DISCUSSION 



Throughout this investigation it has been the custon 

 in each enumeration to determine not only the total number 

 of bacteria taken up by 50 neutrophile leucocytes, but also 

 to record the number of these cells actually taking part in 

 the en,c;ulfment . A survey of these records reveals in general 

 a parallelism between the variations in the phagocytic indices 

 and fluctuations in the percentage of phagocyting cells. Com- 

 monly a high phagocytic index is associated with a large per- 

 centage of phagocyting leucocytes, while a low index generally 

 is obtained in preparations with few ingesting cells. However, 

 this is not uniformly true and of the two methods of determining 

 the degree of phagocytic activity it would appear from this 

 research tiiat the technique of counting the number of or^:anisms 

 ingested is the more delicate and reliable. It has frequently 

 happened that the experimental animal revealed the same per- 

 centage of phagocyting cells as the control but yet exh.ibited 

 the utm.ost variation in the total number of bacteria ingested. 



There is always a quest-ion whether the opsonic results 

 obtained by incubating samples of cells and serum with in- 

 different suspensions of bacteria can be accepted as indicating 

 even approximately the conditions whicn prevail in the animal 

 body. It is, of course, at oncn recognized that a culture of 

 organisms grown on artificial medium may differ fundamentally 

 in their reaction to living cells, from bacteria which develop 



(60) 



