50 THE STORY OF THE BACTERIA. 



what, it was the office of the priest to say. 

 How many lives were sacrificed and homes 

 destroyed through that most honest of eccle- 

 siastical delusions, the miracle of the bleeding 

 Host, it were useless now even to conjecture. 



To-day we cultivate in our tubes the tiny 

 bacteria which, growing in masses, made the 

 drops of blood, and the last elements of 

 romance and tragedy seem to disappear from 

 the story as we name them Bacillus prodigi- 

 osus. 



There are some species of bacteria which 

 are mortal enemies and cannot live together, 

 one species killing out the other almost as 

 soon as they come in contact. The details of 

 this invisible mimic warfare we do not yet 

 understand, nor do we know what are the 

 weapons with which it is carried on. It is 

 probable that it is in virtue of some poison 

 which they form as they live and grow that the 

 victors gain possession of the field. 



On the other hand, there are two or three 

 instances of a sort of one-sided Damon-and- 

 Pythias story among these creatures ; for in 

 the attempts to isolate the species by culture it 



