Immunity against pathogenic micro-organisms 145 



reaction is very slight or absent. To corroborate this general con- 

 clusion, Wagner, instead of lowering the temperature by means of 

 cold water, made use of antipyrin and chloral. The application of 

 this treatment likewise caused enfeeblement of the natural defence 

 of the organism and suppressed the immunity of the fowl against 

 anthrax. 



Trapeznikoff 1 has studied carefully the fate of anthrax spores 

 when injected into fowls. He observed that most of them are 

 devoured by the leucocytes. Some of the spores were first trans- [154] 

 formed into small rods, sometimes growing into real bacilli, but 

 finally they all became the prey of phagocytes and perished in 

 their interior. Those in the vegetative condition are soon digested, 

 the spores, however, persist for some time inside the phagocytes, 

 but ultimately disappear. The phagocytosis in fowls inoculated 

 with spores is very marked, and preparations, stained by Ziehl's 

 method, demonstrate most clearly the reality of this reaction pheno- 

 menon. These preparations have for long been used in the course 

 in bacteriology at the Pasteur Institute for the demonstration of 

 phagocytosis. 



In the face of these facts, well established and confirmed many 

 times, it is impossible to accept Thiltges' 2 denial of the ingestion of 

 these bacteria by the phagocytes of the fowl. Some fault of technique, 

 which I am not at the moment in a position to indicate exactly, 

 has evidently slipped into this author's work. The positive data, 

 however, on phagocytosis in the fowl, obtained by Hess, Wagner, and 

 Trapeznikoff, data confirmed by myself, render unnecessary any fresh 

 researches for the purpose of explaining the negative results obtained 

 by Thiltges. As regards his experiments on the bactericidal action 

 of defibrinated blood and of blood serum of fowls against the bacillus 

 and its spores, experiments whose results are opposed by those of 

 Wagner, the contradiction may be explained pretty easily, at least in 

 part. Thiltges mentions several times that the bacilli, when sown 

 in the blood serum of the fowl, were aggregated in clumps. Never- 

 theless, he has failed to guard against this source of error and has 

 attributed the diminution in number of the colonies on plates to 

 the destruction and not to the agglutination of the bacilli. Thiltges 

 gives so few particulars of the conditions under which his experi- 

 ments were performed that we do not even know at what temperature 



1 Ann. de Flnst. Pasteur, Paris, 1891, t. v, p. 362. 



2 Ztschr.f. Hyg., Leipzig, 1898, Bd. xxvm, S. 189. 



B. 10 



