[Footnote 25: From a note entitled _On the Constitution of Bodies_ which Dalton wrote and had incorporated in Thomas Thompson’s _System of Chemistry_ (3d edition, 1807).] XXIII MARIE FRANÇOIS XAVIER BICHAT 1771-1802 _Bichat was born in the French town of Thoirette (Department of Ain), November 14, 1771. At the University of Lyons he was especially interested in anatomy, surgery, and natural history. In 1793, because of the Revolution, he fled to Paris, where he studied under the eminent surgeon Desault. In 1800 he distinguished between animal and organic functions and after many dissections he developed, in 1801, his famous doctrine of tissues. He died July 22, 1802, from injuries received in a fall._ THE DOCTRINE OF TISSUES[26] OBJECT OF THE WORK The general doctrine of this work has not precisely the character of any of those which have prevailed in medicine. Opposed to that of Boerhaave, it differs from that of Stahl and those authors who, like him, refer everything in the living economy to a single principle, purely speculative, ideal, and imaginary, whether designated by the name of soul, vital principle, or archeus. The general doctrine of this work consists in analyzing with precision the properties of living bodies, in showing that every physiological phenomenon is ultimately referable to these properties considered in their natural state; that every pathological phenomenon derives from their augmentation, diminution, or alteration; that every therapeutic phenomenon has for its principle the restoration of that part of the natural type, from which it has been changed; in determining with precision the cases in which each property is brought into action; in distinguishing accurately in physiology as well as in medicine, that which is derived from one, and that which flows from others; in ascertaining by rigorous induction the natural and morbific phenomena which the animal properties produce, and those which are derived from the organic; and in pointing out when the animal sensibility and contractility are brought into action, and when the organic sensibility and the sensible or insensible contractility. We shall be easily convinced upon reflection, that we cannot precisely estimate the immense influence of the vital properties in the physiological sciences, before we have considered these properties in the point of view in which I have presented them. It will be said, perhaps, that this manner of viewing them is still a theory; I will answer that it is a theory like that which shows in the physical sciences, gravity, elasticity, affinity, etc., as the primitive principles of the facts observed in these sciences. The relation of these properties as causes to the phenomena as effects, is an axiom so well known in physics, chemistry, astronomy,