Doubtless, there is much that might be criticised in the foregoing words of Bichat; nevertheless, to say that the passions expend their influences upon the organic life, is not the same thing as to say that they reside or exist there. Bichat had already remarked, that “Every species of sensation has its centre in the brain, for sensation always supposes both impression and perception.”[9] Furthermore, regarding this distinction, (which as yet has not been drawn with sufficient clearness,) between the parts that are the seats of the passions, and the parts that are affected by their action, Gall might have found in Descartes the following remark, which is not less judicious than acute. “Although,” says he, writing to Leroy, “the spirits that move the muscles come from the brain, we must, nevertheless, assign as seats of the passions, the places that are most considerably affected by them; hence, I say, the principal seat of the passions, as far as they relate to the body, is the heart, because it is the heart that is most sensibly affected by them; but their place is in the brain, in as far as they affect the soul, for the soul cannot suffer immediately, otherwise than through the brain.”[10] As I am quoting Descartes, who, I ask, more clearly than Descartes has perceived that the soul can have only a very circumscribed seat in the economy, and that that circumscribed seat is the brain itself? “We know,” says he, “that, properly speaking, it is not inasmuch as the soul is in the members that serve as organs to the exterior senses, that the soul feels, but inasmuch as she is in the brain, where she exercises the faculty denominated common sense.”[11] He elsewhere observes: “Surprise is expressed because I do not recognise any other point of sensation except that which exists in the brain; but all physicians and surgeons will, I hope, assist me in proving this point, for they are aware of the common fact that a person who has been subjected to amputation of a limb, continues to feel pain in a part that he no longer possesses.”[12] Here then, according to Descartes, we find that the soul is situated, that is to say, _feels_ in the brain, and only in the brain. The following passage shows with what precision he excluded even the external senses from any participation with the functions of the soul. “I have shown,” says he, “that size, distance, and form are perceived only by the reason; and that, by deducing them the one from the other.”[13]