150 Chapter VI 



so that its existence cannot be doubted. Recently, Martel 1 has 

 demonstrated a very distinct phagocytic reaction in all those cases 

 where he has had to deal with dogs that were refractory or not very 

 susceptible. This reaction is shown by the ingestion of the bacteria 

 and by the large accumulation of leucocytes at the seat of inocu- 

 lation. His researches are of special interest by reason of the 

 counter-test that he was able to make upon dogs that were 

 susceptible to anthrax. It was demonstrated some years ago that 

 the natural immunity of the dog against the bacillus, although very 

 real, is, nevertheless, relative and limited. Thus Bardach 2 established 

 the fact that dogs from whom the spleen, an organ full of phagocytes, 

 had been removed, became susceptible to anthrax. Even dogs into 

 whose veins he injected fine wood-charcoal powder suspended in 

 water, with the purpose of "diverting" the phagocytosis, readily 

 succumbed to anthrax. 



Martel endeavoured to suspend the natural immunity of dogs by 

 injecting into them phloridzin or pyrogallic acid. But he obtained 

 much more constant results by inoculating the bacillus into rabid 

 dogs. The organism, weakened by this terrible disease, became 

 very susceptible to anthrax, and the rabid animal succumbed to 

 anthrax before the rabies had completed its evolution. By its 

 passage through the rabid dog the anthrax virus is so augmented 

 in virulence that it becomes fatal for normal dogs. Martel succeeded 

 also in reinforcing the bacillus isolated from a cow affected with 

 anthrax. In all these cases where the reinforced bacilli set up a 

 severe and rapidly fatal infection, Martel could demonstrate only 

 a feeble phagocytic reaction. 



Researches on the phagocytosis of dogs, inoculated with the 

 anthrax bacillus, have always demonstrated a regular and constant 

 relation between this reaction and the resistance of the organism. 

 On the other hand, experiments undertaken for the purpose of 

 establishing the part played by the body fluids in this immunity, 

 have always given negative results. 



As the dog, of all mammals, exhibits the greatest natural im- 

 munity from anthrax, it is very natural that in the bactericidal 

 property of its blood the key to the enigma has been sought. Thus 

 [ico] Nuttall 3 concludes from his experiments that the anthrax bacillus 



1 Ann. de I'Inst. Pasteur, Paris, 1900, t. xiv, p. 13. 

 8 Ann. de FInst. Pasteur, Paris, 1889. t. in, p. 577. 

 3 Zttchr.f. Hyg., Leipzig, 1888, Bd. iv, S. 353. 



