress. In that case, Dr. Clark had in view the importance of the principle now under con- sideration, and a faithful examination appears to have been made with a view to the nervous system, and which resulted in his failure to detect its existence (§ 461^).—Dr. Clark, in Philosophical Trans- actions, London, 1793, p. 154. 265. In the Medical and Physiological Commentaries I have set forth a variety of other important facts to show that motion, voluntary as well as involuntary, is essentially independent of the nervous sys- tem. (See vol. i., p. 17-29, 474-480, 571, 572; vol. ii., p. 385.) The Experiments of Philip are also conclusive upon this subject (§ 476, &c). 266. The nervous power, in developing motion in either organic or animal life, as a stimulus to the organic properties, does not follow the nerves according to their regular order of distribution from the nervous centres. On the contrary, its entire want of uniformity in that respect—operating simultaneously, at one time, through a nerve or nerves proceeding from the cranium and some inferior part of the spinal canal, while it passes over all intermediate nerves—or, at an- other time, electing, without any regularity in respect to order of ar- rangement, two or more of those intermediate spinal nerves—this entire want of respect to anatomical order is so familiar to all that it has not appeared as one of the most difficult and sublime problems of nature. This very extraordinary attribute of the nervous power is rendered the more remarkable by our knowledge of the fact that its operation is determined through particular nerves either by an act of the will, or, in organic life, by particular passions, by their intensity of operation, and by the special nature and intensity of physical agents which may transmit their influences to the nervous centres through some other part; and, in the cases relative to organic life, according, also, to the existing susceptibility of the various parts of the organism (§ 473, no. 6). 267. All the foregoing are established facts, of perpetual occur- rence ; and they should be taken in connection with the doctrines which I have advanced as to artificial modifications of the nervous power, and the modus operandi of morbific and remedial agents (5 226-232, 893, &c). 2. ABSORPTION. 268. Absorption is performed, in animals, by the lacteals and lym- phatics ; those vessels being very similar in their constitution and function. There are corresponding means for the office of absorption in the roots and leaves of plants. 269. Magendie, and others who have copied from him, have fallen into the error of attributing the office of absorption to the veins. He was led into the mistake by an ignorance of the fact that the lymphat- ics terminate variously in small veins* Fallacies of that nature should be apparent upon principle alone—at least to such as recog- nizee a unity of design, and a simplicity in the great institutions of nature. Every system of vessels, so far as known, has but one func- * See Medical and Physiological Commentaries, vol. ii., p. 170, note, 380, 394-396. PHYSIOLOGY.--FUNCTIONS. 129 tion, however that may be modified in different parts, as seen in the lymphatics and lacteals, in the terminal series of the capillary arter- ies in all parts, &c. The distinction depends either upon structure connected with,the modifications of common vital properties, and their relative adaptations to the physical properties of different fluids, or, structure may be apparently less concerned than the organic prop- erties ; which is one of the most universal and important principles in physiology (§ 133-150). 270. The lacteals perform the office of absorbing, and introducing into the organization of animals, foreign nutritive matter. 271. The lymphatics, on the contrary, are destined for the vital de- composition of the body, and for the removal of waste parts, which are conveyed by the lymphatics into the torrent of blood to be ulti- mately cast out of the system, or again to undergo, in part, the process of sanguification. 272. By these vessels, also, the solids are removed in the ulcerative process of inflammation, and mortified parts are detached from the sound,* and foreign substances which are introduced into the body are taken up and removed. 273. Hence it is obvious that the lacteals and lymphatics are antag- onizing systems, and that organic beings are the constant subjects of waste as well as of nutrition; the balance being maintained through the inlet supplied by the lacteals, aa-d the outlet provided by the lymphatics (§ 180-182, 286). Notwithstanding, therefore, the coinci- dence in the general function of these two systems of vessels, the office of one is creative, that of the other destructive. During the period of growth, nutrition overbalances waste ; but, when growth ceases, nutrition and vital decomposition must be in cquilihrio. 274. No substances but such as exist in a fluid or very attenuated state are taken up by the lacteals and absorbents. 275. The lacteals have open orifices in the intestinal villi. I have shown the error of the microscopists who deny these orifices; and I have shown, also, that all vessels of secretion terminate in open ori- fices.t Physiologists, however, continue to copy the projectors of the mechanical theory of porous absorption and secretion. 276. Different substances are absorbed with various degrees of ra- pidity, both in animals and plants. This depends on their peculiar virtues, and on the manner, therefore, in which they affect irritability; thus showing the vital nature of the process (§ 149,188, &c, 207). The same conclusion is also inferable from experiments, as well upon plants as animals. 277, a. Again, the lacteals, in virtue of their special modifications of irritability, exclude every thing but chyle. Bile is not taken up either by the lacteals or lymphatics; cathartics pass off; emetics are rejected. The principle is every where; is shown in the larynx, pylorus, &c, in the exclusion of the red globules from the serous vessels, though their diameters be many times larger than the globules of blood (§ 399). The principle lies in the virtues of the agents and the special modification of irritability which belongs to each part (§ 135). It is designed for the conservation of every part, and of the * Sec Med. and Physiolog. Comm., vol. ii., p. 168,169, 171-173. t Ibid., vol. i., p. 683-690, 699-712. 130 INSTITUTES OF MEDICINE. whole. Had not the lacteals and lymphatics been endowed in this wonderful manner, or were absorption a mere physical process, or ca- pillary attraction, as it is called, all foreign substances would have free access to the internal parts of the organization, and organic beings would have had no continued existence. They would have perished as soon as created. Hence, are the vital properties so modified in all these millions of inlets into the labyrinth of organization, that they shall be not only vigilant sentinels, but recognize, at once, every one of the thousand offenders that may endeavor to steal its way into the sanctum sanctorum (§ 192). 277, b. Some of the most important laws in medicine are founded on the special modifications of irritability in different parts (§ 149, 150); and as it respects the lacteals and lymphatics, the principle not only contradicts the assumption of the operation of medicines by absorption, but confirms, in a beautiful manner, the laws of sympathy. 278. It is only when the lacteals and lymphatics become morbidly affected, or their irritability essentially modified by the morbific action of agents offensive to the organization, that those agents are at all ad- mitted, and then only very sparingly. The principle is the same as when undigested food escapes the pyloric orifice in indigestion, or the red globules of blood gain admittance to the serous vessels in in- flammation ■(§ 14, 74, 117, 137,143, 155, 156, 169/, 266, 3031 a, 306, 310, 311, 325, 387, 399, 409/-422, 514 A, 524 d, 525, 526 d, 528 c, 638, 619 d, 764 b, 811, 847 c, 848, 902/, 905). 279. If, therefore, foreign agents affect the vital properties in the foregoing manner, so also do they affect the condition of the other tissues of the part. This is the beginning of disease, which may now go on accumulating without any farther agency of the exciting cause ; or, if the offending cause gain admission into the circulation, it may con- tinue, per se, to exasperate disease. But, even in this case of the con- tinued operation of morbific or remedial agents after their absorption, I have shown that solidism and vitalism can alone explain their effects (§ 819, &c). 280. I have also shown that when morbific or remedial agents are taken into the circulation, the quantity is so small, their dilution by the blood and other fluids so great, and their elimination by the kid- neys so rapid (from five to fifteen minutes), that little or nothing is likely to be contributed in this way to the morbific or remedial effects. The rapidity with which agents that are not morbific, but useless to the system, are elaborated by the kidneys, is a proof, upon the prin- ciple of Design, that a provision exists for the exclusion of deleterious agents from the circulation. But, since they may, under special cir- cumstances, pass the great sentinel (§ 278), the kidneys are provided as other guards to the general organism, to expel the offenders at once. Just so with the lungs. If offensive objects pass the larynx, all the muscles of respiration, through a beautiful system of Design, imme- diately set at work to get rid of the intruder. The intelligent reader will readily carry this principle to more recondite processes, as the institution of abscesses, and the curious steps that attend their prooress from deep-seated parts toward the surface. 281. It may be also added, that I know of no critical attempt having been made to invalidate the facts and the reasoning set forth in my Essay on the Humoral Pathology, which has for its object the ex- PHYSIOLOGY.--FUNCTIONS. 131 posure of that pathology and the defense of solidism and vitalism; and, although that work has been now five years before the public, I know not that 1 have omitted the investigation of one essential fact or experiment that has been alleged or instituted in behalf of humoralism. If such omission has occurred, let it be shown. 282. Many distinguished men have been led into the error of sup- posing that noxious substances are taken readily into the circulation because the skin is deeply tinged with yellow, in jaundice ; or because the bones become red when madder is eaten; or the urine is colored by rhubarb, or manifests the odor of turpentine, of garlic, &c. But, let it be considered, that the inoffensive coloring matter of the bile is alone absorbed, as is also that of madder and rhubarb, &c.; while the thousandth part of a grain of spirits of turpentine, or of garlic, is enough to impart all the odor to the urine that has been ever observed to at- tend that product. 283. It may be also advantageously stated in this place, that the insoluble nature of many substances, such as the hydrargyri chloridum, the hydrargyri pilula, the hydrargyri unguentum, &c, positively con- tradict the statements which have been made as to their presence in the circulation, and enforce the importance of receiving with greater caution the experiments which are put forth to sustain an hypothesis, or which may apparently aim at notoriety (§ 264). 284. Although a very limited operation of morbific and remedial agents, through their absorption into the circulation, be not incompat- ible with solidism and vitalism (§ 277, 278, 283, 827/), the usual in- terpretation of their effects, according to the doctrines of humoralism, would compel us to abandon the application of physiology to medicine, whether pathologically considered, or in respect to the operation of curative agents. The laws of disease would be totally unlike the laws of health; or, rather, disease would be without laws, and there would, therefore, be no general principles in medicine. Practice would be a blind empyricism. Diseases would be just as various and un- certain as every chemical change in the blood, and these changes, upon the ground of humoralism, would have no resemblances to each other. 285. The properties of life lie at the foundation of physiology. It is a knowledge of their character, and of the laws which they obey, that enables us to conform our habits, at all ages, in the best way for the maintenance of health. But, what is disease 1 It is a deviation from the state of health; and, therefore, if there be any consistency in nature, disease should consist primarily and essentially in modifi-' cations of those vital properties, which, in a different state, constitute the important conditions of health. In this way, therefore, medicine takes the rank of an intelligible and important science. Physiology is the ground-work throughout. Pathology becomes nothing more than physiology modified. And, coming to therapeutics, it is still physiology applied to the cure of diseases; or, in other words, the application of such agents to the morbid properties of life as shall aid their restoration to their natural physiological state. The whole is thus bound together. No new elements come into operation; but, throughout the whole series of changes, the same powers are in action and carry on all the processes. Nor are there any new laws intro- duced. The powers and actions being fundamentally the same. 132 INSTITUTES OF MEDICINE. so are the laws, of health and disease, as are those, also, by which diseased are converted to healthy conditions. But, the powers or properties of life being modified in disease, and again modified in other ways by the action of remedial agents, so are the laws, under which all these results happen, varied in a corresponding manner. The laws are only the conditions under which effects take place ; and, as those effects have always a direct reference to the state of the vital properties, they must be fundamentally of the same nature under all the various conditions of life, since, also, the vital properties never lose their fundamental character (^ 1, 639). 286. When, therefore, I may speak of the laws of health and the laws of disease, I must not be understood as meaning something entirely different in the two cases. And yet, their modifications are always precise, and the results of each are always determined in one uniform manner. This is necessarily so, because the changes in the vital properties are always precise, and according to the nature of the in- fluences by which the changes are effected (§ 149, 150). 287. In this sense, therefore (§ 286), the laws may be assumed to be, in each individual modification, of a specific nature. 288. Laws may be said to be general and specific; which, how- ever, is only another mode of considering the foregoing principle (§ 285). Thus, it is a general law that the absorbents, whether in health or disease, do not take up foreign substances of a deleterious nature; but, it is a specific law, that when the irritability of the lacteals or lymphatics is modified in a certain way, they will admit a small pro- portion of the noxious agent by which the alteration is produced (§ 277, 278). 289. Those mechanical physiologists who have not, or will not have, just conceptions of the properties and actions of life, refer the process of absorption to capillary attraction, or that mechanical principle which determines the ascent of oil in the wick of a lamp (§ 277). The chemists belong to this class of reasoners; even such of them a* allow the existence of a vital principle. Thus, for example, Liebig has it, that, "A cotton wick inclosed in a lamp, which contains a liquid satura- ted with carbonic acid, acts exactly in the same manner as a living plant in the night. Water and carbonic acid are sucked up by capil- lary attraction, and both evaporate from the exterior part of the wick." Again, " All substances in solution in a soil are absorbed by the roots of plants exactly as a sponge imbibes a liquid, and all it con- tains, without selection."—Liebig's Organic Chemistry applied to Physiology and Agriculture. Now all this might be very good philosophy for a common agricultu- rist; but it evinces an unaccountable disregard of facts, and of the plain- est suggestions of nature. And yet it is a common doctrine nowa- days ; a part of the " new experimental philosophy." Iu the first place, however, it is not true that the roots of plants imbibe their nourish- ment " without selection." When plants are cultivated in glass ves- sels containing distilled water, their roots will even decompose the glass, and select its silica, or alkali, or take them both, and assimilate them to themselves, and in the absence of any known chemical affini- ties or influences. Absorption is nearly as exact in plants as in ani- mals ; and so is appropriation. Like animals, their absorbent system PHYSIOLOGY.--FUNCTIONS. 133 is naturally repulsive of every thing that is offensive and not suitable to their economy. If poisons, when artificially applied, get admission, it is by inflicting a violence on the radicles of plants (§ 278). And what is thus prompted by reason, by analogy, by common experience, is fully confirmed by the chemists themselves, in those analyses of all parts of a plant, even the sap, which are designed as standards of the composition which shall serve for any particular part of any given species of plant, as well through all future time as at the hour when the analyses were made (^ 1052, 1053,1054). 290. The simile of the " lamp-wick," and of the " sponge" (§ 289), show us how far astray our friends are from the path of truth. It is not alone the complex mechanism of the root which the absorbed ma- terials traverse, but a labyrinth of highly organized and living tubes, passing through the whole trunk of the plant, till the materials finally reach the leaves. In those respiratory organs, the pabulum vitce is farther subjected to the action of another complicated, unique, and living system of vessels. And what is the " wick of a lamp 1" A mere bundle of dead, disorganized fibres, broken upon the card, and spun upon the wheel (§ 350£ n, o, 826 c). 291. But, the foregoing degrading doctrine of life (§ 289) is not pe- culiar to the chemists. Some reputedly profound physiologists apply it not only to plants, but to animals, and, like Liebig, identify the same vital and physical processes. One example, in a distinguished quarter, will suffice. Thus, Dr. Carpenter: " It will be hereafter shown that the absorption of nutritious fluid is probably due to the physical power of endosmose. A continued absorption may be produced by a physical contrivance which imitates the (fleets of vital action ; [ ! ] as in the wick of a lamp, which draws up oil to supply the combustion above, but will cease to do so when the de- mand no longer exists" ! (§64 g, 175 c).—Carpenter's Comparative Physiology. The work, a standard one, from which the foregoing is quoted, abounds with analogous doctrines. They are, of course, fatal to physiology and tO all medical science. 292. Immediately after the quotation from Liebig, in the preceding section, that author proceeds to reprobate physiologists for their ex- clusion of chemistry from organic life, and charitably regards it as a prejudice arising from our ignorance of the science (§ 350, a). This, however, is quite an untenable position; for, wherever medicine is cultivated, chemistry is justly made a fundamental part of education. It is, indeed, the knowledge which the soundest physiologists possess of chemical science, that enables them to institute the necessary con- trasts, and which convinces them that chemistry, in its proper ac- ceptation, has no connection with the processes of living beings. This, indeed, I have abundantly shown to be the real opinion of the chemists themselves (§ 350, &c). Bold in assumption, inapt in illus- tration, and, at last, like Liebig, contradicting the whole by an ac- knowledgment that " vitality, in its peculiar operations, makes use of a special apparatus for each function of an organ," and that "in the living organism we are acquainted with only one. cause of motion ; and this is the same cause which determines the growth of living tis- sues, and gives them the power of resistance to external agencies. It if the vital force."—Liebig (§ 350, nos. 26, 27, 28, 71-77, &:c.). 134 INSTITUTES OF MEDICINE. 293. Looking at other facts attending the process of absorption in plants, we shall find them all concurring with what I have already stated as to the dependence of this function upon vital actions ; and, if vital here, we need not look for other proof of a similar law in an- imals. Thus, Van Marum demonstrated that absorbed fluids could rise only eight inches by capillary attraction. Hales, Walker, Mirbel, Chevreuil, and others, have shown that the sap moves with such ve- locity and force in plants, that it must be propelled by vital contrac- tions and dilatations of the vessels. We have examples of this sur- prising rapidity of the circulation in grape-vines. Don and Barbieii affirm that they saw the movements of the vessels. Again, the motion of sap is increased by light, heat, and other stim- uli, which have no effect on capillary attraction. And this is the opin- ion even of Liebig, who says that " the functions of plants certainly proceed with greater intensity and rapidity in sunshine, than in the diffused light of day ; but it merely accelerates in a greater degree the action already existing;" "an action," he says, "which de- pends on the vital force alone." It was shown by La Place, that, if the sap rose by capillary attrac- tion, it should not, as it does, flow from the openings made in the ves- sels. But, again, the sap will not flow from the openings, if the plants be poisoned with prussic acid. The effect is the same as upon the circulation of the blood; and it would be equally absurd, in either case, to suppose that the poison acts upon any physical force. As- tringents, and various other substances, applied to the openings, avert the flow of sap, which can only be done through the foregoing prin- ciples (§ 278-284, 1054). 294. Here is another fact, and which appears to be conclusive of the vital nature of absorption, and of the discrimination observed by the radicles of plants (§ 289, 291). It is, that the sap of the root is unlike any thing which it absorbs from the earth. All the substances are decompounded at the moment of entering the roots, just as the carbonic acid is by the leaves. Their elements are then also united according to the modes which prevail in organic compounds (§ 455, c). 295. Equally unfounded as the doctrine of capillary attraction are the supposed processes of endosmose and exdosmose. They are all alike predicated of experiments upon dead matter, and are then car- ried, by way of analogy, to the living organism, and in defiance of all the contradictory phenomena of life. Having entered extensively into a refutation of the hypothesis of endosmose and exdosmose, in the Medical and Physiological Commentaries, I shall not now resume the subject (§ 1052, 1053, 1054). 3. assimilation. 296. By the function of assimilation the substances taken into the body are converted into the homogeneous blood, and identified in com- position and vital properties with all parts of the body. It is there- fore especially concerned in the process of growth, and in supplying the waste which is constantly in progress. It is the function, there- fore, by which the properties of life are communicated to dead matter. 297. All dead matter, before its reception into the body, is subject to the forces of chemistry. The operation of these forces is arrest- ed in the alimentary canal of animals, and in the absorbing vessels of plants. PHYSIOLOG V.--FUNCTIONS. 135 298. The nutriment of vegetables consists always of inorganic sub- stances, or is reduced to the condition of inorganic matter before its appropriation. The food of animals is always organic. The former exists in an elementary or in a state of binary combination, the latter of ternary, quaternary, &c. It is the work of vegetable assimilation to overthrow the chemical combinations, and to unite the elements in those very different modes which constitute organic compounds. This is the most remarkable and comprehensive System of Design of which we have any knowledge (§ 1052). 299. Assimilation, therefore, devolves especially upon the proper- ties vivification and vital affinity (§ 214, 218); though it be certainly true that all the organic powers and functions are necessary to each other, and concur together in producing every result. But, in every result there are some more interested than others. 300. Animals, being incapable of organizing inorganic substances, are dependent upon the vegetable kingdom as their ultimate source of supply (§ 13, 14). Such, indeed, is the final cause of vegetable life. But the food of animals must be dead before it can begin to un- dergo the- action of the vital properties in another being. The gas- tric juice, for instance, has no effect upon any living substance. 301. No organic compound ever undergoes chemical decomposi- tion, or any approximation toward such decomposition, to fit it for the purposes of animal life. On the contrary, every such tendency places the appropriate nutriment of animals, more or less, beyond their as- similating endowments. It is the province of animal life, and of all its provisions for assimilation, not to carry back toward their inorganic condition the peculiar compounds generated by the vegetable king- dom for the foreordained uses of the animal, but to carry them for- ward to yet higher degrees of life and organization. This is one of the most fundamental laws of nature, and is conclusive against all the chemical speculations with which physiology has been so unhappily visited. 302, a. The assimilating organs in vegetables are more simple than in animals, and the complexity increases in animals according to their rank in the scale of life. It would appear, therefore, that organiza- tion bears a ratio more or less proportionate to the endowment of or- ganic compounds with the properties of life (§ 301, 409). 302, b. The process of converting inorganic into organic compounds begins in two orders of vessels, one of which are the radical absorb- ents of plants, the other analogous vessels in the leaves. The matter absorbed by the roots ascends through the stem to the leaves, where, by the operation of a series of vessels, variously mod- ified in different species, it is converted, along with that absorbed by the leaves, into a juice, which, like the blood, is thus fitted for the purposes of nutrition. This juice then descends through other ves- sels, to be appropriated to all parts, and to form the source of all the various products of vegetable organization. 303, a. We come, therefore, to a conclusion as remarkable as it is comprehensive, that the atmosphere is not only essential to plants and animals in its usual acceptation, but that it supplies the great means of nutriment to both organic kingdoms ; directly to the vegetable, and indirectly to the animal department (§ 298-300). The assumption as put forth in Liebig's Animal Chemistry, that " all matters which serve 136 INSTITUTES OF MEDICINE. as food to living organisms are compounds of two or more elements, which are kept together by certain chemical forces," must be aban- doned, and we must look to the atmosphere and what it contains for the four great elements which compose organic beings. The oxygen and the nitrogen of the air, the oxygen and the hydrogen of the vapor which the air contains, and the carbon of the carbonic acid, are as much at this day the great source of nutriment to plants, as before the "mist" went up from the seas, or animals yielded ammonia. 'Oxygen and nitrogen, therefore, as it respects atmospheric air, are appropri- ated by plants in their elementary condition. Upon organic com- pounds thus formed is animal existence, in the main, dependent. Ammonia certainly contributes to the nourishment of plants. But this is an incidental means, at least if there be any truth in Moses. And that his Record is true, is plain enough upon the principle of Design; since it is impossible that Providence should have created the animal kingdom, which yields the ammonia, before he brought forth that kingdom upon which animals depend for their existence. 303, b. As it respects absorption, the leaves and the roots of plants appear to have a common office, though the former are designed es- pecially for assimilation. The carbonic acid, and the oxygen and the nitrogen of the air, are precipitated along with the vapor, and thus reach the organs which are principally devoted to absorption. In no other way can we primarily reach the materials of all organic beings. Before their absorption can have begun, the whole essential elementa must have been embraced originally in the atmosphere, and in the simple conditions which I have stated. Nor is it a difficult process to follow out that circuit of causes and effects in which revolves the economy of nature in making the waste of organic beings during their own existence a subsidiary supply of nourishment to themselves, or to others of their own day, or to generations in the womb of time; or, when consigned " to the dust," how their elements, from one genera- tion to another, form an endless round of materials for reproduction and growth, either in the form of gases and vapor diffused in the air, or as imbodied with the earth. 303, c. Although it be the special object of the radical fibres to carry on. the function of absorption, this office is more or less perform- ed by the leaves of plants, but in various degrees, according to the nature of the species. In arid climates, the leaves have this function strongly pronounced; and*many plants, like the sempervirens, will grow as well when suspended by a string, as when connected by their roots with the soil. 303, d. The leaves of plants absorb carbonic acid mostly during the day, decompound it, as do the roots those binary compounds taken in from the soil, and otherwise prepare it as an important source of nourishment. Light is necessary to this function of the leaves, or, at least, to its proper performance; and it is remarkable that while in progress, it is attended by an evolution of oxygen gas, but that during its suspension, as in the night, oxygen gas is absorbed by the leaves and carbonic acid given out. This, however, is said by distinguished physiologists to be only partially true as it respects these processes at night; some affirming that they have witnessed the same results at night as during the day. The chemists have an interest in makino the light the agent of decomposition. But the light acts only as a vital PHYSIOLOGY.--FUNCTIONS. 137 stimulus to the leaves, by which their organic properties are rendered capable of overthrowing that most refractory compound, carbonic acid (§ 188J- d, 350, nos. 46, 47, 48, 49, 50, 51, 52, 53, 54). 303, e. The leaves of plants being the great organs of assimilation, and light the vital stimulus by which the function is maintained (§ I885, d), it appears from what has been now said that light holds the first rank among the requisites of life. It was therefore brought into existence before the creation of the vegetable kingdom; and being thus indispensable to all living beings, we see the fallacy of a common tenet in theoretical geology, that the most thrifty period of vegetation was through a great cycle of total darkness, and an atmosphere of carbonic acid (§ 74, 1079 b). 303\, a. One of the most interesting facts in vegetable physiology, is the immediate necessity of plants to animal life during their very growth; their final cause, in this respect, being the abstraction of car- bonic acid from the atmosphere, and the renewal of its oxygen. Ani- mals, too, as we have seen, incidentally contribute carbon to the vege- table kingdom, in the form of carbonic acid, and nitrogen in the form of ammonia. There is this remarkable subserviency of the organic kingdoms to each other, though there be not a reciprocal dependence. Vegetables, indeed, preceded animals, and are, therefore, essentially independent, while animals derive all they possess from vegetable creation (§ 303, a). Plants are the producers, animals the consumers. The former directly, and the latter indirectly, live upon the air and what it contains. The plant dies and becomes food for the animal; but it seems scarcely less important in its living state to the exigen- cies of animal life. And so the animal, living and dead, yields back its all to the atmosphere; and thus are the inorganic, and the two de- partments of the organic, kingdoms united (§ 1052, 1053). 303^, b. But, we have seen, as I originally indicated in the Essay on the Philosophy of Vitality, that the supply of ammonia to the atmo- sphere is only a contingent result of the creation of animals, and there- fore not indispensable to vegetation (§ 156 b, 303 a). Liebig, how- ever, reverses the order of Creation, and affirms that " We have not the slightest reason for believing that the nitrogen of the atmosphere takes part in the process of assimilation of plants and animals." " These facts are not sufficient to establish the opinion that it is ammonia which affords all vegetables, without exception, the nitrogen which enters into the composition of their constituent sub- stances. Considerations of another kind, however, give to this opin- ion a degree of certainty which completely excludes all other views of the matter."—Liebig's Organic Chemistry, &c, p. 70, 71. 