714 REPORT— 1881. 



of all, that knowledge -wliich enables us to sort the things known according to their 

 true relations. On this ground we call Haller the father of phj'siology, because, 

 regardless of existing theories, he brought together into a system, all that 

 was then known by observation or experiment as to the processes of the 

 living body. But in the ' Elementa Physiologic' we have rather that out of 

 which science springs than science itself. Science can hardly be said to begin 

 until we have by experiment acquired such a knowledge of the relation between 

 events and their antecedents, between processes and their products, that, in our 

 own sphere, we are able to forecast the operations of nature, even when they lie 

 beyond the reach of direct observation. I would accordingly claim for physiology 

 a place in the sisterhood of the sciences, not because so large a number of new 

 facts have been brought to light, but because she has in her measure acquired 

 that gift of prevision which has been long enjoyed by the higher branches of 

 •natural philosophy. In illustration of this, I have endeavoured to show you that 

 every step of the laborious investigations undertaken during the last thirty 

 years as to the process of nutrition, has been inspired by the previsions of J. R. 

 Mayer, and that what we have learnt with so much labour by experiments on 

 animals is but the realisation of conceptions which existed 200 years ago in the 

 mind of Descartes as to the mechanism of the nervous system. If I wanted 

 another example I might find it in the previsions of Dr. Thomas Young as to the 

 mechanism of the circulation, which for thirty years were utterly disregarded, 

 until at the epoch to which I have so often adverted, they received their full 

 justification from the experimental investigations of Ludwig. 



But perhaps it will occur to some one that if physiology founds her claim to be 

 regarded as a science on her power of anticipating the results of her own experi- 

 ments, it is unnecessary to make experiments at all. Although this objection has 

 been frequently heard lately from certain persons who call themselves philosophers, 

 it is not very likely to be made seriously here. The answer is, that it is contrary 

 to experience. Although we work in the certainty that every experimental result 

 will come out in accordance with great principles (such as the principle that every 

 plant or animal is, both as regards form and function, the outcome of its past and 

 present conditions, and that in every vital process the same relations obtain be- 

 tween expenditure and product as hold outside of the organism), these principles 

 do little more for us than indicate the direction in which we are to proceed. The 

 history of science teaches us that a general principle is like a ripe seed, which may 

 remain useless and inactive for an indefinite period, until the conditions favourable 

 to its germination come into existence. Thus the conditions for which the theory 

 of animal automatism of Descartes had to wait two centuries, were (1 ) the acquire- 

 ment of an adequate knowledge of the structure of the animal organism, and (2) 

 the development of the sciences of physics and chemistry ; for at no earlier moment 

 were these sciences competent to furnish either the knowledge or the methods 

 necessary for its experimental realisation ; and for a reason precisely similar Young's 

 theory of the circulation was disregarded for thirty years. 



I trust that the examples I have placed before you to-day may have been 

 sufficient to show that the investigators who are now working with such earnest- 

 ness in all parts of the world for the advance of physiology, have before them a 

 definite and well-understood purpose, that purpose being to acquire an exact know- 

 ledge of the chemical and physical processes of animal life, and of the self-acting 

 machinery by which they are regulated for the general good of the organism. 

 The more singly and straightforwardly we direct our efforts to these ends, the 

 sooner we shall attain to the still higher purpose — the effectual application of our 

 knowledge for the increase of human happiness. 



The Science of Physiology has already afforded her aid to the Art of Medicine 

 in furnishing her with a vast store of knowledge obtained by the experimental 

 investigation of the action of remedies and of the causes of disease. These 

 investigations are now being carried on in all parts of the world with great 

 diligence, so that we may confidently anticipate that during the next generation 

 the progress of pathology will be as rapid as that of physiology has been in the 

 j)a5t, and that as time goes on the practice of medicine will gradually come more 



