592 BACTERIOLOGY. 



ably the correct explanation of the establishment of im- 

 munity in a number of, if not in all, cases. Experiments 

 that bear directly upon this idea have demonstrated 

 that, if animals be subjected to injections of the poison- 

 ous products of growth of certain virulent bacteria, 

 they respond to this treatment by more or less pro- 

 nounced constitutional reactions, and that during this 

 period, and for a short time following, they are protected 

 from the invasion of the virulent bacteria themselves. 

 This observation has, moreover, not been confined to 

 those cases in which injections of the products of growth 

 were followed by inoculations with the bacteria by 

 which they were produced, but, what is still more in- 

 teresting and confirmatory of Buchner's view, it is 

 claimed that a sort of protection from certain specific 

 infections can also be afforded to animals by the injec- 

 tion into them of cultures of entirely different species of 

 bacteria, or their products, and that in some cases these 

 are not of necessity of the disease-producing varieties. 

 For instance, Emmerich and Mattei 1 claim to have 

 rendered rabbits insusceptible to anthrax through injec- 

 tions into them of cultures of the streptococcus of ery- 

 sipelas. 



This, they claimed, is not due to any antagonism be- 

 tween the two organisms themselves, for in culture 

 experiments they grew well together, without any 

 alteration in their pathogenic properties; but rather 

 to the induction of a tissue activity by which resistance 

 to the inroads of the virulent bacilli was established. 

 Emmerich and Mattei interpret this "reactive tissue- 

 change " as a power acquired by the integral cells of the 

 body, through the influence of a stimulus, of generating 



1 Emmerich und Mattei : Fortschritte der Medicin, 1887, S. 653. 



