322 Chapter X 



cytosis on the part of the macrophages. These cells ingest large 

 numbers of micro-organisms which, after a time, have all passed into 

 the phagocytes. If a drop of the peritoneal exudation is now with- 

 [338] drawn, we find only intracellular cocco-bacilli (fig. 43). If the drop be 

 kept for some time outside the animal and at a suitable temperature 

 the macrophages may be seen to perish and the micro-organisms to 

 develop in their contents. We thus obtain abundant cultures which 

 pass from the interior of the macrophages into the fluid of the 

 exudation (figs. 42, 44, 45). When the animals are not sufficiently 

 protected the same phenomenon is observed in the peritoneal cavity 

 of the living animal. The macrophages, crammed with cocco-bacilli, 

 burst, allowing the micro-organisms to escape. These multiply in the 

 peritoneal fluid and spread through the animal, which soon dies. 



Wassermann affirms that "the artificially increased resistance is 

 nothing but an active and reinforced afflux of the complements 

 (cytases) towards one point in the animal, for the purpose of di- 

 gestion." (Ztschr. f. Hyg., Leipzig, 1901, Bd. xxxvn, S. 199.) 

 Wassermann does not explain how this afflux of cytases is produced. 

 The entirely concordant researches on this point by Issaeff, Funck, 

 Bordet, and ourselves, prove that this afflux takes place not through 

 the mediation of the fluids, but solely through the phagocytes, 

 the carriers of the cytases. Consequently it is beyond dispute that 

 in the immunity conferred by physiological saline solution, broth, and 

 several other fluids, we have to do solely with an augmentation of the 

 phagocytic reaction. In the immunity conferred by normal or specific 

 serums, this same stimulating factor still plays the more important 

 part. Along with it, however, there is an intervention more or less 

 pronounced, according to circumstance, and more or less frequent, of 

 cytases, brought by the serums prepared outside the body or that 

 have escaped during phagolysis, as well as of substances truly 

 humoral, such as the fixatives or the agglutinins. 



Amongst the non-specific substances which are capable of con- 

 ferring an immunity more or less stable, must be placed the 

 products of micro-organisms other than those against which we wish 

 to protect the animal. Pasteur 1 noted that when the anthrax 

 bacillus, mixed with other micro-organisms, in themselves inoffensive, 

 is inoculated into animals, anthrax does not develop and the animals 

 remain well. Later, Emmerich 2 showed that the streptococcus of 



1 Compt. rend. Acad. d. sc., Paris, 1877, t. LXXXV, p. 107. 



2 Arch.f. Hyg., Miinchen u. Leipzig, 1887, Bd. vi, S. 442. 



