*& ■*..^?«****' ...A .***" A LECTURE PHYSIOLOGY OF DIGESTION, INTRODUCTORY TO A COURSE OF LECTURES INSTITUTES OF MEDICINE AND MATERIA MEDICA. DELIVERED BEFORE THE MEDICAL CLASS OF THE UNIVERSITY OF THE CITY OF NEW VORK, AT THE SESSION OF 1844-5. I BY 301 3& MARTYN PAINE, A. M. M. D„ Professor of the Institutes of Medicine and of Materia Medica in the ™£^£2* °f New York ; member of the Royal Verein fiir Heilkunde in P«mssen.-, of the Med ca ^oc.et, of Leipsic; of the Montreal Natural History Society, a»d other Learned Associates. FOURTH EDITION. ^ J NEW YORK: PRINTED FOR THE MEDICAL CLASS OF THE UNIVERSITY, B7 JOSEPH H. JENNINGS, 111 FULTON STREET. 1844-5. New York, November 4, 1844. Prof. Paine : Dear Sir:—At a meeting of the Class of the University Medical College, held on Saturday evening last, Mr. S. S. Satchwell, of North Carolina, being in the chair, and Mr. Edmund R. Dabney, of Tennessee, acting as Secretary, on motion, it was unanimously Resolved—That a Committee be appointed to solicit for publication, a copy of the able and eloquent Introductory Lecture delivered by Prof. Paine on Thursday evening last. The undersigned having been appointed the Committee to perform this pleasing duty, allow us to add our individual wishes to those of the Class, and to hope that you will not refuse so unanimous a request. We need not assure you how truly we are yours, &c., Philip A. Atlett, Alabama. William J. Alexander, Virginia. Cyrus Arndt, New Jersey. John M. K. Alford, North Carolina. John W. Albury, West Indies. W. A. Burleigh, Maine. J. Brown, New Hampshire. E. T. Currie, Maryland. G. W. Clipping er, Pennsylvania. R. H. Clarke, Delaware. Oliver Crooks, Ohio. William Edwards, Mississippi. G. G. Gaithek, Kentucky. W. M. Huntingden, Vermont. B. S. James, South Carolina. John McGregor, Rhode Island. Charles T. Mount, Canada. Valentine Mott, Jr., New York. Edward Perry, Connecticut. George W. Parkhill, Forida. Wm. M. Ryer, Illinois. J. B. Selby, Wisconsin. George M. Tutt, Georgia. T. D. Washburn, Massachusetts. D. E. Warren, Tennessee. New York, November 8, 1844. Messrs. P. A. Aylett, and others, composing a Committee of the Medkal Class of the University of New York, 4-c. : Gentlemen:—-In acknowledging the receipt of your very polite note, inform- ing me of the honor done me by the Medical Class, of soliciting for publication a copy of my late Introductory Lecture, I have much pleasure in acceding to that request, and beg that you will convey to those gentlemen and accept for yourselves my sentiments of respect and esteem. Very truly, and sincerely, yours, MARTYN PAINE. THE PHYSIOLOGY OF DIGESTION. I. " 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, whilst they are fitted only to awaken pity." 2. " 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 associations. They treat these sciences like the vulgar, who despise a foreign litera- ture in exact proportion to their ignorance of it."—Liebig's Organic Chemistry ap- plied to Physiology, etc. 3. " 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." The oft-reiterated con- clusion follows, that it is reserved for chemistry to resolve these problems.— Liebio's Animal Chemistry. [See 1st and 2nd paragraphs p. 15, left hand column.] 4. " A writer, who can so contradict himself, scarcely needs to be exposed by us." —Carpenter's Review ofPaine's "Commentaries." SeePAiNE's " Examination of Revieivs" pp. 12, 86. 5. " For many centuries past a profitless system has been followed, the same system that formerly obtained in natural philosophy, and the uncertainties and doubts of me- dical science are the best proofs of its value. It is the ruling principle of this system to satisfy the inquirer for facts by the use of empty words,—words which mean nothing and prove nothing. Life and vitality, with other sonorous epithets, figure away in these visionary speculations as though they were realities, and change their forms without reason or rule, as do the images that we see in dreams." 6. " Just in the same way that I am willing to admit the existence of forty differ- ent simple metals, so, upon similar evidence, I am free to admit the existence of fifty different imponderable agents, if need be. Is there anything which should lead us to suppose that the imponderables are constituted by Nature on a pian that is elabo- rately simple, and the ponderables on one that is elaborately complex l That the former are all modifications of one primordial ether, and the latter intrinsically diffe- rent bodies, more than a quarter of a hundred of which have been discovered during the present century ?" 7. " We are thus forced to admit that rays of light, rays of heat, tithonic rays, phos- phoric rays, and probably many other radiant forms, have an independent exist- ence, and that they can be separated, by proper processes, from each other.''—Dra- per's Treatise on the Forces which produce the Organization of Plants, pp. 41, 70, 71.—New York, 1844. 8. " The inorganic and the organic world are blended together, depending both of them on common laws."—Draper's Introductory Lecture, 1844—5. 9. " The rays of the sun are the true nervous principle of plants."—Draper's Trea- tise on the Forces, &c. p. 102. 10. " As soon as the young plant has exposed itself to the solar beam, growth rapidly begins to take place, and organized matter to be condensed from the air," &c. —Draper's Introductory Lecture. 11." If, among plants light is the great agent of organization, electricity is the great motive force, which, under a specific modification, determines the movements of nutri- tious juices. The imponderable agents are the vital principle of organized systems." 12. " The oxygenizing action of the arterial blood is therefore the true cause of the systemic (general) circulation. [See 2nd paragraph, p. 11, left hand column.] 13. " The pulmonary circulation is therefore due to the oxydation of the venous blood." 14. " The old medical aphorism,' ubiirritatio ibi affluxus,' translated into the pre- cise language of modem chemistry, simply means, to the point where its deoxydation is taking place, the arterial blood will flow." [See 2nd paragraph, p. 11, left hand.] 15. " By the aid of the principles here laid down, all the various physiological or pa- thological conditions which are met with in inflammation, asphyxia, gangrene, &c. are 4 presented as so many interesting chemical problems for solution."—[See 4th para- graph, page 15th, right hand column.] 16. " It is a vulgar error that a living being possesses a principle of resistance to ex- ternal agents, while a dead one submits itself to them. Both equally change, or of the two, the living one putrifies and changes the more rapidly."—Draper's Treatise on the Forces, &c pp. 23, 36, 41, 6. [See 4th paragraph, p. 10, and 3rd p. 15, and line 5th, &c. p. 12, right column.] 17. " And now I hope to see this University, as it is the first to introduce these cap- ital improvements, keep the first in the emulous race with all its sister institutions. I want to see it the great factory of Chemical discoveries and chemical doctrines in the western world."—Draper's Introductory Lecture. 18. " Chemists and natural philosophers, accustomed to study the phenomena over which the physical forces preside, have carried their spirit of calculation into the the- ories of the vital laws."—Bichat's General Anatomy, vol. 2, p. 54. 19. " 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 object, that every thing else, how remote soever, will be brought under the same view. A metaphysician will bring ploughing and gardening immediately to ab- stract 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 mys- teries thereof, into the philosopher's stone-"—Locke, on the Human Understanding. 20. " Mr. Locke, I think, mentions an eminent musician, who believed that God cre- ated 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 Trinity."—Reid, on the Powers of the Human Mind, vol. 2 Essay 6. c. 8. 21. " 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. Differences of opinion on questions of great moment to mankind are apt to be strongly conveyed, and apparent error to be censured in no measured terms. This, perhaps, is often admissible, considering the obstinacy of error, and so long as it is the doctrine, and not its au- thor, which is assailed. We may revere the names of Voltaire, of Hume, and of Gibbon, yield them a proud rank in the scale of intel- lect, and gratefully acknowledge the rich legacies they have left be- hind. But, who of us would hesitate to speak of their infidelity according to its nature and tendencies ? This is even demanded by what we believe of the precepts of religion. And so of the principles of medicine, which hold as high a relation to the temporal interests of man, as do the precepts of religion to his spiritual welfare. The high- est order of intellect is often devoted to the dissemination of error, and perhaps more frequently in religion and medicine than in any other ol the great interests of mankind. This must be fully and firmly met, not only by evidences of the truth, but by an exposure of its perver- sions and corruptions. In the discussion of my subject, (the controverted physiology of diges- tion,) I shall bring to your consideration the misapplication of chemis- try to the processes of life ; but in doing this, it will be only in the defence of truth, and not with a view of diminishing your respect for an important science. We must regard its defects abstractedly, and endeavor to eradicate such impurities as tarnish its lustre. We must still yield to it all the praise to which it is entitled by the devoted in- dustry of its cultivators, by its elevated rank amongst the sciences, and by its usefulness to man. Indeed, as a science of general usefulness, 5 as a source of mental improvement and of pure and elevated enjoy- ment, as opening to our view many of the most deeply interesting and stupendous institutions of nature, and often with that demonstration which no skepticism can resist,—I say, with all these combined advan- tages, it is the most important of the sciences for the general purposes of life. And I am mostly prompted in making these remarks by the too common neglect of chemistry by the medical