INFECTION AND IMMUNITY. 409 



Hankin believes the globulins or " defensive pro- 

 teids " that he has discovered and the albuminoid bodies 

 studied by Buchner to be identical. The most interest- 

 ing and, in the light of work that has appeared since, 

 the most important, of Hankin's observations were not 

 those upon the power of these globulins to destroy the 

 vitality of living organisms, but rather those upon the 

 relation between them and the poisonous proteid pro- 

 ducts of the organisms. For example, if the poisonous 

 products of virulent anthrax bacilli be isolated and 

 mixed with the globulin extracted from normal tissues, 

 the experiments of Hankin showed a directly destruc- 

 tive action on the part of the bacterial products. He 

 found that the amount of poisonous albumose produced 

 by the attenuated anthrax bacilli, that are employed as 

 vaccines, was much less than that produced by the 

 organisms possessing full virulence, and he suggests 

 that perhaps the protective influence of vaccinations 

 that are practised by introducing into the animal the 

 organisms that have been attenuated in virulence is due 

 to a gradual tolerance acquired by the cells of the tis- 

 sues to the action of the poison when produced in these 

 small quantities ; in the same way that a tolerance was 

 acquired by the tissues for the venom of the rattlesnake 

 in the experiments of Sewall,* and similar to that fol- 

 lowing the injection into the tissues of small quantities 

 of hemialbumose, which in large amounts rapidly 

 proves fatal. 



Of utmost importance to these studies of the blood 

 and fluids of the body are the experiments of Behring 

 and Kitasato' upon the production of immunity to 



1 Journal of Physiology, 1887, vol. viii. p. 203. 



2 Behring and Kitasato ; Deutsche med. Woch., 1890, Bd. xvi. p. 1113. 



