23 



MICROBES AND THE MICROBE- KILLER. 



reaching as they are simple. She does not devise some 

 comphcated plan for producing one particular disease, 

 and then set to work to arrange another cause for a 

 second form of sickness. On the contrary, she lays 

 down certain broad rules upon which all operations are 

 conducted. These rules apply to both kingdoms of or- 

 ganic life, with results that are only modified by circum- 

 stances of each. If they are not respected, trouble 

 ensues. Eesistance brings about catastrophe, and even 

 neglect of their operation has its perils. But when we 

 know what we have to accomplish a great part of our 

 difficulty is cleared away. Directly we are informed as 

 to the cause of a disease, the chief obstacle to finding a 

 remedy is removed. But if we enter upon the investi- 

 gation blinded with tradition and with book-reading 

 only, it stands to reason that the greatest difficulties in 

 the way of discovering a remedy are presented. 



DIATOM ABACUNOIDUS 



