The first period is that of protoplasmic, vital, organic pre-conscious sensibility. We know that the organism has its memory; it preserves certain impressions, certain normal or morbid modifications; it is capable of adaptation: this point has been well established by Bering (who had been preceded by Laycock and Jessen). It is the outline of the superior form of psychic conscious memory. In the same way there exists an inferior unconscious form—organic sensibility—which is the preparation and the outline of superior conscious emotional life. Vital sensibility is to conscious feeling what organic memory is to memory in the ordinary sense of the word. This vital sensibility is the capacity to receive stimuli and to re-act to them. In a well-known memoir, now of ancient date,[2] Claude Bernard wrote: “Philosophers generally only know and admit conscious sensibility, that which their ego bears witness to. It is for them the psychic modification, pleasure or pain, determined by external modifications.... Physiologists necessarily place themselves at another point of view. They have to study the phenomenon objectively, under all the forms which it puts on. They observe that at the moment when a modifying agent acts on man, it not only provokes pleasure and pain, it not only affects the soul: it affects the body, it determines other re-actions besides the psychic re-actions, and these automatic re-actions, far from being an accessory part of the phenomenon, are on the contrary its essential element.” Then he showed experimentally that the employment of anæsthetics, pushed to an extreme, first abolished conscious sensibility, then the unconscious sensibility of the intestines and glands, then muscular irritability, finally the lively movements of the epithelial tissue. In the same way among plants: under the influence of ether the sensitive plant loses its singular properties, seeds cease to germinate, yeast to ferment, etc. Whence follows the conclusion that sensibility resides, not in the organs or tissues, but in their anatomical elements. ----- Footnote 2: “La sensibilité dans le règne animal et le règne végétal”, (1876, in _Science expérimentale_, pp. 218 _et seq._). -----