profession, to whom it is farther recommended by its subserviency to the healing art. At the outset of my subject, it will be necessary to premise a few statements as to the general condition of medicine, and the auspices under which it is now cultivated. The physiological world, as you are probably aware, has been lately divided into three schools. One of these sects virtually regards organic nature as a part only of inorganic, endowed with the same properties and governed by the same laws. It maintains, in short, that there is no real difference between a man and a stone. At the head of this school stands Liebig, the distinguished and able chemist. It is a great and powerful school, but is falling, daily, beneath the weight of its vast errors and corruptions. It is denominated the chemical school of medicine. Contrasted with this is the school of vitalism ; and to the interests of this school, I may now say, the main efforts of my life have been devoted. Their doctrines will be taught in the lectures which I shall have the honor of laying at the foundation of your medi- cal education; not, however, with any concealment of adverse opinions, but with an ample exhibition of their nature, and of their claims to your consideration. This school regards organic and inorganic nature as distinct in their most essential attributes; that each department is governed by properties and laws peculiar to itself. It regards the or- ganic being as fundamentally distinct from the inorganic in its elemen- tary constitution, in the aggregation of its molecules, in the structure of its parts, in its condition as a whole, and in every phenomenon which it evinces. It sees design in every part of the living being, eloquent even in the dry bones of a skeleton ; a design peculiar to every part, whilst all concur in harmony together to the common ends of one uni- versal design. On the contrary, also, this school discerns little of the nature of desio-n in the constitution, or in the abstract condition of inorganic matter. It sees nothing, in respect to power, but mere vis inertia ; which, however, is supposed by the physical school to be capa- ble of evolving from simple matter every variety of organization, with all its specific designs, even instinct and reason, whilst at the same time we hear from the depth of materialism, that " organic nature is the mystery of mysteries." Again, the vitalists, in consideration of the general facts now stated, maintain, in the language of Liebig, the great head of the school of mere physics, " the existence of a power distinct from all other pow- ers of nature, namely, a vital principle ;" which organizes and gov- erns all living beings, and which is the fundamental cause of all their phenomena in health and disease. I say, in the language of Liebig, " a power distinct from all other powers of nature, namely, a vital principle;" for this mere chemist, in his conflicts with living nature, concedes the existence of such a principle as at the foundation of all vital phenomena, yet in the same general manner, and on all specific questions where he has introduced its direct and exclusive agency, he 6 as unequivocally declares that there is no such principle, and that every result of life, and disease, even thought itself, are entirely owing to chemical agencies. His whole system, as set forth in his " Organic Chemistry applied to Physiology," and in his "Animal Chemistry" applied to Pathology and Therapeutics, is a tissue of similar contradic- tions, of the boldest assumptions, and of stultifying doctrines. Yet, with deep mortification I say it, he has been hailed with an enthusi- asm before unknown in the annals of medicine, as the only true ex- pounder of physiology and of medical philosophy. The world, how- ever, is fast awaking from its spellbound delusion, and the doctrines of this " reformer " will soon be mingled with the same and more original chimeras which did their part in " the dark ages of science." Finally, the third school, or that of chemico-physiology, endeavor to form, as it were, a bond of union between the schools of pure vital- ism, and of pure chemistry, though such an alliance be as unnatural as human brains in a block of granite. The chemico-physiologist makes a compromise with philosophy, and takes for his rule, " in medio tutissimus ibis." He professes to loathe all extremes; but takes little trouble to ascertain the fact whether one doctrine or the other be fairly entitled to this appellation. He sees only the direct opposition which exists, without caring whether' one " extreme," as he calls it, may not be perfectly true, whilst the other is as perfectly false. He therefore mingles the doctrines of vitalism and of chemis- try ; allotting to the former one half of the phenomena of life, and the other half to the latter. This is the school to which you have the greatest chance of becoming the victims; for it is apparently recom- mended by the conciliatory principle which I have stated in the form of its motto, and by many of the most distinguished members of our profession. I am now prepared by these explanatory remarks, relative to the three schools of medicine, to enter upon the consideration of the philo- sophy of digestion ; for each denomination have interpreted that phi- losophy according to the general doctrines of life which are peculiar to each. Beginning with pure chemistry, we find the great leader setting forth the process of digestion in the following language, in his late work on Animal Chemistry applied to Pathology and Therapeutics. " Chymi- fication," he says, " is independent of the vital force. It takes place in virtue of a purely chemical action,—exactly similar to those processes of decomposition and transformation which are known as putrefaction, fermentation, or decay." This is exactly the old doc- trine of what are well denominated the " dark ages." Now you will recollect that I have stated that it is a remarkable characteristic of the work which is assumed as the basis of the chemi- cal philosophy of life, that it abounds with staring contradictions ; and such is the fact in relation to the doctrine which I have just quo- ted. And how could it be otherwise, seeing that its author was con- stantly employed about two subjects that have no relation to each oth- er ; that is to say, the philosophy of life and the philosophy of chemis- try. Rut I will go back, for a conflicting doctrine, to the " Reformer's" treatise on Organic Chemistry applied to Physiology, published a year or two antecedently to his work on Animal Chemistry ; by which we 7 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 elements, so as to produce new combinations and forms, indicates the presence of a peculiar mode of attraction and the existence of a power distinct from all other powers of nature, namely, the vital principle." " If the food possessed life, not merely the chemical forces, but this vitality would offer resist- ance to the vital force of the organism it nourished." Such, then, was the opinion of this Chemist when discoursing of life in his " Organic Chemistry applied to Physiology;" and passages of a similar import occur in his late work on " Animal Chemistry,"— ay, and standing in connection with his equally fundamental, and hostile doctrine, which refers every living process and result to the me- rest chemical agencies. The work, however, on Animal Chemistry is more of a distilla- tion from the Laboratory than its predecessor; and as many of the most eminent physiologists in Europe, who were inclined to mingle chemistry with vitalism, were nauseated by the dose which was last administered, Liebig came out in his lectures for the session of the present year, (1844) with the following placebo for the vitalists and the chemico-physiologists. It is of some extent; but, as it embraces exactly the doctrines which I have been always employed in teaching, and which are still fundamental in my lectures, I shall quote it, at length; so that, should there be any present who may have be- come imbued with the popular superstition in regard to Liebig's notions in Physiology, they may rest assured that my lectures will have for their basis what will be allowed by their favorite Liebig to be the only true foundation of the Institutes of Medicine. Thus, then, the Ger- man Chemist, when, only six months ago, he was lecturing, like my- self, on the functions of life. "After the extinction* of the vital Principle," he says, "'in organic atoms, they maintain their form and properties, the state into which they have been brought in living organisms, only by reason of their inherent inertia. It is a great and comprehensive law of matter that its particles possess no self-acting, no inherent power of originating motion, when at rest. Motion must be imparted by some external cause; and, in like manner, motion once imparted to a body can only be arrested by external resistance." So much for simple matter. Now for matter in an organic state. " The constituents of vegetable and animal substances," he goes on, " having been formed under the guidance and power of the vital principle, it is this principle which de- termines the direction of their molecular attraction. The vital princi- ple, therefore, must be a motive power, capable of imparting mo- tion to atoms at rest, and of opposing resistance to other forces producing motion, such as the chemical force, heat and electricity. We are able to reliquify and redissolve albumen after it has been coagulated by heat; but, the vital principle alone is capable of resto- ring the original order and manner of the molecular arrangement in the smallest particles of albumen. Coagulated albumen is again con- * See my " Examination of Revkws," p. 26—28. 