The work which I now offer to the public, will appear to them new, I trust, in three points of view; 1st, in the plan that has been adopted; 2d, in most of the facts which it contains; and 3d, in the principles which constitute its doctrine.
1st. The plan consists in considering separately and presenting with all their attributes, each of the simple systems, which, by their different combinations, form our organs. The basis of this plan is anatomical, but the details that it embraces belong also to medicine and physiology. It has nothing in common, but the name, with what has been lately advanced upon the anatomy of systems; my Treatise on the Membranes alone gives an outline of it.
2d. The facts and observations in this work, in addition to what is already known, form a very numerous series. I shall not give an analysis of them; the reader will supply it, how little soever he may know of works on Anatomy and Physiology. Experiments on living animals, trials with different reagents on organized textures,[1] dissection, examinations after death, observations upon man in health and disease, these are sources whence I have drawn them, and they are the sources of nature. I have not, however, neglected authors, those especially who make the science of the animal economy a science of facts and experiments.
I will make but one remark upon the experiments contained in this work; amongst them will be found a series upon the simple textures, which I subjected successively to desiccation, putrefaction, maceration, ebullition, stewing, and to the action of the acids and the alkalies. It will be easily seen, that it was not the object of these experiments to determine the composition, or ascertain the different elements, and consequently give a chemical analysis of simple textures; for this purpose they would have been insufficient; but their object was to establish the distinctive characters of these simple textures, to show that each has a peculiar organization, as each has a peculiar life, and to prove by the different results which they gave, that the division which I have adopted is not speculative, but that it rests upon the diversity of their intimate structure. The different re-agents, which I used, were only to assist me where the scalpel was insufficient, and on this account, therefore, I presume these experiments will have some influence upon Anatomy.
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.
There are in nature two classes of beings, two classes of properties, and two classes of sciences. The beings are either organic or inorganic, the properties vital or non-vital, and the sciences physiological or physical. Animals and vegetables are organic—minerals are inorganic. Sensibility and contractility are vital properties; gravity, elasticity, affinity, &c. are non-vital properties. Animal and vegetable physiology, and medicine form the physiological sciences; astronomy, physics, chemistry, &c. are the physical sciences. These two classes of sciences have relation only to different phenomena; there are two other classes that correspond to these, which relate to the internal and external forms of bodies and their description. Botany, anatomy, and zoology, are the sciences of organic bodies; mineralogy, &c. of the inorganic. The first will occupy us, and we shall fix our attention especially upon the relations of living bodies with one another, and their relations with those that do not live.
I. General remarks upon physiological and physical sciences.
The differences between these sciences are derived essentially from those existing between the properties that preside over the phenomena, which are the object of each class of sciences. So immense is the influence of these properties, that they are the principle of all phenomena; whether we examine those of astronomy, of hydraulics, of dynamics, of optics, of acoustics, &c. we shall finally arrive by a connexion of causes to gravity, to elasticity, &c. as the end of our researches. So the vital property is the primum mobile to which we must ascend, whether we consider the phenomena of respiration, of digestion, of secretion, circulation, inflammation, fevers, &c.—In giving existence to every body, nature has imprinted upon it a certain number of properties, that particularly characterize it, and by means of which it contributes in its own manner, to all the phenomena that are developed, succeed, and continually connect themselves in the universe. Cast your eyes upon that which surrounds you; turn them upon objects the most distant; whether, aided by the telescope, they examine those that swim in space, or, armed with the microscope, they enter the world of those, whose minuteness almost evades our view, every where you will find on one side physical properties, on the other vital properties, brought into action; every where you will see inert bodies gravitating upon each other, and reciprocally attracting; living bodies gravitate also, but above all they feel, and possess a motion which they owe only to themselves.