DESTRUCTION OF BACTERIA BY PHAGOCYTOSIS 57 



pigeons where they were able to recover anthrax bacilli from the 

 leukocytes of the peritoneal extulate, both by culture and animal 

 inoculation. 



Special stress is laid upon the fact that these results were obtained 

 in immune animals, as it could only be shown in this w r ay that the 

 leukocytes are capable of taking up not only living but also virulent 

 bacteria, i. e., bacteria which in the non-immune organism w r ould have 

 produced a general infection. That living foreign cells are subject 

 to phagocytosis is also well shown by the following experiments: If 

 a guinea-pig is injected intraperitoneally with goose's blood contain- 

 ing the spirillum of Sacharoff, which produces a septicemic infection 

 in geese, and if a drop of the exudate is then examined under the 

 microscope, phagocytosis of the spirilla in this case by macrophages 

 can be observed directly, and it will be seen that many of the organ- 

 isms are quite motile as yet with their free ends, while the remainder 

 of the parasites has already been taken up by the cells. 



While there can thus be no doubt that both microphages and macro- 

 phages can take up living foreign cells the next question of importance 

 is: What happens to the organisms after they have been taken up? 

 Two possibilities, of course, suggest themselves. We may imagine, 

 on the one hand, that the phagocyte destroys the bacteria, and a 

 priori this would seem the most natural thing to expect. On the 

 other hand the possibility at least must be borne in mind that the 

 bacteria may destroy the phagocytes. If this were to happen we 

 could readily understand that phagocytosis might at times be of some 

 danger to the animal, for we could see that a chance might thus be 

 afforded for a wider distribution of the parasites. The possibility of 

 such an occurrence is suggested by the fact that the phagocytosis 

 of tubercle bacilli by giant cells, for example, usually leads to the 

 destruction of the latter and not necessarily to the death of the 

 bacilli. It must be admitted, however, that the greater weight of 

 the evidence goes to show that sooner or later the ingested organisms 

 are killed. The intracellular granular degeneration of bacteria which 

 one can observe directly under the microscope certainly points in 

 that direction 



Destruction of Bacteria by Phagocytosis. Of the manner in which 

 the destruction of the bacteria is brought about, we are as yet in 

 comparative ignorance. Recent research seems to show that the 

 leukocytes contain special endolysins which may be operative in this 



