THE HISTORY OF BACTERIOLOGY. 455 



it has happened merely that one disease entity, 

 the diseased cell, has been replaced by another 

 disease entity, the pathogenic bacillus. On the 

 basis of such a conception, however, thousands 

 of observations upon healthy and diseased 

 human beings remain irreconcilable and just 

 as little capable of comprehension as before. 

 Only on a conception not ontological, but me- 

 chanical or dynamical, forming a part of the 

 monistic conception of the universe, will all 

 discoveries be made more intelligible ; and the 

 variable as well as the constant will find its 

 place, the mysticism of ontology having 

 been taken away from both. By advanc- 

 ing this scientific conception bacteriology is 

 qualified to influence medical thought favor- 

 ably and to render it essentially more pro- 

 found. 



Bearing this possibility in mind the position 

 of scientific bacteriology in medicine and 

 hygiene is sharply and clearly defined. As I 

 have tried to show connectedly in the present 

 work, the striving of scientific medicine after 

 unity finds in this scientific exposition of 

 bacteriology a clear and comprehensive ex- 

 pression. 



