380 Chapter XII 



regeneration of antitoxin after bleeding can only be understood 

 by accepting that antitoxin, like the blood, may be reproduced in 

 the actively immunised animal without any fresh introduction of 

 toxin. It is, however, just as simple, we think, to explain the fact 

 in question by the hypothesis of a provision of toxin stored up in 

 [399] certain cells. This also is sufficient explanation of another observa- 

 tion made by Salomonsen and Madsen 1 , who showed that pilocarpin 

 is capable of augmenting the production of antitoxin. Since it is 

 the living cells which transform the toxin and excrete the antitoxin, 

 it is quite natural to suppose that every factor which stimulates cell 

 function may be capable of causing an increase of the product trans- 

 formed by the cells. 



The third argument invoked against the possibility of the trans- 

 formation of toxins into antitoxins is based on the fact that the 

 serum of normal horses has sometimes a certain degree of antitoxic 

 power against diphtheria toxin. The horses have never suffered 

 from diphtheria, therefore the antidiphtherin of their blood has 

 nothing to do with diphtheria toxin. It is not known why the 

 blood serum of certain untreated horses is from the first active 

 against diphtheria toxin, whilst that of others exerts absolutely no 

 action on the same poison. We know only that this property is far 

 from being constant in the equine species. Perhaps it is acquired 

 as the result of the penetration into the animal of some pseudo- 

 diphtheria bacillus, whose frequency and number are very great. 

 In order that the microbial products may give rise to the formation 

 of antibodies, it is not at all necessary that the micro-organisms 

 should produce an evident disease. Thus, to cite one example only, 

 Foerster 2 observed a considerable agglutinative power against the 

 typhoid cocco-bacillus in the serum of a child which was found 

 living among a family of typhoid patients but which, itself, pre- 

 sented no morbid symptom. 



The criticism, directed against the hypothesis that modified toxin 

 enters into the production of antitoxin, may not be sufficient to show 

 the incorrectness of this view ; it does not follow, however, that the 

 view is right. In the present state of our knowledge it is impossible to 

 solve the problem definitely, and as the hypothesis of transformation 

 gives us the best idea of the specificity of the action of antitoxins, 

 it has a right to be taken into consideration as much as any other. 



1 Compt. rend. Acad. d. sc., Paris, 1898, t. cxxvi, p. 1229. 



2 Ztschr.f. Hyg., Leipzig, 1897, Bd. xxiv, S. 514, 



