ESSAYS ON BACTERIOLOGY. 57 



yet, too often at the mercy of the almost invisible foes 

 which prey npon and destroy the majority of onr race. 

 But we are steadily advancing in knowledge, which is 

 power, and one day we shall conqner. It may be by 

 this means, it may be by that, but we shall conquer. 

 One day, we believe, we shall issue to the pestiferous 

 brood the authoritative command: Out upon you; 

 hence, begone! 



