on non -virulent streptococci. He .was unable to confirm the view ad- 

 vanced by Bordet and others that a rabbit which is injected with strep- 

 tococci into a pleural cavity containing leucocytic exudate can stand a 

 larger dose than a rabbit of the same size which is injected in the normal 

 pleura. The pleural exudate was produced by the injection of aleuronat 

 suspension forty-eight hours previously. These results are quite 

 contradictory to those of other investigators, and it was, therefore, 

 thought desirable to repeat these experiments with leucocytes. 



Neufeld and Rimpatt* have shown that the leucocytes play an im- 

 portant role in combating streptococcus infections in immunized rabbits. 

 They have shown also that the addition of antistreptococcus serum to a 

 suspension of leucocytes and streptococci aids phagocytosis and that this 

 is not due to a stimulation of the phagocytes but to an effect of the serum 

 on the cocci. The specific substance in the immune serum they found 

 to be fairly resistant to heat, it being unchanged by heating at 59 C. for 

 ^2 hour. 



TEST TUBE EXPERIMENTS WITH LEUCOCYTIC EXUDATE FROM NORMAL ANI- 

 MALS. 



The leucocytic exudate used in these experiments was obtained 

 by injecting a 6-8% suspension of aleuronat in Na Cl solution into the 

 right pleural cavity of a rabbit or large guinea-pig and bleeding the 

 animal to death eight to ten hours later. The aleuronat suspension is 

 best prepared by sterilizing the aleuronat in dry heat at 150 to 160 C. 

 and suspending it in sterile physiological salt solution. No sodium 

 oxalate was added to the exudate, as this salt is strongly streptococcidal, 

 but the coagulation of the exudate was prevented by occasional agitation 

 of the tubes during the first hour. The contents of each tube were 2 c. c., 

 which were inoculated with three loopfuls of a twenty-four-hour broth 

 streptococcus culture and three loopfuls were plated at intervals. Tube 

 7 differs from Tube 6, in that it contains the washed leucocytes which 

 had been centrifugated out of 2 c. c. of the exudate, suspended in rabbit 

 serum, whereas Tube 6 contained a mixture of I c. c. of the entire exu- 

 date -f- i c. c. of serum. The fluid of the exudate in Tube 7 was removed 

 to show that the effect of these mixtures is not due entirely to the liquid 

 portion of the exudate, but in a large measure to the leucocytes. The 

 Tables show that non-virulent streptococci are destroyed by the leuco- 

 cytic exudate, by mixtures of leucocytes and serum and by leucocytes in 

 clefibrinated blood. Defibrinated blood and serum alone, the heated exti- 



**D. Med. Wool]., 11)04, XXX, 1458. 



