25 



the bacteria in the leucocytes of septic blood freshly de- 

 posited on the first slide, watch them multiply until they 

 break out of the containing cell and extend over the gel- 

 atine, transfer these to a second slide, observe their 

 continued multiplication, and so on indefinitely. By this 

 method, and by no other at present employed, we have 



Fig. 5. Anthrax culture invaded by other bacteria. X 300. 



ocular demonstration that the organisms injected into an 

 animal from the tenth, fiftieth, hundredth culture are 

 structural continuities of the organisms present in the 

 first animal ; by this method we know that the tenth 

 culture, for example, contains absolutely nothing of the 

 original tissue except that incorporated into the living 

 2 



