FERMENTATION. 281 



ply, directly ruining the tissue on which they subsist, 

 or destroying life indirectly by the generation of poison- 

 ous compounds within the body. This conclusion, 

 which comes to us with a presumption almost amount- 

 ing to demonstration, is clinched by the fact that viru- 

 lently infective diseases have been discovered with 

 which living organisms are as closely and as indissolu- 

 bly associated as the growth of Torula is with the fer- 

 mentation of beer. 



And here, if you will permit me, I would utter a 

 word of warning to well-meaning people. We have now 

 reached a phase of this question when it is of the very 

 last importance that light should once for all be thrown 

 upon the manner in which contagious and infectious 

 diseases take root and spread. To this end the action of 

 various ferments upon the organs and tissues of the 

 living body must be studied ; the habitat of each special 

 organism concerned in the production of each specific 

 disease must be determined, and the mode by which its 

 germs are spread abroad as sources of further infection, 

 It is only by such rigidly accurate enquiries that we 

 can obtain final and complete mastery over these de- 

 stroyers. Hence, while abhorring cruelty of all kinds, 

 while shrinking sympathetically from all animal suf- 

 fering suffering which my own pursuits never call 

 upon me to inflict, an unbiassed survey of the field of 

 research now opening out before the physiologist causes 

 me to conclude, that no greater calamity could befall the 

 human race than the stoppage of experimental en- 

 quiry in this direction. A lady whose philanthropy 

 has rendered her illustrious said to me some time ago, 

 that science was becoming immoral ; that the researches 

 of the past, unlike those of the present, were carried OD 

 without cruelty. I replied to her that the science of 

 Kepler and Newton, to which she referred, dealt with 