303^, Cm The same mistake has arisen with the chemists as to the reciprocal dependence of animals and plants, in regard to the excre- tion of carbon by one and oxygen by the other. However true it may be that animals are dependent on plants for oxygen gas, it is certainly an assumption that the vegetable kingdom is alike dependent on the animal for its carbonaceous element. If the primary creation of plants be admitted, that is sufficient; and to those who reject the Mosaic Record, and the concurring testimony of geologists, I may adduce the admitted fact that vegetables are the ultimate source of supply to all animals. The former, therefore, are essentially independent, the latter dependent; while this universal fact corroborates, also, 138 INSTITUTES of medicine. the original account of the primary creation of the vegetable kingdom (§ 303J-). As to the relations of the living plant to organic life, it is computed by Saussure, and allowed by others, that the atmosphere contains about TJL__th part of its weight of carbonic acid. The atmosphere must be also losing, through the processes of respiration, combustion, &c, a proportion of its oxygen. It is estimated, also, that the present num- ber of human beings would, alone, double the existing quantity of car- bonic acid in the air in 1000 years ; and, in 303,000 years would ex- haust its oxygen. It is also found that atmospheric air of the present day does not contain less oxygen than that which is found in jars buried for 1S00 years in the ruins of Pompeii. From all this it is inferable that there is a universal cause in oper- ation, by which the carbonic acid of the air is consumed, and oxygen supplied; and, from the various well-known, and indispensable uses of the vegetable kingdom to the animal, which declare its creation for the benefit of the latter, and, therefore, its antecedent or simultaneous creation, we should naturally be prompted, by analogy, to look to this subordinate provision as the universal source through which the great purposes of respiration are maintained unimpaired. Chemistry has here elegantly illustrated this great element in the final causes of the vegetable kingdom, and the contingent aid which it derives from the animal; while it enlarges our view of the vast conceptions of Unity of Design. 303^. It is also worth our while to observe of these important laws, as we go along, how they are perverted by the ignorant in physiolo- gy, and how incapable the chemist is constantly proving himself of "pursuing his reasoning," as said of him by Hunter, "even beyond the simple experiment itself." Vegetables, as we have seen, are composed mainly of carbon, oxy- gen, hydrogen, and nitrogen (§ 37, 303). The carbonic acid of the air (as well as of the soil) is absorbed by plants, and appropriated to their nourishment and growth. This gaseous substance, therefore, is decomposed by vegetable organization, the carbon vivified and ap- propriated, and a part of the oxygen thrown off to replenish the at- mosphere. It is incorrectly said, however, by Liebig, that " the at- mosphere must receive by this process a volume of oxygen for every volume of carbonic acid which has been decomposed." Oxygen gas is a large and important element of vegetable substances, and a pro- portion, therefore, of the oxygen of the carbonic acid is evidently re- tained, and combined under a new form along with the carbon and other elements. In making all plants yield the whole of the oxygen of the carbonic acid to the air, Liebig sacrificed vegetable physiology to one of his favorite chemical assumptions. His hypothesis, also, as to the dependence of absorption upon the mechanical process of cap- illary attraction, has led him to overlook the fact that the water which is absorbed by plants is actually decompounded, and its elements com- bined with others according to the laws which determine organic com- pounds. It is water, indeed, which yields, far more than ammonia, the hydrogen which abounds in plants (§ 303, b). Water, therefore, being composed of oxygen and hydrogen, furnishes a source of the supply of that oxygen which goes to the increase of vegetables ; and, for aught that can be said to the contrary, it may form a part of what is evolved into the air. PHYSIOLOGY.—functions. 139 There are also other sources from whence vegetables derive their oxygen, namely, from some mineral compounds appertaining to the earth, and directly, by means of the leaves, from the air itself (§ 303). The latter process goes on, mostly, in the night, and the decomposi- tion of the carbonic acid is then, also, more or less arrested; or, as is generally supposed, a certain proportion is generated and emitted by plants ; and that those actions are analogous, to a certain extent, to the respiration of animals, having for their object, in part, the separation of carbon from some of the vegetable constituents. 303 J. Here, again, let us pause to observe the windings of the chemist and his conflicts with nature. "At night," says Liebig, "a true chemical process commences, in consequence of the action of the oxygen of the air upon the sub- stances composing the leaves, blossoms, and fruit. This process is not at all connected with the life of the vegetable organism, because it goes on in the dead plant exactly as in a living one" ! Here, in the first place, is an important fallacy in the premises from which the induction is made; since the processes have not the least analogy in the living and dead plant. In the former, the oxygen is taken into the organization, and goes to form organic compounds. In the dead plant, it is an agent of chemical decomposition, by which the organic compounds are destroyed, and the structure broken up. Now we shall always find that authors who reason in the foregoing manner perpetually contradict themselves. In the case before us, a contradiction necessarily arises from the fundamental differences be- tween the processes of organic and inorganic beings, and the laws by which they are governed. A little farther on from the quotation I have just made, Liebig affirms that " the laws of life cannot be investi- gated in an organized being which is diseased or dying." Here, then, is a contradictory opinion, which inculcates as great an error in physi- ology as that of identifying the effects of oxygen on " living beings" and on such as are actually dead. Here is an absolute denial of any analogies between the laws which govern living " diseased beings" and the "laws of life." But, this declaration of the chemist, devoid of truth as it is, is universally applicable where he would be least disposed to see it operate. Such an application, too, is an irresistible sequitur ; since, if " the laws of life cannot be investigated in an organ- ized being which is diseased or dying," it certainly follows that the laws which relate to dead, or inorganic beings, and the forces upon which those laws depend, can have no agency in living beings. Such, however, is the material which is now-a-days denominated " experimental philosophy," and "the progress of medical science." And, if the reader will now turn to the parallel columns (§ 350), he will see yet other contradictions directly relative to the ibregoin°- quotation (§ 1052, 1053). But, it may, perhaps, be well enough, before dismissing this sub- ject, to say, that, although "the laws of life" cannot be investigated in an organized being which is dying," the laws which govern diseased actions and their results are only slightly modified "laws of life," and often reflect great light upon their strictly healthy condition. We are, or should be, constantly reasoning in this manner in all cases of disease ; and it is only by comparisons of the modifications, which constitute disease, with the natural conditions of life, that we can have 140 institutes of medicine. any just knowledge of diseases. In proportion, however, as the indi- vidual approximates a state of death, all this reasoning fails; and, when actually dead, no such comparisons can be instituted. Here, then, it is that the foregoing admission of the chemist applies with all the force of truth. 304. The greater complexity of the organs of assimilation in ani- mal life gives rise to a variety of subordinate functions in animals not found in plants; such, for example, as digestion by the gastric juice, saliva, bile, &c.; then a farther advancement of the process in the lacteals, in the blood-vessels, in the lungs, &c. Some of these subor- dinate functions, however, have their analogies in plants ; such as the action of the sap-vessels upon the circulating fluid, the imbibition and exhalation of gaseous substances by the leaves, &c. But, in all the cases, the extreme vessels which perform the office of nutrition are the main instruments of organic life. All the functions which are carried on by compound structures are subsidiary only to that of the nutritive vessels (§ 171). 305. The organs of assimilation in animals are more or less com- plex, according to the nature of the food. Probably every animal has a stomach, or some analogous organ, and a mouth, and anus, which would form, as supposed by Aristotle, a fundamental distinc- tion between plants and animals (§ 11). The analogies which are supplied by the higher orders of animals would prompt this conclu- sion in respect to the most inferior. 306. In vertebrated animals, the stomach is generally an expand- ed portion only of the intestinal canal. In fishes, the intestine is commonly short; but this is often compensated by folds in the mu- cous membrane. In birds, there is a complexity of the alimentary organs which does not exist in fishes, amphibia, or reptiles. In mam- malia, the digestive organization is still different; and here it is more remarkably various according to the nature of the food, and as the necessity of supplies may be felt at short or at longer intervals. The more, also, the phenomena of animal life are multiplied, the greater is the development of the digestive system (§ 131, 251, 409 I). Its complex nature has an intimate relation to the qualities of the food, and these relations have an affinity with that principle of instinct which directs animals in the selection of food. The more dense and tough the food, and the more removed from the nature of the body which it is destined to nourish, the more complex are the organs of digestion. And so, on the contrary, the softer the food; and the more it is like the animal in its composition, the more simple are the assim- ilating organs. Animals, therefore, which live on hay, have these or- gans much more complex than such as are nourished by animal food; especially that part of the organization which is destined to make the first and greatest change. 307. The principal agent in the assimilating process, in animals, is the gastric juice; a vital organic fluid, which is secreted by the inter- nal coat of the stomach (§ 135 a, 316, 419, 827 b). This secretion is especially promoted by the stimulus of food, which is dissolved and altered in its elementary constitution by the vital influences of the juice. This is the first and greatest step in the process of assimilation. It is here that dead matter receives its first impressions from the prop- erties vivification and vital affinity (§ 216, 218). The chemists tell us PHYSIOLOGY.--FUNCTIONS. 141 that the process is a chemical one; and that, notwithstanding the va- rious, and unique, and astonishing devices of nature for the elaboration of the gastric juice, they would stultify physiologists with the pretense that many different processes of the laboratory will generate a gastric juice with all the unique properties that appertain to the fluid as elab- orated from the blood by the various modifications of organization which were instituted by Almighty Power for these specific objects. And having been thus regardless of the most sublime and profound institutions of that Power, they proceed to assume that the product of these artificial compounds, in their action upon food, is the homoge- neous chyme of living nature, and which is apparently the same in all animals, whatever the kind or the variety of food. But the chemist is met at the very threshold by the fact, that there is nothing in or- ganic nature itself that can elaborate that fluid from the blood but that particular part of the great system of mucous membranes which forms a component part of the stomach (§ 135, a). 308. The plainest analogy leads us, therefore, to the conclusion that all animals possess a stomach ; while the universality of the gas- tric juice shows its fundamental importance in the animal economy. 309. In most animals that consume food of a solid nature, there are preparatory organs which assist mechanically, by dividing the food. The construction of these organs of mastication, both as to their osse- ous and muscular parts, has a strict reference to the kind of food upon which the animal is destined to subsist. Animals of prey are furnish- ed with organs for the destruction of life and organization; since no substance which possesses life can undergo digestion, and all solids must be divided to admit of a free access of the gastric juice and saliva. 310. The organs of mastication are more various than any other parts; yet so uniform in each species, so allied among numerous spe- cies, that naturalists have taken these characters not only as signifi- cant of the species, but as the foundation of a systematic distribution of the species into genera, and of genera into orders. 311. Where the usual organs of mastication are deficient in ani- mals, the species is often supplied with means in the stomach itself for reducing the aliment to a soft substance, so that it may be pene- trated by the gastric juice. The stomach of the armadillo, which sub- sists on insects, and of the granivorous birds, is endowed with a pow- erful muscle for crushing, or grinding the food. The stomachs of other animals are armed with bony or horny parts, as in many insects. 312. The food is moved about in the stomach by the muscular ac- tion of the organ; but so peculiar and exquisite is the modification of irritability of the pyloric orifice, the food is not permitted to pass this outlet till it is converted into chyme (§ 278). Much of the aque- ous portion, however, is early and rapidly absorbed by the stomach. 313. When, however, as we have seen, the irritability of the pylo- rus is artificially modified, as in disease, it will often allow undigested food to pass, more or less readily, into the duodenum (§ 278). But it is more remarkable that it will suffer many hard, indigestible sub- stances to escape, while it detains such as are most congenial to its nature. The passage of indigestible substances is effected gradually by repeatedly presenting themselves at the pylorus, and thus so habit- uating the irritability of that orifice to their own irritant effects, but not to those of digestible food, that they are allowed to pass, while 142 INSTITUTES of medicine. the latter is detained; the stomach thus electing what is most conge- nial to its nature and to the wants of life (§ 188, &c, 539 a, 543 a, 551). 314. The saliva, bile, and pancreatic juice are auxiliary to the gas- tric juice, though how far is considered problematical. The liver is found, under a great variety of forms, in all animals whose structure can be made the subject of ocular demonstration, and it is known to generate bile in all instances. The pancreas and salivary glands oc- cur in all the mammifera, birds, and reptiles, and in many fishes, mol- lusca, and insects. From the great universality, therefore, of the foregoing organs, it cannot be doubted, independently of the more direct facts, that the fluids which they secrete have an important vital agency in the pro- cess of assimilation. 315. Animals which live on vegetables have larger salivary glands than such as feed on animal substances ; and, since vegetables require greater assimilating means than animal food, it is a just inference from final causes that the saliva answers a far more important object than, as is commonly imputed to it, of moistening the food and facili- tating its passage to the stomach. On the other hand, however, it has been with still less reason imagined by others that it contributes more than the gastric juice to the conversion of food into chyme. But here, as on all speculative questions, some distinguished chemists re- fer the agency of the saliva in the process of digestion to the atmo- spheric air it conveys to the stomach, while others of equal renown attribute this high office to its own specific virtues. 316. The bile and pancreatic juice mingle with the chyme in the upper part of the duodenum, where it is probable that the latter fluid contributes an assimilating influence analogous to that of the saliya; while the disappearance of some of the components of the bile, and other relative facts, show a direct connection of this fluid with the process of assimilation. The bile also separates the excrementitious from the nutritious part of the chyme; the former portion occupying the centre of the canal, and the latter the parietes (417, b). Connected with these important uses of the bile, is its well-known function of maintaining peristaltic action. Such, therefore, beino- its great final causes, we may safely reject the hypothesis of the mechan- ical theorists, that the liver, like the lungs, is designed to depurate the blood. The injury consequent on the failure of the liver, by ex- periment or otherwise, to perform its function, no more proves its supposed depurating office than a like contingency befalling the stom- ach would place that organ in the same category. 317. The intestinal tube, like the roots of plants, is supplied with absorbing vessels, which are called lacteals in animals of complex or- ganization. The nutritive part of the chyme is taken up by these vessels, where it undergoes a farther assimilation, and receives the name of chyle. Nothing is absorbed by the lacteals which is offensive to their exquisitely modified irritability, excepting under the circumstances already set forth (§ 278). 318. In the higher animals, the chyle is transmitted by the lacteals to the thoracic duct, and by this vessel to the left subclavian vein, where it mingles with the general mass of blood. Thence it passes to the right cavities of the heart to be sent to the lungs, where it re- PHYSIOLOGY.--FUNCTIONS. 143 ceives another important impress of vivification, parts, for the first time, with a portion of its carbonaceous matter, and undergoes a de- velopment of its coloring principle. From the lungs, it passes with the old blood, with which it is now fully incorporated, to the left cav- ities of the heart, to be transmitted to all parts of the body to under- go the last act of assimilation. 319. Assimilation advances progressively from the first conversion of food into chyme, till the nutritive matter becomes vitally united with the solid parts. At each step of the process, in the stomach, in the duodenum, through the lacteals, in the lungs, and at its final des- tination, the degree and kind of assimilation is forever the same, at each of its stages, in every species of organic beings ; thus denoting specific powers and laws by which all this unvarying exactness is maintained (§ 42). Assimilation is more simple in animals low in the scale of organi- zation ; but close analogies prevail throughout. 320. The chyle is said to exhibit globules under the microscope, which is probably true. Others affirm that they have seen them in the chyme ; but Muller thinks that impossible, as the lacteals, accord- ing to him, have no open orifices, and, therefore, the globules could not be admitted through the " invisible pores" of the closed lacteals. These vessels, however, have open terminations in the villi of the in- testines (§ 275). These questions as to the existence and shape of the globules of blood, chyle, milk, &c, are of no farther practical importance than as they lead to much waste of time, and encumber medicine with specu- lation and false doctrine; while the instrument, through the aid of which the imagination is thus sent upon its airy flight, is also the im- bodyment of a thousand falsehoods in the path of truth (§ 131). 321. Since, however, no one doubts that the nutritive part of the chyme undergoes a very positive change in the lacteals (§ 320), and a higher degree of assimilation, the proof is the same here, as in absorp- tion by plants, that the fluid is not taken up and carried forward by capillary attraction (§ 289-291). 322. Looking back upon the variety of parts which are concerned in the work of assimilation; their exact adaptation to each other; their peculiarities in different species of animals according to the na- ture of their food—varying, indeed, more or less in every species, yet always alike in all individuals of the same species; the universality of four specific digestive fluids, and.each of these analogous in all an- imals, notwithstanding the variety in the structure of the secretino- or- gans, yet only generated, respectively, by one special part, their pro- duction in unusual quantities, especially of the gastric juice, to meet the exigencies of digestion; the apparently exact similarity in the composition of the chyme of all animals, whatever the nature and the variety of the food ; it appears to be one of the highest absurdities to suppose that all this complexity of parts, all this magnificence and variety in Design, should be merely intended to subserve a chemical reduction of food in the stomach, especially, too, as all that is known of chemistry is in conflict with every part of this stupendous whole. And when we pursue the other steps through which the great end of digestion is attained, and steadily regard each individual part forever giving rise to certain unvarying results, each part in its anatomical 144 INSTITUTES OF MEDICINE. and vital relations to all the rest, the necessity of every part to every step in the process of assimilation, the necessity of the whole to every secreted solid and fluid, the derivation of the whole unique and for- ever exact variety (millions upon millions, § 41-46) from four ele- ments mainly, from one homogeneous fluid which embraces yet fourteen other elements, the necessary co-operation of many of the secreted fluids toward their own formation individually, and toward every for- mation in the complex animal—when, I say, we duly consider this labyrinth of complexities, moving on in one unvarying round of har- monious action and results, moved by a power within which has no known analogy in the world where chemical results obtain, we may reconcile unbelief in all this Design with a yet higher order of infi- delity, but certainly not with the ordinary promptings of reason, or with the plainest rules of evidence (§ 638). But, let us analyze, in another section, the great plan of nature for the maintenance of organic life in animals. 323. Let us analyze, after the manrier of Cuvier, the constitution of animals in respect to the subserviency of the various parts of the fabric to the single function of digestion, and according to the nature of each species of animal; and when we shall have reflected upon the principles which determine the coincidences, and see that no one of them can be explained by any of the forces and laws of the inor- ganic world, let us cast from us, as unworthy a thoughtful mind, the supposition that the final act, or that of digestion, is a chemical pro- cess ; and let us also apply the same induction to every other process of living beings. " Every organized being," says Cuvier, " forms a whole, a unique, and perfect system, the parts of which mutually correspond, and con- cur in the same definite action by a reciprocal reaction. None of those parts can change without the whole changing; and, consequent- ly, each of them, separately considered, points out and marks all the others. Thus, if the intestines of an animal are so organized as only to digest flesh, and that fresh, it follows that the jaws of the animal must be constructed to devour prey, its claws to seize and tear it, its teeth to eat and divide it, the whole structure of the organs of motion such as to pursue and catch it, its perceptive organs to discern it at a distance. Nature must have even placed in its brain the necessary instinct to know how to conceal itself and lay snares for its victims. That the jaw may be enabled to seize, it must have a certain-shaped prominence for the articulation, a certain relation between the posi- tion of the resisting power and that of the strength employed with the fulcrum; a certain volume in the temporal muscle, requiring an equiv- alent extent in the hollow which receives it, and a certain convexity of the zygomatic arch under which it passes. This zygomatic arch must also possess a certain strength to give strength to the masseter muscle. That an animal may carry off its prey, a certain strength is requisite in the muscles which raise the head; whence results a de- terminate formation in the vertebrae and muscles attached, and in the occiput where the muscles are inserted. That the teeth may cut the flesh, they must be sharp, and they must be so more or less according as they will have more or less exclusively flesh to cut. Their roots should be more or less solid, as they have more and larger bones to break. All these circumstances will, in like manner, influence the de- PHYSIOLOGY.--FUNCTIONS. 145 velopment of all those parts which serve to move the jaw. That the claws may seize the prey, they must have a certain mobility in the talons, a certain strength in the nails; whence will result determinate formations in all the claws, and the necessary distribution of muscles and tendons. It will be necessary that the forearm have a certain facility in turning, whence, again, will result certain determinate for- mations of the bones which compose it. But, the bone of the fore- arm, articulating in the shoulder-joint, cannot change its structure without this also changes." Again, observe what may be inferred from some other given part, as from the shape of the bones : " The formation of the teeth bespeaks that of the jaw ; that of the scapula that of the claws ; just as the equa- tion of a curve involves all its properties. So the claw, the scapula, the articulation of the jaw, the thigh-bone, and all the other bones separately considered, require the certain tooth, or the tooth requires them, reciprocally; and, taking any one of them, isolated from the skel- eton of an unknown animal, he who possesses a knowledge of the laws of organic economy, could expound every other part of the animal. Take the hoof, for example. We see, very plainly, that hoofed ani- mals must all be herbivorous, since they have no means of seizing upon prey. We see, also, that having no other use for their fore- feet than to support their bodies, they have no occasion for a power- fully-framed shoulder; whence we infer, what is the case, the absence of l lie clavicle and acromion, and the straightness of the scapula. Not having any occasion to turn their fore-legs, their radius will be solidly united to the ulna, or, at least, articulated by a hinge-joint, and not by ball and socket, with the humerus. Their herbivorous diet will require teeth with a broad surface to crush seeds and herbs. This breadth must be irregular, and for this reason the enamel parts must alternate with the osseous parts. This sort of surface compelling hor- izontal motion for grinding the food to pieces, the articulation of the jaw cannot form a hinge so close as in carnivorous animals. It must be flattened, and correspond with the facing of the temporal bones. The temporal cavity, which will only contain a very small muscle, will be small and shallow," &c. (§ 169,/). 324. An intestine, claw, tooth, hoof, or other bone, therefore, of an unknown animal being given, we may construct a skeleton that shall be nearly true to nature in all its parts. We may then proceed to cover it with muscles ; and, lastly, we can tell from that tusk, or claw, or hoof, or other bone, what was the structure of the digestive appa- ratus, and to what kind of food the gastric juice was specifically adapt- ed, and what were the peculiar instinct and habits of the animal,—so special is the adaptation of all other parts of the organization, both in animal and organic life, and all the habits and instincts of animals, to the peculiarities of the digestive organs in every species (§ 18). 325. Now the whole of the foregoing mutual concurrence of all parts of the body, the adaptation of each part to the others in structure and use, being directly designed to subserve the purposes of diges- tion, and since it cannot be seriously entertained that any physical or chemical force is concerned in such a labyrinth of harmonious struc- ture and actions, and so distinguished throughout by a multitude of the most consummate Designs, and all conspiring to one common end, it is manifestly absurd to imagine that digestion, the final cause of the 146 INSTITUTES OF MEDICINE. whole, is carried on by agencies which have no connection with the va- - rious subordinate means (§ 14, 74, 80, 117, 129 i, 133-137, 143, 155, 156, 169/ 266, 3031 a, 306, 318, 336, 387, 399, 422, 514 h, 524 d, 525, 526 d, 528 c, 638, 649 d, 733 b, 764 b, 811, 847 c, 848, 902/ 905). 326. What we have now seen of fundamental Design in the con- struction and subservience of all parts to the function of assimilation, and of the exact concurrence of the whole toward the incipient step, may well prepare the mind to realize the same Design throughout the whole system of organic processes, the same exact foundation in an- atomical structure, and in vital properties, the same precise and ever- lasting laws (§ 169,/). Do we look again, therefore, at the stupen- dous fabric upon which, and its special vital endowments, the laws of sympathy depend 1 Astonishment abates, and unbelief yields as well to the force of analogy as to direct demonstration. 327. The philosophy of assimilation applied pathologically, and in conformity with the doctrines of solidism, is the following : The func- tion of assimilation, being performed by the organic properties through their media of action, there will be a corresponding change in the elementary combination of the new compounds which are added to the parts affected, and the same morbid condition of the vital proper- ties will be imparted to the new compounds. 328. If the stomach be diseased, then the nature of the gastric juice will be altered according to the manner in which the properties of the stomach may be affected. If, also, we allow, in this case, that the chyme will have a corresponding variation, and that this will in itself affect the whole character of the circulating mass of blood, so that the new elementary combinations, those of the solids and secreted fluids, will be more or less modified in all parts, we shall in no respect com- promit the consistency of nature, or the fundamental principles of physiology (§ 44, 52, 78, 153-155, 218-220). However such admis- sion may look like humoralism, it has no affinity with it. The whole process resolves itself into a primary disease of the solids; and the modified condition of the blood, which I am now supposing, does not derange the vital properties and actions of the system (§ 156 b, 845, &c). But when chylification is affected by diseased states of the stomach, sympathetic influences are then so exerted by that organ upon other parts, that their vital states do actually sustain a change, and often a far greater one, from that sympathetic cause. This more gen- eral modified condition of the solids contributes still farther to modify the new combinations, and to give rise to what are called vitiated se- cretions. The most striking examples are seen, of course, when di- gestion fails altogether, and the solids become universally affected by disease, as in fever (§ 143 c, 148, 657 b, 776, &c). 329. If the heart and vascular system at large feel, mainly, the in- fluence of gastric or some other local disease, the blood is always more or less affected in its composition, and assimilation is otherwise va- riously modified in all other parts, not only in consequence of the change in the blood, but of the affection of all the organs and fluids which are concerned in assimilation. Nothing affects the composition of the blood so rapidly as- disturbances of the vital conditions of the heart and blood-vessels; or, perhaps, I should rather say of the ex- treme capillary blood-vessels. Nothing can prove more distinctly the truth of solidism and the fallacies of humoralism; especially those PHYSIOLOGY.—ru.NOTIONS. 147 more instantaneous changes which are effected in the entire circula- ting mass of blood by abstracting only an ounce of it from the arm (§ 845, Sec). 330. Now, suppose, instead of treating disease upon some broad principles, we were to undertake the specific object of the humoralists in any of the foregoing cases (§ 327-329) ; that is to say, the resto- ration of the blood in its composition and nature. The humoral pa- thologist would attempt its direct medication, in the vain hope that his drugs can produce, by their direct action upon the fluid, that natural combination of its elements, and that natural state of its vital properties, for doing which Nature has provided the whole system of the great vital organs, and many living secretions (§ 845, &c). Since, there- fore, the humoralist has not a physiological principle for his govern- ment, he has departed wholly from nature. The duty of cure thus devolves upon the solidist, who proceeds to restore assimilation by re- establishing the natural condition of the various tissues and organs whose functions had become deranged and had been the cause of the altered condition of the blood; and this is effected according to the manner set forth in my chapter on the modus operandi of remedial agents. There, to">, you shall find, as well as in my disquisitions upon the philosophy of solidism, that the living solids are the only agents which can possibly effect any salutary changes in the pabulum vitce, and, therefore, that when the former are diseased along with the latter, they must take the initiating step both in the morbid and healthy processes. Just in proportion, therefore, as the solidist improves the condition of the diseased organs, assimilation will approximate its natural state, and the blood be regenerated according to established physiological laws. 331. The condition, therefore, of the blood and of the products elaborated from it, in all cases of disease, should be regarded only as more or less significant of the morbid changes which may affect the solid parts. 332. Having now gone over the general philosophy relative to as- similation, I shall proceed to consider its principal element, or what is denominated THE PHYSIOLOGY OF DIGESTION. In my investigation of this subject I shall enter rather extensively upon the ground of Organic Chemistry, in all its applications to the science of medicine ; since it is here, especially, as said in the Com- mentaries, that chemistry has reared its batteries, and from whence it sends forth its artillery into the various dominions of organic life. A contrast will be instituted under the general designations of Physiol- og v and Organic Cm-^.hstry, in their relation to healthy and morbid processes. 333. The doctrines of life, as hitherto expounded, should be appli- cable to all the problems in organic beings which may seem to a su- perficial observer to fall under the laws of chemistry, or of physics. Such problems are especially presented by digestion, respiration, and the production of organic heat; and these are the main intrenchments of chemistry. If the philosophy, therefore, which I have thus far pro- pounded lie at the foundation of the foregoing results, it is probable that chemistry must be abortive in facts, and wild in conclusions; and 148 INSTITUTES OF MEDICINE. the more so as it advances to the greater obscurities in physiology pathology, and therapeutics. Such are the realities ; and their expo sure is the overthrow and the perpetual doom of organic chemistry. 