8 verted into its original form ; it is transformed into flesh and blood in the animal organism. " In the formation of vegetable and animal substances the vital prin- ciple opposes, as a force of resistance, the action of the other for. ces,—cohesive attraction, heat, and electricity,*—forces which render the aggregation of atoms into combinations of the highest order impos- sible, except in living organisms. " Hence it is, that when those complex combinations which consti- tute organic substances are withdrawn from the influence of the vital force,—when this no longer is opposed to the action of the other dis- turbing forces, great alterations immediately ensue in their proper- ties, and in the arrangement of their constituents. The slightest chemical action, the mere contact of atmospheric air, suffices to cause a transposition in their atoms, and to produce new arrangements; in one word, to excite decomposition. Those remarkable phenomena then take place which are designated by the terms fermentation, putrefaction, and decay. These are the processes of decomposition, and their ul- timate results are to reconvert the elements of organic bodies into that state in which they exist before they participate in the processes of life." —London Lancet, May 18, 1844. Now, gentlemen, you are no doubt astonished, and well you may be, to hear such language, and the latest, too, that he has spoken, from the chief of the school who, in reality, admit of nothing but pure chemistry in their system of physiology. The language which I have just quoted from Liebig, should place him amongst the unqualified vi- talists. It conveys the doctrines which lie at the foundation of my Medi- cal and Physiological Commentaries, and which are opposed, in toto, to the hallucinations of Chemistry. And yet I have already made other quotations from the same writer, and on the same subjects, which you will have observed contradict, in the broadest and most absolute manner his doctrines as to the vital principle. The latter seem to be thrown out " as springes to catch woodcocks," or as others have it, as "a tub to the whale." Such, then, are examples of the medley of contradictions in great fun- damental principles, with which the writings of this very extraordinary and successful pretender in medicine, abound. On the same page we meet a purely chemical and a purely vital philosophy of digestion ; and equally so of other important organic processes. Each is laid down without qualification, and with the dictum of a master who is con- scious that the preponderance he gives to the purely chemical philoso- phy of life will establish his Empire in that philosophy with an age more prone than ever to the doctrines of materialism. On the very subject of a vital principle itself he is asjlatly contradictory as on the cause of digestion; for at one moment he avows the existence of such a princi- * Heat, light, and electricity, are often absurdly supposed to constitute forces in their relation to living beings. In that relation they are merely vital stimuli, calling into action the properties of life. These properties are the only forces which have anv con- nection with the phenomena evinced by animals or plants. As to the doctrine of cap- illary attraction, whether applied to the capillary circulation of plants or animals it is th<- vory worst of all the physical views of life; since it strikes a fatal blow at all or- ganic processes §.nd results, and at all the physiological and pathological doctrines which are founded upon them. The doctrine, on the other hand, is contradicted by all the phenomena and results which appertain to organic life; since they are all dependent on special modes of vital action carried on by the capillary system. 9 pie, " distinct from all other powers of nature," and calls it " the vital principle," which he says governs all the processes of living beings, and at the next moment he avers that " in the animal body we re- cognize, 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 in plants, is A chemical process." Thus, also, he increases the medley of contradictions in relation to digestion, by making that process to depend on a purely chemical action, and to evolve that vital principle which he had already avowed is the only power concerned in chymification. But be not deceived; for, however this " reformer " may beguile you with words, and seem to persuade rather than to rule, remember that, at most, he does but invalidate his own edicts by countermands, and that in the end he tells you that those apparently adverse decrees are, in their absolute import, one and the same; that they are consis- tent laws delivered from the laboratory, though apparently in conflict on account of the opposing forces, the attraction and repulsion, which preside in the chemistry of nature; that, however, in reality, there is no difference whatever in the seemingly two great principles which lie at the foundation, which are one and identical, since " the mysteri- ous VITAL PRINCIPLE CAN BE REPLACED BY THE CHEMICAL FORCES,"* and since, also, " the vital force unites in its manifestations all THE PECULIARITIES OF THE CHEMICAL FORCES, AND OF THE NOT LESS WONDERFUL CAUSE WHICH WE REGARD AS THE ULTIMATE ORIGIN OF ELECTRICAL PHENOMENA, "fr ! I dwell upon these absurdities, that you may the better realize the shal- lowness of that pretended philosophy which has so lately swept, like a hurricane, over the intellectual world ; that you may see, in this system of contradictions, the equal fallacy of that school who endeavor, with greater sincerity, to mingle the conflicting principles, and that you may the better cultivate and enjoy the simple and consistent philosophy which nature teaches. Nor will I yet leave 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 prac- tice of medicine, without showing you the depth of the materialism in which it was submerged. I say nothing now of the avowed infidelity to which it has led. Examples of that disregard of instinctive faith I have al- ready placed in their proper connection with my present subject.:): But, I will merely quote from Liebig's revolutionary work a doctrine of the chemical school, from which, if I mistake not your ambition as intellectual and immortal beings, the very impulse of nature will turn you with a loathing aversion. You will see from it, also, how utterly degraded to the rank of the merest matter is every thing relating to or- ganic life ; even man himself. Thus, then, our author in behalf of the school of chemistry. " Physiology," he says, " has sufficiently decisive grounds for the opinion, that every motion, every manifestation of force, is the result of a transformation of the structure or of its sub- * Liebig's Organic Chemistry applied to Physiology, &c. i Liebig's Animal Chemistry. t See my "Medical and Physiological Commentaries," vol. 2, p. 122—140. Also the Essay on the Vital Powers. 10 stance ; that every conception, 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 composi- tion of the substance of the brain."—" Every manifestation of force is the result of a transformation of the structure or of its substance." Many organic chemists, however, are disposed to admit the existence of a spiritual part, and they should therefore recollect that the exist- ence of a principle of life is substantiated by far more numerous facts than the spirituality of mind, which they are so ready to concede when inviting your attention to their physical doctrines of life. They should be as ready to yield to one series of facts as to the other, and especially to the more cogent series when the minor is obtruded upon your belief. Let us now observe the hostile attitude of some of the important doc- trines which I have quoted from Liebig, by repeating them in direct connection, that we may the more distinctly realize the absurdities which come to us from the laboratory of the chemist, when its ambi- tious aim is turned upon physiology. Examples of similar conflicting views abound in the writings of " the reformer."—Thus :— " Mi object has been, in the present work, to direct attention to the points of intersection of chemistry with physiology, and to point out those parts in which the sciences become, as it were, mixed up together. It contains a collection of problems, such as chemistry at present re- quires to be resolved, and a number of conclusions drawn according to the rules of that science. These questions and problems will be resolved ; and we can- not doubt that we shall have in that case a new phtsiologt and a rational pathology."—Liebig's Animal Che- mistry. " In the animal body we recognise 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 in plants, is a chemical process. If this be prevented, the phenomena of life do not mani- fest themselves. If the chemical action be impeded, the vital phenomena must take new forms" " All vital activi- ty arises from the mutual action of the oxygen of the atmosphere and the ele- ments of the food."—Liebig's Animal Chemistry. " Physiology has sufficiently decisive grounds for the opinion, that evert mo- tion, every manifestation of force, IS the result of a transformation of THE STRUCTURE OR OF ITS SUBSTANCE; that every conception, every mental affec- tion, is followed by changes in the che- mical nature of the secreted fluids ; that tvery thought, every sensation, is accom- " A rational physiology cannot be founded on mere re-actions, and the liv- ing body cannot be viewed as a chemi- cal laboratory."—Liebig's Animal Chemistry. " The^study of the uses of the func- tions ofrnfferent organs, and of their mu- tual connection in the animal body, was formerly the chief object in physiological researches; but lately this study has fallen into the background."—Ibid. [See 3rd motto.] " In the animal ovum, as well as in the seed of a plant, we recognize a CERTAIN REMABKABLE FORCE,THE SOURCE of growth, or increase in the mass, and of reproduction, or of supply of the mat- ter consumed; a force in a state of rest.* By the action of external influ- ences, by impregnation, by the presence of air and moisture, the condition of sta- tic equilibrium of this force is disturb- ed. Entering into a state of motion or activity, it exhibits itself in the pro- duction of a series of forms, which, al- though occasionally bounded by right lines, are yet widely distinct from geo- metrical forms, such as we observe in crystallized minerals. This force is call- ed the vital force, vis vita, or vitali- ty-"—Liebig's Animal Chemistry.—[See my Essays on Vitality, &c. p. 13—18.] "The vital principle must be a mo- tive power, capable of imparting mo- tion TO atoms at rest, and of opposing * See my " Examination of Reviews,' p. 7—24. 