13- APPLICATION OF METHOD IN IXrECTlOUS DISEASES 



oat liu\v the organism defends itself when dishar- 

 monious 'substances introduce a disturbing element 

 into its metabolism, so delicately poised and har- 

 monized even in its finest details. In these problems 

 the most varied hypotheses regarding cellular meta- 

 bolism are to be met with. The more the biologist 

 enlarges the limits of his researches, and the more he 

 follows up all general phenomena, the more may he 

 venture to hope that he will gain new means and 

 new lines for the study of special processes. The 

 appearance of the defensive ferments in the animal 

 organism, when it is invaded by substances that are 

 out of harmony either with its body, with its blood, 

 or even with some of its cells, gives us an insight into 

 many problems of pathology, and particularly into 

 those of immunity. Every approximation of fields 

 of thought that are at first sight dissimilar, arising 

 cut of observations which allow us to presume 

 common reactions and common processes, must be 

 met with approval. It will then be possible that, 

 by an exchange of results based on very different 

 methods and hypotheses, we shall acquire a wide 

 outlook over the fundamental properties of cells of 

 different origin. 



Prolonged observations on a particular case of 

 definite disease will be of the greatest importance. 

 It would be absurd to investigate, sav, a hundred 



