THE CAUSE OF INFECTIOUS DISEASE. 221 



tive necessity for personification, for animate 

 cause. Men abandon the idea of such animate 

 causes only after more profound thought and 

 arrive first at a mechanical, then at a monistic 

 conception of the universe. Guided by the 

 pervasive, all-embracing law of the conserva- 

 tion of energy, the exact sciences have every- 

 where struggled through to a mechanical, and 

 in part even to a monistic standpoint. The 

 extraordinary complexity of the phenomena 

 which confront us in the consideration of the 

 origin of disease doubtless accounts for the 

 fact that up to this time no one of the concep- 

 tions in medical theory, either the dominant 

 ones or those in direct conflict with them, 

 have been freed altogether from the old mys- 

 tical animism. For this very reason not only 

 do scientific periodicals resound daily with the 

 clash of antagonistic principles, but the conflict 

 is continued in the daily press and even in the 

 conversations on street corners. 



In the presence of the great pestilence which 

 the Greeks before Troy T ascribed to the arrows 

 of the offended god Apollo, Homer makes the 

 father of gods and men say : 



" Lo, how men blame the gods ! From us they say, 

 spring troubles. But, through their own perversity, and 

 more than is their due, they meet with sorrow." 



1 The passage in question occurs in the Odyssey I.,32-34 E. O. J. 