11 panied by a change in the composition of the substance of the brain" !—Liebig's Animal Chemistry. " In the processes of nutrition and re- production, we perceive 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 condi- tions of the vital force are chemical for- ces." " 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 results of processes of de- composition, to which either the food it- self, or the structures formed from it, or parts of organs, are subjected."—Liebig's Animal Chemistry. [See 6th and 7th paragraphs, page 13, left hand column, and right hand column, page 11-12, and 12th, 13th, and 14th mottos. This summary principle, were it true, would be truly beautiful. But it appears to be not only deficient in every necessary element, but to be contradicted by all the phenomena of sympathy and by all that is known of pathology and therapeutics; and this, too, according to the author's own repeated and fullest affirmations and doctrines to the contrary.] " The power to effect transforma- tions does not belong to the vital princi- ple. Each transformation is owing to a disturbance in the attraction of the ele- ments of a compound, and is, consequent- ly, A PURELY CHEMICAL PROCESS."—LlE- big's Organic Chemistiy applied to Phy- siology, &c.—[See, also 1st paragraph, page 14, and 6th paragraph, page 14, right hand column, and others equally contradictory.] [I occupy this space to indicate to the reader that he will find that Liebig considers the " che- mical action which the elements of the food and the oxygen of the air mutually exercise on each other," to be the effect of life and the cause of life, and the cause of death, and the cause of animal heat, and that respiration is the essential cause of the whole,—even of death itself. Thus we have all the phenomena of organic beings, from the cradle to the grave, referred to a single chemical process.] " Every thing in the animal organism, to which the name of motion can be ap- plied, proceeds from the nervous appa- ratus. The phenomena of motion in ve- getables, the circulation of the sap, for example, observed in many of the chara- ceae,and the closing of flowers and leaves, depend on physicaL and mechanical cau- ses. Heat and light are the remote resistance to other forces producing motion, such as the chemical force, heat and electricity."—Liebig's Lec- tures for 1844. [See 16th motto.] " In the animal organism we are ac- quainted with only one cause of mo- tion ; and this is the same cause which determines the groiolh of living tissues, and gives them the power of resistance to external agencies. It is the vital force." " 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 wonder- ful peculiarity. It may, therefore, be con- sidered as a resting point from which an investigation 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 mat- ter or other, which has no farther con- nection with the laws ascertained by in- vestigation."—Liebig's Animal Chem- istry. " Our notion of life involves something more than mere reproduction, namely, the idea of an active power exercised by vir- tue of a definite form, and production and generation in a definite form. The produc- tion 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 original form and with all their properties, are charac- ters belonging exclusively to organic life, and constitute a form of reproduc- tion independent of chemical powers. The chemical forces are subject to the invisible cause by which this form ia produced. Of the existence of this cause itself we are made aware only by the phenomena which it produces. Its laws must be investigated just as we in- vestigate those of the other powers which effect motion and changes in matter." "The vital principle is only known to us through the peculiar form of its instru- ments ; that is, through the organs in which it resides. Hence, whatever 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 ac- tion. Light, heab> electricity, or other 1 1 causes of motion in vegetables ; but in animals we recognize in the nervous ap- paratus a source of power, capable of renewing itself at every moment of their existence."—Liebig's Animal Chemistry. —[See, also, 3rd paragraph, page 10,right hand column.] Nevertheless, although— " Plants require light, and, indeed, sun light, it is not necessary that the di- rect rays 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 mere- ly accelerates in a greater degree the action already existing."—Liebig's Or- ganic Chemistry applied to Physiology, &c. [See note p. 8, and opposite para- graph.] " The vital force unites in its mani- festations all the peculiarities of che- mical forces, and of the not less wonder- ful cause which we regard as the ultimate origin of electrical phenomena."—Lie- big's Animal Chemistry. [See, also, 4th paragraph, page 10, right hand column, and first paragraph, page 8, and note.] " The mysterious vital principle can be replaced by the chemical forces."— Liebig's Organic Chemistry applied to Physiology, &c. " While the assimilation of food in vegetables and the whole process of their formation, are dependent on cer- tain external influences which produce motion, the development of the animal or- ganism is, to a certain extent, independ- ent of those external influences, just be- cause the animal body can produce with- in itself that source of motion which js indispensable to the vital process." —Liebig's Animal Chemistry. " Neither the emission of carbonic acid n or the absorption of oxygen (by plants) has any connection with the process of assimilation ; nor have they the slightest relation to each other. The one is purely a mechanical, the other a purely chemical process. A cotton wick, in- closed in a lamp, whjgh contains a liquid influences [justly considered here by Lie- big as vital stimuli and not forces] may increase, diminish, or arrest this ac- tion ; but they are not its efficient cause." " The vital principle opposes to the continual action of the atmosphere, moisture, and temperature, upon the orga- nism, a resistance which is, in a certain degree, invincible. It is by the constant neutralization and renewal of these ex- ternal influences that life and motion are maintained."—Liebig's Organic Chemis- try applied to Physiology, &c. " An abnormal production of certain component parts of plants presupposes a power and capability of assimilation, to which the most powerful chemical ac- tion cannot be compared. The bestidea of it may be formed, by considering that it surpasses in power the strongest galva- nic 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." " All that we can do is to supply those substances which are adapted for assimi- lation by the power already present in the organs of the plant."—Liebig's Orga- nic Chemistry applied to Physiology, &c. —See, also, third quotation in this col- umn, page 10. " The living part of a plant acquires the whole force and direction of its vital " In what form or in what manner the vital force produces mechanical effects in the animal body is altoge- ther UNKNOWN, AND IS AS LITTLE TO BE ASCERTAINED by experimfnt as the con- nection OF CHEMICAL ACTION WITH THE PHENOMENA OF MOTION, which we can produce with the galvanic battery. We know not how a certain invisible something, heat, gives to certain bodies the power of exerting an enormous pressure on surrounding objects. We know not even how this something itself ia produced when we burn wood or coals. " So it is with the vital force, and with the phenomena exhibited by living bodies. The cause of these phenomena is not chemical force ; it is not electrici- TY,nor magnetism. It is a peculiar force, because it exhibits manifestations which are formed by no other known force." " In regard to the nature and essence of the vital force, we can hardly deceive ourselves, when we reflect, that it be- haves, in all its manifestations, exactly like other natural forces ; that it is de- void of consciousness or of volition, and is subject to the action of a blister."—Lie- big's Animal Chemistry. 13 saturated with carbonic acid, acts exactly in the same manner as a living plant in the night."—Liebig's Organic Chemistry applied to Physiology, &c. " At night, a true chemical process com- mences, [though every process is either purely mechanical or purely chemical, by night or by day, according to the last quo- tation] in consequence 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 exactly as in a living one." ! Nevertheless,— ■" What value can be attached to experi- ments, in which all those matters which a plant requires in the process of assimi- lation, besides its mere nutriment, have been excluded with the greatest care ? Can the laws of life be investigated in an organized being which is diseased or dying ?" — Liebig's Organic Chemistry applied &jc —Or, can those laws be inves- tigated in " a Cotton wick, inclosed in a lamp" ? " 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 Organic Chemistry applied to Physiol- ogy, &c.—[See, also, right hand column p. 12.] Plants, when properly placed in glass vessels containing distilled water, will, by means of their roots, decompose the glass, and absorb its silex and alkali, and assim- ilate those substances to themselves, and in despight of any chemical affinities; yet, "All substances in solution in a soil are absorbed by the roots of plants, ex- actly as a sponge imbibes a liquid, and all that it contains, without selection," and "their assimilation is a purely chem- ical process."—Liebig's Organic Chem- istry applied, &c, " The most decisive experiments 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 SIM- ILAR to those processes of decomposition or transformation which are known as PUTREFACTION, FERMENTATION, or DE- CAY."—Liebig's Animal Chemistry. " Those remarkable phenomena, fer- mentation, putrefaction, and decay, are the processes of Decomposition, and their ultimate results are to reconvert the ele- energy from the absence of all conductor* of force. By this means the leaf is ena- bled to overcome the strongest chemical attractions, to decompose carbonic acid, and to assimilate the elements of its nou- rishment."