X. Bichat and G. Cuvier: Vital and Physical Properties Antagonistic.—The archeus and the blas of Van Helmont were but a first rough outline of vital properties. Xavier Bichat, the founder of general anatomy, wearied of all these incorporeal entities, of these unsubstantial principles with which biology was encumbered, undertook to get rid of them by the methods of the physicist and the chemist. The physics and the chemistry of his day referred phenomenal manifestations to the properties of matter, gravity, capillarity, magnetism, etc. Bichat did the same. He referred vital manifestations to the properties of living tissues, if not, indeed, of living matter. Of these properties as yet but very few were known: the irritability described by Glisson, which is the excitability of current physiology; and the irritability of Haller, which is nothing but muscular contractility. Others had to be discovered.
There is no need to recall the mistake made by Bichat and followed by most scientific men of his time, such as Cuvier in France, and J. Müller in Germany, for the story has been told by Claude Bernard. His mistake was in considering the vital properties not only as distinct from physical properties but even as opposed to them. The one preserve the body, the others tend to destroy it. They are always in conflict. Life is the victory of the one; death is the triumph of the other. Hence the celebrated definition given by Bichat: “Life is the sum total of functions which resist death,” or the definition of the Encyclopædia: “Life is the contrary of death.”
Cuvier has illustrated this conception by a graphic picture. He represents a young woman in all the health and strength of youth suddenly stricken by death. The sculptural forms collapse and show the angularities of the bones; the eyes so lately sparkling become dull; the flesh tint gives place to a livid pallor; the graceful suppleness of the body is now rigidity, “and it will not be long before more horrible changes ensue; the flesh becomes blue, green, black, one part flows away in putrid poison, and another part evaporates in infectious emanations. Finally, nothing is left but saline or earthy mineral principles, all the rest has vanished.” Now, according to Cuvier, what has happened?
These alterations are the effect of external agents, air, humidity, and heat. They have acted on the corpse just as they used to act on the living being; but before death their assault had no effect, because it was repelled by the vital properties. Now that life has disappeared the assault is successful. We know now that external agents are not the cause of these disorders. They are caused by the microbes of putrefaction. It is against them that the organs were struggling, and not against physical forces.
The mistake made by Bichat and Cuvier was inexcusable, even in their day. They were wrong not to attach the importance they deserved to Lavoisier’s researches. He had asserted, apropos of animal heat and respiration, the identity of the action of physical agents in the living body and in the external world. On the other hand, Bichat, by a flash of genius, decentralized life, dispersing the vital properties in the tissues, or, as we should now say, in the living matter. It was from the comparison between the constitution and the properties of living matter and those of inanimate matter that light was to come.
§ 3. Scientific Neo-Vitalism.
We can now understand the nature of modern neo-vitalism. It borrows from its predecessor its fundamental principle—namely, the specificity of the vital fact. But this specificity is no longer essential, it is only formal. The difference between it and the physical fact grows less and almost vanishes. It consists of a diversity of mechanisms or executive agents. For example, digestion transforms the alimentary starch in the intestines into sugar; the chemist does the same in his laboratory, only he employs acids, while the organism employs special agents, ferments, in this case a diastase. It is a particular form of chemistry, but still it is a chemistry. That is how Claude Bernard looked at it. The vital fact was not fundamentally distinguished from the physico-chemical fact, but only in form.
This expurgated and accommodated vitalism (Claude Bernard pushed his concessions so far as to call his doctrine “physico-chemical vitalism”) was revived a few years ago by Chr. Bohr and Heidenhain.
Other biologists, instead of attributing the difference between the phenomena of the two orders to the manner of their occurrence, seem to admit the complete identity of the mechanisms. It is no longer then in itself, individually, that the vital act is particularized, but in the manner in which it is linked to others. The vital order is a series of physico-chemical acts realizing an ideal plan.
Neo-vitalism has therefore assumed two forms, one the more scientific and the other the more philosophical.