334. Human physiology has been greatly vitiated, in recent times, by experiments upon animals, and conducted under the most unnat- ural circumstances. They have been extensively made, in a physio- logical aspect, without any view to the differences in organization and vital constitution between animals and man, and often with a ref- erence to more functions than belong to any organic being. When prompted by pathological and therapeutical considerations, the ex- periments have been liable not only to the foregoing objections, but to the greater one of assuming that there is no difference in the sus- ceptibility of organs to the action of natural, morbific, and remedial agents in the varying states of health and disease (§ 149, 150, 240). These experimental fallacies, and the vast errors to which they have led and are still leading, I have considered extensively in my Essay on the Humoral Pathology. In a physiological sense, the greatest evil attending the foregoing experiments consists in neglecting the fact that the constitution of man is different from that of animals, when applying the results of such otherwise unnatural experiments to explain the vital laws which gov- ern the functions of the human species. The disparity increases between the natural laws and results of the human and those of vegetable organization, and others, again, of chemical affinities, just in the ratio of the difference between the va- rieties of organization and vital constitution, and the attributes of the inorganic kingdom. 335. What, then, shall be said of those experiments which are con- ducted in the laboratory of the chemist to determine the physiology of the highest function of life, but in which organization takes no part, and the whole process is carried on by artificial " mixtures" and chemical reagents 1 This is now the almost universal philosophy, and therefore demands an investigation which shall lead either to its con- firmation or to its overthrow. 336. It is in the stomach that vitality is exemplified in its most im- pressive and astonishing aspects, and where unequivocal demonstra- tions abound that fluids, as well as solids, are endowed with the prin- ciple of vital operations, " a principle distinct from all other powers of nature" (§ 64, 339). It is here, especially, that nature has illus- trated her distinction between the animate and inanimate world, and established her chain of connection. It is here, in the incipient change of dead into living matter, that we witness a full display of those powers which operate in the most elaborate organization, and an equal exclusion of the forces which appertain to dead matter. It is here the line of separation begins abruptly ; but where analogies are pre- sented in the conversion of dead into living matter, through new modes of combining the same elements; and admiration increases, as we mount along the entire function of assimilation, and find, at each step of the ascending series, that the whole agency is committed to forces that have no existence in the inorganic world ; that the whole is the harmonious result of a principle which may form an interme- diate link between spirit and matter; and that there is no power with- in our control by which we can determine the nature of the changes. PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 149 Casting a glance at the vegetable world, we find the connection con- tinued, by other analogous links, with elementary matter itself; but here, as in the higher department of nature, the line of separation is equally defined, however low in the scale of analogy may be the prop- erties of life which have their beginning in vegetable organization. It is here, then, at the threshold of life, as in the propagation of the species, that we especially witness a substitution of Creative Power ; and, as all that appertains exclusively to the organic world was per- fectly distinct in its Creation from the inorganic, so are the substituted processes of generation, and of the conversion of dead into living mat- ter, equally distinct from the causes and results of inorganic processes (§ 32, &c, 63, &c). For conducting that connected series of changes which make up the process of assimilation in animals, a complex apparatus has been provided, whose beginning in the vegetable kingdom, and whose pro- gressive development in the higher kingdom, have been contrived upon consummate principles of Design, that the elements of matter shall be gradually brought into those perfectly new conditions, both as to composition and properties, which contradistinguish the organic from the inorganic kingdoms, and thus, as in all things else in the nat- ural world, that abrupt transmutation of inorganic into organic matter which distinguished the Creative Act shall be avoided, and remain a characteristic of Creative Power (§ 14* 172, 325). 337. In the early part of this work, I set forth some general facts which evince an incongruity of doctrines that clearly divides the physi- ological world into three schools; one of them (pure chemistry) mak- ing no distinction between the properties and laws of organic and in- organic beings; a second (pure vitalism) contradistinguishing the two kingdoms in those fundamental conditions; and the third (chemico- vitalism) blending the doctrines of chemistry and vitalism (§ 4^). Now, each of these denominations has interpreted the philosophy of di- gestion according to the general doctrines of life which are peculiar to each. 338. Beginning with pure chemistry, we find the great leader set- ting forth the process of digestion in the following language in his late work on Animal Chemistry applied to Pathology and Therapeutics. " Chymification," he says, " is independent of the vital force. It takes place in virtue of a purely chemical action,—exactly sim- ilar to those processes of decomposition and transformation which are known as putrefaction, fermentation, or decay" (§ 365). It will be also seen from the foregoing quotation, that the chemist is regardless of his own rules of philosophy, and of the fundamental principles of chemistry; since he identifies the organizing act, or that which combines the elements of matter into complex organic com- pounds, with the chemical process that resolves these compounds into their ultimate elements. We are told, indeed, that this is " experi- mental philosophy," and that, therefore, we must submit to it (§ 350). 339, a. I shall now set forth the exact doctrine of the vitalists rela- tive to the physiology of digestion, in the language of the same dis- tinguished " reformer" whom I have quoted in the preceding section. It is true, the doctrines are as fundamentally opposed as contradiction can possibly make them. But, as will have been abundantly seen, the most remarkable characteristic of the writings of this distinguished 150 INSTITUTES OF MEDICINE. man are their palpable contradictions. Nor can there be any proof so conclusive of the radical distinction between the philosophy of life and the philosophy of chemistry, about which " the reformer" was simultaneously concerned. But, I will go back for a conflicting doctrine to the treatise "on Organic Chemistry applied to Physiology," published a year or two antecedently to his work " on Animal Chemistry ;" by which we shall learn the extent of the confusion which pervades his writings, and the tardiness with which it is discerned, by his medical disciples. In that work he says, " The equilibrium in the chemical attractions of the constituents of food is disturbed by the vital principle. The union of its ele- ments, so as to produce new combinations and forms, indicates the presence of a peculiar mode of attraction, and the existence of k power distinct from all other powers of nature, namely, the vital principle." " If the food possessed life, not merely the chem- ical forces, but this vitality would offer resistance to the vital force of the organism it nourished."—Liebig. Such, then, is exactly the doctrine of the vitalist and solidist, mis- taken by the chemist for his own, when he happened to be reasoning according to the promptings of organic nature. The same views are presented in the work on Animal Chemistry (§ 350). 339, b. And here, perhaps, it may be worth our while to say that the resuscitated chemical doctrine (§ 338) is apparently too wide a de- parture from fact even for that part of the British medical profession who have received most of the sayings of Liebig as oracular revela- tions ; for we read in the late edition of the " Pharmacologia," now devoted to the authorized philosophy (§ 349 d, 676 b), that, " According to the experiments of Spallanzani, and still more re- cently of Dr. Beaumont, if, after putrefaction has actually advanced, a substance in such a condition be introduced into the living stomach, the process is immediately checked, and no signs of putrefaction are presented by the digested food, although were the same substances left at the temperature of 99° F., they would soon evince evidence of its progress. It is therefore clear that the vital powers of the di- gestive organs must, in such cases, reverse or suspend the ordinary chemical affinities" (§ 676, b).—Paris's Pharmacologia, p. 148. Lon- don, 1843. And such, in reality, is one of Liebig's conflicting state- ments. And why should not the " vital powers reverse or suspend the ordi- nary chemical affinities" in all other cases of food, where it is far more obvious that such resistance does happen ; and why may we not con- clude that the law in relation to digestion has- a wide foundation in liv- ing beings 1 Why does not the blood putrefy1? Why not any other animal or vegetable fluid 1 Why not any living animal or vegetable solid 1 340. Let us now hear the student of organic nature upon the phys- iology of digestion. What says John Hunter, of whom it is said by one, that "he stands alone in our profession;" that, "in his immense career, every thing bore reference to one great idea,—the discovery and elucidation of'nature'slaws ;" "who," says another, " was neither anatomist, physiologist, surgeon, nor naturalist, alone, but the most remarkable combination of all these which the world has yet seen ;'; PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 151 for, " where," says another, "in the calendar of time, shall we look for an equal in the compass, the variety, and the depth of his researches into the mysteries of animal life, or for consequences such as those that have resulted from his labors to universal pathology ;" while an- other apostrophizes, " how humble do any of the men of the present day appear when placed by the side of Hunter!" "The genius of Hunter," says another, "long ago explained the objections to other theories of digestion. These have been turned into ridicule to smooth the way for hypotheses that have no better foundation." Well may we ask, what says John Hunter on the physiology of di- gestion 1 " Digestion," he says, "is an assimilating process. It is a species of generation ; but the curious circumstance is its converting both veg- etable and animal matter into the same kind of substance or com- pound, which no chemical process can effect. Those who took it up chemically, being ignorant of the principles of the animal economy, have erroneously referred the operations of the animal machine to the laws of chemistry." 341. The illustrious George Fordyce, after a thorough experiment- al investigation of the subject, comes to the conclusion that, " The changes which take place in the substances capable of giving nourishment, and, therefore, of being converted into the essential parts of the chyle, are totally different from those changes which take place any where but in the stomach, duodenum, and jejunum, when alive. Therefore, no experiment made any where, excepting in these intestixkh of.the living animal, can in the smallest degree influence the doctrine of digestion." " Food placed in all the chemical circum- stances that can be conceived similar to those in which it is placed in the living animal, will never be converted into chyme, but will under- go other changes totally different." He finally adds, as the result of his own experiments out of the stomach, that, " whether we employ the gastric juice, or bile, or saliva, in no case has chyle, or any thing like it, ever been produced." The reason is, that the gastric juice, like the blood, loses its vitality as soon as abstracted from the stomach. Hunter arrived at exactly the same conclusion from his observations (§ 365). 312. It is the opinion of Tiedemann, another distinguished inquirer into the nature of digestion (§ 340, 341), that, " All the phenomena of digestion and assimilation, and which are only observed in living bodies, appear to rest, as to their foundation, on the vital property which organized liquids possess of producing, under certain circumstances, in other organic matters, similar changes that cause these bodies to acquire the properties themselves are en- dowed withal."' Again : " It cannot be mistaken that digestion is an operation exclusively the property of living bodies, and is in no way to be compared with the changes of composition which general physical forces and the play of chemical are capable of producing in inorganic matters. It must be considered as a vital act, as an effect of life." As to assimilation by vegetables, Tiedemann holds the same doc- trine as Hunter, Fordyce, and all other physiologists whose opinions have survived the day on which they were promulgated. Thus : "On the subject of the material changes which vegetable parts un- 152 INSTITUTES OF MEDICINE. dergo in nutrition, chemistry has hitherto given us no satisfactory in- formation, simply because, being effects of life, such changes are beyond the domain of chemical science. All that we are authorized to admit is, that the changes of composition that occur during the nutrition of vegetables are the consequence of vital manifestations of activity, and not the effects of chemical affinities, such as are observed in inorganic bodies." " All the attempts," he goes on, " of the intro-mechanicians and in- tro-chemists to reach this point (assimilation) have failed; and it is well ascertained that such ideas are both unsatisfactory and erroneous. We are therefore under the necessity of regarding them as effects, sui generis, as vital manifestations, founded on a power peculiar to, and inherent in, organic bodies."—Tiedemann's Physiology. 343. Turning to the greatest of French physiologists, we hear from him the same general protest against the corruption of medicine by ingrafting upon it the physical sciences (§ 5J, b). 344. In considering farther the physiology of digestion, I shall in- troduce, in the first place, a series of general conclusions which have been derived from chemistry, both as to digestion and other organic processes, and when in this respect and otherwise prepared, I shall state the remaining grounds upon which I rely more specifically for establishing the vital doctrine. 345. Let us hear, then, the distinguished chemist, Dr. Prout, as the representative of those who mingle chemistry with vitalism. "First," says Dr. Prout, "the stomach has the power of dissolving alimentary substances, or, at least, of bringing"them to a semi-fluid state. This operation seems to be altogether chemical. " 2d. The stomach has, within certain limits, the power of changing into one another the simple alimentary principles," and " this part oi the operation of the stomach appears, like the reducing process, to be chemical; but not so easy of accomplishment. It may be termed the converting operation of the stomach. " 3d. The stomach must have, within certain limits, the power of organizing and vitalizing the different alimentary substances." " It is impossible to imagine that this organizing agency of the stomach can be chemical. Its agency is vital, and its nature completely unknown." 346. Such, then, is the doctrine of digestion as entertained by the chemico-vitalist (§ 345). But, from what we shall have seen of the absolute contradictions which abound in the writings of those who at- tempt the application of pure chemistry to the functions and results of organic life, we may expect that the chemico-vitalist will be equally inconsistent when he applies himself, at one time, to the phenomena of living beings, and, at another, reasons from the results of the labor- atory to those phenomena. Accordingly, we find within a few pages of the foregoing doctrine of the chemico-physiologist, that he broadly affirms that " There is no relation whatever between the mechanical ar- rangements and-the chemical properties to which they administer." " There is no reason why the chemical changes of organization should result from the mechanical arrangements by which they are accom- plished ; neither is there the slightest reason, why the mechanical arrangements in the formation of organized beings should lead to the chemical changes of which they are the instruments" ! PHYSIOLOGY.--ORGANIC CHEMISTRY—FUNCTIONS. 153 Here, then, in a single sentence, are not only the strangest contra- dictions, but a full admission that there is not the " slightest reason" for the application of chemistry to any process, function, or result of living beings. 317. Nor is that all. For the chemico-vitalist, the same eminent chemist whom I have just quoted, goes on to say, that " with the liv- ing, the animative properties of organic bodies, chemistry has not the smallest alliance, and probably will never, in any degree, elucidate those properties. The phenomena of life are not even remotely anal- ogous to any thing we know in chemistry as exhibited among inorganic agents." And, as if to complete the overthrow of the chemical part of the philosophy of digestion, the same reasoner observes that, "the means by which the peculiarities of composition and structure are produced, which is so remarkable in all organic substances, like the results themselves, are quite peculiar, and bear little or no resem- blance to any artificial process of chemistry ;" that "those who have attempted to apply chemistry to physiology and pathology have split on a fatal rock by hastily assuming that what they found by experi- ment to be wanting, or otherwise changed, in the animal economy, was the cause of particular diseases, and that such diseases were to be cured by supplying, and adjusting artificially, the principle in error. But the scientific physician will soon discover that Nature will not al- low him to officiate as her journeyman, even in the most trifling de- gree."—Dn. Prout's Bridgewater Treatise. 348. And, to the same effect may be quoted Dr. Carpenter, one of the foremost, as we have seen, in the school of pure chemistry (§ 64, g). " The agency of vitality," says this reasoner, in his Comparative Physiology, where he generally ridicules the term and all that is rela- tive to it, " the agency of vitality, as Dr. Prout justly remarks, does not change the properties of the elements, but simply combines the elements in modes which we cannot imitate" ! So, also, Dr. Roget, alike distinguished in the school of chemico- vitalism (§ 64,/) : "Vital chemistry," he says," is too subtle a power forhuman science to detect, or for human art to imitate." And thus the eminent Wagner, not less arrayed on the side of chemistry: " The existence of one or more powers, commonly called vital powers, is not, however, denied. The final cause of the secretion of the gastric juice lies in the nature of the animal organism, and is unknown to us."—Wagner's Physiology, London, 1842, p. 346. And yet this distinguished observer is one of the manufacturers of gas- tric juice. 349, a. Thus might I go on with one after another, till I should have exhausted the whole that have attempted to confound the science of life with the science of chemistry, and prove by their own state- ments that there is not the slightest intelligible connection between them. Indeed, I have already, in the Medical and Physiological Commentaries, pointed out this universal admission. The ground of chemistry being thus virtually abandoned to the vi- talist, it would seem superfluous to pursue an adversary who is al- ways upon the retreat. But, as he flies, he is forever shooting from behind, and his Parthian weapons fall thickly and heavily upon the vast multitude. He must therefore be subdued into a practical acqui- 154 INSTITJTES OF MEDICINE. escence with those consistent principles of nature which exact his con- sent, but not his compliance. 349, b. Perhaps no author has supplied so many examples of con- tradictions in great fundamental principles, and in so small a compass, as he who has so lately taken captive the physiological world. In the Preface to the Essays " On the Philosoj)7iy of Vitality and the Modus Operandi of Remedial Agents" I had occasion to say of the article on " Poisons, Contagions, and Miasma," in Liebig's " Organic Chemistry applied to Agriculture and Physiology," that " it is certainly the most stupendous exhibition of perverted facts, of combinations of conflict- ing doctrines, and of the rudest system of pathology and therapeutics, that can be found in the records of dreamy speculation." It was objected by the editor of the London Lancet,, thai I did not prove my allegations (§ 5|, a). Nor was it in any respect the object of that work to do so. I was satisfied with calling attention to the facts, and with what I had already published in the Medical and Phys- iological Commentaries. Since that day, the work on " Animal Chem- istry" has appeared ; and it is now my purpose to sustain the allega- tions of the " Preface," and this more especially from the objections alleged by Liebig against physiologists (§ 350, mottoes, a, b, c, and d). I say, therefore, that we meet on the same page a purely chemical and a purely vital philosophy of digestion; and equally so of other important organic processes. That each is laid down without quali- fication, and with the dictum of a master, who is conscious that the preponderance he gives to the purely chemical philosophy of life will establish his Empire in that philosophy with an age more prone than ever to the doctrines of materialism. 349, c. Let us, therefore, not be deceived; for, however this very extraordinary and successful pretender in medicine may beguile us with words, and seem to persuade rather than to rule, let us- remem- ber that, at most, he does but invalidate his own edicts by counter- mands, and that in the end he tells us that these apparently adverse decrees are, in their absolute import, one and the same ; that they are consistent laws delivered from the laboratory, though apparently in conflict on account of the opposing forces, the attraction and repul- sion, which preside in the chemistry of nature ; that, however, in re- ality, there is no difference whatever in the seemingly two great prin- ciples which lie at the foundation, which are one and identical, since " the mysterious vital principle can be replaced by the chemical forces;" and since, also, " the vital force unites in its manifestations all the pe- culiarities of the chemical forces, and of the no less wonderful cause which we regard as the ultimate origin of electrical phenomena." And again, " in the processes of nutrition and reproduction, the ultimate cause of the different conditions of the vital force are chemical forces" (§ 64, e). —Liebig's Organic Chemistry ; and Animal Chemistry. 349, d. It is painful to speak thus of one so highly endowed, so devoted in mind, so accomplished in chemistry; but science and hu- manity demand the sacrifice. But, again, I wish to be understood, that neither here, nor in any other case, is it the individual of whom I speak, but of his doctrines alone (§ 1 b, 4 b). Nor yet would the doctrines of an individual become the subject of extended remark, did they not represent the existing state of the three high branches of medicine. The gigantic physical school had too much of the Pro- PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 155 tean character, too little unity of purpose, and demanded greater sta- bility. The learned men of a great Nation, The British Associa- tion for the Advancement of Science, united in the object, and be- Btowed the honor of achieving the enterprise upon a foreign Chemist. The note of proscription has been sounded in high quarters, in due conformity (§ 51 a, 350f kk), and medical philosophy has nothing to hope even from a spirit of toleration. The subject, therefore, must be brought to the test of observation and reason, and he who arraigns the authorized doctrines will cheerfully abide an unsuccessful issue (§ 1 b, 676 b, 709, note). I shall therefore dwell upon the conclusions of those who have engendered the corruptions, and shall array them in all the force demanded by the magnitude of my subject, that we may the better realize the shallowness of that pretended philosophy which has so lately swept, like a hurricane, over the intellectual world, that we may see, in the system of contradictions, the equal fallacy of that school who endeavor, with great sincerity, to mingle the conflict- ing principles, and that we may the better cultivate and enjoy the simple and consistent philosophy which nature teaches. Nor will I yet leave this general reference to that stupendous system of assump- tion and contradiction which was so lately hailed by physiologists as the harbinger of a total revolution in medical science, ay, in the very practice of medicine, without showing you, the depth of the material- ism in which it was submerged. I say nothing now of the avowed infidelity to which it has led. Examples of that disregard of instinct- ive faith I have already placed in their proper connection with my subject.* But, I will merely present, in relief, from Liebig's revolu- tionary work, a doctrine of the chemical school, from which, if I mis- take not the ambition of intellectual and immortal beings, the very impulse of nature will turn the most indifferent with a loathing aver- sion. We shall see from it, also, how entirely degraded to the rank of the merest matter is every thing relating to organic life ; even man himself. Thus, then, " the Reformer," in behalf of the school of chemistry: 349, e. " Physiology has sufficiently decisive grounds for the opin- ion that every motion, every manifestation of force, is the result of a transformation of the structure or of its substance ; that every concep- tion, every mental affection, is followed by changes in the chemical nature of the secreted fluids; that every thought, every sensation, is accompanied by a change in the composition of the substance of the brain." " Every manifestation of force is the result of a trans- formation of the structure or of its substance." And now may it not be reasonably asked, what is the cause of those chemical changes in the cerebral substance which give rise to " every conception, every mental affection, every thought, and every sensa- tion" (§ 175,c, 500 n, 1054, 1076 a) ? Many organic chemists, however, are disposed to admit a spiritual part, and they should therefore recollect that the existence of a prin- ciple of life is not less substantiated by facts than the existence of the soul, which they are so ready to concede when inviting our attention to the physical doctrines of life. 350. I have just said that I would present such an array of contra- * See Medical and Physiological Commentaries, vol. ii., p. 122-140. Also, the Essay on the Vital Powers, in vol. i. 156 INSTITUTES OF MEDICINE. dictory opinions on the physiology of digestion, and the general phi- losophy of life and disease, from the two brief National Essays by Liebig (§ 349, d), as should induce physiologists to retrace their steps, and thus make some atonement to the science which was surrendered with an acclamation that had been worthy the original institution of medicine. In the first place, however, with a view to the cause which I advo- cate, and in justice, also, to able and independent philosophers, I shall quote the following remarks from a letter addressed to myself by a distinguished writer, of Manchester (England) : "Manchester, May 5, 1846. " Dear Sir, " I made your pamphlet (a Lecture on Digestion) the subject of a Paper which I read before the Manchester Literary and Philo- sophical Society, and which provoked a discussion two nights. The result was almost unanimously in favor of your views in reference to the Philosophy of Digestion. lam, &c, "Charles Clay, M.D." I shall now exhibit, in parallel columns, the new philosophy which forms the present science of medicine, preceded by some appropriate mottoes. a. " Animal and vegetable physiologists institute experiments without being ac- quainted with the circumstances necessary to the continuance of life—with the qualities and proper nourishment of the animal or plant on which they operate—or with the nature and chemical constitution of its organs. These experiments are considered by them as convincing proofs, while they are fitted only to awaken pity" (no. 50). b. "All discoveries in physics and in chemistry, all explanations of chemists [!], must remain without fruit and useless, because even to the great leaders in physi- ology, carbonic acid, ammonia, acids, and bases, are sounds without meaning, words without sense, terms of an unknown language, which awaken no thoughts, and no asso- ciations. They treat these sciences like the vulgar, who despise a foreign literature in exact proportion to their ignorance of it."—Liebig's Organic Chemistry applied to PhyS' Mogy, &c. [See no. 2.]—(§ 1034). c. " None of them (the most distinguished physiologists) had a clear conception of the process of development and nutrition, or of the true cause, of death., They professed to explain the most obscure psychological phenomena, and yet they were unable to say what fever is, and in what way quinine acts in curing it" (no. 2. 40). The oft-reiterated conclu- sion follows, that IT IS RESERVED FOR CHEMISTRY TO RESOLVE THESE PROBLEMS. d. "Thus medicine, after the fashion of the Aristotelian philosophy, has formed certain conceptions in regard to nutrition and sanguification. Articles of diet have been di- vided into nutritious and non;nutritious ; but these theories [ ! ] being founded on observations destitute of the conditions most essential to the drawing of just conclusions, could not be received as expressions of the truth. How clear are now to us the relations of the different articles of food to the objects which they serve in the body, since organic chemistry has appliedto the investigation her quantative method of research" ! (§ 18, 409.) e. "The limited acquaintance of physiologists with the methods of research employed in chemistry will continue to be the chief impediment to the progress of physiology, as well as a reproach which that science cannot escape."—Liebig's Animal Chemistry. f. " What has the soul, what have consciousness and intellect to do with the develop- ment of the human foetus, or the fcetus in a fowl's egg ? Not more, surely, than with the development of the seeds of a plant. Let us first endeavor to refer to their ultimate causes those phenomena of life which are not psychological; and let vs beware of drawing con- clusions before we have a ground-work. We know exactly the mechanism of the eye ; but neither anatomy nor chemistry will ever explain how the rays of light act on conscious ness, so as to produce vision. Natural science has fixed limits which cannot be passed, and it mast always be borne in mind that, with all our discoveries, we shall never know what light, electricity, and magnetism are in their essence, because, even of those things which are material, the human intellect has only conceptions. We can ascertain, how- ever, the laws which regulate their motion and rest, because these are manifested in phe- nomena. In like manner, the laws of vitality, and of all that disturbs, pro- motes, or alters vitality, may certainly be discovered, although we shall never learn what life is" (§ 168, h).—Liebig's Animal Chemistry. PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 157 g. " A writer, who can so contradict himself, scarcely needs to be exposed by us."— Carpenter's Review of Paine's " Commentaries." See Paine's " Examination of Re- views," p. 12, 86. h. " Chemists and natural philosophers, accustomed to study the phenomena over which the physical forces preside, have carried their spirit of calculation into the theories of the vital laws."—Bichat's General Anatomy, vol. ii., p. 54. i. " Let a man be given up to the contemplation of one sort of knowledge, and that will become every thing. The mind will take such a tincture from a familiarity with that ob- ject, that every thing else, how remote soever, will be brought under the same view. A metaphysician will bring ploughing and gardening immediately to abstract notions ; the history of nature will signify nothing to him. A chemist, on the contrary, shall reduce divinity to the maxims of his laboratory, explain morality by sal, sulphur, and mercury and allegorize the Scripture itself, and the sacred mysteries thereof, into the philosophers stone."—Locke, on the Human Understanding. k. " Mr. Locke, I think, mentions an eminent musician, who believed that God created the world in six days, and rested on the seventh, because there are but seven notes in music. I myself knew one of that profession who thought there were only three parts in harmony, to wit, base, tenor, and treble, because there are but three persons in the Trin- ity."—11kid, on the Powers of the Human Mind, vol. ii., Essay 6, c. viii. I. " When education takes in error as a part of its system, there is no doubt that it will operate with abundant energy, and to an extent indefinite."—Burke (§ 675). CHEMICAL DOCTRINES. VITAL DOCTRINES. 1. " My object has been, in the 47. "A rational physiology present work, to direct attention to cannot be founded on mere re- the points of intersection ofchem- actions, and the living body cannot istry with physiology, and to point be viewed as a chemical labor out those parts in which the sci- atory." ences become, as it were, mixed " The study of the uses of up together. It contains a collec- the functions of different organs, lion of problems, such as chemis- and of their mutual connection try at present requires to be re- in the animal body, was formerly solved, and a number of conclu- the chief object in physiological sions drawn according to the rules researches; but lately this study of that science. These questions has fallen into the back-ground." and problems will be resolved; —Liebig's Animal Chemistry.