morbid agency of the trichina, but would merely call atten- 

 tion to the fact that for this belief we have really no more 

 conclusive evidence than we have for accepting the path- 

 ogenetic influence of bacteria in leprosy and in several 

 other diseases. Yet it will doubtless be years before 

 some of us realize the fact that in this unreasoning and 

 prejudiced opposition to demonstrated facts, we are play- 

 ing the unenviable role of the cow to the locomotive of 

 advancing science. George Stephenson's prophecy 

 that the result of such collision would be "bad for the 

 con" has been often fulfilled; neither horned cattle 

 nor pseudo-bacilli have materially retarded the progress 

 of science. The improvement of means and methods 

 for minute investigation has ever been and must still be 

 followed by further advance into the realm of the minute, 

 whose boundaries doubtless stretch far beyond the pres- 

 ent means of optical exploration. After centuries of 

 controversy the intestinal worms banished the " ver- 

 micular diathesis ;" the acarus scabiei conquered the 

 " itch cachexia ;" the step from the acarus to the bacil- 

 lus tuberculosis is not quantitatively greater than from 

 the tape-worm to the acarus ; each is merely the measure 

 of successive improvements in means for minute obser- 

 vation. Yet the same spirit which nursed the vermicu- 

 lar and itch diatheses, will doubtless for years see in 

 bacteria only fibrin threads and fat crystals ; and will 

 cling with heroic devotion to the tubercular diathesis, 

 to "micro-necrosis," and to narrow lymph-spaces. 



When we glance over the progress of the last few 

 years ; when we consider the life-saving revolution in 

 surgical methods ; when we regard the enhancement, in- 

 deed the very salvation of enormous economic interests 

 by the eradication of the bacterial disease of silkworms, 

 without mentioning preventive vaccination against anthrax 

 and chicken-cholera, we may search in vain the records 

 of other departments of science during the same period 

 for discoveries which have secured direct personal and 

 pecuniary advantages comparable to those derived from 

 our present incomplete knowledge of the relations of mi- 