—Liebig's Animal Chemistry. " In vegetable physiology, a leaf is re- garded in every case merely as a leaf, notwithstanding that leaves generating oil of turpentine 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. Vegetable 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 inves- tigation."—Liebig's Organic Chemistry applied to Physiology, &c. " In the living plant, the intensity of the vital force far exceeds that of the chemical action of oxygen. We know, with the utmost certainty, that, by the influence of the vital force, oxygen is separated from elements to which it has the strongest affinity ; and that it is given out in the gaseous form, without exerting the slightest action on the juices of the plant." " The animal organism is a higher kind of vegetable." " Assimilation, or the process of ror- mation 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."—Liebig's Animal Chem- istry. , " The constituents of vegetable and animal substances are formed under the guidance and power of the vital principle, which determines the direction of their molecular attraction." " In the formation of vegetable and animal sub- stances, the vital principle opposes, as a force of resistance, the action of the other forces," &c.—Liebig's Lectures for 1844. " The equilibrium in the chemical at- tractions of the constituents of food is dis- turbed by the vital principle "; and "the union of its elements,so as to produce new combinations and forms, indicates a peculiar mode of attraction, and the ex- istence of a power distinct from all other powers of nature, namely, the vi- tal principle."—Liebig's Organic Che- mistry applied to Physiology, &c. " The vital force causes a decompo- sition of the constituents of food, and de- 14 ments of organic bodies into that state in which they exist before they participate in the processes of life."—Liebig's Lectures for 1844. " In the action of the gastric juice on the food, no other element takes a share except the oxygen of the atmosphere." " This air by means of the saliva, reaches the stomach with the food, and there its oxygen enters into combination."—Lie- big's Animal Chemistry. " The power of elements to unite to- gether, and to form peculiar compounds which are generated in animals and vege- tables, is CHEMICAL AFFINITY."--LlEBIG'S Organic Chemistry applied to Physiolo- gy, &c . [See, also, as to elements, the 6th, page 12, and 2d paragraph, page 13, and 3rd paragraph, page 10, and the 3rd, 4th, 5th, and 6th paragraphs, page 14, right hand column ; and other places. ] " We should not permit ourselves to be withheld, by the idea of a vital principle, from considering in a chemical point of view, the process of transformation of the food, and its assimilation by the va- rious organs. This is the more necessary, as the views, hitherto held, have produced no results, and are quite incapable of use- ful application."—Liebig's Organic Chem- istry applied &c.—[See third paragraph, page 11, right hand column, and other contradictory quotations in same column.] " 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. Although—" the process of chymifica- tion 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 pu- trefaction, fermentation, or decay";— nevertheless, " Inorganic compounds dif- fer from organic in as great a degree as in their simplicity of constitution."— Liebig's Animal Chemistry, and Organic Chemistry. [See next quotation, this col- umn, and 1st and 2d paragraphs page 22.] " By chemical agency we can produce the constituents of muscular fibre, skin, and hair"! "We are able to form, in stroys the force of attraction which is con- tinually exerted between their molecules. It alters the direction of the chemical forces in such wise, that the elements of the constituents of the food arrange themselves in another form, and com- bine to produce new compounds. It for- ces the new compounds to assume forms altogether different from those which are the result of the attraction of cohe- sion when acting freely, that is, without resistance." " The vital force appears as a moving force or cause of motion, when it over- comes the chemical forces, cohesion and affinity, which act between the constit- uents 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, farther, the cause which compels them to combine in a new ar- rangement, and to assume new forms."— Liebig's Animal Chemistry. " When a chemical compound of sim- ple constitution is introduced into the sto- mach, its chemical action is, of course, OPPOSED BY THE VITAL PRINCIPLE. The results produced depend upon the strength of their respective actions. 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 occasioned. Or, the acting body yields to the superior force of vitality, that is, it is digested. Or, lastly, the chemical action obtains the ascendency and acts as a poison."— Liebig's Organic Chemistry applied to Physiology, &c. " The individual organs, such as the stomach, cause all the organic substances conveyed to them, which are capable of transformation, to assume new forms. The stomach compels the elements of these substances to unite into a compound fitted for the formation of the blood."— Liebig's Organic Chemistry, &c " The first substance capable of afford- ing nutriment to animals is the last pro- duct of the creative energy of veget- ables."—Liebig's Animal Chemistry. " The special characters of food, that is of substances fitted for assimilation, are absence of active chemical properties, and the capability of yielding to trans- formations."—Liebig's Organic Chemis- try applied to Physiology, &c. " The constituents of vegetable and animal substances having been formed under the guidance and tower of the 15 our laboratories, formic acid, urea, &c. We see, therefore, that this mysterious VITAL PRINCIPLE CAN BE REPLACED BY THE chemical forces " !!—Liebig's Organic Chemistry applied to Physiology, &c— [See page 22d, second paragraph.] "The influence of poisons and of reme- dial agents on the living animal body evi- dently shows that the chemical decompo- sitions and combinations in the body, WHICH MANIFEST THEMSELVES IN THE PHE- NOMENA of vitality, may be increased in intensity by chemical forces of an analo- gous character, and retarded or put an end to by those of opposite character; and that we are enabled to exercise an influence on every part of an organ by means of substances possessing a well de- fined chemical action."—Liebig's Ani- mal Chemistry. [See 3d motto.] " With respect to the action of qui- nine, or the alkaloids of opium, &c, physiologists and pathologists entertain no doubt that it is exerted chiefly on the brain and nerves. If we reflect that this action is exerted by substances which are material, tangible and ponderable ;£hat 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 produce the action a second time; all these conside- rations, viewed chemically, [.'] permit on- ly one form of explanation; the supposi- tion, namely, that these compounds, by means of their elements, take a share in the formation of new or the transfor- mation of existing brain and nervous matter "!!—Liebig's Animal Chemistry. " It is impossible to mistake the modus operandi of putrefied sausages, or muscle, urine, cheese, cerebral substance, and other matters, in a state of putrefaction." "It is obvious that they communicate their OWN STATE OF PUTREFACTION TO THE sound blood, from which they were pro- duced, exactly in the same manner as gluten in a state of decay or putrefaction causes a similar transformation in a so- lution of sugar ".' " The mode of action of a morbid virus exhibits such a strong similarity to the action of yeast upon liquids containing sugar and gluten, that the two processes have been long since compared to one an- other, although merely for the purpose of illustration. [They have often been rep- resented as identical.] But, when the phenomena attending the action of each respectively are considered more closely, vital principle, it is this principle which determines the direction of their molecu- lar attraction." —" The vital principle alone is capable of restoring the original order and manner of the molecular ar- rangement in the smallest particles of albumen."—Liebig's Lectures for 1844. " From the theory of disease developed in the preceding pages, it follows, obvi- ously, that a diseased condition once es- tablished, in any part of the body, cannot be made to disappear by the chemical action of a remedy."—Liebig's Animal Chemistry. " The vital force is subject to the action of a blister."—Ibid. " The vital force in a living 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 sub- stance of the tissue in which the vital energy resides."—Liebig's Animal Chem- istry. [See 16th motto, and 4th para- graph, p.10, and 5th line p.12, right hand.] The following unscrupulous declaration ap- appears to be addressed to that class of readers to whom' 1 have adverted in the 3rd paragraph. p. 8. Thus: " It is not the true chemist who has end eavored to apply to the animal organism his notions de- rived from purely chemical processes. He has not had the remotest intention of undertaking the explanation of any really vital phenomenon, upon chemical principles. 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 phenomena, and to the task of controlling the correctness of infe- rences, and ensuring the accuracy of all obser- vations 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 synthesis, or of producing them again by the union of these elements " !!!—Lie- big's Lectures for 1844.—[See, particularly, 3d paragraph, p.10,6th paragraph, p.14, left column, and 3rd and 15th mottos. Alto, the opposite paragraphs.] " The vivifying agency of the blood must ever continue to be the most impor- tant condition in the restoration of a dis- turbed equilibrium, and the blood must, therefore, be considered and constantly kept in view, as the ultimate and most powerful cause of lasting vital re- sistance, as well in the diseased as in the unaffected parts of the body."