xlii INTRODUCTION. 



not so gifted often discerns nothing but the extra- 

 vagance, which it avoids. Names, not yet forgotten, 

 could be given to illustrate these two classes of minds. 

 As representative of the first class, I would name a 

 man whom I have often named before, who, basing 

 himself in great part on the researches of Pasteur, 

 fought, in England, the battle of the germ theory with 

 persistent valour, but whose labours broke him down 

 before he saw the triumph which he foresaw completed. 

 Many of my medical friends will understand that I 

 allude here to the late Dr. William Budd, of Bristol. 



The task expected of me is now accomplished, and 

 the reader is here presented with a record, in which 

 the verities of science are endowed with the interest 

 of romance. 



JOHN TYNDALL. 



ROYAL INSTITUTION : December 1884 



