168 ANTI-BACTERIAL PROPERTIES OF SERUM 



1. Hcemolytic Action. 



2. Opsonic action, tested on emulsion of Staphylococcus 

 aureus. 



Average number of cocci ingested per leucocyte 



It is thus seen that treated serum A is practically without 

 haemolytic and opsonic action. Treated serum B occupies 

 an intermediate position, and its haemolytic action appears 

 to be more reduced than its opsonic action. This is prob- 

 ably, however, due to there being excess of opsonin in the 

 normal serum, so that a considerable reduction of the 

 quantity might be produced without there being a marked 

 effect on the number of cocci ingested. 



The following is another example, guinea-pig's serum 

 being treated as above with B. coli + its anti-serum, and 

 with the bacillus alone : 



1. Hcemolytic action , shown by the minimum haemolytic 

 dose. 



2. Opsonic action. 



Average number of cocci ingested per leucocyte two 

 suspensions (a) and (b). 