—Liebig's Animal Chemistry. Nevertheless,— " No other component part of the or- ganism can be compared to the blood, in respect of the feeble resistance which it offers to exterior influences." — "The chemical force and the vital principle hold each other in such perfect equilibrium, that every disturbance, however trifling, or from whatever cause it may proceed, 16 it will in reality be seen that their influ- ence defends upon the same cause." " Or- dinary yeast and the virus of human smallpox, effect a violent tumultuous transformation, the former in vegetable juices, the latter in the blood".' " The action of the virus of cowpox is analo- gous to that of low yeast [.'] It commu- nicates its own state of decomposition to a matter in the blood, and from a second matter is itself regenerated" ! "The susceptibility of infection by the virus of human smallpox must cease after vacci- nation, for the substance to the pres- ence of which this susceptibility is owing has been removed from the body by a peculiar process of decomposition artifi- cially excited " ! " Cold meat is always in a state of decomposition. It is possi- ble that this state may be communicated to the system of a feeble individual, and may be one of the sources of consump- tion" ! '.—Liebig's Organic Chemistry applied to Physiology, &c " In all chronic diseases, death is produced by the same cause, namely, the chemical action of the atmo- sphere." And so, also, of death from acute diseases; breathing, in all the cases, being the cause of death.—Liebig's Ani- mal Chemistry. EFFECTS A CHANGE IN THE BLOOD."—LlE- big's Organic Chemistry applied, &c But, again, nevertheless,— " It is obvious, moreover, that in all diseases where the formation of conta- gious matter and of exanthemata is ac- companied by fever, two diseased condi- tions simultaneously exist, and two pro- cesses are simultaneously completed \ and that the blood, as it were, by re-action, that is, fever, becomes a means of cure." —Liebig's Animal Chemistry. " We can have no very high idea of experiments made by gentlemen, (chem- ists, with reference to digestion,) who, for want of anatomical knowledge, have not been able to pursue their reasoning even beyond the simple experiment itself."— John Hunter's Observations on Diges- tion. *** The quotations from "Liebig's Organic Chemistry applied to Physiology," are derived from Mr. Playfair's edition, London, 1840 ; those from " Liebig's Animal Chemistry," are taken from Professor Gregory's edition, reprinted Neve York, 1842. The italics and capitals are mine. It only remains now to say of the foregoing contradictions (hitherto unnoticed,) that, whenever and wherever they, or their resemblances, occur in any department of science, we may of course rely upon it that the writer is in pursuit of any thing but truth, or is most inexcusably ignorant of his subject. In medicine, too, we may readily suspect that every thing is spurious which comes to us upon the wings of the imagination, or where we meet with tropes and metaphors instead of crucibles and acids, or with harmonious words instead of obstinate facts and hard thinking. It follows, therefore, from what I have stated of the incongruities of the chemical school on the philosophy of digestion, as well as of all • other functions of life, that I need not say much of the groundless nature of that mingled system of contrarieties by which the chemico- physiologists interpret the same functions. Their doctrine of digestion is thus laid down by the distinguished chemist, Dr. Prout; for you should understand that chemists, not physiologists and physicians not the students of organic nature, are the great leaders in the medical schools of pure chemistry and of chemico-physiology. " First " says Dr. Prout, " the stomach has the power of dissolving alimentary sub- stances, or, at least, of bringing them to a semi-fluid state. This ope- ration 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 of 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. 17 ' " 3d. The stomach must have, within certain limits, the power of organizing and vitalizing the different alimentary substances." " It is impossible," he says, " to imagine that this organizing agency of the stomach can be chemical. The agency is vital, and its nature com- pletely unknown." Such, then, is the doctrine of digestion as entertained by the chemico- physiologists. But, from what we have already seen of the absolute contradictions which abound in the writings of those who attempt the application of pure chemistry to the functions and results of organic life, we may expect that the chemico-physiologist will be equally in- consistent when he applies himself, at one time, to the phenomena of living beings, and, at another, reasons from the results of the labora- tory 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 ar- rangements in the formation of organized beings should lead to the chemical changes of which they are the instruments." 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. Nor is this all. For the chemico-physiologist, the same eminent chemist whom I have just quoted, goes on to say, that " with the living, the animative properties of organic bodies, chemistry has not the small-' est alliance; and probably will never, in any degree, elucidate those properties. The phenomena of life are not," he says, " even remotely analogous to anything we know in chemistry as exhibited among inor- ganic 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 " nature will not per- mit the chemist to officiate as her journeyman in the most trifling de- gree." So, also, Dr. Roget, alike distinguished in the school of chemi- co-physiology. " Vital chemistry," he says, " is too subtle a power for human science to detect, or for human art to imitate." And to the same effect may be quoted Dr. Carpenter, one of the foremost in the school of pure chemistry. " The agency of vitality," says this rea- soner, who generally ridicules the term and all that is supposed to re- late to it, " the agency of vitality," he says, " as Dr. Prout justly re- marks, does not change the properties of the elements, but simply com- bines the elements in modes which we cannot imitate." And 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 show you by their own statements that there is not the slightest intelligible connection between them. Indeed, I have already, on a former occasion, pointed out this universal admission. 2 18 The ground of chemistry being thus virtually abandoned to the vi- talist, it would seem superfluous to pursue an adversary who is always upon the retreat. But, as he flies, he is for ever shooting from behind, and his Parthian weapons fall thickly and heavily upon the vast mul- titude. He must therefore be subdued into a practical acquiescence with those consistent principles of nature which exact his consent, but not his compliance. The subject of digestion supplies one of the numerous opportunities of pushing the chemico-physiologist upon open ground, and of exhib- iting truth in its unadulterated purity. It is here, too, especially, that chemistry has reared its batteries, and whence it sends forth its artil- lery into the various dominions of the organic world. Yet it is here, that vitality is exemplified in its most impressive and astonishing as- pects, and where unequivocal demonstrations abound that fluids, as well as solids, are endowed with the principle of vital operations.— It is here, especially, that nature has illustrated her distinction be- tween the animate and inanimate world, and established her chain of connection. It is here, in the incipient change of dead into living mat- ter, 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 ab- ruptly ; but where analogies are preserved in the conversion of dead into living matter, through new modes of combining the same elements ; and doubtless our admiration would increase, should we mount along the entire functions of assimilation, and find, at each step of the ascend- ing series, that the whole agency has been committed to forces that have no existence in the inorganic world ; that the whole is the har- monious result of a principle which may form an intermediate link be- tween spirit and matter; and that there is no power within our control by which we can determine the nature of the changes. Casting a glance at the vegetable world, we find the connection continued, by other analogous links, with elementary matter itself; but here, as in the higher department of nature, the line of separation is equally de- fined, however low in the scale of analogy may be the properties 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 for 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. However, also, we may scrutinize the process of digestion in either of the organic kingdoms, we find that nature has provided intricate means for the purpose, and established analogies in their organization as well as their phenomena, that are unknown in the inorganic world. And if we carry the analysis through the whole labyrinth of animal and vegetable creation, we meet, at every step, with so much Unity of Design, such gradual modifications of structure and functions, and all conspiring to a specific end, we must conclude that the whole are gov- erned by forces peculiar to themselves. But, notwithstanding the astonishing Unity of Design, and the gra- dation of analogies which connect together the most dissimilar of the 19 systems which are designed for digestion, there are peculiarities at- tending each in every species of animals, which place at a remote dis- tance the laws of chemistry. " An alimentary Canal is observed in every class of animals, and almost in every species, but its form and structure vary according to the situation of animals in the scale, or according to the kind of food on which they are destined to subsist, and the extent of the elaboration it requires to undergo. The peculiarities presented by the digestive organs are, therefore, intimately connected with the diversities of form manifested by the organs of animal life, and with all the living habits and instincts of animals." We see, also, an extension of this principle in relation to certain periods of life. In ruminating animals, for instance, the fourth stomach is alone employed during dentition. And yet, with all this variety, there is but one com- mon result, one homogeneous chyle. The same principles, the same vital impulses which ultimately develope and call into action the three