164 ANTI-BACTERIAL PROPERTIES OF SERUM 



(&) FoW c.c. of a bouillon culture of B. dysenterice 

 (Kruse). 



It is thus seen that while the normal serum has a marked 

 bactericidal action on both the organisms tested, the treated 

 and the heated serums alike have been deprived of their 

 bactericidal properties. (Controls were made at the same 

 time without serum, and also to test the sterility of the 

 serums.) 



3. Opsonic Action 



This was tested, according to the method of Wright 

 and Douglas, against a suspension of Staphylococcus aureus, 

 with the following results : 



Average number of cocci ingested per leucocyte 



It thus appears that the serum treated in the manner 

 indicated has practically the same opsonic effect as the 

 heated serum. In the films prepared with both of these 

 serums, one met here and there with single leucocytes 

 containing a considerable number of cocci, but nearly all 

 were quite empty. 



The general result of these experiments is to show that 

 the receptors of red corpuscles in union with the correspond- 

 ing immune-body take up not only ' hsemolytic comple- 

 ment', but also ' bactericidal complement ' and ' opsonin J 

 of normal serum. 



