12 ESSAYS ON BACTEKIOLOGY. 



This now we are able to do. We can see bacteria, 

 can cultivate them, can identify and grow the differ- 

 ent varieties. We can plant them in the bodies of 

 men and animals, and reproduce at will the diseases 

 from which the bacteria were obtained. And thus 

 we are able to prove our theory. It is the invention 

 of methods for the artificial cultivation of bacteria 

 which has made it possible for us to handle and work 

 with these minute organisms, and which, with the aid 

 of the microscope, has removed the germ theory of 

 disease from the realm of speculation and established 

 it, as I have said, as a demonstration of science. 



The germ theory of disease is no longer matter of 

 dispute. It is as clearly demonstrated as the laws of , 

 gravitation. Of him who does not know it it is to be 

 said that he has not as yet really heard the evidence 

 in the case. If anyone is still held in the bondage of 

 doubt, he has but to hear with an open ear this evi- 

 dence, and he will know the truth. And this truth 

 will make him free. 