— and we cannot doubt that we shall (See motto c.) have in that case a new physiol- 4S. "With all its discover- ogy and a rational pathology." ies, Modern Chemistry has per- —Liebig's Animal Chemistry. formed but slender services to 2. " In earlier times, the attempt physiology and pathology."—Lie- has been made, and often with big, ibid. great success, to apply to the ob- 49. " Physiology still endeavors jects of the medical art the views to apply chemical experiments to derived from an acquaintance the removal of diseased conditions- with chemical observations. In- but, with all these countless ex- deed, the great physicians, who periments, we are not one step lived toward the end of the 17th nearer to the causes and essence of century, were the founders of disease."—Liebig. ibid. chemistry, and in those days 50. "Mechanical philosophers the only philosophers ac- and chemists justly ascribe to quaixted with it."—Liebig's their methods of research the Animal Chemistry. (See mottoes greater part of the success which ^» e-) has attended their labors."—Lie- big's Animal Chemistry (a). 3. "In the animal body Ave rec- 51. "In the animal ovum, as ognize as the ultimate cause of all well as in the seed of a plant, 158 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. force only one cause, the chemical action which the elements of the food and the oxygen of the air mutually exercise on each other. The only known ultimate cause of vital force, either in animals or in plants, is a chemical process. If this be p>revented, the phenom- ena of life do not manifest themselves. If the chemical ac- tion be impeded, the vital phenom- ena must take new forms." " All VITAL ACTIVITY ARISES from the mutual action of the oxygen of the atmosphere and the elements of the food."—Liebig's Animal Chemis- try. 4. " The life of animals exhib- its itself in the continual absorp- tion of the oxygen of the air, and its combination with certain parts of the animal body."—Liebig's Animal Chemistry. 5. " Physiology has sufficiently decisive grounds for the opinion, that EVERY MOTION, EVERY MANI- FESTATION OF FORCE, IS THE RE- SULT OF A TRANSFORMATION OF THE STRUCTURE OR OF ITS SUB- STANCE ; that every conception, ev- ery mental affection, is followed by changes in the chemical nature of the secreted fluids; that every thought, every sensation, is accom- panied by a change in the composi- tion of the substance of the brain" ! —Liebig's Animal Chemistry (no. 41,18-J). 5\. Nevertheless, " we ascribe the higher phenomena of mental exist- ence tO AN IMMATERIAL AGENCY, and that, in so for as its manifes- tations are connected with matter, an agency entirely distinct from the vital force, with which it has nothing in common."—Liebig's Animal Chemistry. vital doctrines. we recognize a certain remark- able FORCE, THE SOURCE OF growth, or increase in the mass, and of reproduction, or of supply of the matter consumed ; a force in a state of rest. By the ac- tion of external influences, by im- pregnation, by the presence of air and moisture, the condition of static equilibrium of this force is disturbed. Entering into a STATE OF MOTION OR ACTIVITY, it exhibits itself in the production of a series of forms, which, al- though occasionally bounded by right lines, are yet widely distinct from geometrical forms, such as we observe in crystalized miner- als. This force is called the vi- tal force, vis vitce, or vitality." " The increase of mass is effect- ed in living parts by the vital force."—Liebig's Animal Chem- istry. (See my Essays on Vitali- ty,^., p. 13-18.) 51i. " The oxygen of the at- mosphere is the proper, active, ex- ternal cause of the waste of mat- ter in the animal body. It acts like a force which tends to disturb and destroy the manifestations of the vital force at every moment. But its effect as a chemical agent (in producing waste), the disturb- ance proceeding from it, is held IN EQUILIBRIUM BY THE VITAL force."—Liebig's Animal Chem- istry. 52. " The vital force is manifest- ed in the form of resistance, in- asmuch as by its presence in the living tissues, their elements acquire the power of withstanding the dis- turbance and change in their form and composition, which exter- nal agencies tend to produce; a power, which, as chemical com- pounds, THEY DO NOT POSSESS." —Liebig's Animal Chemistry. 53. "The vital principle must be a motive power, capable of PHYSIOLOGY.—organic chemical doctrines. 6. " In the processes of nutri- tion and reproduction, we per- ceive the passage of matter from the state of motion to that of rest (static equilibrium). Under the in- fluence of the nervous system, this matter enters again into a state of motion. The ultimate causes of these different conditions of the vi- tal force are chemical forces." 7. " The cause of the state of motion is to be found in a series of changes which the food under- goes in the organism, and these are the results of processes of decomposition, to which either the food itself, or the structures formed from it, or parts of organs, are subjected" (§ 1054). 8. " The change of matter, the manifestation of mechanical force, and the absorption of oxygen, are, in the animal body, so closely con- nected with each other, that we may consider the amount of mo- tion and the quantity of living TISSUE TRANSFORMED, AS PROPOR- TIONAL TO THE QUANTITY OF OX- YGEN inspired and consumed in a given time by the animal."—Lie- big's Animal Chemistry (no. 3, 4). 9. " If we employ these well- known facts as means to assist us in investigating the ultimate cause of the mechanical effects in the an- imal organism, observation teaches us that the motion of the blood AND OF THE OTHER ANIMAL FLU- CHEMISTRY--FUNCTIONS. 159 VITAL DOCTRINES. IMPARTING MOTION TO ATOMS Al REST, and of OPPOSING RESISTANCE to other forces producing mo- tion, such as the chemical force, heat and electricity."—Liebig's Lectures for 1844. " Every thing in the organism goes on under the influence of the vital force, an immaterial agent, which the chemist cannot employ at will."—Liebig's Ani- mal Chemistry. 54. " There is nothing to pre- vent us from considering the vital force as a peculiar property, which is possessed by certain ma- terial bodies, and becomes sensi- ble when their elementary parti- cles are combined in a certain ar- rangement or form. This suppo- sition takes from the vital phenom- ena nothing of their wonderful pe- culiarity. It may, therefore, be considered as a resting point from which an investigation into these phenomena, and the laws which regulate them, may be com- menced ; exactly as we consider the properties and laws of light to be dependent on a certain lu- miniferous matter or ether, which has no farther connection with the laws ascertained by investigation." —Liebig's Animal Chemistry. 55. " Every thing in the ani- mal organism, to which the name of motion can be applied, pro- ceeds from the nervous appara- ^ tus." " In animals we recognize in the nervous apparatus a source of power capable of renewing itself at every moment of their existence." — Liebig's Animal Chemistry. 5.6. " We may communicate motion to a body at rest by means of a number of forces, very differ- ent in their manifestations. Thus, a time-piece may be set, in motion by a falling weight (gravitation), or by a bent spring (elasticity). 160 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. ids proceeds from distinct organs, which, as in the case of the heart and intestines, do not generate THE MOVING POWER IN THEM- SELVES, BUT RECEIVE IT FROM OTH- ER quarters."—Liebig's Animal Chemistry (no. 3, 4). 10. " Now, since the phenome- na of motion in the animal body ARE DEPENDENT ON THE CHANGE of matter, the increase of the change of matter in any part is fol- lowed by an increase of all the motions. Consequently, if, in con- sequence of a DISEASED TRANS- FORMATION OF LIVING TISSUES, a greater amount of force be gener- ated than is required for the pro- duction of the normal motions, it is seen in the acceleration of ALL OR SOME OF THE INVOLUNTARY motions, as well as in a higher TEMPERATURE OF THE DISEASED part."—Liebig's Animal Chem- istry. [Such, with § 3504;, no. 11, and a, is the chemical substitute for the medical aphorism, " ubi irrita- tio ibi affluxus." It will be also seen from the foregoing nos. 7, 8, 9, that Liebig considers the circula- tion of the blood due to the agen- cies of oxygen, and not at all to the action of the hearty 11. " The powERto effectTRANS- formations does not belong to the vital principle. Each transforma- tion is owing to a disturbance in the attraction of the elements of a compound, and is, consequently, a PURELY CHEMICAL PROCESS." -- Liebig's Organic Chemistry ap- plied to Physiology, &c. 12. " The combinations of the chemist relate to the change of matter, forward and backicard, to THE CONVERSION OF FOOD INTO THE various tissues and secretions, and to their metamorphosis into lifeless compounds ; his investiga- tions ought to tell us WHAT HAS VITAL DOCTRINES. Every kind of motion may be pro-. duced by the electric or magnetic force, as well as by chemical at- traction ; while we cannot say, as long as we only consider the man- ifestation of these forces in the phe- nomenon or result produced, which of these various causes of change of place has set the objects in mo- tion. In the animal organism we are acquainted with only one cause of motion, and this is the same cause which determines the growth of living tissues and gives them the power of resistance to ex- ternal agencies. It is the vital force."—Liebig, ibid. 57. " In order to attain a clear conception of these manifestations of THE VITAL FORCE, SO DIFFERENT in form, we must bear in mind, that every known force is recog- nized by two conditions of activi- ty," &c.—Liebig's Animal Chem- istry. 58. " Our notion of life involves something more than mere repro- duction, namely, the idea of an ac- tive power exercised by virtue of a definite form, and production and generation in a definite form. The production of organs, and their power not only to produce their component parts from the food presented to them, but to gen- erate themselves in their orig- inal form and with all their prop- erties, are characters belonging exclusively to organic life, and constitute a form of reproduction INDEPENDENT OF CHEMICAL POW- ERS. The chemical forces are sub- PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 161 CHEMICAL DOCTRINES. VITAL DOCTRINES. TAKEN PLACE AND WHAT CAN TAKE ject TO THE INVISIBLE CAUSE BY PLACE IN THE BODY."--LlEBIo'S WHICH THIS FORM IS PRODUCED. Animal Chemistry. Of the existence of this cause 13. " How beautifully and admi- itself we are made aware only rably simple, with the aid of these by the phenomena which it pro- discov(;iies (chemical), appears the duces. Its laws must be inves- process of nutrition in animals, tigated^'w^ as we investigate those the formation of their organs," of the other powers which effect &c. motion and changes in matter."— 14. "In the hands of the physiolo- Liebig's Organic Chemistry ap- gist, organic chemistry must be- plied to Physiology, &c. come an intellectual instrument, by 59. "It is not the true chemist means of which he will be enabled who has endeavored to apply to to trace the causes of phenomena the animal organism his notions invisible to the bodily sight."— derived from purely chemical pro- Liebig's Animal Chemistry. cesses. He has not had the re- motest intention of undertaking the explanation of any really vital phenomenon, upon chemical prin- ciples. The only part which chemistry now, or for the future, can take in the explanation of the vital processes, is limited to a more precise designation of the pheno- mena, and to the task of controll- ing the correctness of inferences, and insuring the accuracy of all observations by number and weight. Although the chemist is able to analyze organic bodies, and tell us their ultimate elements, he does not claim the power of syn- thesis, or of producing them again by the union of these elements" ! ! ! —Liebig's Lectures for 1844 (§ 350|-350f). 15. " The self-regulating steam- 60. " In what form or in what engines furnish no unapt image manner the vital force pro- ofwhat occurs in the animal body." duces mechanical effects in " The body, in regard to the pro- the animal body is altogether duction of heat and force, acts unknown, and is as little to just like one of these machines."— be ascertained by experiment Liebig's Animal Chemistry. as the connection of chemical 16. "The vital force unites in action with thf phenomena of its manifestations all the peculi- motion, which we can produce aritif.s of chemical forces, and with the galvanic battery. We of the not less wonderful cause know not how a certain invisible which we regard as the ultimate something, heat, gives to certain orioin of electrical phenomena." bodies the power of exerting an —Liekig's Animal Chemistry. enormous pressure on surround- 17. " The mysterious vital ing objects. We know not even 162 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. VITAL DOCTRINES. principle can be replaced by the how this something itself is pro. chemical forces."—Liebig's Or- duced when we burn wood or ganic Chemistry applied to Phys- coals. iology, &c. " So il is witn THE yITAL force, and with the phenomena exhibit- ed by living bodies. The cause of these phenomena is not chem- ical force; it is not electricity, nor magnetism. It is a peculiar force, because it exhibits mani- festations which are formed by no OTHER KNOWN FORCE." 61. " In regard to the nature and essence of the vital force, we can hardly deceive ourselves, when we reflect, that it behaves, in all its manifestations, exactly like other natural forces; that it is devoid of consciousness or of vo- lition, and is subject to the action of a blister." — Liebig's Animal Chemistry. 17 a. " The high temperature of 6l£. "Certain other constitu- the animal body is uniformly and ents of the blood may give rise to under all circumstances the result the formation of carbonic acid in of the combination of a combusti- the lungs. But, all this has no ble substance with oxygen." connection with that vital pro- " The carbon of the food, which cess by which the heat necessa- is converted into carbonic acid ry for the support of life is gen- within the body, must give out ex- erated in every part of the body." actly as much heat as if it had been —Liebig's Animal Chemistry. directly burned in the air, or in oxygen gas. The only difference is, that the amount of heat pro- duced is diffused over unequal times." " By the combination of oxygen with the constituents of the meta- morphosed tissues, the tempera- ture NECESSARY TO THE MANIFES- TATIONS of vitality is produced in the carnivora."—Liebig's Ani- nal Chemistry (§ 440, nos. 17 and 18. " The nerves which accom- 62. " In the present state of our plish the voluntary and involunta- knowledge, no one, probably, will ry motions in the body (no. 7-9) imagine that electricity is to be are, according to the preceding considered as the cause of the exposition, not the producers, phenomena of motion in the but only the conductors of the body." " Every thing in the ani- vital force (§ 59). They permit mal organism to which the name PHYSIOLOGY.—organic CHEMICAL DOCTRINES. the current to traverse them, and present, as conductors of elec- tricity, ALL THE PHENOMENA WHICH THEY EXHIBIT AS CONDUCT- ORS OF THE VITAL FORCE" !--LlE- big's Animal Chemistry. [Com- pare with no. 55.^ ISj. " If CHEMICAL ACTION be excluded as a condition of nervous agency, it means nothing else than to derive the presence of motion, the MANIFESTATION OF FORCE, FROM NOTHING. But NO FORCE, NO POW- ER, CAN COME FROM NOTHING" !-- Liebig's Animal Chemistry (no. 5). 19. " By means of the nerves, all parts of the body receive the moving force which is indispen- sable to their functions, to change of place, to the production of me- chanical effects. Where nerves are not found, motion does not occur. [In plants, for example 1] The excess of force generated in one place is conducted to other parts by the nerves. The force which one organ cannot produce in itself is conveyed to it from other quar- ters, [ ! ] and the vital force which is wanting to it, in order to furnish resistance to external causes of disturbance, it receives in the form of excess from another organ, an excess which that organ cannot consume in itself"!—Liebig's An- imal Chemistry (§ 422, 423, 733 e). 20. " The phenomena of motion in vegetables, the circulation of the sap, for example, observed in many of the characeae, and the closing of flowers and leaves, de- pend on physical and mechanical causes. Heat and light are the REMOTE CAUSES of MOTION in VEG- ETABLES ; but in animals we rec- ognize in the nervous apparatus a source of rowER, capable of re- newing itself at every moment of their existence."—Liebig's Ani- mal Chemistry. 21. "While the assimilation chemistry—functions. 163 vital doctrines. of motion can be applied proceeds from the nervous apparatus. In animals we recognize in the ner- vous apparatus a source of pow- er, capable of renewing itself at every moment of their exist- ence."—Liebig's Animal Chem- istry (no. 55). 63. " Pathology informs us that the true vegetable life is in no way dependent on this apparatus (the cerebro-spinal); that the pro- cess of nutrition proceeds in those parts of the body where theNERVES of sensation and voluntary motion are paralyzed, exactly in the same way as in other parts where these nerves are in the normal condi- tion ; and, on the other hand, that the most energetic volition is inca- pable of exerting any influence on the contractions of the heart, on the motion of the intestines, or on the processes of secretion."—Lie- big's Animal Chemistry. 64. "Although plants requirt light, and, indeed, sun light, it h not necessary that the direct ray.- of the sun reach them. Their functions certainly proceed with greater intensity and rapidity in sunshine, than in the diffused light of day; but it merely accelerates in a greater degree the acticn ALREADY EXISTING." -- LiEBIG'k Organic Chemistry applied to Physiology, &c. 65. " The vital principle is only known to us through the pe- culiar form of its instruments 164 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. of food in vegetables, and the WHOLE PROCESS OF THEIR FORMA- TION, arC dependent on certain EXTERNAL INFLUENCES which pro- duce motion, the development of the animal organism is, to a certain extent, independent of those exter- nal influences, just because the animal body can produce within ITSELF THAT SOURCE OF MOTION WHICH IS INDISPENSABLE TO THE VITAL PROCESS."--LlEBIG's Ani- mal Chemistry. 22. " Neither the emission of carbonic acid nor the absorption of oxygen (by plants) has any con- nection with the process of assim- ilation ; nor have they the slight- est relation to each other. The one is purely a mechanical, the other a purely chemical process. A cotton wick, inclosed in a lamp, which contains a liquid sat- urated with carbonic acid, acts ex- actly in the same manner as a liv- ing plant in the night."—Liebig's Organic Chemistry applied to Physiology, &c. 23. " At night, a true chemical process commences, in conse- quence of the action of the oxygen of the air upon the substances composing the leaves, blossoms, and fruit. This process is not at all connected with the life of the vegetable organism, because it goes on in the dead plant exact- ly as in a living one" ! Nevertheless, 23|. " What value can be at- tached to experiments, in which all those matters which a plant requires in the process of assim- ilation, besides its mere nutri- ment, have been excluded with the greatest care ] Can the laws of life be investigated in an organized being which is dis- eased or dying?"—Liebig's Or- ganic Chemistry applied, &c.—Or, can those laws be investigated in VITAL DOCTRINES. that is, through the organs in which it resides. Hence, what- ever kind of energy a substance may possess, if it is amorphous and destitute of organs from which the impulse, motion, or change, proceeds, it does not live. Its energy depends, in this case, on a chemical action. Light, heat, electricity, or other influences [justly considered here by Liebig as vital stimuli and not forces] may increase, diminish, or arrest this action ; but they are not its efficient cause." " The vital principle opposes to the continual action of the atmosphere, moisture, and temperature, upon the organism, a resistance which is, in a certain degree, invincible. It is by the constant neutralization and renewal of these external in- fluences that life and motion are main*'lined." — Liebig's Organic Chemistry applied to Physiology, &c. (§ 188^, d). 66. " An abnormal production of certain component parts of plants presupposes a power and capabil- ity of assimilation, to which the most powerful chemical action cannot be compared. The best idea of it may be formed, by con- sidering that it surpasses in power the strongest galvanic battery, with which we are not able to separate the oxygen from carbonic acid, as is done by the leaves of plants," " and without the direct solar rays." 67. " All that we can do is to supply those substances which are adapted for assimilation by the power already present in the or- gans of the plant."—Liebig's Or- ganic Chemistry applied to Phys- iology, &c. 68. " The living part of a plant acquires the whole force and di- rection Of its VITAL ENERGY from the absence of all conductors of force. By this means the leaf is PHYSIOLOGY.--ORGANIC CHEMICAL DOCTRINES. ' a cotton wick, inclosed in a lamp]" And so of animals. 24. " The permeability to gases is a mechanical property, common to all animal tissues; and is found in the same degree in the living as in the dead tissue" !— Liebig's Animal Chemistry (§ 350 2, n, and Medical and Phys- iological Commentaries, vol. i., p. 565, 569, notes, 683-690, 1052, 1054). 25. " Analogy, that fertile source of error, has unfortunately led to the very unapt comparison of the vital functions of plants with those of animals."—Liebig's Or- ganic Chemistry applied to Physi- ology, &c. 26. "All substances in solu- tion in a soil are absorbed by the roots of plants, exactly as a sponge imbibes a liquid, and alt, that it contains, without SELECTION," and " THEIR ASSIMI- LATION is a PURELY CHEMICAL PRO- CESS."— Ibid. (no. 22, § 289-291). Nevertheless) CHEMISTRY--FUNCTIONS. 165 VITAL DOCTRINES. enabled to overcome the strongest chemical attractions, to decompose CARBONIC ACID, and tO ASSIMILATE the elements of its nourishment." —Liebig's Animal Chemistry. 69. "In vegetable physiology, a leaf is regarded in every case merely as a leaf, notwithstanding that leaves generating oil of tur- pentine or oil of lemons, must pos- sess a different nature from those in which oxalic acid is formed. Vitality, in its peculiar operations, makes use of a special apparatus for each function of an organ. Veg- etable physiologists, in the study of their science, have not directed their attention to that part of it (the laws of vitality) which is most worthy of investigation."—Lie- big's Organic Chemistry applied to Physiology, &c. 70. " In the living plant, the in- tensity of the vital force far ex- ceeds that of the chemical action of oxygen. We know, with the utmost certainty, that, by the in- fluence of the VITAL FORCE, OXYGEN is separated from elements to which it has the strongest affinity ; and that it is given out in the gas- eous form, without exerting the slightest action on the juices of the plant."—Liebig's Animal Chem- istry. 71. " The animal organism is a higher kind of vegetable." " Assimilation, or the process of formation and growth, goes on in the same way in animals and in vegetables. In both the same cause determines the in- crease of mass. This constitutes the true vegetative life."—Lie- big's Animal Chemistry. 72. " The constituents of veg- etable and animal substances are formed under the guidance and power of THE VITAL PRINCIPLE, which determines the direction of their molecular attraction." " In 166 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. 26£. " When roots find their more appropriate base in suffi- cient quantity, they will take up less of another."—And, again (in opposition to the simile of the " sponge," and " lamp-wick") : "It is thought very remarkable, that those plants of the grass tribe, the seeds of which furnish food for man, follow him like the domestic animals. But saline plants seek the sea-shore or saline springs, and the Chcenopodium the dung- hill from similar causes. Saline plants require common salt, and plants which grow on dung-hills, only, need ammonia and nitrates, and they are attracted whither these can be found, just as the dung-fly is to animal excrements." " The roots of plants are con- stantly engaged in collecting from the rain those alkalies which form- ed part of the sea-water, and also those of the water of springs which penetrates the soil." 27. " Each new radical fibril which a plant acquires may be re- garded as constituting, at the same time, a mouth, a lung, and a stomach. The roots perform the functions of the leaves from the first moment of their formation ; ihey extract from the soil their proper nutriment, namely, the car- bonic acid generated by the hu- mus."—Liebig's Organic Chem- istry applied to Physiology. 28. [" Nature speaks to us in a peculiar language, in the language of phenomena. She answers, at all times, the questions which are put to her ; and such questions are exper- iments. An experiment is the ex- pression of a thought. We are near- er the truth, when the phenom- enon, elicited by the experiment, corresponds to the thought ; while the opposite result shows that the question was falsely sta- ted, and that the conception was VITAL DOCTRINES. the formation of vegetable and an- imal substances, the vital prin- ciple opposes, as a force of re- sistance, the action of the other forces," &c.—Liebig's Lectures for 1844. 73. " The force which gives to the germ, the leaf, and the radi- cal FIBRES of the VEGETABLE THE SAME WONDERFUL PROPERTIES (di- gestion, circulation, and secretion), is the same as that residing in the secreting membranes and glands of animals, and which en- ables every animal organ to per- form its own proper functions."— Liebig's Animal Chemistry. 74. " In the animal organism the VITAL FORCE EXHIBITS ITSELF AS in the plant, in the form of growth, and AS the means of RE- sistance to external agencies." —Ibid. 75. " If we assume that all the phenomena exhibited by the or- ganism of plants and animals are to be ascribed to a peculiar cause, different in its manifestations from all other causes which produce motion or change of condition; if, therefore, we regard the vital force as an independent force (no. 3), then, in the phenomena of organic life, as in all other phe- nomena ascribed to the action of forces, we have the statics, that is, the state of equilibrium determ- ined by a resistance, and the dy- namics of the vital force" !— Ibid. 76. " Vegetables produce in their organism the blood of all animals."—Liebig, ibid. To occupy space, nos. 26^ and 27 are contrasted with nos. 25 and 26 in the same column. And so with 5^, 23^. But here is more in the more appropriate place, upon this fundamental point. Thus : 77. " When it is considered, that sea-water contains less than PHYSIOLOGY.--ORGANIC CHEMICAL DOCTRINES. erroneous."—Liebig's Organic Chemistry, &c. ($ 1052,1054). 29. " The most decisive exper- iments of physiologists have shown that the process of chymification is independent of the vital force; that it takes place in virtue of a purely chemical action, exactly similar to those processes of de- composition or transformation which are known as putrefac- tion, FERMENTATION, OT DECAY." —Liebig's Animal Chemistry. " Those remarkable phenom- ena, fermentation, putrefac- tion, and decay, are the pro- cesses of Decomposition, and their ultimate results are to re- convert the elements of organic bodies into that state in which they exist before they participate in the processes of life."—Liebig's Lec- tures for 1844. 30. " The second part of the work will treat of the chemical processes which effect the com- plete destruction of plants and animals after death, such as the peculiar modes of decomposition usually described as fermentation, putrefaction, and decay."—Lie- chemistry—functions. 167 vital doctrines. to olo o o of ^s own weight of io- dine, and that all combinations of iodine with the metallic bases of alkalies are highly soluble in wa- ter, some provision must necessarily be supposed to exist in the organ- ization of sea-weed and the dif- ferent kinds offeree by which they are enabled, during their life, to extract iodine in the form of a soluble salt from sea-water, and tO ASSIMILATE IT IN SUCH A MAN- NER that it is not again restored to the surrounding medium. These plants are collectors of iodine, JUST AS LAND PLANTS ARE OF AL- KALIES ; and they yield us this el- ement IN QUANTITIES Such as We could not otherwise obtain from the water without the evaporation of WHOLE SEAS."--LlEBIG's Or ganic Chemistry applied to Physi- ology, &c.—(§ 1054). 78. " The equilibrium in the chemical attractions of the constit- uents of food is disturbed by the vital principle ;" and " the un- ion of its elements, so as to pro- duce new combinations and forms, indicates a peculiar mode of at- traction, and the existence of a POWER DISTINCT FROM ALL OTHER powers of nature, namely, the vital principle." — Liebig's Or- ganic Chemistry applied to Physi- ology, Sec. 79. " The vital force causes a decomposition of the constituents of food, and destroys the force of attraction which is continually ex- erted between their molecules. It alters the direction of the chemi- cal forces in such wise, that the elements of the constituents of the food arrange themselves in an- other form, and combine to pro- duce new compounds. It forces the new compounds to assume forms ALTOGETHER DIFFERENT from those which are the result of the attrac- tion of cohesion when acting free- 168 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. big's Organic Chemistry applied to Physiology, &c 31. " In the same way as mus- cular fibre, when separated from the body, communicates the state of decomposition existing in its elements to the peroxide of hydro- gen, so a certain product, arising by means of the vital process, and by consequence of the transposition of the elements ofpatts of the stom- ach and of the other digestive or- gans [ ! ] while its own metamor- phosis is accomplished in the stom- ach, acts on the food. The in- soluble matters are digested" !— Liebig's Animal Chemistry. 32. " Is it truly vitality, which generates sugar in the germ for the nutrition of young plants, or which gives to the stomach the power to dissolve and to prepare for assimilation all the matter in- troduced into it 1 A decoction of malt possesses as little power to reproduce itself, as the stomach of a dead calf. Both are, un- questionably, destitute of life. But, when starch is introduced into a decoction of malt, it changes, first into a gummy matter, and lastly into sugar. Hard-boiled albumen, and muscular fibre, can be dis- solved in a decoction of a calf's stomach, to which a few drops of muriatic acid have been added, precisely as in the stomach it- self."—Liebig's Organic Chemis- try, &c. (no. 11). 33. " All substances which can arrest the phenomena of fermen- tation and putrefaction in liquids, also arrest digestion when taken into the stomach" !—Liebig's An- imal Chemistry. 34. " In the natural state of the digestive process, the food only undergoes a change in its state of cohesion, becoming fluid without any other change of properties."— Liebig's Animal Chemistry. VITAL DOCTRINES. ly, that is, without resistance."— Liebig's Animal Chemistry. 80. " It is well known that in many graminivorous animals, where the digestive organs have been overloaded with fresh juicy vegetables, these substances un- dergo IN THE STOMACH THE SAME decomposition as they would at the same temperature out of the body. They pass into fermenta- tion and putrefaction, whereby so great a quantity of carbonic acid gas and of inflammable gas is generated, that these organs are enormously distended, and sometimes even to bursting."— Liebig's Animal Chemistry. 81. " The vital force appears as a moving force or cause of mo- tion, when it overcomes the chem- ical forces, cohesion and affini- ty, which act between the con- stituents of food, and when it changes the position or place in which their elements occur. The vital force is manifested as a cause of motion in overcoming the chemical attraction of the constituents of food, and is, far- ther, THE CAUSE WHICH COMPELS them to combine in a new arrange- ment, and to assume new forms." —Liebig's Animal Chemistry. 82. " It will be shown in the second part of this work, that all plants and vegetable structures undergo two processes of decom- position after death. One of these is named fermentation, the other decay or putrefaction."— Liebig's Organic Chemistry ap- plied to Physiology, &c, (§ 349, c,e). 83. " The individual organs, such as the stomach, cause all the organic substances conveyed to them, which are capable of trans- formation, to assume new forms. The stomach compels the ele- PHYSIOLOGY.—organic chemical doctrines. 35. Although " the process of CHYMIFICATION IS INDEPENDENT of the vital force, and takes place in virtue of a purely chemical action, exactly similar to those processes of decomposition which are known as PUTREFACTION, FERMENTATION, or decay ;" nevertheless, " Inor- ganic compounds differ from or- ganic in as great a degree as in their simplicity of constitutionr— Liebig's Animal Chemistry, and Organic Chemistry. 36. " The power of elements to unite together, and to form pecu- liar compounds which are genera- ted in animals and vegetables, is CHEMICAL AFFINITY."-- LlEBIG's Organic Chemistry applied to Physiology, &c. 37. "We should not permit our- selves to be withheld, by the idea of a vital principle, from consid- ering in a chemical point of view, the process of transformation of the food, and its assimilation by the various organs. This is the more necessary, as the views hith- erto held have produced no re- sults, and are quite incapable of useful application."—Liebig's Or- ganic Chemistry applied, Sec 38. " We know that an organ- ized body cannot generate sub- stances, but only change the mode of their combinations, and that its sustenance and reproduction depend upon the chemical trans- formation of the matters which are employed as its nutriment, and which contain its own constituent CHEMISTRY--FUNCTIONS. 