ADDRESS. 13 



the tendencies whicli it exhibits in its origin. I wish now to complete 

 the sketch I have endeavoured to give of the way in which physiology 

 entered on the career it has since followed for the last half-century, by 

 a few words as to the influence exercised on general physiological theory 

 by the progress of research. We have seen that no real advance was 

 made until it became possible to investigate the phenomena of life by 

 methods which approached more or less closely to those of the phy- 

 sicist, in exactitude. The methods of investigation being physical or 

 chemical, the organism itself naturally came to be considered as a complex 

 of such processes, and nothing more. And in particular the idea of 

 adaptation, which, as I have endeavoured to show, is not a consequence 

 of organism, but its essence, was in great measure lost sight of. Not, I 

 think, because it was any more possible than before to conceive of the 

 organism otherwise than as a working together of parts for the good of 

 the whole, but rather that, if I may so express it, the minds of men were 

 so occupied with new facts that they had not time to elaborate theories. 

 The old meaning of the term 'adaptation ' as the equivalent of ' design ' had 

 been abandoned, and no new meaning had yet been given to it, and con- 

 sequently the word ' mechanism ' came to be employed as the equivalent of 

 ^process,' as if the constant concomitance or sequence of two events was in 

 itself a sufficient reason for assuming a mechanical relation between them. 

 As in daily life so also in science, the misuse of words leads to miscon- 

 ceptions. To assert thab the link between a and b is mechanical, for no 

 better reason than that i always follows a, is an error of statement, which 

 is apt to lead the incautious reader or hearer to imagine that the relation 

 between a and b is understood, when in fact its nature may be wholly 

 ■unknown. "Whether or not at the time which we are considering, some 

 physiological writers showed a tendency to commit this error, I do not 

 think that it found expression in any generally accepted theory of life. 

 It may, however, be admitted that the rapid progress of experimental in- 

 vestigation led to too confident anticipations, and that to some enthusiastic 

 minds it appeared as if we were approaching within measurable distance 

 of the end of knowledge. Such a tendency is, I think, a natural result 

 of every signal advance. In an eloquent Harveian oration, delivered last 

 autumn by Dr. Bridges, it was indicated how, after Harvey's great dis- 

 covery of the circulation, men were too apt to found upon it explanations 

 of all phenomena whether of health or disease, to such an extent that the 

 practice of medicine was even prejudicially affected by it. In respect of 

 its scientific importance the epoch we are considering may well be com- 

 pared with that of Harvey, and may have been followed by an undue 

 preference of the new as compared with the old, but no more permanent 

 unfavourable results have shown themselves. As regards the science of 

 medicine we need only remember that it was during the years between 

 1845 and 1860 that Yirchow made those researches by which he brought 

 the processes of disease into immediate relation with the normal processes 



