282 Chapter IX 



ated animals, never bringing about this result in susceptible animals. 

 Taking all the data on this question into consideration, it is easy to 

 convince oneself that this view cannot be accepted as correct, for not 

 [296] only the definite phenomena observed below the skin but also the no 

 less demonstrative process appearing in the peritoneal cavity prove 

 most clearly the existence of this negative chemiotaxis of the 

 leucocytes. I need only recall Bordet's experiment on the fate of 

 streptococci and Proteus vulgaris when injected together into the 

 peritoneal cavity of guinea-pigs. Whilst the Proteus bacilli at the 

 end of a very short time are all ingested by the leucocytes, the 

 streptococci remain free in the peritoneal fluid up to the death of 

 the animal. The leucocytes which exhibit a positive chemiotaxis as 

 regards the former, manifest a negative chemiotaxis as regards the 

 streptococci. 



In spite of the great force of these arguments, the discovery of a 

 means of reconciling the results obtained from the inoculation of 

 micro-organisms subcutaneously or into the peritoneal cavity, with 

 those observed after they had been injected into the blood vessels 

 would be of great interest, and Zilberberg and Zeliony x have under- 

 taken a series of experiments with this object. Following Werigo 

 they made use of the cocco-bacilli of fowl cholera, and found, in 

 accordance with his observations, that the intravenous injection of 

 these organisms, obtained from cultures in nutrient media, causes a 

 very marked phagocytosis of the cocco-bacilli. When, however, they 

 injected into the veins of rabbits cocco-bacilli that had been grown in 

 the peritoneal fluid of other rabbits, they found the micro-organisms 

 free in the blood plasma and observed only a very restricted phagocy- 

 tosis in the microphages of the liver. It follows from these experiments 

 that the ingestion of the cocco-bacilli, in Werigo's experiments, was 

 dependent on the presence of a large number of attenuated micro- 

 organisms which were present in the cultures that he employed for 

 his injections. Alongside these organisms, slightly or not virulent, 

 were others, endowed with their normal pathogenic activity and 

 quite numerous enough to set up a fatal infection. When Zilberberg 

 and Zeliony replaced cultures on agar by the peritoneal exudation 

 which contained virulent cocco-bacilli almost exclusively, the phago- 

 cytosis in rabbits, injected into the veins, was found to be almost 

 suppressed. With the object of establishing whether the absence of 

 the phagocytic reaction, in this case, really depended on negative 

 1 Ann. de I'Inst. Pasteur, Paris, 1901, t. xv, p. 615. 