169 VITAL DOCTRINES. ments of these substances to unite into a compound fitted for the for- mation of~ the blood."—Liebig's Organic Chemistry, &c. 84. " The first substance ca- pable of affording nutriment to an- imals is the last product of the creative energy of vegetables." —Liebig's Animal Chemistry. 85. " The special characters of food, that is, of substances fitted for assimilation, are absence of ac- tive chemical properties, and the capability of yielding to trans- formations." — Liebig's Organic Chemistry applied to Physiology, &c. 86. " All experience proves that there is in the organism only one source of physical power; and this source is the conversion of liv- ing parts into lifeless, amorphous compounds." — Liebig's Animal Chemistry. 86|. " It is only with the com- mencement of chemical action that the separation of a part of an or- gan in the form of lifeless com- pounds begins." — Liebig's Ani- mal Chemistry. 87. " When a chemical com- pound of simple constitution is in- troduced into the stomach, its chemical action is, of course, op- posed BY THE VITAL PRINCIPLE. The results produced depend upon the strength of their respective ac- tions. Either an equilibrium of both powers is attained, a change being effected without the destruc- tion of the vital principle ; in which case a medicinal effect is occa- sioned. Or, the acting body yields TO THE SUPERIOR FORCE OF VITAL- ITY, that is, IT IS DIGESTED. Or, lastly, the chemical action ob- tains the ascendency and acts as a poison." — Liebig's Organic Chemistry applied to Physiology, Sec 87$. "The vital power in veg- 170 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. elements. Whatever we regard as the cause of these transforma- tions, the act of transformation is a PURELY CHEMICAL PROCESS. It will be shown, when considering the processes of fermentation and -putrefaction, that any disturbance of the mutual attraction subsist- ing between the elements of a body gives rise to a transforma- tion."—Liebig's Organic Chem- istry, &c. 39. "By chemical agency we can produce the constituents of muscular fibre, skin, and hair" ! " We are able to form, in our la- boratories, formic acid and urea, &c, all products, it is said, of the vital principle. We see, there- fore, that this MYSTERIOUS VITAL PRINCIPLE CAN BE REPLACED BY THE CHEMICAL FORCES" ! !--LlE- big's Organic Chemistry (no. 16, 51, § 53). 40. " The influence of poisons and of remedial agents on the liv- ing animal body evidently shows that the chemical decompositions and combinations in the body, WHICH MANIFEST THEMSELVES IN THE PHENOMENA OF VITALITY, may be increased in intensity by chem- ical forces of an analogous char- acter, and retarded or put an end to by those of opposite character; VITAL DOCTRINES. etables accomplishes the trans- formation of mineral substances into an organism endowed with life." — Liebig's Animal Chem- istry. 87f. " The cause of waste of matter is the chemical action of oxygen. This waste of matter oc- curs in. consequence of the absorp- tion of oxygen into the substances of living parts. This absorption of oxygen occurs only when the resistance which the vital force of living parts opposes to the chem- ical action of the oxygen is weak- er than that chemical action."— Liebig's Animal Chemistry (nos. 3, 4, 7, 8, 11, 86^). 88. " The constituents of veg- etable and animal substances having been formed under the GUIDANCE AND POWER of the VITAL principle, it is this principle which determines the direction of their molecular attraction." " The vi- tal principle alone is capable of restoring the original order and manner of the molecular arrange- ment in the smallest particles of albumen."—Liebig's Lectures for 1844 (§ 48-50). " We cannot expect from or- ganic chemistry the synthetic proof of the accuracy of the views entertained, because every thing in the organism goes on under the influence of the vital force, an immaterial agent [!] which the chemist cannot employ at will." —Liebig's Animal Chemistry. 89. " From the theory of dis- ease developed in the preceding pages, it follows, obviously, that a diseased condition once establish- ed, in any part of the body, can- not be made to disappear by the chemical action of a remedy."— Liebig's Animal Chemistry. 90. " The vital force is sub ject to the action of a blister.' —Ibid. physiology.—organic chemistry--FUNCTIONS. 171 CHEMICAL DOCTRINES. and that we are enabled to exer- cise an influence on every part of an organ by means of substances possessing a well-defined chem- ical action."—Liebig's Animal Chemistry (mottoes a-e). 41. " It is singular that we find medicinal agencies all depend- ent on CERTAIN MATTERS, which differ in composition [moral emo- tions, heat, cold, change of air, ex- ercise ?] ; and if, by the introduc- tion of a substance, certain abnor- mal conditions are rendered nor- mal, it will be impossible to reject the opinion, that this phenomenon depends on a change in the com- position of the constituents of the diseased organism [no. 5], a change in which the elements of the REMEDY TAKE A SHARE SIMILAR TO THAT WHICH THE VEGETABLE ELE- MENTS of food have taken in the formation of fat, of membranes, of the saliva, of the seminal fluid, &c. [!] Their carbon, hydrogen, or ni- trogen, or whatever else belongs to their composition, are derived from the vegetable organism ; and, after all, the action and effects of quinine, morphia, and the vegeta- ble poisons in general, are no hypotheses" ! — Liebig's Animal Chemistry (§18, and motto d). 42. " With respect to the action of quinine, or the alkaloids of opi- um, Sec, physiologists and pathol- ogists entertain no doubt that it is exerted chiefly on the brain and nerves. If we reflect that this ac- tion is exerted by substances which are material, tangible, and ponder- able ; that they disappear in the organism ; that a double dose acts more powerfully than a single one; that, after a time, a fresh dose must be given if we wish to pro- duce the action a second time; all these considerations, viewed chem- ically, [!] permit only one form of explanation; the supposition, VITAL DOCTRINES. 91. " The vital force in a liv- ing animal tissue appears as a cause of growth in the mass, and of resistance to those external agencies which tend to alter the form, structure, and composition of the substance of the tissue in which the vital energy resides."— Liebig's Animal Chemistry. 92. " The slightest action of a chemical agent upon the blood ex- ercises an injurious influence. Even the momentary contact with the air in the lungs, although ef- fected through the medium of cells and membranes, alters the color and other qualities of the blood." —Liebig's Organic Chemistry ap- plied to Physiology, Sec. 93. " Every substance may be considered as nutriment, which loses its former properties when acted on by the vital principle, and does not exercise a chemical action upon the living organ. An- other class of bodies change the direction, the strength, and inten- sity of the resisting vital principle, and thus exert a modifying influ- ence upon the functions of its or- gans. These are medicaments. A third class of compounds are called poisons, when they possess the property of uniting with or- gans or with their component parts, and when their power of ef- fecting this is stronger than the re- sistance offered by the vital princi- ple."—Liebig's Organic Chemis- tryr Sec. 172 INSTITUTES OF MEDICINE. CHEMICAL DOCTRINES. namely, that these compounds, by means of their elements, take a share in the formation of new or the transformation of existing BRAIN AND NERVOUS MATTER" ! !-- Liebig's Animal Chemistry. 43. " Owing to its volatility and the ease with which its vapor per- meates animal tissues, alcohol CAN SPREAD THROUGHOUT THE BODY IN ALL DIRECTIONS" !--LlE- big's Animal Chemistry (§ 350J, n). 44. " It is impossible to mistake the -modus operandi of putrefied sausages, or muscle, urine, cheese, cerebral substance, and other mat- ters, in a state of putrefaction." " It is obvious that they communi- cate THEIR OWN STATE OF PUTRE- FACTION TO THE SOUND BLOOD, from which they were produced, exactly in the same manner as glu- ten in a state of decay or putrefac- tion causes a similar transforma- tion in a solution of sugar" ! 45. " The mode of action of a morbid virus exhibits such a STRONG SIMILARITY TO THE ACTION of yeast upon liquids containing 6ugar and gluten, that the two processes have been long since compared to one another, although merely for the purpose of illustra- tion. [They have often been rep- resented as identical.] But, when the phenomena attending the ac- tion of each respectively are con- sidered more closely, it will in re- ality be seen that their influence DEPENDS UPON THE SAME CAUSE." " Ordinary yeast, and the virus of human small-pox, effect a violent tumultuous transformation, the for- mer in vegetable juices, the latter in the blood" ! " The action of the virus of cow-pox is analogous to that of low yeast [ / ] It commu- nicates its own state of decomposi- tion to a matter in the blood, and from a second matter is itself re- VITAL DOCTRINES. 94. " According to all the obser- vations hitherto made, neither the expired air, nor the perspiration, nor the urine, contains any trace of alcohol, after indulgence in spirituous liquors."—Liebig's An- imal Chemistry. 95. " The vivifying agency of the blood must ever continue to be the most important condition in the restoration of a disturbed equilibrium, and the blood must, therefore, be considered and con- stantly kept in view, as the ulti- mate and most powerful cause OF LASTING VITAL RESISTANCE, as well in the diseasrd as in the un- affected parts of the body."— Liebig's Animal Chemistry. Nevertheless, " No other component part of the organism can be compared to the blood, in respect of the fee- ble resistance which it offers to exterior influences." " The chem- ical force and the vital principle hold each other in such perfect equilibrium, that every disturb- ance, however trifling, or from whatever cause it may proceed, EFFECTS A CHANGE IN THE BLOOD." —Liebig's Organic Chemistry ap- plied, Sec. But, again, nevertheless, " It is obvious, moreover, that in all diseases where the forma- tion of contagious matter and of exanthemata is accompanied by fe ver, two diseased conditions simul- taneously exist, and two process- es are simultaneously completed; and that the blood, as it were, by reaction, that is, fever, becomes a means of cure."—Liebig's An- imal Chemistry. PHYSIOLOGY.--ORGANIC CHEMISTRY--FUNCTIONS. 173 CHEMICAL DOCTRINES. generated" ! " The susceptibility of infection by the virus of human small-pox must cease after vacci- nation, for the substance to the presence of which this suscepti- bility is owing has been removed from the body by a peculiar pro- cess of decomposition artificially excited" ! " Cold meat is always in a state of decomposition. It is possible that this state may be communicated to the system of a FEEiiLE individual, and may be one of the sources of consump- tion" !!—Liebig's Organic Chem- istry applied to Physiology, Sec. (§ 821). " From the unequal degree of the conducting power in the nerves, we must deduce those conditions which are termed paralysis, syn- cope, and spasm "!—Liebig's An- imal Chemistry. 46. " In all chronic diseases, death is produced by the same cause, namely, the chemical action of the atmosphere." " tlie true cause of death is THE RESPIRATORY PROCESS, [ ! ] that is, the chemical action of the at- mosphere." — Liebig's Animal Chemistry (§ 674-676), • **j* Jhe 440^ nos. 17 and 18, 447i_/*]. These observations cannot be gainsayed, and are far more convincing than those arbitrary and artificially produced phenomena, sometimes called experiments [by the " digestive mix- ture," retorts, acids, lamp-wick, &c. ]]; experiments which, made, as too often they are, without regard to the necessary and natural con- ditions, possess no value, and may be entirely dispensed with; espe- cially, when, as in the present case, Nature affords the opportunity for observation, and when we make a rational use of that opportunity." It remains only to say of the foregoing, that the chemist was not duly mindful of the fact that all the principal tenants of the deep, warm-blooded and cold-blooded, are alike carnivorous; and that the exalted temperature of the blubber-whale, the porpoise, &c, breath- ing, also, with lungs, and in their comparison with the low tempera- ture of their associates that respire with gills, contrasts forcibly with those carnivorous animals whose respiration of oxygen is said to pre- vent an accumulation of fat. Such, I mean, is the fundamental doc- trine of "fat" (§ 440 bb, no. 10). But since animal food, especially fat. contains more of the " fuel" than vegetable food, how does it hap- PHYSIOLOGY.--FUNCTIONS. 253 pen, according to the foregoing statement as to the relative propor- tions of oxygen consumed and carbonic acid expired by the graminiv- orous and the carnivorous animal, respectively, that the former should Burpass the latter in the formation of fat] Wherever, therefore, we look at the " facts" of the organic chem- ist, we find ourselves not only in the midst of contradictions, but em- ployed in refuting assumptions that are opposed by universal experi- ence (§ 54j. That experience I had employed in the Commentaries for the very purposes to which its adverse assumptions are now con- secrated by the disciples of the " improved philosophy" (§ 349 d, 3501). 441, d. In the case of the hibernating animals (§ 441, c), the ex- cessive cold, and mechanical irritation, in rousing the calorific func- tion, operate as a stimulus to the vital properties, and thus restore the organic functions, and the natural temperature as a consequence, along with the other organic products; though the heat more per- fectly than any other. In a less degree, cold is a sedative to the hi- bernating animals (§ 188^, 743). This, also, is an example illustra- tive of the opposite influences of vital agents, according to their in- tensity of action, and the circumstances under which they are applied, and of the wonderful adaptation of the natural agents of life to the pe- culiarities of particular species of organic beings (§ 191, 446 d, 500 o). The impression of cold, or mechanical irritation, in the foregoing case, is transmitted from the skin to the cerebro-spinal axis, where the nervous power is developed and radiated abroad upon the or- ganic properties of the entire body, by which they are brought into operation (§ 222-233, 500, 512, Sec, 638, 1044, b). Respiration and other organic functions nearly cease during the State of torpor; but the restoration of heat is far more than com- mensurate with the progressive return of respiration. Of all the products, an evolution of heat takes the lead, as indispensable to the other important results. This appears to have been seen by Liebig. Nor is there any principle in physiology, nor any facts, which will at all explain the operation of cold in diminishing respiration, or cir- culation, till it has first reduced the temperature of the surface. And, were the chemical hypothesis true, the hibernating, and the young of other warm-blooded animals, should not sustain the remarkable re- duction of heat which is produced by an atmospheric temperature of 45° F., since more oxygen is then consumed than at higher tempera- tures. There can be no such positive exceptions to a fundamental law. If peculiarity of constitution be assigned as the cause, then is the chemical hypothesis abandoned, and the vital theory admitted. It is therefore apparent, that the reduction of temperature depends essentially on other causes than diminished respiration. The con- verse of this must be equally true; and when heat, therefore, is re- stored, the first step in the process is an increased action of the cap- illary blood-vessels, through the stimulus of the nervous power (§ 222, &c), by which an evolution of heat is immediately started; and then begins an increase of the respiratory movements. " We can al- ways hasten respiration," says Bichat, truly, " by making an animal suffer; but an acceleration of the pulse is always prior to that of res- piration, which appears to be determined by it."—(See § 484, Exp. C.) 441, c. That is a test. If the heat rises without oxygen, it certain- ly does not, in such a case, depend upon combustion. The "carriers" 254 INSTITUTES OF MEDICINE. must be regularly supplied (§ 447£, a). I have said that Liebig ap- pears to have been sensible that internal heat is important to the or- ganic processes, though vastly more so in the warm-blooded than the cold-blooded race, and his statement upon this subject is one of his numerous contradictions of the hypothesis which he assumes. Thus: "It is obvious that the cause of the generation of force is diminished, because, with the abstraction of heat, the intensity of the vital force diminishes. It is also obvious, that the momentum of force in a living part depends on its proper temperature." " The increase of mass is effected in living parts by the vital force. The manifesta- tion of this powen is dependent on heat; that is, on a certain temper- ature peculiar to each specific organism." " The abstraction of heat must be viewed as quite equivalent to a diminution of vital energy." —Liebig's Animal Chemistry. Now, according to this reasoner, " in the animal body we recognize as the ultimate cause of all force only one cause, the chemical action which the elements of the food and the oxygen of the air mutually ex- ercise on each other." We are also told that " the mutual action between the elements of the food and the oxygen conveyed by the circulation of the blood to every part of the body is the source of animal heat."—Liebig's Ani- mal Chemistry. But, we have just seen that the same reasoner affirms that these very movements are " dependent on heat" (§ 350, no. 171, &c). The cause depends upon the effect, and the effect depends upon the cause (§ 440, f). And how could it be otherwise with an hypothesis so estranged from nature 1 Indeed, our author not unfrequently quits, entirely, the chemical ground of animal heat, as we have seen of many other assumptions (§ 350), and gives way to the simple dictates of nature. For example, " Certain other constituents of the blood may give rise to the for- mation of carbonic acid in the lungs. But, all this has no connec- tion with that vital process by which the heat necessary for the support of life is generated in every part of the body."—Liebig's Animal Chemistry. And yet it is both a doctrine of this philosopher in physiology and medicine, that the evolution of animal heat is a purely chemical pro- cess, and that carbonic acid cannot be formed in the body without the disengagement of heat (§ 350, no. 17^ ; § 440, no. 17). Taking, also, in connection the two parts of the foregoing quotation, we have one fif those palpable contradictions of a fundamental assumption which are the never-failing characteristic of false doctrines. There is the double affirmation that carbonic acid resulting from any other source than a vital process is not a cause of animal heat, and that animal heat is alone generated by a vital process. (See, particularly, § 440, nos. 6 and 16.) Or, allowing what the language does not admit, the dependence of animal heat upon carbonic acid " generated in every part of the body," we should then have the curious phenomenon in chemistry of the production in the animal body of carbonic acid by a chemical process and by a vital process, while that of the former, the very gist of the -doctrine, does not, as avowed, contribute to animal heat (\ 1044). 441,/. Again, it is reiterated, that " the mutual action between tho PHYSIOLOGY.--FUNCTIONS. 255 elements of the food and the oxygen conveyed by the circulation of the blood to every part of the body is the source of animal heat" (§ 350, no. 3). Now, frogs have a feeble power of generating heat, as have " all living creatures, whose existence depends on the absorption of oxy- gen" (§ 443, c). But, these animals contradict our author's hypothesis as to the " carriers of oxygeri," not only in its relation to animal heat, but other important matters, such as the production of force, of motion, Sec (see § 350, nos. 3, 4, 8). Spallanzani, for instance, eviscerated the heart, large blood-vessels, &c, of a number of frogs and toads, and buried them in the snow, along with others which retained their circulation and vivacity. The whole soon became completely torpid, and " appeared as if frozen." In a few hours they were all removed to a warm situation, where all of them began to leap and make their escape ; the reanimation being apparently as perfect in those which had been deprived of blood as in those which had not. When ex- posed to greater degrees of cold, they perished in equal times (§ 44l£ d, 443 b, 494). How simple an experiment, therefore, may overthrow the most pop- ular hypothesis in philosophy. It cannot be true of frogs that will leap and jump without.blood, as well as frogs with blood, after being " apparently frozen," that their independent source of heat is owing to " the oxygen conveyed by the circulation of the blood," any more than their " amount of motion is proportional to the quantity of oxyger inspired and consumed in a given time by the animal" (§ 350, no. 8). And then, too, according to our author, " Since physiology has proved, that the globules of blood take no share in the process of nutrition, it cannot be doubted that they play a part in the process of respiration." Especially in white-blooded ani- mals.—Liebig's Animal Chemistry. From all which it is more and more apparent, that "the Reformer" was employed about a plan of human chemistry rather than of animal chemistry (§ 440, c). The foregoing subject is farther continued in § 443-445. 44l£, a. What has been said in the preceding section of the hiber- nating and cold-blooded animals is true, in principle, of all other an- imals who suffer only a partial reduction of temperature. The differ- ences do not arise from different fundamental laws, but from different modifications of the properties of life in different species of animals, and at different ages of the same individual (§ 155, 185, 191). There are many animals that approximate the hibernating in their feeble power of maintaining heat; and others, again, which sustain interme- diate relations to the more perfect of the warm-blooded vertebrata. " The high temperature," says Edwards, in his Influence of Physical Agents on Life, " which seems to characterize the mammalia and birds, does not belong to them exclusively, since examples of it are found among insects; and, on the other hand, among the mammalia themselves (as the hibernating), which, at certain periods, present the principal phenomena of the cold-blooded vertebrata; and, lastly, a great number of non-hibernating mammalia and birds, in the early periods of their life, show, as far as the phenomena of heat are con- cerned, a strong resemblance to the cold-blooded animals." It may Ih- thence inferred, that what is so remarkably conspicuous 256 INSTITUTES of medicine. in the torpid hibernating animals is only the result of a law that pre- vails throughout the animal kingdom. This law extends equally to the vegetable kingdom, which possesses a far greater power of gen- erating heat than frogs and other cold-blooded animals. The trees and shrubs which belong to northern climates have, also, exactly the peculiarity of the hibernating animals, while those of tropical regions maintain a greater uniformity of temperature, and are destroyed by a degree of cold in which some northern herbaceous plants spring into active life, and pierce their way through snow and ice. 441^, b. And this leads me to say, that, through the same law, the warm-blooded vertebrata have their standard of heat modified by cli- mate ; and even man himself sustains variations of 1° to 2° F. And, as I have said in my former Essay on Animal Heat, it is important to remark, as showing the entire independence of this phenomenon of respiration, this change does not take place till such as remove from one climate to another shall have been for some time subjected to the new condition of vital stimuli. It is the result of acclimation, and, trivial as it may seem, it is full of the most instructive illustration to a reflecting mind. The phenomenon, I say, is owing to permanent modifications of the vital constitution, and is of the same nature as the change of temperament which the melancholic undergoes on passing from the temperate to the equatorial regions (§ 602), and about which the law of vital habit is interested (§ 561, 585, 602, 603). 441|, c. It is equally a fatal circumstance to the chemical hypothe- sis, that the standard of heat is lowest in cold, and highest in hot cli- mates, whatever the amount of clothing, &c, since more oxygen is respired in the former, and, according to our author, a far greater quantity of " fuel" is consumed both by the mouth and by oxygen gas (§ 440, nos. 8, 9, &c). It is not difficult, therefore, to understand the bearing of the following statement: " The most trustworthy observations prove that in all climates, in the temperate zones as well as at the equator or the poles, the tem- perature of the body in man, and in what are commonly called warm- blooded animals, is invariably th6 same."—Liebig's Animal Chemistry. And why, again, is the temperature of man higher in tropical than in temperate climates 1 The reply is another proof of the tampering of chemistry with a subject utterly beyond its reach; since the heat of the tropics operates gradually as a vital stimulus to the calorific function, and thus slowly establishes that condition by which an ex- alted temperature is determined throughout the universal body (§ 350, no. 65, 441 c, 445 e). 4411, j/m Nor may I neglect the striking characteristic of the egg, which possesses the power of resisting cold " in a degree equal to that of many of the inferior animals." This is one of the facts which led Mr. Hunter to believe that the vital properties are capable of generating heat independently even of circulation (§ 441,/), while its greater evolution is seen to be the result of those properties in active operation through the mature organization (§ 65). The former con- dition, associated, also, with the power of resisting the causes of putre- faction, is a beautiful illustration of the nature of life, that it is an ac- tive, not a passive state, that it consists essentially of power, and that its laws are specific. But, how will the combustion hypothesis dis- pose of the internal source of heat in the egg t PHYSIOLOGY.--FUNCTIONS. 257 442, a. In respect to the affirmation that "clothing is merely an equivalent for a certain amount of food" (§ 440, no. 11), I have addu- ced, in my former Essay, many facts to prove that our clothing is greatly a matter of habit, and this is shown by the facts which will be soon presented. It is, indeed, a forcible illustration of the nature of the properties of life, of the dependence of animal heat upon vital ac- tion, and of its obedience to the law of vital habit, and to the consti- tutional law by which all results shall be so regulated as to maintain the integrity of organic processes, and, therefore, a uniform tempera- ture of non-hibernating warm-blooded vertebrata; while, as I have endeavored to show in the same work, the modifications of these pro- cesses in hibernating and cold-blooded animals, as well as in the veg- etable kingdom, are not only perfectly consistent with what is observ- ed of the non-hibernating warm-blooded vertebrata, but go to con- firm the whole philosophy which is founded upon the phenomena of these animals. There, too, I have shown by an examination of facts, that the rapid change in the power of elaborating heat in early life depends on the same common principle which determines the changes in all other functions and results, that they are all on a par in principle, and that tho rapid increase of the resistance of cold in the young of the warm- blooded vertebrata proves the vital character of the calorific function (§ 153-159, 441 b, 1047,1048). 4 42, b. In illustration of the law of vital habit as it respects the power enjoyed by man of resisting cold (§ 441, c), and in farther dis- proof of the assumption that a living animal is "like any other heated mass in relation to the temperature of surrounding objects," I shall quote from the Commentaries one of the facts which are there present- ed for the purpose which is now in view. Thus : " Mackenzie says, that some of the northern savages follow the chase in the coldest weather with only a slight covering. Lewis and Clark state, that two Indians slept upon the snow during the night in a light dress, when the thermometer was 40 degrees below the zero of Fahrenheit. The man was uninjured; the boy had his feet frozen. Now it is evident that no civilized man could sustain such an exposure. The phenomenon fs owing to the power of habit in rela- tion to the forces of life, and is utterly insusceptible of explanation on any other principle."—Commentaries. On the other hand, an individual froze to death in the woods of Peacham, Vermont, on the night of the 7th of June, 1S17; notwith- standing, also, he was full, to intoxication, of the most combustible substance (§ 440, no. 9). But, again, we are informed by Captain Wilkes, that, when the thermometer was at 40° F., "the Petcherai Indians were entirely naked, with the exception of a small piece of seal-skin, only sufficient to cover one shoulder, and which is generally worn on the side from which the wind blows, affording them little shelter against its pierc- ing influence." Again, says Captain Wilkes, "On the 11th of March, three bark canoes arrived, containing four men, four women, and a girl about sixteen years of age, four little boys, and four infants, one of the latter about a week old, and quite naked. The thermometer was at 46° R 258 institutes of medicine. Fh."—Wilkes's Narrative of the United States Exploring Expedi- tion, vol. i., p. 121, 124. 1845. The foregoing, in relation to the infants, should be considered in connection with what has been ascertained by Dr. Edwards as to the comparative inability of infants to bear a cold atmosphere, when un- accustomed, and with what is known of hereditary constitution (§ 447 h, 540, 561. See, also, Medical and Physiological Commenta- ries, vol. ii., p. 27, 52, 56, 69-74). " The power of the Russian Zincali of resisting cold," says Barrow, "' is truly wonderful, as it is not uncommon to find them encamped in the midst of snow, in slight canvas tents, when the temperature is 30° or 40° below the zero of Fahrenheit."—Barrow's Zincali of Spain. No two individuals under apparently equal circumstances, of the same health, age, sex, and with the same quantities and qualities of food, clothing, &c, are alike in the power of resisting cold. Place them in a temperature at zero of Fahrenheit, and one will perish while the other will not suffer. One shall enjoy a gfow of warmth from athletic exercise, while the other shall perish with the same counteracting means. It is a common event to witness the blasters, in the vicinity of New York, at work in winter with heavy drills in their naked hands, while others, unaccustomed, would be frost-bitten at the same temperature. The difference is manifestly owing in part to a difference in constitution, but especially to the influence of habit, which engenders the power of enduring intense degrees of cold, and which no-chemical principles can possibly expound (§ 535-568). 442, c. The foregoing facts show us, also, how it has happened that animals have spread abroad from the spot where they were created, and become specifically adapted to different climates. The element of their adaptation was implanted in their vital constitution at the time of their creation, and relates to almost all physical agents. And so with vegetables, which may be gradually transplanted from the equator to high northern latitudes, where they also undergo changes of organization (§ 155, 535, 538, &c). Thus do we also again bring the philosophy of physiology to the overthrow of that infidelity which departs from the Mosaic account of organic Creation (§ 74, 450f ,h-n). 442, d. Again, do the beasts or the birds of the polar clime change their fur or their plumage, when transported to a temperate region 1 What, for example, answers the white bear, with which we are all familiar 1 And yet their temperature sustains but a slight change, though a change subversive of the combustion theory (§ 441 c, 441^). Here, too, in truth, they consume a far greater quantity of food ; and, if the chemist's hypothesis as to an interchange of caloric with the at- mospheric air be adopted (§ 440, no. 14), these transplanted creatures should sustain a very exalted rise of temperature. But, upon the physiological action of external heat, as a vital stimulus, the high tem- perature of a warm climate would much more than compensate for any supposed deficiency of oxygen (§ 440 e, 441^ c, 1047). " And then, on the other hand," turning again to man, and as I have said in the Commentaries, " are the experiments of individuals subjecting themselves to an excessively high temperature, without sus- taining any sensible variation of heat. This was fully demonstrated by Blagden, Banks, Fordyce, Solander, G. Home, Dundas, Dr. North, Phipps, Seaforth, and Dobson, who exposed themselves to a temper- ature of 260° Fh."— Comm., vol. ii., p. 61, 62. physiology.—functions. 259 442, c. We see, then, in the various demonstrations, which have now been made, of the power of all warm-blooded, non-hibernating vertebrata to maintain a uniform degree of heat under the greatest vicissitudes of atmospheric temperature that are compatible with life, a proof of a most astonishing law of the living body, in perfect con- flict with the laws of caloric as they exist in the inorganic world. " We know it" as exactly as we comprehend the nature and opera- tion of the most precise law in physics. It is, in itself, demonstrative of the government of living beings by specific forces. It establishes a positive; distinction between these forces and the organized structure. If I am not right in this construction, I say, once more, let the ground of objection be shown. I mean not the usual denial, or by renewed misrepresentations of my statements. The objections must be found- ed upon a broad and philosophical survey of all the phenomena of heat that relate to living objects as they may be modified by natural causes, or by morbid states of the system ; and the ground must cover the general physiological condition of organized beings. How wide from all this are the assumptions, and those mostly relative to man (§ 440, c), that have been lately consecrated as the true " experimen- tal philosophy" of animal heat"(§ 349 d, 1047) ! 