PRESENT STATE OF MEDICAL SCIENCE. 61

the greatest physiological discovery since that of Harvey.

In the department of general pathology alone, I only mention the labors of Williams, Chomel, and Henle; though the list might easily be made a long one.

Progress of hygiene and therapeutics since 1700.

III. The third department, or the science of conservation, includes two subdivisions, viz.: hygiene, public and private, and therapeutics. The number is so great of those who have advanced the science of therapeutics, that I cannot undertake to enumerate them. It would include every eminent practical writer—medical, obstetrical, and surgical—from Hoffman to the present time. I need only say, that the science of therapeutics, or the treatment of diseases, in the three departments of practice just mentioned, has kept pace with that of pathology, on which all true advancement in therapeutics must be based; and that the science of hygiene, or the preservation of health, has also advanced together with physiology.

And at length the question presents itself, what is the present state of our science? And I will attempt as brief a reply as possible.

PRESENT STATE OF MEDICAL SCIENCE.

I. We may regard descriptive and surgical anatomy as nearly complete in their development. Pathological anatomy, also, so far as its facts are concerned, may be regarded as susceptible of no very great additional advancement, unless some new aids to observation are adopted. The 120,000 bodies inspected post mortem by Rokitanski alone, we may well suppose, presented almost every structural lesion cognizable by our present means of observation, that the human body is liable to. But deductions of great importance and value are yet to be made from this vast array of facts. Rokitanski, like most pathological anatomists, is merely the cautious observer and the accurate reporter. Some deductive mind will yet give these observations their true scientific value.

In histology many facts are yet wanting, and will be supplied. Here also the labor of a deductive intellect is required to coordinate the facts ; which promise future discoveries not inferior to those of Harvey and Hall.

Microscopic anatomy, aside from histology, which is a particular phase of it, needs, and will acquire far greater definiteness, and advancement. Of comparative anatomy also the same may be remarked, from its importance in elucidating human physiology and pathology.

Present state of physiology and pathology.

II. On the recent rapid advancement of the science of function, we have much reason for congratulation. But we must still affirm that the physiology and the pathology of the present day are altogether too intensely chemical; and simply because we

PRESENT STATE OF PHYSIOLOGY. 63

implicitly receive our physiology, at the hands of chemists. Certainly the science of physiology cannot be formed without the aid of chemistry; but chemists should not, therefore, claim the whole field for themselves, nor should physiologists to such an extent have surrendered it. Chemistry conducts us to the threshold of physiology; but it can carry us no further. It is, therefore, a valuable and an indispensable guide thus far, but can be nothing more. But the chemists assuming, as did Paracelsus 300 years ago, that all the functions of the living body are merely the result of chemical actions,* virtually include physiology within their own domain. They next assume that a man weighs a certain number of pounds, say 140, and proceed to tell us how many ounces of food, both solid and fluid, he requires daily and per annum; just how much oxygen he consumes, and how much carbonic acid he exhales, and just what proportion of his weight he secretes in bile or gastric juice; and this they call making physiology a positive science. Physiologists, on the other hand, assert there is a distinct vital force; but still admit that possibly, after all, this force may be correlated with, or convertible into, chemical force, which is practically yielding the point to the chemists. Besides, we are reminded, that physiology is an inductive science, like chemistry; and therefore to be advanced in a similar way, and of course equally well, if not best of all, by chemists, from mere chemical facts.

But against this we enter our protest, for the following reasons:

1st. It is a principle to which there should be no exception, "never to attempt to solve the problems of one science, by the order of perceptions peculiar to another since each science has its own canons of interpretation and investigation and reasoning.

2d. If Physiology were mainly an inductive science, like chemistry, I have shown that physiologists alone can judge of the value and the true bearing of physiological facts, and they alone can collate them for the inductive process (pp. 20-21).

The doctrine of final causes.

But while chemistry is merely an inductive science, in the sense already assigned to that term —it being far more inductive than deductive— physiology is something more than an inductive science. It is at the same time both inductive and teleological. In other words, it is partly inductive, and partly relies for its advancement on the assumpof final causes. Prof. Whewell asserts that the "assumption of final causes has given rise to the science of physiology;" but if so, it consists, also, of principles obtained by the inductive process. The phrase "final cause" originated with Aristotle,* and is merely synonymous with the word "purpose." The doctrine of final causes has recently been expressed

* Aristotle's expression is, rt ov Ivekcv—icai rb ctyaBov, as indicating this kind of cause. See his Metaphysics.

by the word '1 teleology this word having reference, from its derivation, to the end, object, or purpose, of the part or organ under consideration. E. g. In order to ascertain the function or use of a part, we begin by assuming that it has some purpose— was formed for some particular end; and reasoning out that end or purpose from the structure and other circumstances, is applying the doctrine of final causes or reasoning teleologically. Bacon * regarded the "philosophy of final causes as sterile," and so does Geoffroy St. Hilaire. But it is the fact, that the use of every organ has been discovered by starting with the assumption that it must have some end.f The discovery of the circulation was due to the persuasion of a purpose in every part of the circulatory apparatus. In the science of function, we must, as Kant has remarked, "adopt the maxim, that nothing is in vain; and proceed upon it in the same way, in which in natural philosophy, we proceed upon the principle that nothing happens by chance."

Practically, therefore, the physiologist must adopt the principle of final causes; a principle entirely unknown to chemistry, or any other merely physical science, and peculiar to the physico-vital sciences— or physiology and pathology. He may say, with Geoffroy St. Hilaire, "I take care not to ascribe to God any intention; for I mistrust the feeble powers of my reason. I observe facts merely, and go no further. I only pretend to the character of the his

* "It is so far from being beneficial, that it even corrupts the sciences, except in the intercourse of man with man."—Nov. Organum, book ii.,. Aphorism ii. t Appendix, note ii.