first stomachs of the ruminantia, appear to be not less concerned in the consummation of their final cause. One of the most important arguments in favor of vital digestion con- sists in the remarkable endowments of the stomach, as manifested by its vital signs, and by the sympathies which prevail between this organ and all other parts. The final cause of this peculiar constitution of the stomach, this lavish supply of the properties of life, this subservi- ence of other organs to its dominion, must be sought in its adaptation to the generation of a fluid that may bestow the first and most difficult act of vitalization upon dead matter. There would also have been something harsh and abrupt in nature, to have admitted into the recesses of her living organization mere dead matter. It is opposed to all anal- ogy, and is, therefore, opposed to all reason. But, that a fluid should perform this astonishing office, this first and great step in the ascending series, it must possess in a high degree the principle of life. Mysteri- ous as it may be represented, we must all of us come at last to the ad- mission of the existence of a vital principle; yet far less mysterious, and far less difficult of comprehension than the human soul. It is fair, then, to conclude that an organ destined for such a high function should possess that principle, in common with all other parts, as the means on which its function depends; and the best evidences in favor of (his analogical inference are to be seen in its diversified manifestations of life. To deny the dependence of vital results upon specific powers, necessarily involves an exclusion of all the evidence by which we infer the existence of gravitation, or of the intangible properties of matter.— As well may we doubt the reality of spirit, " or the Maker of the eye, because it cannot see Him that made it." We have seen, also, that it is conceded by philosophers who defend, in extenso, the chemical hypothesis of life, that there may be something appertaining to the stomach totally distinct from the chemical powers, and which is capable of imbuing the chyme with vitality and an or- ganic condition ; and it is, therefore, quite a philosophical conclusion, that this vital something has an important agency in preparing the ma- terial for the admitted exercise upon it of the vivifying or organizing power. Nor can there be any valid objection to the supposition that this vitalizing power, which so far transcends the chemical forces in the organizing effect it is allowed to exert, may be fully adequate 20 to any transmutations the food may undergo; and this inference is the more corroborated by the consideration that matter already in an or- ganic state must be better fitted for the process of vivification, than it can possibly be after its elements are broken up and recombined by forces with which those of life are in absolute opposition. Besides, the vitality of the gastric juice, or the vital influence of the stomach itself, being fully admitted, and even capable of organizing the food anew, this, in itself, should protect the alimentary matter against any chemi- cal agencies which have been supposed to operate. That this counteract- ing power, indeed, prevails to the full extent which I have alleged, ap- pears to be rendered certain by the ordinary absence of any of those chemical changes which take place where numerous substances are mixed together out of the stomach,—substances which often possess strong chemical affinities for each other, and whose operation within the stomach would be promoted by its high temperature. On the contrary, whatever the variety, it is uniformly resolved into one and the same homogeneous substance, utterly unlike the results of chemical reac- tions of one kind of food upon other kinds ; and what is also as conclu- sive as it is astonishing, the chyle is apparently the same substance in all animals. Chemistry must here be consistent with itself, and not renounce, for the sake of hypothesis, those precise laws by which, in its legitimate pursuit, it lays open, with astonishing exactness, what had appeared the arcana of nature. Here, too, upon the chemico-phy- siological hypothesis, is presented an instance in which it must be ne- cessarily assumed that the properties of life and the forces of chemis- try must act together in concert in converting dead into living matter, —one destroying, and at the same moment the other vitalizing ; whilst the assumption is contradicted by all that is known of the relation of these forces to each other. It will be also readily conceded that it is the demand of philosophy not to multiply causes, where one is perfectly adequate ; and especially where it is admitted that all the others are of themselves wholly inade- quate. This remark may be also equally applied to a common assumption which is set forth in the following apparently plausible manner. "The vitalists," says one of their opponents, "are loth to admit the operation of chemical agents at all, and would seem to consider it derogatory to suppose that any changes, save the subtle ones effected by the powers of life, are worked upon the aliment." " The vital principle," he says, " whatever it may be, incessantly makes use of chemical and mechani- cal agents for its purposes ; and it is no more degrading to it to employ an acid liquid, and a triturating process, in order to digest the aliment, than it was to have recourse to bony levers, cartilaginous pulleys, and tendonous ropes." Here, in the first place, you will observe an entire begging of the question as to digestion by an acid, since that has never been shown, and is the main point at issue. It is a perfectly unfounded and extor- ted inference from the factitious analogy supposed to be seen in the ad- mitted mechanical movement of the food in the stomach, bony levers cartilaginous pulleys, dec. But the pretended analogy, I say, is utter- ly inapplicable, were it admissible to reason from better premises of this nature to the existence of important facts which have no other 21 foundation. The bony levers, muscles, tendons, heart, and large blood- vessels, are mere instruments acted upon by the vital principle, and have no part in the vital results, except as they are the passive instruments of the properties of life. You will observe the same distinction be- tween the process of digestion, and the mechanical movement of the food in the stomach, or the "trituration" of the food, as it is erroneous- ly called by the writer just quoted; since food is not triturated by the stomach excepting where that organ is designed to supply the place of teeth. You will observe, I say, the total want of analogy between that mechanical movement of the food, and the assumed action of an acid ; since, in the latter case, a radical change is supposed to be wrought in the alimentary mass, whilst no such change is wrought by the mere movement, or even by the trituration or grinding of food in the stomach. The contractions of the stomach, which are purely of a vital nature, facilitate the process of digestion ; but they do no more than to expose the food freely to the action of the gastric juice, by which, alone, the conversion into chyme is performed. The contractions, or " trituration," are exactly on a par, as auxiliaries to digestion, with the teeth, or with the knife, which divide the food. The acid alone applies to the sup- posed chemical process of chymification. This is the only agent, in- volving the only force distinct from the vital principle that is supposed to operate, and to take part with the properties of life in the functions which belong to those properties. Nor is this all. Those chemical forces, or an equivalent agent, are supposed to appertain to the gastric juice, (a product of the most highly endowed organ in the animal sys- tem) ; and through that product, and by that product, to operate inde- pendently of the vital properties, or, under their control. But, here it may be again affirmed that throughout nature there is not an analo- gical fact to warrant the conclusion ; and with equal truth it may be said that there is nothing to aid our conception of the cooperation of the chemical and vital forces, whilst all that is known of their relations to each other proclaims their absolute independence. But, again, it is the admitted final cause of the gastric juice to be- stow life upon dead matter, whilst it is incontrovertible that inorganic matter is insusceptible of any such influence from gastric action.— Every fact proclaims that nature has provided the vegetable kingdom for the purpose, especially, of determining organic combinations out of inorganic substances for the sustenance of animal life. In the lan- guage of Liebig, " The first substance capable of affording nutriment to animals is the last product of the creative energy,"—ay, " the creative energy," he says, " of vegetables."—(Animal Chemistry.) It is manifest, therefore, that it would be an absurdity on the part of nature to have ordained that chemical agencies should operate even at the very threshold of life, at the very fountain for which she had pro- vided elaborate means to subvert the combinations of chemistry, and to bring them into those entirely new arrangements that approximate the changes they are destined to undergo in the animal stomach. And far less probable is it, that this fundamental principle should be lost as we ascend from vegetable to animal organization; since every chemical result within the stomach would tend to reduce the aliment to the state of that inorganic matter whose complete reduction into organic com- pounds was effected by the vegetable kingdom for the uses of the ani- 22 mal. Such chemical results, therefore, would counteract the great final cause of nature, in either organic kingdom; and, in the animal, would render the means of sustenance more and more indigestible, and progressively liable to the condition of inorganic matter. This is fully allowed by the chief of the school of pure chemistry ; as shown in the foregoing parallel quotations. But again I say, if the vital principle be " capable of making use of chemical agents," no reason can be assigned why it may not be equal to the whole work of digestion, and of every other process of living be- ings. The simple construction may be comprehended, whilst the other is utterly unintelligible. The former alone is agreeable to the rules of philosophy, and abolishes the inextricable confusion which attends the chemical hypothesis. What, indeed, can be meant, by the vital properties making use of chemical forces 1 Can there be a more glar- ing absurdity ? more absolute nonsense ? How are those chemical for- ces brought into use, how held in subjection, how for ever maintained in one exact operation in each particular organic process, of which there are multitudes, distinct from each other, going on in the same in- dividual ? How do they elaborate from one common, homogeneous fluid, either the blood, or the sap, all the various, unique, unchanging, secreted products of the whole organic being ? Products, for ever the same in every part, yet differing from each other according to the na- ture of the part ? Did you ever hear or dream of any thing analogous to this in that inorganic world where chemistry holds its empire ?