443, a. As my former Essay embraces an extensive range of inquiry into the facts and philosophy attending the calorific function in the cold-blooded race, I shall now add only a few remarks to what I have already stated upon this subject, and as suggested by the present stage of my inquiry (§ 441/, 441£ a). 443, b. Frogs and other coid-blooded animals are supplied with capacious lungs; and, however it may be argued that their consump- tion of oxygen is less than that of warm-blooded animals, they have, nevertheless, the same respiration, nutrition, vital decomposition, and the same " charcoal fire," in the ratio of the food consumed, and yet is their temperature principally regulated by that of the surrounding medium. They also emit a large amount of carbonic acid, which proves a free consumption of oxygen and a liberal supply of food. All this is as essential to frogs as to man; and they equally perish when deprived of atmospheric air, and so of all the cold-blooded finny tribe (§ 350, no. \1\, and § 440, no. 10). And what will chemistry answer to the exalted temperature which attends the inflammations of the cold-blooded vertebrata1? Chemistry must here be consistent, and in being so it necessarily abandons the hypothesis that the evolution of heat, in warm-blooded animals, depends on the union of oxygen with the carbon and hydro- gen of the body, and that it occurs in the ratio of that combination. "In the animal body," says Liebig, "the food is the fuel; with a prop- er supply of oxygen ice obtain the heat given out during its combus- tion." (Also, § 440, nos. 5, 6, 17.) 443, c. The difference in the law regulating temperature is owing to a difference in vital constitution, of which the chemist takes no ac- count (§ 440, no. 12). But, there are also many other peculiarities in the vital phenomena of cold and warm-blooded animals which are due to the same condition of constitution, and by which their relative power of generating heat is shown to depend on a common cause, and which is common to all the phenomena. It is this which ren- ders cold-blooded animals greatly subject to the temperature of the 260 INSTITUTES OF MEDICINE. surrounding medium, but which also enables them to resist its influ- ence by some 2 or 3 degrees at all seasons of the year. 443, d. If the chemist resort to difference of constitution in explain- ing the foregoing phenomena, as is generally done, he resorts to the properties and functions of life, and abandons his own ground. In one case he says, it is because they are cold-blooded, and in the other, because they are warm-blooded, and so on. Such, indeed, is the fact. But, is it not because the organization and vital endowments are not adapted to the same generation of heat in one case as prevails in the other; and this, too, when the organization may be in a high de- gree simple (§ 409, e) 1 444. Let us, therefore, settle this question by reference to an animal without lungs, or gills, and in which, also, the temperature is clearly influenced by causes which can alone operate as vital stimuli, the temperature, for example, of a hive of bees is at about 90° F., when the air is at 40°, and upward of 70° in winter. Their power of gen- erating heat is also increased during the breeding season. This phe- nomenon corresponds with the observations that I have made upon vegetables; having found the temperature highest when the leaves and blossoms are putting forth.—(Medical and Physiological Commen- taries, vol. ii., p. 75-78.) 445, a. Still more conclusively, than the obvious dependence of or- ganic heat in the cold-blooded vertebrata, insects, Sec, upon vital principles, do the phenomena of vegetable heat evince the same great law of organic nature. This subject has been ably explored by John Hunter, and, as I have intimated in the foregoing section, has re- ceived a careful attention from myself. Senebier, also, saw the ther- mometer rise from 79° to 143° F., when placed in the midst of a dozen spathes of the arum cordifolium, at the time of opening their sheaths. And so Huber, and others. 445, b. That fact, and the ability of plants to generate a tempera- ture often far above the earth or the surrounding atmosphere, are so apparent that they are universally admitted ; but obtain from the chemist no farther notice. Indeed, the following is all that we have from Liebig on the subject of vegetable heat. Thus : " All living creatures, whose existence depends on the absorption of oxygen, possess within themselves a source of heat independent of surrounding objects. This truth applies to all animals, and extends, besides, to the germination of seeds, to the flowering of plants, and to the maturation of fruits."—Animal Chemistry. And yet is the " combustive process" always in progress, more or less, in all parts of vegetable organization. The question, therefore, arises as to the motive for not only concealing an important fact, but in thus implying, by circumstantial statements, that no other parts of vegetables "possess within themselves a source of independent heat." The very fact that such a source belongs to seeds in their germinating state, Sec, is sufficiently conclusive that it extends to every part of the plant, and " the Reformer" could not have been ignorant that the very egg resists a temperature below the freezing point in virtue of its in- ternal source of independent heat. But, all this is fatal to our author's hypothesis. Eggs do not con- sume oxygen, have no " carriers of oxygen," and trees, it is said, do not " burn" like the animal body (§ 302, 303|). Consequently, the PHYSIOLOGY.—FUNCTIONS. 261 chemist, to carry out his hypothesis of animal heat, must maintain the anomaly that seeds, flowers, and fruits, during their development, are the only parts of the vegetable world that possess " an independent Bource of heat." The secret of all this will be farther seen in the fol- lowing passage: 445, d,. " The distinguishing character of vegetable life is a contin- ued passage of matter from the state of motion to that of static equilib- rium. A plant produces within itself no cause of motion" (see § 350, nos. 7, 8, 10, and § 440, nos. 5, 6, 8, 9, 12, &c). "In a word, no waste occurs in vegetables. [ ] ] Waste, in the animal body, is a change in the state or in the composition of some of its parts, and consequently is the result of chemical action." — Liebig's Animal Chemistry. And, again : " Analogy, that fertile source of error, has unfortu- nately led to the very unapt comparison of the vital functions of plants with those of animals."—Liebig's Organic Chemistry, Sec. 445, c. Thus is the problem solved. There is either no heat gen- crated by plants, or, otherwise, the chemical doctrine of animal heat is radically false. To show how this may be, I shall now introduce an abstract of some observations made by myself on the temperature of trees. It is unnecessary to state the mode in which the observa- tions were conducted, or the precautions adopted, as they are record- ed in the Commentaries. On the 9th of April, 1839, in a neighboring forest, the following re- sults were obtained: "Range of the thermometer in the shade, during the observations, which lasted six hours, from 38° to 52° F. Near freezing at sunrise. " A dead upright tree was selected as a standard of comparison. Its diameter was 12 inches. The temperature of this tree, at the close of my observations, was 45° at the centre and in all other parts (§ 440, nos. 14, 15, and 16). Juglans squamosa, diameter 10 inches, 48° Buds slightly enlargim Do. do. « 6 49° do. Fagus sylvatica, " 10 " 49° Buds swelling. Quercus tinctoria, " 7 " 49° No budding. Castanca Americana, 12 " 50 do. Betula nigra, " 4 " 51° Flowering. Salix Babylonica, " 18 " 53 Buds unfolded. Do. do. " 18 53° do. Pinus Canadensis, 18 54° Platanus occidentalis, 18 " 50° No budding. Do. do. " 6 54° do. Do. do. « 4 55° do. Juniperus Virginiana, 4 « 55° Rotuna pseudacacia, " 3 " 62° do. Populus laevigata, " 4 " 62° In bloom. Do. do. " 4 " 64° do. Do. do. 3 63° do. Do. do. " 3 65° do. Do. do. " 2 67° io. Do. do. " 1$ " 68° do. " Believing that if the vital doctrine of the generation of animal heat were correct, I should find an elevation of vegetable heat as the warmth of the season increased, and the energy of vegetable life be- came more exalted, on the 19th of the same April I made another visit (§ 4411, c). " Range of the thermometer in the shade, during the observations, which lasted five hours, from 40° to 65°. 262 INSTITUTES OF MEDICINE. " Temperature of two dead, dry, upright birch trees, one eight inches in diameter, the other six inches, at end of observation 60° in all their parts. Temperature of the earth six inches below surface 47° in shade, at close of observation. Probably 50° at two feet. Betula nigra, diameter 15 inches, 54° Buds swelling. Platanus occidentalis, 6 59° do. Cluercus virens, Do. do. Do. tinctoria, Do. da 8 24 " 18 6 62° 73° 65° 66° do. Buds much more advanced Buds swelling. do. Juniperus Virginiana, Do. do. Acer rubrum, Castanea Americana, Oornus Florida, 5 " 2 " " 12 " 4 "2 64° 79° 65° 66° 68° In bloom. Buds swelling. 5 Flower-bads advancing"; no I leaves. Fagus sylvatica, Juglans alba Do. do. Do. do. 12 4 " 1 68° 75° 83° 82° Buds opening. Buds swelling. Buds larger. Buds opening. 445, f. " It is abundantly manifest from the foregoing observations that vegetables possess a vital power of generating heat, according to the activity of their organic forces; and I carry the analogy to the animal kingdom. The temperature was not influenced by that of the earth, as seen by the preceding statement. The heat of the lat- ter, however, was not ascertained at the first observation. It appears, also, that the power of generating heat is greater in proportion to the youth of trees. This remarkable fact is not only especially indicative of the vital agencies in the generation of vegetable heat, but is worthy of notice on account of its opposition to what obtains in the animal kingdom in respect to age. It corresponds, also, with observations upon herbaceous plants. The difference depends upon the relative difference in organization and vital properties at the corresponding periods of life."—Commentaries (§ 153-155, 441 b—i, 1054). 445, g. It is a fundamental principle, therefore, that " the general phenomena of the disengagement of heat remain always the same in, an- imals with lungs, in those without them, and in plants, all of which have an independent temperature."—Bichat. 446, a. The relation of the nervous power to animal heat is the same as that of all other products of animal organization; its influ- ence, however, being sometimes remarkably pronounced in the elabo- ration of heat, as seen in the quick transition of the hibernating animal from temperatures below 40° to upward of 90° F. This subject, how- ever, has been so extensively investigated in my former work, that I shall only now say that the elaboration of animal heat does not depend on the nervous power, as often maintained, but, like other functions of animals,is only influenced by it(§ 183-185,188,222-233,489,492,500). These are variously affected by varying influences exerted upon the cerebro-spinal and ganglionic systems, as, of course, are also the se- creted products in a corresponding manner. In the perfectly natural state, the nervous system has no important agency in the production of the phenomena, but may become powerfully instrumental in modi- fying the properties, and actions, and products of life, when unusual conditions exist, or when unusual impressions are transmitted to the cerebro-spinal axis. We have seen, too, that analogy, as supplied by the vegetable kingdom, affords the strongest presumptive evidence that the nervous system may have no active participation in the elab- TUVSIOLOGY.—FUNCTIONS. 263 oration of heat, in the natural condition'of the body, while this induc- tion is strengthened by what is known of other secreted products in both of the animated kingdoms. Still, in respect to the animal king- dom, the mere existence of the cerebral and ganglionic systems, their remarkable properties and susceptibilities, and their intimate connec- tion with all parts of the organization, is, prima facie, conclusive that they have important offices in relation to animals, and that their pres- ence, in the natural state of the complex being, is indispensable to the integrity of every function. This, as will have been seen, has been ex- perimentally ascertained fn relation to many; and that unusual, or sudden impressions that are not unnatural, as the operation of the pas- sions, for instance, may be extensively and profoundly propagated from the brain to other organs. It has been fully demonstrated that the natural condition of the secretions depends upon the integrity of the nervous connection between the secerning organs and the cerebro- spinal axis; while it has been equally shown that the organic func- tions, and all vascular action, may be immediately and powerfully influenced by impressions made upon the brain and spinal cord, whether in a direct manner, as in Philip's Experiments, or indirectly through the medium of sympathy, as in blows upon the stomach, sur- gical operations, the action of medicines and of poisons upon the in- testinal canal, &c. (§ 1043 b, 1044). Assuming, then, that animal heat is also a secreted product, it would come philosophically under the common law; and since it ap- pears from experiment, that animal heat depends even more upon the presence of the brain than an imperfect production of gastric juice and other secreted fluids, and may be as powerfully influenced through the nervous system, the physiological analogy between heat and other secreted matters becomes quite apparent; while it ex- plains the remarkable effect of a low atmospheric temperature in developing heat in the torpid hibernating animal (§ 441, 441^ a); and thus conducts us, also, to the philosophy of the operation of oth- er causes in modifying animal temperature. To maintain the foregoing conclusion, I have examined, in my for- mer Essay, the merits of Brodie's, Philip's, Chaussat's, and other ex- periments upon the nervous system, the phenomena of hibernating animals, the modifications of temperature that spring from injuries, diseases, and other affections of the nerves, &c, the admissions of distinguished chemico-physiologists, and other important considera- tions. Some of these facts in relation to the nervous influence upon animal temperature will appear in the next following section. 446, b. It should be said, however, that it has been stated by some that the experiments of Philip conflict with those of Brodie and Chaussat, which establish an influence of the nervous power over the phenomena of animal heat. But that is an error; since the deduc- tion of Philip himself from his own observations ascribes to the ner- vous power what is due to the organic power. Thus : " That the maintenance of animal temperature is a function of the nervous system, properly so called, appears from a variety of facts generally known ; the temperature either of a part or of the whole body being lessened by any cause that impairs the action of particu- lar nerves in the former instance, or of the whole nervous system in die latter."—Philip, on Acute and Chronic Diseases, p. 48. 264 INSTITUTES OF MEDICINE. Again he says, " I here consider it as proved, by experiments al- ready laid before the reader, that the evolution of caloric is a function of the nervous influence."—Philip's Inquiry into the Laws of the Vi- tal Functions, Exp. 77. (Also, § 437, c.) 446, c. It is, of course, erroneously stated by " the Reformer," that, "by the division of the pneumogastric nerves, the motion of the stom- ach and the secretion of the gastric juice are arrested." The juice is only modified in quality, while it is actually increased in quantity (§ 461, 489). " The Reformer" has also high conceptions of the agency of the nervous system in organic results, notwithstanding they are all exclu- sively due, in his estimation, to the merest chemical processes (§ 350). " Every thing in the animal organism," he says, " to which the name of motion can be applied, proceeds from the nervous apparatus." Our author, however, is entirely mistaken in his opinion that "the singular idea that the nerves produce animal heat has obviously arisen from the notion that the inspired oxygen combines with carbon in the blood itself." Nevertheless, we are told by our author that " every thing in the animal organism to which the name of motion can be ap- plied proceeds from the nervous apparatus;" and we are also told that without this motion there can be no animal heat (§ 350, nos. 3, 17i 6, 7, 18i, 19). But, take the ordinary construction of those who mingle together, but virtually contradistinguish, the powers and processes of living and dead matter, and impute to the nervous influence no small share, along with chemical agencies, in the production of heat and other products of the living organism, we are asked to sanction one of the most un- philosophical and incongruous medleys of powers, processes, laws, and principles, acting and reacting upon each other, that ever pre- sented itself for well-merited satire. The nervous power is also apt to be regarded by the chemico-vitalist, as by the chemist, a mere chemical agent. But, we shall have seen that this construction is en- cumbered with difficulties (§ 222, &c, 451 f, 500 n). 446, d. The modifying influence of the nervous system upon the generation of animal heat being established not only by experiments, but especially, also, by facts relating to morbid states of the system, to which I shall soon advert, and by all that is philosophical in physi- ological science ; and when we consider, also, how easily and rapidly the nervous influence may be determined upon the vascular system (as in blushing), and upon the organic viscera, we have an intelligible explanation of the operation of a very low degree of cold in recall- ing into action those vessels upon which depends the exaltation of temperature in the torpid hibernating animal (§ 441 d, 44l£ a). That the intensity of the cold, like the mechanical irritant (§ 441, c, d), op- erates, also, in a direct manner, upon the organic properties, as in other instances of foreign agents, is undoubtedly true (§ 189). The law being also universal, explains the influences of other causes, in health and disease, in modifying animal temperature, and only regards the agency of respiration, like that of digestion, &c, as being instru- mental in perfecting the blood, and thus adapting it to the uses of the various organs which are concerned in the elaboration of heat and other products. 447, a. Whatever is true, in a fundamental sense, o£ the production PHYSIOLOGY.--FUNCTIONS. 265 of heat in the natural state of the organic being, must be equally so in its morbid conditions. It is true, we are told by " the Reformer," that " we cannot investigate the laws of life in an organized being which is diseased ;" but we have seen that this will not hold in experience or philosophy (§ 303|). It serves, however, its useful purpose in the chemical doctrine of animal heat. But, since the truth is just the re- verse (§ 160, 163), I shall present from the Commentaries, in this sec- tion, a series of facts which contribute an important light upon the physiology of calorification, and upon the general constitution of or- ganic beings. We shall learn yet farther, by this demonstration, that the evolution of animal heat is exactly on a par with all other organic products, and has a corresponding dependence upon decarbonized blood, and can be regarded in no other aspect (§ 764, c). And here our author's philosophy is consistent, since he imputes alike the for- mation of animal heat, and all other products, even the circulation of the blood, nay, all diseases, yea, death itself (§ 350, no. 46), to the union of oxygen gas with the elements of food. 417, b. Indeed, it cannot be too often said, as shown by the ques- tion before us, that the phenomena supplied by diseased conditions are often the most important in illustrating the properties and laws of organic beings; and upon no question have they a greater bearing than the one under consideration. Morbid states are only physiolog- ical changes, and the resulting products and phenomena are simply modified conditions of such as are more natural, and are dependent upon the same laws, the same causes, the same functions as deter- mine the healthy results (§ 155, 156). This is an undeniable propo- sition. In the conflict of doctrines, therefore, which are predicated of the perfectly natural phenomena, we should seek for the light of such as emanate from diseased conditions; and here the chemist is even more disqualified for investigation than in the dark mazes of physiology. To him, the vast field of pathology, which every where stamps with falsehood his chemical views of life, is as hidden as undis- covered regions; and since all pathological and therapeutical conclu- sions necessarily refer to the natural physiological conditions, their impracticability, absurdity, and destructiveness, when deduced from the chemical premises, as clearly demonstrate the shallowness of then foundation. The student of organic nature, therefore, appreciates, as he deplores, the ignorance which is received as the light of knowl- edge (§ 349, d). 447, c. It should be considered, also, in respect to the vast differ- ences in temperature that spring from morbid conditions, whether high or low, the diet is often the same, very spare, or when the tem- perature is most exalted, as in active forms of fever and inflammation, there is a total abstinence from food. Consider, also, the brute ani- mal under the same circumstances, abstaining totally, yet suffering a very exalted temperature (§ 440, nos. 1, 4, 5). I shall proceed, therefore, to a statement of some of the important facts which are supplied by disease, as set forth in my former Essay on Animal Heat. For the authorities quoted, see the Essay. 417, d. Diseases of the brain supply a variety of facts which illus- trate our inquiry. Thus, in phrenitis, one arm, or one side of the body, is colder than the other. " That the temperature of a paralyzed part is generally below the normal standard is now universally admit- 266 INSTITUTES OF MEDICINE. ted." That this is owing to impaired vitality, is also shown by the frequent failure of nutrition in the paralyzed part, as well as other co- incident phenomena. In a case related by Mr. Earle, he found the temperature at 70° F., in the hand of a paralyzed arm, while that of the opposite hand was 92°. He could also effect a temporary res- toration of temperature by electricity and by blisters. " The circula- tion of the blood did not appear to have suffered, the pulse at the wrist being synchronous, and equally strong with that of the other limb." In an injury of the sympathetic nerve, Chaussat saw the temperature fall from 104-88°-to 78-8° F., in ten hours. On the other hand, there is a remarkable exaltation of temperature in a part at the invasion of tic douloureux. So, when the nerves are mechanically injured. There was a patient at St. George's Hospital, whose temperature rose 11° F., in consequence of an injury of" the spinal column; and this took place when the respirations did not ex- ceed five or six in a minute. It is stated by Dr. Macartney and other observers, that when the principal nerve of an extremity is divided, the temperature of the limb is immediately exalted several degrees, The philosophy of this is well expounded by an advocate of the chem- ical doctrine. "We should be disposed," he says, "to regard it as due to the temporary excitement of the molecular changes by the ir- ritation produced by the section of the nerve, and propagated to its extremities." Now apply this language to the exaltation of tempera- ture in any inanimate substance, however produced, and we may ap- preciate the merits of the chemical solution in the former instance. " In some subjects of insanity," says Dr. Cox, of Fish Ponds, "who were under strong coercion in the horizontal position, with the head much elevated, whose face was red, and the vessels turgid, the differ- ence of heat was very obvious, varying 10, 12, and even 15 degrees." In apoplexy, the temperature has been known to rise, after death, a number of degrees above the natural standard; and its persistence has been found so uniform in apoplexy, that Dr. Cheyne regards it as a diagnostic symptom. The temperature of a lawyer, dead of apo- plexy, was so high at twenty-four hours after death, that Portal delay- ed an examination of the body. The same phenomenon is observed after death from other diseases,—especially when the nervous system has been unusually concerned in the morbid process. " In opening bodies at the Hotel Dieu," says Bichat, " I have ob- served that the time in which they lost their animal heat was very va- riable ; that a body continues warm a greater or less time, especially among those who have died suddenly of an acute affection, in the par- oxysm of an ataxic fever, for example, or by a fall; for those who die of a chronic disease, lose almost immediately their caloric. The difference in the first is often three, four, or even six hours. This phenomenon arises from the fact, that whenever death is sudden, it interrupts only the great functions; the tonic action of the parts con- tinues for a greater or less time after. Now this action disengages a little caloric from the blood that is in the general system." " When the disengagement of caloric has ceased in the body, that which re- mains in it becomes in equilibrium with that of the external air, ac- cording to the general laws of this equilibrium. Now these laws be- ing uniform, their effect would be the same in every case." Again, sometimes the temperature in apoplexy is greatly depressed PHYSIOLOGY.--FUNCTIONS. 267 before death takes place; and this, too, while the circulation is such as to admit of blood-letting. Two cases of violent apoplexy (" vio- lcnto paroxysmo") are recorded in the Ephemendes ^ermanlli m which the blood, as it flowed from the veins, was actually cold. Mor- gagni mentions an instance of another affection m which the blood flowed " in an icy cold stream" from the arm. Thackrah saw a sim- ilar phenomenon. So, also, De Haen. I need scarcely say, also, that when respiration is extremely labored and slow in apoplexy, the nat- ural temperature is often either undiminished or considerably exalted. Our familiarity with the fact, however, only increases its importance, and shows, by the frequency of the coincidence, that respiration can be only remotely concerned with the generation of heat. Here is another variety in apoplectic affections: " While a gentleman," says Mr. Hunter, " who was seized with an apoplectic fit, lay insensible in bed, covered with blankets, I found that his whole body would, in an instant, become extremely cold in every part, continuing so for some time; and as suddenly would be- come extremely hot. While this was going on alternately, there was no sensible alteration in his pulse for several hours." Here is another case, from the same observer, not less fatal to the theory of respiration : " A man fell from his horse, and pitched on his head, and produced all the symptoms of a violent injury. There was concussion, and per- haps extravasation of blood. The pulse was at first 120, but came to 100, and sometimes to 90, and was strong, full, and rather hard. He was very hot in the skin, but breathed remarkably slow, only half the common frequency." Other injuries exalt the temperature in other modes of an equally vital nature. Thus, extirpation of the kidneys through the increased stimulus of the blood, often raises the temper- ature of the body more than six degrees. The following case, by Mr. Hunter, also, seems also to have been inter.ded for our special purpose : " February, 1781, a boy, about three years old, appeared not quite so well as common, being attacked with a kind of shortness of breath- ing in the night. It had become excessively oppressive about five o'clock on Sunday morning, so difficult that he appeared dying for want of breath. The common rate of breathing in such a boy is about thirty inspirations in a minute. At 10 o'clock, he was drawing his breath with a jerk,—about two and a half inspirations, or even less, in a minute. Pulse sixty, faint, slow. On tying up the arm, the vein did not appear to rise in the least, so that the blood did not go its round. Body purplish, especially the lips. He had a fine warmth on the skin all over the body, although in a room without afire,—-not covered with more clothes than common in the month of February, with snow fall- ing at noon."—Hunter. This, and the preceding case, appear to differ in some physiolog- ical details. In the former, the disposition of the capillaries to gener- ate heat seems to have been a good deal determined by the cerebral influence; in the latter, the alteration of the vital forces was probably owing to other causes. Like other cases, therefore, which I have re- cited, they serve, by their variety, to illustrate the vital nature of the principles which are mainly concerned in the production of animal hear But, standing alone, they must either subvert the hypothesis 268 INSTITUTES of medicine. which concerns respiration, or we must have a chemical theory for the natural state of the body, and a vital one for its morbid conditions. This would be clearly absurd; at least, if there be any such thing as philosophy, or any consistency in the powers and functions of life. These examples show us, also, how very probable it is, that all our chemical hypotheses in relation to life are the mere offspring of habit, or imitation, or of narrow observation. It is certainly hard to give up the fruit of great toil and research; but it is harder for others to endure it, who prefer to be instructed by the voice of nature, rather than by artificial results.* I shall present other examples to the foregoing effect, as supplied by morbid conditions of the system; since these, more than experi- ments, conduct us to the true philosophy of animal heat. Every physician is familiar with the variations of temperature in disease ; which, indeed, engage his attention in almost every case. It is often exalted when respiration is slow, and again depressed when breathing is hurried ; and it is one of the most common phenomena to find it different, by many degrees, in different parts of the body, and under every variety of respiration and circulation. It will, there- fore, be my purpose only to mention a few of the more unusual in- stances. Dr. Philip has known the temperature of the skin at 74° Fh. in the cold stage of an intermittent, while in the hot stage it rose to 105°. Craigie found it at 107°, and 109°. Here the respiration and circu- lation are often most accelerated during the cold stage. This, with the vast difference in temperature, refers the depression of heat to other causes than the mere constriction of the capillaries in the cold stage. Here, too, as in all analogous cases, we have a coincident diminution of all other secretions. Piorry has seen the temperature in six cases of typhoid fever varying from 108° to 117°; and in one of these, the blood was at 113° Fh. In phthisis, he has known it at 114°, and in a case of pneumonia, the blood was 113°. Prevost found the temperature of the body at 110° in tetanus. Granville says it sometimes rises in the uterine system to 120° Fh., and that it de- pends on the degree of action in the organ. In hydrophobia, where respiration is probably always accelerated, Currie found that "there was no increase of animal heat in any one of five cases." " The Reformer" says that, "for a given amount of oxygen the heat produced is, in all cases, exactly the same ;" and that " the consumption of oxygen in equal times may be expressed by the number of respira- tions" (§ 440, no. 5 ; 441, b). But, in stating this, he did not reply to the following interrogatories propounded in my former Essay. Thus: How is the natural temperature maintained in consumption, where res- piration is sometimes so greatly impaired as not to be compensated by any acceleration of its movements 1 Or why is it, when the lungs are impervious from condensation, and their function otherwise great- ly impaired by destructive ulceration, the heat rises habitually in the afternoon, even to 114° Fh., and that, too, without any previous re- duction of temperature, and often without any increase of respiration ] * I commend, also, to our minute philosophers Mr. Hunter's experiment upon the carp. It was partly intended to illustrate a vision of our author, by which, as he says, " like other schemers, he thought he should make his fortune." But our author had not only the good sense to abandon it, but the magnanimity to hold it up as a weakness of the human un- derstanding. > PHYSIOLOGY.--FUNCTIONS. 