STUDY OF ANTISTREPTOCOCCUS SERUM. 131 



being absolutely instantaneous, phagocytosis in these cases is so 

 rapid as to prevent any extracellular reproduction of the strepto- 

 coccus. In addition, cases are met with in which the phagocytic 

 crisis, although somewhat delayed, is yet so rapid that no exuberant 

 development of the bacterium takes place; we have found such 

 phagocytosis 10 hours after inoculation. Cases like this show a 

 connection between the two forms of phagocytosis and it seems 

 logical to admit that if the leucocytes in prepared rabbits, with 

 small doses of culture, can rapidly take up all the bacteria inocu- 

 lated, that it is owing to a mechanism identical with that which 

 brings about delayed phagocytosis. 



As we have already seen, phagocytosis may be brought about by 

 injecting into the peritoneal cavity of a rabbit previously prepared 

 with bouillon, a mixture of preventive serum and young strepto- 

 coccus culture. The question arises whether the accomplishment 

 of this delayed phagocytosis is favored or accelerated when the mix- 

 ture of bacteria and serum injected has been in contact for several 

 hours; or whether the phagocytic phenomena are as distinct and 

 as rapid when the two factors are injected separately into the peri- 

 toneal cavity without having been previously mixed. 



Let us take two rabbits of the same weight and prepare them 

 by injecting 6 c.c. of pepton bouillon into the peritoneal cavity of 

 each. On the following day rabbit A is given 4 c.c. of preventive 

 serum intraperitoneally; at this time of course the peritoneum con- 

 tains many leucocytes. Rabbit B is given 4 c.c. of normal horse 

 serum at the same time. There have been prepared a few hours 

 before two mixtures composed as follows: No. 1, 4 c.c. of preven- 

 tive serum and 0.5 of a cubic centimeter of young streptococcus 

 culture; No. 2, 4 c.c. of normal horse serum and 0.5 of a cubic 

 centimeter of the same streptococcus culture.* These mixtures 

 have been kept at room temperature. At times varying from one- 

 half or three-quarters of an hour to seven or eight hours after the 

 first injection of rabbits A and B, these two mixtures may be in- 

 jected into the respective peritoneal cavities as follows: rabbit A. 

 that has received preventive serum, is given the mixture containing 

 normal serum. Rabbit B that has received the injection of normal 

 horse serum, subsequently receives the mixture containing preven- 



* We have varied these doses in different experiments. 