— When do those chemical forces begin to operate, in the living body, what part do they perform, and what is the allotment of the properties of life ? Is there any known concert of action between the two species of forces 1 On the contrary, is it not every where demonstrated that the properties of life are in direct opposition to the forces of chemistry ? Whatever be the construction, by uniting the two forces, (as is done by the only chemical school that is entitled to a respectful notice,) we convert what is a simple problem, like all other processes of nature, into the greatest paradox that has been yet devised by the ingenuity of man. It is in vain to say that some one or two of the products of or- ganization, such as carbonic acid, and urea, are such as result from chemical affinities, since these are excrementitious; whilst chemistry assures us that all organic compounds are utterly different in their ele- mentary combinations from any compound of a chemical nature. Thus might I go on to argue this subject upon general principles alone ; whilst at every step of the argument, we should see the whole chemical hypothesis of life taking its proper rank as a dream of the im- agination, or as a project of ambitious minds. But, I must hasten to the specific facts which are brought by the chemical and the chemico-physiological schools to the support of their preconceived hypotheses; for you must understand that digestion was regarded as a chemical process, and according even to its present in- terpretation, whilst chemistry was yet in its infancy. Digestion having been assumed to be more or less, or altogether, a chemical affair, it rationally followed that it might be imitated by art. Accordingly, when this ambitious science had succeeded in turning the whole inorganic world into the laboratory, it set itself at the manu- facture of organic compounds, and even at the entire animal. It did 23 not, like Alexander, sit down and weep because it had no more worlds to conquer; but, like Shakspeare, having " exhausted worlds, it then imagined new." Even eminent physiologists, who should look with jealousy upon any invasions upon the laws of nature, especially upon such as it is their peculiar province to illustrate, began the manufac- ture of gastric juice by fire and acids, and metallic salts. We are thus presented by these philosophers with artificial compounds, of a most incongruous nature, and we are told that each one is the gastric juice ; that each is capable of the same precise results as that universal pro- duct of animals, apparently the same in all, and elaborated from the blood by an organ of the highest vital endowments, and to which there is nothing analogous in all the^other products of living beings, each pro- duct being, also, equally unique, and all derived from one common source. A diversity of opinions exists as to the real nature of the chemical agent supposed to be employed by nature in the process of digestion. Free muriatic acid having been found, or supposed to exist, in the stom- ach, it has been concluded by many that this must be the great agent; whilst Dr. Prout, and others, affirm that " free muriatic acid more or less retards the process of reduction." Dr. R. Thompson, however, states that, by digesting muscular fibre in dilute muriatic acid, he pro- duced a substance " exactly resembling chyme." This experiment was pretty widely repeated, and many were equally successful with " dilute muriatic acid" as was Dr. Thompson. Others, on the contra- ry, declared their failure, and others, like Dr. Prout, maintained that this acid retarded digestion. Eberle had already advanced the hy- pothesis that mucous membranes, no matter whether of the stomach or the bladder, dissolved either in muriatic or acetic acid, would form the true gastric juice, and perform its wonderful operations. There is now a general bias in favor of one of these compounds, though other preparations are supposed by many to form very good gastric juice. Again, it is said that the " digestive mixture," as it has been well de- nominated by the manufacturers, " retains its solvent properties for months," whilst the gastric juice loses its solvent power soon after its abstraction from the stomach. And what equally establishes a total difference between the " mixture" and the gastric juice is the no small circumstance that the chemist may torture and extinguish the artificial " digestive principle" in a variety of ways, and then transmute it back in all its vigor. Thus, according to Schwann and Miiller, the artifi- cial " digestive principle" may be neutralized by an alkali, and after- wards " precipitated from its neutral solution by acetate of lead, and ob- tained again in an active state from that precipitate by means of hydro- sulphuric acid." This precipitate, we are told, when thus treated, and thus compounded of principles radically different from the original mixture, is essentially the same as the gastric juice, and that the results of such artificial preparations must be taken as the test of the physiolo- gy of natural digestion; that, abandoning nature, we must look to the resources of the laboratory for any satisfactory account of her vital processes. Nor do I at all exaggerate ; for it is distinctly avowed that we knew nothing of digestion till the invention of the artificial mixtures. Thus, it is said of Schwann by one so able and distinguished as Miil- ler, that he, (Schwann) " having discovered that the infusion of dry mucous membrane with dilute acid, even after it is filtered, still retains 24 its digestive power, the digestive principle, therefore, is clearly in solu- tion, and the theory of digestion by contact falls to the ground." Here, a most important physiological induction is wholly founded upon a pro- cess which has not the most remote connection with organized matter ; and as to the paradox which involves the combined agencies of muri- atic acid, alkalies, acetate of lead, hydro-sulphuric acid, and mucous membranes, it is certainly a burlesque upon the science of chemistry. I have said that the experimenters took the hint of manufacturing gastric juice from the occasional discovery of an acid in the stomach. But, this is undoubtedly a rare phenomenon in a healthy stomach, and where the food has been at all appropriate in quality and quantity.— The chemical hypothesis, as I have said, was long ago in vogue, and was put at rest by demonstrative proof. Distinguished observers, Hun- ter, Haller, Willis, Spallanzani, Fordyce, and more recently Dumas, Schultz, and others, insist that the reputed acid is the result of a true chemical decomposition of vegetable matter. Spallanzanf, whose ex- periments were almost endless, Scopoli, Chevreuil, and others, rarely succeeded in finding it at all, and in some animals never. Spallanzani, indeed, affirms that the gastric juice is neither acid nor alkaline in its natural state. As far back as Haller's day, when this subject was agitated, it is said by this illustrious and accurate observer, that, " although there may be some rare signs of an acid in the stomach, it does not, there- fore, become us to suppose that food is animalized by a chemical pro- cess; much less to compare this process with the action of an acid." And, anticipating the modern experiments with the " digestive mix- ture," he declares of analogous proceedings at his own era, " frustra etiam quisquam, imitatus liquores acres chemicos, liquorem corroden- tem invenerit, qui carnem in pultem resolvat." And there can be no doubt that Hunter's prophecy holds good to this day, that— " If ever any matter is formed in any of the juices secreted in any part of a vegetable or animal body similar to what arises from fermen- tation, we may depend on it, it arose from that process ; but we may also depend on it, that there is a defect of the living principle in these cases." These are not the mere speculations of genius, but the facts and the conclusions of genius after a long, and wide, and experimental survey of nature.* And are these observations, nay, our own experience, our own senses, to be set aside to accommodate a hypothesis of life which identifies dead, even inorganic, with living beings ? I might thus go on to multiply proofs of the foregoing nature, not a lit- tle of which is supplied by distinguished observers of the present day ; and a variety of other facts might be brought in opposition to the che- mical hypothesis of digestion. But time presses, and I must come to a conclusion ; but not without expressing the conviction that it is here, especially-, that the physiologist must raise his principal defence against the invasions of chemistry. Defeated upon this ground, the adversary may be easily expelled from the whole domain of organic life. * See mottos, 1st, 2nd, 3rd, 5th and 16th paragraphs. Yet is it said that the chemical speculations " must command the respect of their opponents." ,.**,* Paine's Medical and Physiological Commentaries, in 3 volumes, may be had only at the Au lota»r M no' mT^ «7 1N6W ^rk> Nu°- °f royal OCtavo PaSes 1988- Pric* of th« lst and ^ \oiumes, $().uo. the 3d volume without charge.