, n / •^ CONTRIBUTIONS IN PHYSIOLOGY BY DR. [Communicated for the Boston Medical and Surgical Journal.] Note to the " Institutes of Medicine," <§>350.—Professor Liebig's Physiology.—In my communication of Sept. 25 (vol. 39, p. 209), I stated Professor Liebig's summary doctrine relative to all organic and animal motions; namely, that— " The cause of the state of motion is to be found in a series of changes which the food undergoes in the organism, and these are the re- sults of processes of decomposition, to which either the food itself, or the structures produced from it, or parts of organs, are subjected." That, I remarked, is his combustive doctrine of life ; and, with the exception of its palpable contradictions by other doctrines, it is carried out in all parts of his celebrated work on " Animal Chemistry." In- deed, the hypothesis is often repeated ; thus— " 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 exercise on each other. The only known ultimate cause of vital force, either in animals or plants, is a chemical process." And again—" All vital activity arises from the mutual action of the oxygen of the atmosphere and the elements of the food." I see, now, that we are presented in a work just published by the author of the foregoing doctrine (" Researches on the Chemistry of Food, and the Motion of the Juices in the Animal Body," and re-published under the patronage of English and American Professors), with the following interpretation of the same phenomena. It will be seen that it is nearly the common doctrine relative to the evaporation by leaves in explaining the circulation of sap, as propounded by Dr. Hales, and as set forth in my article referred to above. The Professor infers the prin- ciple from experiments made upon dried membranes! Having found the membranes pervious to water, oil, &c, he proceeds to say, in a letter to Professor Horsford, re-published in the American Journal of Science and Arts (May, 1818, p. 415), and which I quote for the brevity of the conclusion, that— " The employment of these results upon the processes in the animal body, scarcely requires a more detailed explanation. " The surface of the body is the membrane from which evaporation goes constantly forward. In consequence of this evaporation, all the fluids of the body, in obedience to atmospheric pressure, experience mo- tion in the direction towards the evaporating surface. This is obviously the chief cause of the passage of the nutritious fluids through the walls of the bloodvessels, and the cause of their distribution through the body. We know now what important function the skin fulfils through evaporation " ! 2 Contributions in Physiology. Now, it is hardly necessary to say, in refutation of the foregoing hy- pothesis, that it is not only founds! upon experiments upon dead matter, and ascribes all the processes of life to the merest physics, but it isolates the functions of the; skin from al! the other secretory processes, whose effect would be the same as imputed to the skin, if evaporation and atmospheric pressure were " the chief cause of the passage of the nu- tritious fluids through the walls of the bloodvessels, and the cause of their distribution through the body." The straining off of bile, urine, saliva, ha., and even of the " nutritious fluids," would be exactly the same in effect as perspiration ; for it is unimportant whether the pro- ducts escap3 into the air or go into the bladder, he. The pressure of the atmosphere, therefore, would be equally balanced throughout, and amount to nothing. That the reader may see, at a glance, how far the distinguished che- mist is also a physiologist, and for the benefit of his numerous admirers, I will close this notice with an extract from the author's work on Animal Chemistry, which, it will be seen, is near a-!rin to the foregoing. Thus—■ " If we consider the fatal accidents which so frequently occur in wine countries from the drinking of what is called feather-white wine, we can no longer doubt that gases of every kind, whether soluble or in- soluble in water, possess the property of permeating animal tissues, as water permeates unsized paper. This poisonous wine is wine still in a state of fermentation, which is increased by the heat of the stomach. / The carbonic acid gas which is disengaged permeates through the parie- tcs of the stomach [!], through the diaphragm [!], and through al! the in- tervening membranes [!] into the air-ceils of the lungs [!], out of which it displaces the atmospherical air " !!! Such is only p common example of the physiology of a most able chemist, and it derives its importance alone from the eclat with which his physiological writings have been received wherever science has been cultivated, and, I may say, wherever it has not been. The consequences, therefore, are not merely such as arise from idle words, but they seriously vitiate the whole fabric of theoretical and practical medicine. Note to $18; 42; 409; 419.—Secretion.—As p. consequence of the doctrine that the secreted fluids exist in the blood, as "constituent parts," it is assumed that they are habitually strained off (as we have seen in the foregoing extracts from Prof. Liebig), and that when an or- gan fails of i*s appropriate: ofnve, its secreted product may escape from the blood by way of another organ. "Sometimes," says Muller, "the / suppression of a secretion in one part of the body gives rise to the appearance of the same fluid in another part." And again, " The sole secretion, of which the constituents do not exist as such in the blood, but which can, nevertheless, be formed at all times and in all parts of the body, is pus; the organ for its production being generated anew in the process of inflammation." (Midler's Physiology, vol. 1, pp. 474, 475, First Eiilion.) The latter quotation is omitted in the second edition (p. 520), perhaps from the late reputed discovery of pus-globules in the natural blood; Contributions in Physiology. 3 and this eminent physiologist supposes that perfect milk cannot be elimi- nated by any other organ than its appropriate gland. There occurs, also, the following general qualification—" ](. however, the essential in- gredient of the secretion does not exist in the blood itself, the sup- pression of this secretion in the organ destined to form it cannot cause its metastatic appearance in other parts. The instances which have been adduced of such an occurrence are ill supported by proofs." And, again, he says,—" The formation of any one of the peculiar secretions, the essential proximate constituents of which do not exist in the b'ood itself, pre-supposes the operation of a spcricd chemical apjmratus, whether this be a membrane or a gland." " A part of the liquor sanguinis^ with the matters dissolved in it, is imbibed by the tissues (by endos- tnosis), by the agency of which it undergoes a chemical change." And yet he says—" The chemical process of secretion is not at all under" stood." Midler finally yields to the philosophy which about balances the cheinieal, in his great work on Physiology, and argues that—" The nature of the secretion depends, therefore, solf.ly on the peculiar vital properties of the organic substance which forms the scenting canals, and which may remain the same, however different the conformation of the secreting cavities may be; while it may vary extremely, although the form of the canals or ducts remains unchanged."—[Ibid., Second Edi- tion, pp. 429, 474, 510, 511.) Now the question arises, whether all these conflicting doctrines upon one and the greatest topic in organic life, put forth by the ablest phy- siologist of our time, can possib'y be tree; and if not, which are we to elect, the mechanical, the chemical, or the vital 1 Each one stands forth conspicuously in the work from which I have quoted. The mechanical and chemical are surrounded by conjectures, contradictions, and admis- sions of absolute igno-ance of their nature and philosophy, while the vital is alone consistent, is isolated from the others, is extensively con- cerned with the ner-o is power in animals but excludes it from plants, is expounded with adminble ability and in toial opposition to the others. Whence comes this confusion in fundamental principles and laws? Or- ganic Chemistry will supply an answer. I began this article with a view of o.Tering a single consideration against "the mechanical hypothesis of secretion, which has now become so incorporated with the chemical, that the distinction '•? not readily a p- precuhle but in instances like the present, where it is assumed that the " pioximates " are about as numerous in the blood as the secreted pro- duet-, and generally the same. Owing to the prevalence of this doc- trine we ha^e come to be qriie familiar with the tern vicarious* as i! ef- fusions of urine from the mammary gland vicarious of eeilk," &.c. Hueing exununed extensively the whole of this subject at former times, it is my ojje-ct now only to add some conclusions from a fact which ap- pears to tiie sufficiently corroborative of the doctrines of life, and op- posed 10 a'! other?. Chemical annlyses of the blood inform us that its composition in males and ice