ON THOUGHT IN MEDICINE. 201 



you about the metamorphosis which has taken place in 

 medicine during this period, and with the results of 

 whose development you are better acquainted than I 

 am. I should like the impression of this development 

 and of its causes not to be quite lost on the younger of 

 my hearers. They have no special incentive for con- 

 sulting the literature of that period ; they would meet 

 with principles which appear as if written in a lost 

 tongue, so that it is by no means easy for us to transfer 

 ourselves into the mode of thought of a period which 

 is so far behind us. The course of development of 

 medicine is an instructive lesson on the true principles 

 of scientific inquiry, and the positive part of this 

 lesson has, perhaps, in no previous time been so im- 

 pressively taught as in the last generation. 



The task falls to me, of teaching that branch of the 

 natural sciences which has to make the widest gene- 

 ralisations, and has to discuss the meaning of funda- 

 mental ideas ; and which has, on that account, been 

 not unfitly termed Natural Philosophy by the English- 

 speaking peoples. Hence it does not fall too far out of 

 the range of my official duties and of my own studies, if I 

 attempt to discourse here of the principles of scientific 

 method, in reference to the sciences of experience. 



As regards my acquaintance with the tone of 

 thought of the older medicine, independently of the 

 general obligation, incumbent on every educated 