269 Why do the palms of the hand " burn" when the rest of the surface is cool'f Will chemistry explain 1 Will it explain, also, at the same time, the analogous phenomena, and the vicissitudes of heat and cold, the quick transitions from one to the other, that are forever perplex- ing the physician in his treatment of continued, remittent, and inter- mittent fevers 1 Will chemistry maintain, in conformity with its doc- trine, that these periodical evolutions of heat are due to paroxysmal combustions of the tissues, especially where little remains to undergo the process, respiration obstructed, and yet a high exaltation of tem- perature 1 Explain, I say, all this in conformity with the " oxygen and fuel" system, and vitalism will surrender to the devices of human ingenuity. Why is it, that when the general temperature of the body is at some 85° Fh., it may exist at the scrobiculus cordis at 106° and up- ward 1* Mr. Malcolmson states, that in the Asiatic cholera, " the skin is sometimes colder during life than after death, and a partial rise of temperature over the trunk is frequently a fatal symptom." I have witnessed the same phenomena. Mr. M. also observes, that beriberi supplies analogous instances; and that when the temperature was extremely reduced, " it was not different when the limbs were closely wrapped in woolen, or when the thermometer was held between the soles of the feet or hands, and free evaporation carefully prevented." Is it not obvious, in these instances, that the power of generating heat was lost in consequence of modified vascular action; and if so, then the generation of heat depends upon vascular action, and is, of course, a vital product. This, too, is most emphatically shown, in the instan- ces here and elsewhere stated, by the "partial rise of temperature over the trunk" just antecedently to death. It is analogous to those cases in which profuse perspiration breaks out in syncope, or as pa- tients are in the act of expiring. It grows out of a powerful impres- sion determined upon the vires vita, by which a sudden change of action is induced in the elaborating vessels. Why is the temperature often exalted in congestions of the lungs, " where life is endangered by diminished communication with the air;" and why, in such a case, will " the abstraction of blood dimin- ish the power of producing heat,"t although, by this means, we ex- tend the communication of the lungs with the air? Or, ao-ain, in congestions of other organs, when the respiration is natural, the cir- culation in the lungs unobstructed, but the animal heat greatly re- duced, why does it happen that the abstraction of blood will at once exalt the temperature, without affecting the respiration, or even in- creasing the force or frequency of the general circulation (§ 961, d) 1 In the latter cases, the rationale appears to be, as I have endeavor- ed to explain in my Essay on Blood-letting, that a direct change is exerted by the abstraction of blood upon the instruments of all vital actions, by which the calorific, as well as other functions, are improv- ed or restored. It is here, animating these minute vessels, that we shall find the principles residing, by which we are to account for all the remarkable phenomena of animal heat. As the operation of these forces is modified, whether by natural or artificial causes, so will be the phenomena which depend upon them. This is universally true * See my Letters on the Cholera Asphyxia, and other authors upon this disease. t Edwards, on die Liflueuce of Physical Agents on Life, p. 275. 270 institutes of medicine. of all the manifestations of the organic forces, whether they consist of vital phenomena, or of material products. The function of respira- tion is just as much concerned with one as with the other, and prob- ably no more. It ai;ds, like the chylopoietic viscera, in perfecting the great material from which bile, urine, the gastric juice, &c, are elab- orated by the vital properties and their instruments. And just so is respiration concerned in the production of animal heat. Again, " sympathy," says Bichat, " as we know, has the greatest in- fluence upon heat. According as this or that part is affected, there is disengaged in others more or less of this fluid. How does all this happen 1 In this way : the affected organ acts sympathetically on the tonic forces of the part; these being raised, more caloric than usual is disengaged. It is precisely the same as in sympathetic secretions or exhalations. Whether the vital forces are raised by a stimulus direct- ly applied, or by the sympathetic influence they receive, the effect that results from it is exactly the same" (§ 1044, a, b). And again, the same accurate philosopher : " Each system has its own degree of heat." This fact was not so well known in Bichat's time as now. But it was his induction from general principles. I shall only advert to the example of the dog's nose, which is familiar to all. Hunter, however, rendered the fact sufficiently obvious;— Davy and others have confirmed it. Now, how exactly all this cor- responds with what is known of the vital endowments of particular or- gans. Where they are most strongly pronounced, there the temper- ature is apt to be highest, there the phenomena of organic life pre- dominate, and there it is that morbific causes make their most fre- quent and deep impressions, and develop the most exalted tempera- ture.—(See Essay on Venous Congestion, § 8, 9, in Comm., § 1045). 447, e. Finally, I come to what I consider an experimentum crucis, supplied by an able philosopher, and by one of the most able defend- ers of the chemical doctrine of animal heat. He states that great dif- ferences arise as to oxygen, during the respiration of atmospheric air: " The real causes are chiefly certain inherent differences in the state of the venous blood, which are indicated, indeed, by other physiologi- cal facts, but by none so unequivocally as by this variety in the power of altering the oxygen of atmospheric air. The first cause is a differ- ence in the degree of venosity or venalization of the blood in passing through the capillaries." The second and last " cause of diversity in the action of venous blood on atmospheric air is a difference in the proportion of coloring matter contained in the blood." Now, if the chemical doctrine have any foundation, its advocates should show that there is a greater, or, at least, as great a consump- tion of oxygen in those states of the system which are attended by an exaltation of temperature, as in the natural condition of the body. On the contrary, however, they show just the reverse of this. Thus, the high authority whom I have just quoted : " The inferior action of the blood on the oxygen of the air in its passage to the arterial state simply indicates, that it is less removed from a state of arterialization, that is, partakes less than usual of the characters of venous blood. Accordingly, the least alteration of oxy- gen invariably occurs in those febrile diseases where the circulation is much excited, and the respiration at the same time free. These con- ditions exist most especially in acute rheumatism ; and it was, there- PHYSIOLOGY.--FU NCTIONS. 271 fore, in cases of this disease that the four instances of slight action (on the air) formerly mentioned have occurred. On all these four occa- sions the blood was evidently more florid than usual, and in the in- stance where the loss of oxygen was only 0#57 of a cubic inch, the Btream from the vein was so bright, that the gentleman who opened it had at first some suspicion that he had opened the artery."* Here, also, we have, from a distinguished chemist, a philosophical resort to the modified condition of the system in disease, for an inter- pretation of the wonderful peculiarity of living organized matter in manifesting the power of generating heat. 447, f. We have thus again seen that the chemical hypotheses which immediately concern the functions of respiration are surround- ed by too many exceptions to come within the pale of nature. These exceptions meet us every where in the habitual state of the animal, and in the history of disease they become almost as multiplied as the individual cases. Here it is, that we may most successfully contem- plate the law and its operations, in the various modifications which it sustains from the influence of remote causes, and those within the body. Among the latter, are those of the mind, and the derange- ments to which the lungs are liable, both in their general and organic functions. But far more frequently, and more profoundly, is animal temperature directly exalted, or diminished, by affections of the stom- ach and of the nervous system. I need scarcely repeat, it would be absurd to have one theory to explain the phenomena of heat in health, and another in disease. It would be a violation of all philoso- phy, as well as a reckless disregard of all facts. According to the common designs of nature, there cannot be one law for the genera- tion of heat in the healthy state of the body, and another which deter- mines the exalted heat of fever and of local inflammations. While the various functions proceed in their natural manner, the evolution of heat, like the other products, remains without any radical alteration. But when the latter are disturbed in their natur-al character, the former is liable to corresponding variations, which can only be explained on the principle that the power of generating heat is as much an attri- bute of vitality, as any that may be concerned in the process of dis- ease, and that their various modifications are constantly determined by analogous causes. It is a broad, fundamental principle, that " the general phenomena of the disengagement of heat remain always the same in animals with lungs, in those without them, and in plants, all of which have an independent temperature." 447, g. Some chemical philosophers, like the able Edwards, in treating of animal heat, have called to their aid the "constitution" of animals to explain certain anomalies which defy the chemical hypoth- esis. \\re hear much about the "power of the system to generate heat," without being let into the secret in what that constitution, and that power, consist. To allow that the forces of life have a large and uniform share in the generation of animal heat, would make a repul- sive medley, in its connection with the chemical hypothesis. Now that " constitution," and that" power," are something more than ideal; something different from the organized structure ; for, in the latter case, many variable phenomena, in adults, proceed from unvarying conditions of structure. * Dr. Christison, in Edin. Med. and Surg. Journ., 1831, p. 101, 103. 272 INSTITUTES of medicine. Just so is it with all the varying conditions of animal heat. In health, the varieties are owing to peculiarities in the natural condition of the vital properties ; in disease, they arise, like all the other changes, from morbid alterations of those properties; and, if the blood sustain any want of its proper influences from defect of respiration, this will contribute toward the modifications of temperature, in the same way that it affects the other results of life, and, I apprehend, in no other. Although Dr. Edwards derives some illustrations regarding the con- nections of the phenomena of animal heat with respiration from cer- tain morbid conditions of the body, as in asphyxia from carbonic acid, syncope, the cold stage of intermittents, &c, yet it is manifest that he looks upon disease as supplying facts which it is prudent not to inves- tigate. " The question now is," he says, " what is the influence of the respiratory movements on the temperature of the body, when they are raised beyond the rate of health ] We cannot answer this inquiry by observations on the sick. The circumstances are then too complicated to admit of our deriving conclusions from them."—Op. oil. In this conclusion I do not at all agree. It is an unwarrantable abandonment of nature for the contrivances of art. Morbid conditions, above all others, give us a clew to the true philosophy. The vital properties are altered by disease, and with them there is a change in all the phenomena and results, of which the modifications of animal heat are one. Hence, it appears to me, that a very obvious "conclu- sion" may be deduced. 447, h. In respect to the natural differences in constitution that are denoted by apparently contradictory facts in relation to animal heat, they are as clearly constituted by natural modifications of the same forces, which are as much, or more influenced by other causes than by respiration ; whose power of evolving heat in young animals is great- ly and rapidly depressed by the operation of cold, notwithstanding the respiration is accelerated during the first stages of the decline of temperature; but which, again, as the same animals advance in life, acquire the power of completely resisting the same cause without the former acceleration of the respiratory movements ; " the animals thus passing from the state of cold-blooded to that of the warm-blooded," while in the hibernating mammalia, diminution of heat still goes on although respiration have come to a stand; or, when the cold be- comes intense, is carried to its highest pitch by the very cause which had produced its great decline; which maintain an almost unaltered state of heat when the respiratory movements are greatly accelerated by external heat, and resist equally the heat of the surrounding me- dium ; which actually abate the exalted heat of fever; which are so influenced by season, that their power of producing heat is said to be less when its production is greatest; which power " may be varied, in some, by suitable food and a graduated temperature ;" which " is gen- erally diminished in natural sleep, though modifications occur which change the relation;" which is so modified in the cholera asphyxia, that the temperature may greatly fail while respiration is accelerated, and the lungs free from congestion; or, is undiminished in asphyxia from carbonic acid, " when the respiratory movements are no longer seen ;"* or may attain, as in apoplexy, preternatural vigor after res- piration and circulation have entirely ceased. * Portal says that the heat has been known to remain very high in these cases, as in npoplexy, for many hours after death.—Sur VApop. PHYSIOLOGY.--FUNCTIONS. 273 "Constitution," then, and the "power of generating heat," mani- festly relate to the vital properties, and to nothing else. The united operation of these powers, through their instruments of action, results in the elaboration of bile, gastric juice, heat, &c, from the blood. That particular determination by which they eliminate heat, in all parts of the body, may be called a law, though it is but the joint re- sult of the vital powers, concurring in a certain manner to a specific effect. The result is variously affected by climate, season, the quality and quantity of food, stimulants and sedatives, cold or warm air ap- plied externally or to the lungs, by morbific agents, and other causes; or, as the vital properties happen to sustain peculiarities in relation to individuals, age, &c, so will the generation of heat be modified when respiration is exactly the same; and along with those modifications of heat are variations, more or less coincident, of other products. The causes are obvious from the effects. The former are few and simple ; the latter are diversified without end (§ 1047). Most of the reasoning which abounds in authors who believe animal heat to depend specifically upon respiration, or the result of a chemi- cal process, consists in reconciling difficulties by referring them to the vital powers, and sometimes to the entire exclusion of the chemi- cal hypothesis. True, they do not say vital powers. They would otherwise be non-conformists. They speak of " constitution"—" the power of evolving heat,"—yet turn into ridicule the only true philos- ophy, and the only possible thing which they themselves can mean. If they hazard the " term vitality," it " is employed for the want of a bet- ter," but " without any connection with the mystification which some- times attends its use;" while others, like Dr. Elliotson, can see noth- ing in " animal heat," "but a peculiar state only ;" and here, as in the case of " vitality," Dr. E. " adopts the common language in speak- ing of animal heat," to make the subject intelligible. It is from the blood, like all other animal products, that heat is de- rived. And since decarbonization, and, perhaps, an absorption of ox- ygen, is indispensable to the healthy performance of all other func- tions, it is doubtless important to the generation of heat; though man- ifestly less so in the latter instance, since we see the evolution of heat sometimes going on when respiration is nearly, or quite extinct- while in the cold-blooded animals it exerts but little, if any, influence upon temperature. Decarbonization of the blood, and probably the absorption of oxygen, are among the numerous processes by which its vivification is perfected, and by which it is prepared for an elabora- tion of the various animal products, and in animals of a certain consti- tution for the evolution of heat. When respiration ceases, all the most important functions immediately fail; but it is remarkable that the evolution of heat appears to be the very last. I conclude, therefore, that the elaboration of animal heat, and all other secretions, are on a par in regard to principle. It is true a cer lain proportion of latent heat may be extricated by the conversion of blood into the solid parts. But this would be counterbalanced by a corresponding change of the solids, particle for particle, into fluids. 1 Ins appears to me to be fatal to a late doctrine which imputes animal heat to this cause; as well, also, to the condensation of gases. Be- sides, what becomes of the principle of condensation where the tem- perature rises after apparent death (§ 447, d) ? Where is oxygen gas 1 o 274 INSTITUTES OF MEDICINE. 447|, a. In my former Essay I have also considered the hypothe- sis relative to the absorption of oxygen gas by venous blood, and the conditions under which it was supposed to unite with carbon, in the process of respiration. It only remains now to state circumstantially the views entertained by Liebig upon this subject. 1. " During the passage of the venous blood through the lungs, it absorbs oxygen from the atmosphere. Farther, for every volume of oxygen absorbed, an equal volume of carbonic acid is, in most cases, given out." " The globules of venous blood experience a change of color, and this change depends on the action of oxygen." " The red globules contain a compound of iron ; and no other con- stituent of the body contains iron." " The compound of iron in the blood has the characters of an ox- ydized compound." " No other metal can be compared with iron for the remarkable properties of its compounds." 2. Many "observations, taken together, lead to the opinion that the globules of arterial blood contain a compound of iron saturated with oxygen, which, in the living body, loses its oxygen during its passage through the capillaries." The last quotation is a universal theory with our author. By it "the Reformer" interprets all motion, the generation of all power in the animal body, the circulation of the blood, inflammation and fever, obesity and emaciation, the various phenomena of life, and even death itself. " The oxygen of the air and the carriers of oxygen" are all in all. The " carriers lose their oxygen during their passage through the capillaries," when a " combustion of the tissues is set up," which is the true and only cause of the principle of life, of its extinction at death, and of all the unique phenomena of the animal creation (§ 350, nos. 3, 4, 5, 7, 8, 9, 10, 15, 18, 19, 46; § 440, nos 1 4, 5, 6, 8, 9, 10, 11, 12, 14, 16). It is not, therefore, remarkable that " the Reformer" should have considered animal heat as life itself,—both the cause and effect of life (§ 441 g, 440, nos. 8, 9, 11, 12, 14, 16),—since every known process and result in the animal " machine" is due to " combus- tion." 3. " The compound, rich with oxygen (no. 2), passes, therefore, by the loss of oxygen, into one far less charged with that element. One of the products of oxydation formed in this process is carbonic acid. The compound of iron in the venous blood possesses the property of combining with carbonic acid, and it is obvious that the globules of the arterial blood, after losing a part of their oxygen, will, if they meet with carbonic acid, combine with that substance (§ 440/, no. 18, and h). When they reach the lungs, they will again take the oxygen they have lost; for every volume of oxygen absorbed, a corresponding volume of carbonic acid will be separated; and they will again ac- quire the power of giving off oxygen." "_ In their return toward the heart, the globules which have lost their oxygen combine with carbonic acid, producing venous blood; and when they reach the lungs, an exchange takes place between this carbonic acid and the oxygen of the atmosphere." " The organic compound of iron, which exists in venous blood, recovers in the lungs the oxygen it had lost; and, in consequence of PHYSIOLOGY.--FUNCTIONS. 275 this absorption of oxygen, the carbonic acid in combination with it is separated." 4. "Hence, in the animal organism, two processes of oxydation are going on ; one in the lungs, the other in the capillaries. By means of the former, in spite of the degree of cooling, and of the in- creased evaporation which takes place there, the constant temperature of the lungs is kept up ; while the heat of the rest of the body is sup- plier! by the latter."—Animal Chemistry (§ 438, b, c). 447-j, b. If, therefore, we exclude the vegetable kingdom as an im- portant element in our interpretation of organic heat, we shall have seen by this fundamental hypothesis as to the globules of blood, that there can be no doubt that the general theory of animal heat has been founded upon certain speculations relative to a limited number of red-blooded animals, and often, as we have reason to suppose, to man alone. It takes no cognizance of all those white-blooded races that possess no ferruginous globules, and therefore no "earners of oxygen gas," and whose temperature in some instances, as in the bee, approximates that of the human race (§ 444). However much a general theory may draw upon contingencies for its support, it must be universally applicable to the same combination of phenomena. It will not answer to have " ferruginous carriers of oxygen" for one class of animals, and something very different for another class, to explain what is common to both. 447, c. In the former Essay I have devoted to the questions rela- tive to the elimination of carbon from the blood, and the formation of carbonic acid, all the attention which the subject might otherwise now require; and in another section of this work an argument is present- ed to sustain my former conclusions (§ 419). In the foregoing Essay I have endeavored to show that the distinguished chemical theorist, Dr. Edwards, is right in his position, that " Carbonic acid is not formed at once, in the act of respiration, by the combination of the oxygen of the air with the carbon of the blood, but is entirely the product of exhalation."—Edwards. I there urged, that the carbonic acid evolved from the chest does not exist in the state of that inorganic compound in the blood; but that the carbonaceous matter exists in intimate union with the blood, from which it is eliminated in the form of carbonic acid gas by the joint agency of the pulmonary mucous tissue and oxygen ; the former taking the lead in the process (§ 419). The carbon of the blood is thus readily convertible into carbonic acid while undergoing that special vital process of the mucous tissue. I may quote from the Commentaries a remark which is not less extensively applicable in these Institutes. Thus: " Before going farther, I may say, that, in having employed, as I shall continue to do, the established phraseology of chemical science, I have assigned many reasons in my first volume, as I shall others in my Essay on Digestion, for believing that every product of the ani- mal system, including the excrementitious, is differently constituted in its elements from such as result from the agency of chemical forces; that, what we may find in our test glasses and crucibles has been really different before, or at the time of its elimination from the body. Chemical changes may accrue in excrementitious substances immediately after their elaboration; and the ultimate combination 276 INSTITUTES OF MEDICINE. may be uniform, especially where, as in carbonic acid, only two ele- ments are ultimately concerned."—Med. and Phys. Comm., ut cit. Although our author, while employed about the chemical rationale of organic products, speaks of them as though they were generated by the living organism as he is accustomed to observe them in the laboratory, and looks upon carbonic acid as equally the product of the organization as of the combustion of carbon (or, in his own lan- guage, "the animal body acts in this respect as a furnace which we supply with fuel," § 440, no. 1), he now and then yields to the force of facts, and even allows, at one time, that the iron of the red glob- ules exists in the state of an "organic compound" (no. 3, this sec- tion). 447£, c. It is also important to consider that the absorption of oxy- gen from the air, and the excretion of carbonaceous matter, take place through a highly organized tissue, and the moment life ceases, so also do these processes, notwithstanding artificial respiration. The same tissue, too, which performs those functions, secretes, also, a mucous fluid. This secretion being distinctly the result of vital action, it will hardly be insisted that the same tissue is simultaneously performing, in respect to another product, a mere chemical, or the physical func- tions of endosmose and exdosmose (§ 419). There is here the same in- congruity as we have seen of the chemical theory of digestion, in es- tablishing antagonizing processes for the conversion of food into chyme (§ 358, 360, 374). 447^,/. It remains now to notice, of the foregoing quotations (§ 447^- a, nos. 3 and 4), another of those extraordinary mistakes in fun- damental principles, and where pure chemistry is concerned, which so much abound in our author's work on Animal Chemistry. In the first place, we had been told again and again, that " animal heat is produced by the combination of oxygen with carbon or hydro- gen," and in no other way (§ 440). That is the combustion theory, and without it there is no animal heat (§ 440, no. 6). By referring, however, to § 447£ a, 2 and 3, it will be seen that oxygen does not unite with any combustible substance in the process of respiration, but only with an oxyd of iron; and that in no. 4, it is asserted that by this supposed union of oxygen with iron " the con- stant temperature of the lungs is kept up, in spite of the degree of cooling, and of the increased evaporation which takes place there.' " Hence" says Liebig, "in the animal organism, two processes ofoxy- dation are going on ; one in the lungs [the union of oxygen with an "organic compound of iron"], the other in the capillaries [the union of the absorbed oxygen with carbon, &c.]. By means of the former, tn spite of the degree of cooling, and of the increased evaporation which takes place there, the constant temperature of the lungs is kept up; while the heat of the rest of the body is supplied by the latter."—Liebig. The general concurrence, even of chemists, in the foregoing expo- sition of the laws of animal heat, can alone justify any farther com- ment. But the work must be efficiently done to operate as a perpet- ual barrier to the pernicious invasions of chemistry. I say, then, in whatever aspect the foregoing statement may be re- garded, it is deeply discreditable even to chemical philosophy. In the first place, a distinct chemical provision is made for the " lungs' and for " the rest of the body," respectively, for the maintenance of PHYSIOLOGY.--FUNCTIONS. 277 the same uniform temperature in all the parts, while it is assumed that the union of oxygen with the iron of the blood is exactly equiv- alent as a source of heat, and under all circumstances, to the union of oxygen with carbon and hydrogen in the process of combustion; without regarding the auxiliaries, " clothing," " laborious efforts," " cold water," &c, which are brought to the aid of the chemical pro- cess in " the rest of the body." But that is not the worst of the doctrine ; for it denies to the lungs any participation in that combustive process which is not only the foundation of animal heat " in the rest of the body," but of every re- sult which appertains to life. Chemistry, of course, abandons the ground ; but it must carry with it a mortification which is due from the physiologist (§ 350, mottoes a, b, c, d, e), and a farther recognition of the justice of the rebuke administered by Hunter (§ 350, no. 95). It will have been seen, however, that the foregoing is only one of a constant succession of blunders whenever the chemist trespasses upon organic life. And were we to look yet farther into the last of the series, it would be found laden with objections. The physiologist, for example, has a right to insist that the general doctrine shall apply as well to the lungs as to the " rest of the body," and that there is an equal combustion of both. The chemist, therefore, necessarily places the temperature of the lungs at 196°, in making the union of oxygen with the iron of the blood equivalent to the combustive process. And having thus rectified the hypothesis, we find ourselves presented with a fundamental auxiliary to the general principle, that its integrity may be preserved in the lungs, which are beyond the reach of" clothing," while the surface of the body, which is more exposed to the operation of cold, is left to the general principle supported by the contingencies of dress, along with those other provisions, " food," " laborious ef- forts," " candles," Sec, that are designed for the maintenance of the same temperature in " the rest of the body" which is accomplished by the two chemical processes in the lungs (§ 440, nos. 10, 11, 12, 13,14). While now adverting to the subject of carbonic acid in its supposed relation to animal heat, I will place in contrast two doctrines by our author, which make up a part of his system of pathology, as the best evidence I can offer, in parting forever with Organic Chemistry, of the sincerity of the motives which have governed the demonstrations I have endeavored to make in behalf of sound philosophy, the honor of my profession, and the best interests of man (§ 1 b, 350±, 376f b, 820). Chi: mis try as founded on the basis Physiology as founded on the ba- of" Experimental Philosophy." sis of" Experimental Philosophy." " Vie find, in point of fact, that "If we consider the fatal acci- the living blood is never, in any dents which so frequently occur in state,saturated with carbonic acid; wine countries from the drinking that it is capable of taking up an of what is called feather-wine, we additional quantity, without any can no longer doubt that gases of apparent disturbance of the func- every kind, whether soluble or in- tion of the globules. Thus, for soluble in water, possess the prop- example, after drinking efferves- erty of permeating animal tissues, cing wines, beer, or mineral wa- as water permeates unsized paper. 278 institutes of medicine. ters, more carbonic acid must ne- This poisonous wine is wine still cessarily be expired than at other in a state of fermentation, which is times. Less, however, will be increased by the heat of the stom- given out after the use of vat and ach. The carbonic acid gas which still wines, than after Champagne." is disengaged, penetrates through —Liebig's Animal Chemistry. the parietes of the stomach, through the diaphragm, and through all the intervening membranes, into the air- cells of the lungs, out of which it displaces the atmospheric air."— Liebig's Animal Chemistry (§ 350, nos. 24, 43). 448, a. The main objection to the vital doctrine of animal heat, or that which places it on the common ground of secreted products, seems to have arisen from a difficulty of comprehending the manner in which heat can be generated by any process than such as has been most familiar to the senses. The objectors, however, have no diffi- culty in assuming that the " nervous power governs the chemical for- ces in the formation of animal heat." This admission of the instru- mentality of the nervous power is founded upon certain irresistible facts which chemistry cannot appropriate, and goes very far in allow- ing the force of analogy which refers the production of animal heat to the same great principles of life that are known to preside over all other products of animated beings. 448, b. But, is there any stability to the doctrines which relate to the evolution of caloric in the inanimate world 1 None at all. Even Lavoisier's hypothesis is overthrown. "A new theory is, therefore," says Turner, "required to account for the chemical production of heat. But, it is easier to perceive the fallacies of one doctrine, than to substitute another which shall be faultless, and it appears to me that chemists must, for the present, he satisfied with the simple statement, that energetic chemical action does, of itself, give rise to increase of temperature."—Turner's Chemistry. 448, c. Let us now borrow from the same distinguished chemist, an example by which the foregoing statement is sustained, and which will remove all difficulty as to the problem that animal and vegetable heat are elaborated by the organic force through the instruments of vital action, according to the other products of organic beings. Facts will receive their proper interpretation, an important analogical in- duction will remain inviolate, while the uniformity of other secreted products, coinciding with the uniformity of temperature, or each va- rying together under the same vital influences, expounds the latter phenomenon and corroborates the vital interpretation. Thus, Turner: " It is a well-known fact, that increase of temperature frequently attends chemical action, though the products contain much more insen- sible heat than the substances from which they were formed. This hap- pens remarkably in the explosion of gunpowder, which is attended by intense heat; and yet its materials, in passing from the solid to the gaseous state, expand to at least 250 their volume, and conse- quently render latent a large quantity of heat."—Turner. 448, d. Now, although it be allowed that phenomena of the fore- going nature may have been explained by supposed differences be PHYSIOLOGY.—FUNCTIONS. 279 tween specific and latent heat, they show us that heat exists, and is developed, under different conditions; and to expound the variety of results in the mineral world, it has been necessary to multiply yet farther the natural states of caloric (§ 448, e). 4 48, c. As showing farther, also (c), that there is some obscurity attending the phenomena of ordinary combustion, I may quote the high authority, Dr. Kane, to that effect, who says, that, " Laying aside altogether the attempt at deducing the phenomena of combustion from any change in the amount of latent or specific heat in the bodies which enter into combination, it remains only to be admitted as a general and independent principle, that chemical com- bination is a source of heat and light. It is, however, impossible to arrest inquiry at that point; and, accordingly, the speculations of phi- losophers have been directed, in seeking a cause for the phenomena of combustion, to the disengagement of electricity," &c.—Kane's Elements of Chemistry, 1841. 