BACTERICIDAL ACTION OF NORMAL SERUM 201 



We have also made a series of tests to determine what, 

 if any, effect the amounts of dead bouillon culture which 

 give positive results in the above table have on the haemo- 

 lytic dose of complement. In these experiments varying 

 amounts of guinea-pig's serum were treated for two hours 

 at 37 C. with 0-1 c.c. of dead bouillon culture of the several 

 organisms, and the smallest amount of treated serum which 

 gave complete lysis with the test amount of sensitized 

 corpuscles was thereafter ascertained in the usual way, 

 similar quantities of untreated serum being used as a control. 

 It was found that the amount of dead culture mentioned 

 was practically without effect on the haemolytic dose of 

 complement in the case of B. dysenteries, V. cholerce, V. 

 Metchnikovi, and B. typhosus; in the case of B. Gaertneri 

 there was a distinct increase of the hsemolytic dose, but 

 this organism was not used as an absorbing agent in 

 the experiments. This test for the reduction of hsemolytic 



