314 Chapter X 



body of the animal subjected to the action of antistreptococcic horse 

 serum. Bordet began by studying the properties of this serum and 

 accepted Denys' and Marchand's statement that bactericidal power, 

 however small, was absent. The streptococcus grows as well in 

 this serum as it does in that of the untreated horse. In the specific 

 serum, however, markedly longer chains are produced than in normal 

 serum. This difference is found only in the earliest period of the 

 growth. The agglutinative power of the antistreptococcic serum is 

 but feebly marked. The injection of a large quantity of this serum 

 into a normal rabbit confers no bactericidal power upon the serum of 

 this animal. "The serum extracted 24 hours after injection is quite 

 as suitable for use as a culture medium as that furnished by the 

 blood before the introduction of the serum. In both the micro- 

 organism grows rapidly and vigorously" (p. 195). Consequently, in 

 [330] the antistreptococcic serum there is nothing comparable to what we 

 obtain so readily with antivibrionic serum: nothing which recalls 

 Pfeiffer's phenomenon, even of an attenuated nature. We have 

 already noted the result obtained by Bordet, according to which the 

 streptococci, developed in the specific horse serum, were found to be 

 endowed with their normal high virulence. 



The antistreptococcic serum, injected into the peritoneal cavity of 

 the rabbit the day previous to the microbial inoculation, protects 

 the animal absolutely, provided that the micro-organisms be not too 

 numerous or the quantity of serum not too small. Under these 

 conditions the virus is ingested pretty rapidly and, so far as we know 

 at present, completely. The micro-organism is thus prevented from 

 developing and the animal remains in good health, whilst the control 

 animal, which has received no serum, dies in a very short time. 



When the number of streptococci is increased the effort of the 

 animal organism to get rid of them becomes, in spite of the 

 protective serum, more severe and much more prolonged. Some 

 of the micro-organisms certainly become the prey of phagocytes, but 

 a sufficient number remain free in the peritoneal cavity to multiply 

 rapidly. When the number of streptococci has become sufficiently 

 great a phenomenon, to which Bordet gives the name of " phagocytic 

 crisis," is suddenly observed. In the peritoneal exudation, which has 

 become thick and has taken on the aspect of a homogeneous and 

 white pus, a most rapid phagocytosis is evidently set up. In a short 

 time the whole of the streptococci, which were swarming outside the 

 cells, are ingested by the leucocytes. "The essential condition for 