448, f. Now, however it may be that the results are the same in the inorganic world, upon the theories either of caloric or electricity, the remarkable differences in views in that respect show the difficul- ties which chemistry must encounter when it approaches the philoso- phy of organic heat; and this, especially, when we consider the vital nature of the development of electricity and light in living animals. —(See Medical and Physiological Commentaries, vol. i., p. 107-119.) The physiologist undertakes no explanation of the modus in which organic heat is elaborated. He avoids all inquiries of that nature, although he might proceed to interrogate the manner in which the vital principle operates with as much propriety as the chemist " spec- ulates upon the cause of the phenomena of combustion." But, in do- ing this, he would trespass upon inscrutable difficulties, and encumber philosophy with useless hypotheses. 8. GENERATION. 449, a. The eighth and last great function common to animals and plants is generation. This function, being alone designed for the per- petuation of the species, is not necessary to organic life. It is here, however, in all the processes that are connected with the formation of the germ, and of semen, in the preparation of the generative or- gans for impregnation, in the moral and physical circumstances attend- ing the act of copulation, in the impregnation of the ovum, in the de- velopment and growth of the foetus, in the sympathetic influences of the uterus upon the mammae which result in the formation of milk, and in all their individual and connected designs, and in their great final cause of perpetuating the species, and in the various incidental provisions which are supplied for the fulfillment of that end, that chemistry and physics may be as effectually banished from physiol- ogy, as by the demonstrations which I have made in relation to the germ, or by those which respect digestion, or organic heat, or the nervous power. 4 49, J. What may be the extent in which the male participates in producing the offspring, it is impossible to know; probably as impos- sible as a knowledge of Creative Energy. We know, however, that the male and the female impress, alike, their own moral, vital, and physical character upon it. But the mother supplies the germ, also. 280 INSTITUTES OF MEDICINE. 449, c. In another work I have examined the merits of the old doc- trines of seminal animalcula, and their germinal character; lately re- vived along with other illusions or pretensions of the microscope. The subject is scarcely worthy a renewed discussion (§ 131). 449, d. It may be finally said, that whatever is true of the essen- tial physiology of generation, as it relates to animals, is equally so of plants. The coincidences, too, which are so striking in this function of the two organic kingdoms, remove every ambiguity which has been supposed to attend the more important functions of plants, confirm the vital character of the whole, and, with the universal analogies, re- fer the whole to the same properties of life which carry on the organic functions of the animal kingdom. It were impossible, according to the ways of nature, that a function, like generation, which depends in animals upon a vital condition of all other processes, and which is a great final cause of all those processes, should, in plants, depend on others of a different nature. By the coincidences, therefore, in the function of generation between animals and plants, I prove a likq coincidence in the vital character of all the organic functions of both animated kingdoms (§ 185). But little can be said relative to the function of generation, beyond certain important relations that have been considered, that can serve as a ground for Institutes in Medicine (§ 63-81). Its more extended consideration belongs to elementary works on physiology. II. PECULIAR, OR ANIMAL FUNCTIONS. A. Functions of Relation. 1. SENSATION. 450, a. Having distinguished three kinds or principal modifications of sensibility, namely, common, specific, and sympathetic, and as sen- sation is performed through that property, there are naturally three modifications of the function ; to wit, common sensation, specific sen- sation, and sympathetic sensation (§ 194-204, 1037 b). 450, b. The nerves are the organs of the functions, and the nervous centres the recipients of the transmitted impressions. But, it is im- portant to remark, that the parts most essential to sensation are the extremities of the nerves at their origin and termi nation, and that the trunks are, mainly, the conductors. This is also true of voluntary mo- tion, and of those involuntary movements that are excited by the ner- vous power. The nerves of the organic viscera, therefore, follow this rule, as it respects all natural, morbific, and remedial agents. A neg- lect of this consideration has led to fallacious conclusions in medicine from experiments on the trunks of nerves (§ 110-117, 826 d). 450, c. Common and specific sensation require a continuity of the nerves with the brain, and a co-operation of the mental power, per- ception. Sympathetic sensation may be excited in the brain, or spi- nal cord, or certain parts of the ganglionic system, either in their connected state, or when disconnected. In their most natural con- dition, it is probable that all the parts concur more or less together in giving rise to sympathetic sensation; though some parts more than others, according to the nature of the impressions transmitted and the part from which they are transmitted (§ 201). PHYSIOLOGY.—FUNCTIONS. 281 450, d. Common sensation appertains to all parts, and is the cause of pain. In the natural state of* the body it is inappreciable, but may be greatly roused by injuries and by disease. Its intensity will then depend upon the nature of the part and the exciting cause. It is apt to be most exquisite in parts where specific sensation is least; as in tendons, ligaments, membranous tissues, &c. (§ 198). 450, c. Specific sensation corresponds with specific sensibility. It is the function through which we acquire a knowledge of external things, and is, therefore, the great inlet of knowledge. It has, of course, the several modifications which appertain to specific sensibil- ity (§ 199, 200); consisting, indeed, of five apparently different func- tions. The expanded nerves of sense, which are the organs of this function, it is superfluous to say, are supplied with auxiliary means, Buch as the various appendages to the retina, to the auditory nerve, &c. A close analogy exists among the whole, and they may be brought more or less to the aid of each other. Although a common function, its remarkable modifications are shown by their uses, respect- ively, and by the necessity of certain specific stimuli to each. As with common sensation, the specific kind requires the aid of percep- tion. The rationale of the entire function is far more wonderful and incomprehensible than that of sympathetic sensation and its various results which terminate in the influence of the nervous power on or- ganic actions, and for which the grossest doctrines in chemistry and physics have been substituted, because the vital interpretation is " in- conceivable," or cannot be subjected to the critical inspection of that far more obscure, but acknowledged, causation in the chain of per- ception, specific sensation (§ 222-237). What can task the under- standing more than the step in the process of intellection as connected with the functions of sense; beginning with light and its properties, or wnth the odor which none but the dog can discern, or the abstrac- tions that convey to the mind all the varieties in taste, or the modified undulations of air which render so distinct from each other all the gradations of sound, from the iEolian harp to the braying of a jack- ass ; the impressions of each upon the extremities of the nerves of sense, one alone upon the eye, another alone upon the nose, and an- other upon the ear alone ; the transmission of these impressions along the trunks of the nerves to their other extremities in the brain, but in either of which no such impressions can be originally excited; their excitement of the brain and the co-operation of the mind, by which the nature of the primary impression is discerned, and the external objects realized by the inward immaterial agent according to their real material existence (§ 188£, d, 500, n) 1 450, / The common hypotheses which have been propounded to explain specific sensation, such as the motion of a nervous fluid, gal- vanism, vibration of the nerves, the passage of light, of undulations of air, &c, to the brain, betray a general disposition to avoid the phe- nomena of life for those which are manifested by inanimate objects. But, of this I have already had enough (§ 189, 234-237). 451, a. The action of material objects upon the mind through the function of sensation, and the astonishing influences of mental emo- tions upon irritability (§ 188, a), and of the will upon the voluntary muscles (§ 227, 1st, 233), bring the laws of organization and those of t*>3 immaterial mind and instinct into harmonious relation • while the 282 INSTITUTES OF MEDICINE. nature of mind and the impressions it receives illustrate the character of the vital properties (§ 450 e, and Medical and Physiological Com- mentaries, vol. i., p. 92-102). 451, b. Impressions upon the brain through the medium of specific sensation leave no transcript; and perception of objects without sen- sation, as in reveries and dreams, has led to a denial of the material- ity of the world; supported, too, by far greater ingenuity than those objections to a vital principle which are regardless of all its unique phenomena. 451, c. It has been seen that perception is necessary to sensation, in the usual acceptation of this function, which is essentially mental. This term, however, is employed to represent the cerebro-spinal im- pressions which give rise to involuntary motions, whether in animal oi organic life ; and " feeling" is used by Mr. Hunter, and others, to de- note the susceptibility of organs to the existing condition of each oth- er, by which their concerted action is maintained through the medium of the nervous system. It is obvious, however, that the mind takes no cognizance of those impressions which result in involuntary motions; no perception, no act of the will, is excited, so far as it respects the direct results. And, although there be an analogy between all the influences of sensation in animal life, it reaches least to the move- ments which spring from the nervous system in organic life, since the impressions made upon the brain through specific sensation never af- fect the organic actions ; while there is a perfect identity of effect be- tween those impressions which give rise to involuntary movements in animal and organic life.* 451, d. As the term sensation, therefore, has a very different import in the different cases; and as in one the transmitted impressions ter- minate in exciting an act of the mind, while in the other no such act is called into operation ; but differently, also, from the former case, the nervous power is excited in the nervous centres and then determined with the effect of a vital agent upon all other parts (§ 226); and since, also, the impressions through specific sensation must be exerted upon the brain, while in the latter case the results may be equally pro- nounced whether the impressions be made exclusively upon the brain or on the spinal cord (§ 473 c, no. 5), I have made a third distinction in sensibility to separate its office in the function of sympathy from its province as described under the varieties of common and specific sensibility, and to avoid the confusion which has hitherto prevailed by an indiscriminate use of the term sensation (§ 194, 199£, 201, 204, 453, 523, 1037 b). 451, e. This third distinction in sensibility, I have called sympa- thetic sensibility (§ 201); and this conducts me to a third distinction in the corresponding function, and which should be known by the same epithet (§ 464-467, 473 c, no. 5, 474, no. 4). The epithet sympathetic denotes the special function of sympathetic sensation, which has been sufficiently described in the preceding sec- tion, and in what has been said of sympathetic sensibility (§ 201-204). 451,/. The considerations made in § 450, e, illustrate the vital phi- losophy of sympathetic sensation as one of the functions concerned in the transmission of impressions from one part to another through the medium of the nervous centres, and in which the nervous power is the agent by which the reflected impressions are exerted (§ 222, &c). * If specific or common sensation affect organic actions, it is through some mental emo- tion which it excites. The mind is the efficient cause, p. 77-79, note. PHYSIOLOGY.--FUNCTIONS. 283 The facts in tho former case bear with the strongest force of analogy in demonstrating the entire absence of all chemical agencies in the phenomena of the nervous power. The alliance of the whole, through- out the moral and physical results of specific sensation, place the whole upon common ground in respect to principle ; and if it be true that nervous agency in one case is chemical, it is equally so in all, and equally so with perception itself (§ 1881, d). Other demonstrations to the same effect will be presented in another section (§ 500, n). 2. SYMPATHY. 452, a. I now enter upon the consideration of a function which be- longs not only to animal life, but has far greater and more important relations to the organic life of animals. Although it have no existence in the vegetable kingdom, where its anatomical medium is also want- ing, it docs not bestow those striking distinctions in the organic life of the two animated departments of nature which the importance of the function, and the presence of the nervous system, in the animal economy, would denote. The organic actions are essentially alike in both, conducted in both by common properties appertaining to the various tissues and organs, and only influenced through the function of sympathy in animals (§ 185). 452, b. Nevertheless, it is a function of wonderful characteristics, and can only be appreciated by an extensive investigation of its endless vari- ety of phenomena. And yet is this function extensively ridiculed by enlightened men ; and even Muller, who has written more luminously upon its laws than any other observer, applies them only in certain natural processes, considers the nervous power the actual cause of motion, construes the function of absorption according to the physical rationale, defends the hypothesis of endosmose and exdosmose in ex- tenso, interprets all the secreted products upon chemical principles, expounds diseases by the humoral pathology, and recognizes no ther- apeutical influences of medicine but through its absorption into the circulation. For all this he was well commended by the British and Foreign Medical Review, while the same critical survey of that re- markable work on Physiology stamped its displeasure upon those doctrines of life which render the work a proud monument of the age. Again, no one has employed his knowledge of the laws of sympa- thy more usefully than Bichat. " The word," he says, "is of but little consequence, provided what it expresses is understood." And yet, while he also affirms that " we know the principle exists," he also says, that the " word is only a veil for our ignorance in respect to the relations of the organs to each other" (§ 234). 452, c. Sympathy is the most important function which is peculiar to animals ; since upon it depend, very greatly, the right performance of the organic functions, and a vast range of pathological conditions, and the greatest amount of therapeutical influences. It also over- throws the venerable doctrines in humoralism, in all their contempla- tions of vitiated blood, morbid lentor, "living putrefaction," and of those conformable therapeutical means which were invented under the significant names of incisives, deobstruents, inviscants, incrassants, diluents, attenuants, astringents, relaxants, refrigerants, &c. 453. Sympathy has been commonly reputed as one of the proper- ties peculiar to animals; but it is not only a function, but one of great 284 INSTITUTES OF MEDICINE. complexity, since it involves the united operation of sensibility and the nervous power. The result of that concerted action is sympathy, in its proper acceptation. All other functions correspond, respective- ly, with individual properties, as sensation with sensibility, motion with mobility, &c, though the various properties may be necessarily instrumental to each other. In the farther prosecution of this subject, I shall consider, I. The general uses of the nervous systems. II. The different orders of nerves (§ 462, &c). III. Experiments to determine the Laws of the Vital Functions (§ 476, &c). IV. The varieties or kinds of sympathy (§ 495, Sec). V. The laws of sympathy, and their application to pathology and therapeutics (§ 512, &c). I. OF THE GENERAL USES OF THE NERVOUS SYSTEMS. 454, a. The phenomena of the nervous systems (the cerebro-spinal and ganglionic), in their connection with organic processes, forcibly declare how broad is the gulf between the properties and laws of dead and living beings, and how vast, magnificent, and profound is the science of life in its varied aspects of health and disease. 454, b. The nervous system having no existence in plants, has giv- en rise to the fundamental distinction of " animal and organic life" (§ 96-123). 454, c. The cerebro-spinal system appertains particularly to the or- gans of animal life, though it contributes largely to the organic viscera (§ 111-117). The ganglionic system is universally appropriated to the organs of organic life, and pervades every part of the animal; since organic actions are carried on as well in the organs of animal life, as in the organic viscera (§ 115). 455, a. The great final cause of the brain is to subserve the intel- lectual powers in man, and instinct in the lower animals (§ 241, 454 b, 500 p). But, reason and instinct would avail but little, were their op- erations circumscribed by the limits of their organ. Hence the brain is prolonged into nerves, and various connections are thus established with all parts of the body, and with the external world. Admirable as is this Design of associating in harmonious action the immaterial with the material parts, it would still be defective, and the economy of nature obviously violated, were not an organ so prominent in the animal mechanism rendered subservient to the great purposes on which its existence depends. Therefore that other system, the gang- lionic, has been established, with intimate connections with the cere- bro-spinal ; while the brain itself contributes nerves directly to the most important 6f the organic viscera. The principal relations to the great final cause of the brain are determined by direct prolongations of the organ to the different parts of animal life ; but those which are more especially designed to answer its secondary uses belong to the- ganglionic system, which binds together, in harmonious action, every part of the complex organization^ and influences the organic functions of every part (§ 129, 523, 1058). 455, b. It appears, therefore, that one of the great secondary uses of the cerebral system is that of co-operating with the ganglionic in PHYSIOLOGY.--FUNCTIONS. 285 establishing a circle of sympathies among the organs of organic life, and preserving the whole in that harmony of action that is indispensa- ble to the life of complex animals. 455, c. Thus we learn that the various parts of the organic mechan- ism of animals are not only indispensabio to each other, but that a cer- tain established influence of one upon the other is necessary to each, and that the functions of the whole may be fatally deranged, either directly, by causes that may interrupt the common chain by which the relations are established, or indirectly, as by a blow on the stomach, or by poisons acting upon some part of the intestinal mucous tissue, or by withdrawing some particular organ from the symmetrical whole (§ 109, 129). 455, d. Whatever, indeed, may affect the powers and embarrass the functions of the cerebro-spinal system, will more or less disturb this con- cert of action, may modify the functions of every part, and may derange the whole series of vital phenomena. The nature of the disturbances will depend entirely upon the nature of the impressions produced upon the nervous systems, as well as upon the rapidity and violence with which the impressions are made. Direct injuries do it in one way, and according to their nature and extent. Morbific, or other causes, acting upon other parts, affect the nervous centres, and consequently give rise to remote derangements1, in other ways, according to their nature, and the violence with which they operate. Medicines do the same thing, and according to their nature, their dose, and according to the nature of the part, as well as the existing state of the part to which they are applied, or that of other parts upon which they may act sympathetically. New circles of sympathy, however, in all these cases, are liable to spring up, and that, too, in rapid succession (§ 222- 233^, &c.). 455, e. The same laws, precisely, are concerned throughout. We do not, however, witness the same demonstrations of sympathy in health as in disease, or as when remedial agents operate ; since, in the nat- ural state of the body, the nervous influence is more or less in equilib- ria ; operating uniformly and equally on all the organic viscera, and thus maintaining among them one concerted, harmonious action. But this power being constituted with the greatest sensitiveness to the va- rious conditions of all parts, that it may transmit the existing condition of each one to the whole (as strikingly seen in the almost instant inter- change of function between the kidneys and skin, on the contact of cold air, &c, § 422), it necessarily happens that when the state of any one part is varied from its natural standard, that part will transmit an unnatural influence to the brain and spinal cord, will develop the ner- vous power in an unnatural manner, and thus produce disturbances in other parts (§ 350, no. 19). The alterative influences, therefore, of morbific and remedial agents necessarily result from the natural phys- iological laws of the nervous power in connection with the instability of the organic properties, nor can it be otherwise. The principle is absolutely ingrafted upon the constitution of animals. 455,/ I say, therefore, that when unusual causes operate, whether upon the nervous centres or upon remote parts, they necessarily de- velop the nervous power in greater intensity than it exists in health; when it is reflected abroad upon various organs, and with the greatest variety of effect. The parts upon which it may fall will depend upon 286 INSTITUTES OF MEDICINE. their existing susceptibility and the nature of the remote causes; and the nature of the effects produced will depend greatly upon the par- ticular virtues of the morbific or remedial agents ; for it is also an im- portant law that the nervous power itself will be altered according to the particular nature of the impression which may be produced upon the part on which the agent may exert its direct effect (§ 222,' &c). 455, g. The actions which are thus influenced through the connect- ing medium of the nerves are not alone the great general functions of organs, such as digestion, the action of the heart, &c, but, also, those of their minute constitutional organization. Here it is, indeed, that mor- bific and remedial agents exert their principal effects (§ 483, &c). 456, a. In the ordinary rhythm of the organic system, however, the capillary and extreme vessels are not as dependent on the nervous influence for the precision of their functions, as the complex organs (§ 455, e). It is greatly with these vessels as with the analogous ones in plants. They have an independent function in each particular part, in the performance of which no assistance is wanted from each other or from other organs (§ 383, 394). And this leads us to observe the reason of the absence of a nervous system in plants, while it is more or less necessary to animals. The vessels go up continuously from the roots to the leaves, and continuously back again, and there are only vessels; no complex organs. Each part of a plant has within itself an organization adequate, or nearly so, to its independent exist- ence. It is otherwise, however, with animals. Here, other essential parts are superadded to the simpler mechanism, are made dependent on each other, and a certain correspondence of action rendered ne- cessary to the integrity of the whole. For the fulfillment of these ends the nervous system is also superadded, with its wonderful attri- bute, the nervous power, that a perpetual change of influences shall be maintained among the great organic viscera (§ 222-233). But not so with the capillary vessels, since the functions of these may go on independently of the nerves, nor is a consent or correspondence of action among them at all necessary (§ 257, 233). 456, b. Slight influences, however, upon the nervous centres will determine the nervous power, with a very manifest effect, upon the capillary and extreme vessels, as seen in blushing, and in the experi- ments by Philip (§ 227, 477, &c.); and coming to the ordinary oper- ation of disease, and of morbific and remedial agents, we have con- stant demonstrations of the great susceptibility of these vessels to the action of the nervous power, and of strong reciprocal sympathies among them (§ 394, 1040). 457. One of the most striking peculiarities of the ganglionic system is that of its not transmitting the influences of the will to the organs which it supplies, notwithstanding it is so intimately combined with the cerebro-spinal nerves; while, on the other hand, the passions op- erate more powerfully through the ganglionic than through the cere- bro-spinal nerves (§ 476 c, 500 e). This fact shows us, at once, that the sympathetic system must have certain special functions; and when we trace out its anatomical con- stitution, and its distribution to the essential parts of organic life, we perceive that its special office must be that of maintaining a harmony of actions among these parts; and experimental observation confirms this induction. Nevertheless, from the exquisitely delicate nature of PHYSIOLOGY.—FUNCTIONS. 287 this high office the nerve is rendered intensely susceptible, and from the intimate manner in which it pervades the organic tissues, it is made to exercise a certain, but scarcely appreciable, influence upon their organic actions (§ 456 b, 1040). 458. The relations of the cerebro-spinal and ganglionic systems to each other, their special or mutual functions, and those of individual nerves, all having their distinct individuality, yet all more or less re- lated and concurring in harmony, and for important purposes in ani- mal and organic life, supply the most complex and astonishing in- stances of Design to be found in nature; and their natural attributes, existing under the most absolute laws, afford a ready interpretation of the endless phenomena of remote sympathy, as the result of disease, or of morbific or remedial agents. 459, a. All parts of the nervous centres are not only more or less mutually connected in function, but all parts of the nervous system are subordinate to the brain. There are no distinct, separate, and independent influences, of an involuntary nature, exerted by any parts of the nervous systems in their state of integrity. They all con- cur more or less together. This is experimentally demonstrable, as well as denoted by the natural phenomena. If, therefore, it should appear from experiments upon the spinal cord, for example, while connected with the brain, through any remaining communications, that the influences are determined by the cord alone, we may be as- sured that the brain has participated (§ 201, 473, 481, Exp. 15). 459, b. I have said in my Essay on Bloodletting (in Med. and Phys. Comm.), that the injuries which are inflicted on the spinal cord, to determine the specific functions which have been assigned to it, are so severely propagated to the brain, and may so affect the prop- erties of that organ, that the results which appear to flow from the spinal cord may be actually due to the cerebral influence, or to an in- terruption of that influence when the spinal cord is divided or de- stroyed. Both principles, in the latter case, may act in co-operation; the cerebral influence being determined through the superior nerves and the ganglionic system, and otherwise impressed by a reflected influence from below that part of the spinal cord, where its direct connection with the brain is interrupted (§ 480, c,f). V\ bile, therefore, the brain remains, experiments upon the spinal cord are entitled to much less confidence than those which are made upon the brain. But even when the brain is removed, the vital prop- erties of all parts become so profoundly modified in consequence, that we can scarcely infer with accuracy the specific functions of the spinal cord from subsequent experiments (§ 476, c). 459, c. The late experiments by Dr. Stilling, with strychnia applied to the spinal cord, are entirely consistent in their results with the fore- going remarks (b). From these experiments he supposes that the spinal cord is greatly independent of the brain, and that when divided in numerous places, each portion is capable of the same influences upon the parts it may supply, as when the whole cord is in its natural state. Thus, when the small portion connected with the fore-legs is separated from the rest of the cord by two incisions, and strychnia is applied to this isolated part, the legs will be convulsed. Still, how- ever, there are remaining and important communications of this ap- parently isolated part with the head, and with all other parts of the 288 INSTITUTES OF MEDICINE. spinal cord, which will forever embarrass these critical inquiries, un- less there be a removal of the brain (§ 473 a, no. 2, 473 c, 494 d, 514 e). 459, d. " The experiments of M. Le Gallois," says Wilson Philip, " prove, in the most satisfactory manner, that a principal function of the spinal marrow is to excite the muscles of voluntary motion, and that it can perform this office independently of the brain, as after the removal of the brain. Yet we constantly see injuries of the brain im- pairing the functions of the spinal marrow. Of this apparent incon- sistency, M. Le Gallois justly remarks, that two facts, well ascertain- ed, however inconsistent they may seem, do not overturn each other, but only prove the imperfection of our knowledge." Now, in the foregoing case, there is no difficulty in reconciling the facts by the interpretation which I have given to the action of the will and of the nervous power. The will operates as an exciting cause to the nervous power, which then determines voluntary motion. But, the motions are never voluntary after the removal of the brain; but the nervous power pervades the whole system of motor nerves, and when stimuli are applied to the spinal cord after removing the brain, the nervous power becomes an exciting cause of involuntary motions (§ 226, 473, 500). 459, e. Every principal part of the nervous system has a certain special office which is exercised in conjunction with the whole. " The cerebrum does not act like the cerebellum, nor the cerebellum like the medulla oblongata, nor the medulla oblongata like the spinal cord and nerves. In the cerebral lobes resides the faculty by which the animal thinks, wills, recollects, judges, becomes conscious of sensa- tions, and commands its movements. From the cerebellum is derived the faculty which co-ordinates the movements of locomotion ; from the tubercula bigemina or quadrigemina, the primordial principle of the action of the optic nerve and retina; from the medulla oblongata, the motor or exciting principle of the respiratory movements; and, lastly, from the spinal cord, itself, the faculty of blending or associating into combined movements the partial contractions immediately excited by the nerves in the muscles of animal life." 459, f. Enough, however, is known to show us, that when the cere- bro-spinal and sympathetic systems exist as a whole and unimpaired, they act more or less as a whole ; but that different parts have certain peculiarities of function, and that when injuries befall any part of these great systems, a portion of the whole may perform certain cir- cumscribed functions, at least for a limited time, and often, perhaps, as perfectly as the whole apparatus in its state of integrity (§ 201, 515 a, 516 d, no. 8). Impressions, as I have said, when transmitted through sympathetic sensibility, may be received either by the brain, spinal cord, or certain parts of the ganglionic system; and either connectedly or independ- ently. But, in the natural state of the nervous system, all such im- pressions, when received especially by an individual part, are doubt- less propagated to the other parts, and institute that harmonious con- currence in all the parts which renders the whole nervous system in- strumental in determining the ultimate phenomena. This is even true of so local a phenomenon as the contraction of the sphincter mus- cles, however that contraction may be maintained after destruction of Ihe brain and of the superior parts of the spinal cord (§ 461£, a). These PHYSIOLOGY.--FUNCTIONS. 289 conclusions are warranted in experiment, and by all that is known of the dependence of the harmonious relations of organs upon the presiding influence of the nervous system. There must be harmony there as a fundamental requisite (§ 129). 459, g. In the application which I have made of the nervous power, in the present and in my former works, to the theory of disease and to the modus operandi of remedial agents, it is important to regard the whole nervous system in its unimpaired relations to its own and to other parts. 460. No experiments upon the sympathetic nerve can show that it has any fundamental agency in the organic processes; for the mo- ment any unusual impressions are made upon it, the nervous influ- ence is unnaturally excited, and determined with more or less vio- lence upon the organic properties, and thus deranges the functions. 461. It is an assumption to say that the nerves have any generating effect upon the secreted products, however probable it may be that they influence the organic processes and their results. If the prod- ucts are altered by impressions made upon the brain or nerves, it is because the nervous influence is preternaturally determined, as a mor- bific agent, upon the Organic viscera, or because the influence is with- drawn, or a violence done by interrupting the relation of parts; as when the pneumogastric nerve is divided. Such division of nerves may have all the effect of a morbific agent, producing congestion and inflammation; the very division of the nerve