OPSONIC ACTION 



169 



In this experiment treated serum A has still traces of opsonlc and 

 hsemolytic action, but both properties are much more reduced than in 

 serum B. 



The following is another example where the normal guinea-pig's 

 serum was treated with Spirillum Metchnikovi + its anti-serum, and 

 with the spirillum alone : 



1. Hcemolytic action. 



Minimum Hcemolytic Doses 



2. Opsonic action. 



Number of cocci ingested per leucocyte 



The hsemolytic action of Serum A is less reduced than in the previous 

 examples, and the opsonic action is also relatively more marked. 



3. Bactericidal action , tested on ^uVo c - c - ^ bouillon 

 culture of B. dysenterice. 



Number of Colonies 



Both of the treated serums have been practically deprived of 

 their bactericidal power, though there is evidence of a small residuum. 

 The colonies appeared to be approximately the same in the two 

 series but were too numerous to estimate accurately. 



The marked reduction of bactericidal action resulting 

 from treatment with a heterologous organism (V. Metchni- 

 kovi) is in accordance with the results to be recorded later 

 (p. 201). 



