DISEASE-GERMS. 245 



new direction he has given to scientific inquiry, the number of new- 

 paths of research he has opened out, and of new clews he has afforded 

 to those who will follow them up, and, last but by no means least, by 

 the admirable example he has afforded, in the strictness and severity 

 of his own methods (which have made him almost unerring in his pre- 

 dictions, and have given his conclusions the force of demonstrations), 

 to those who would carry on the same lines of inquiry. 



And here I would stop to note, as honorable to the disinterested 

 character of a profession which has been lately the object of violent 

 abuse for its (alleged) selfish and mercenary spirit, that this unique 

 welcome was given, not to a great physician who had discovered a 

 cure for gout, cancer, or consumption, by the use of which it would be 

 enriched not to a bold surgeon who had brought into vogue some 

 wonderful operation, the success of which would tend to its renown 

 but to the scientific investigator of the causes of disease, whose work 

 belongs altogether to the domain oi preventive medicine, and thus, so 

 far from being likely to benefit its members pecuniarily, tends only to 

 diminish their remunerative employment. I never felt so proud of 

 belonging to the body which still does me the honor to recognize me 

 as one of its members as I did when Sir James Paget, the President 

 of the Congress, paused in his opening address to point out on the 

 platform behind him the greatest living exemplar of the truths he was 

 so admirably enforcing, and when the whole of his vast audience 

 the like of which had never before been gathered in St. James's Hall, 

 and perhaps never will be again enthusiastically cheered, not once 

 only, but again and again, the scientific veteran whose renown has 

 spread from his quiet Parisian laboratory over the whole civilized 

 world. 



In order that the last of Pasteur's great achievements which, 

 with some of the ideas it suggests, it is my object now to bring be- 

 fore the readers of " The Nineteenth Century " may be properly ap- 

 preciated, it will be well for me to sketch out briefly what has been 

 the nature of his life-work from the time when the singular beauty of 

 some of his chemico-physical researches (which obtained for bim in 

 1856 the Rumford Medal of the Royal Society) marked him out as 

 one likely to attain further distinction. 



It seems to have been by his special interest in the chemistry of 

 organic substances that he was early led to examine into the question 

 of fermentation, which had come to present an entirely new aspect 

 through the discovery of Cagniard de la Tour that yeast is really a 

 plant belonging to one of the lowest types of fungi, which grows 

 and reproduces itself in the fermentable fluid, and whose vegetative 

 action is presumably the cause of that fermentation, just as the devel- 

 opment of mold in a jam-pot occasions a like change in the upper 

 stratum of the jam, on whose surface and at whose expense it lives 

 and reproduces itself. Chemists generally especially Liebig, who 



