3d. 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 every thing 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 them augmentation, diminution, or alteration; that every therapeutic phenomenon has for its principle the restoration of the part to 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, &c. 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, &c. at the present day, that it is unnecessary to repeat it. If this work establishes an analogous axiom in the physiological sciences, its object will be attained. GENERAL OBSERVATIONS.