164 LIFE OF ELIE METCHNIKOFF 



it is not the same cells which digest cholera microbes 

 and cholera toxins : the microphages digest the 

 vibriones whilst the macrophages digest the poisons 

 and, probably, manufacture as products of this 

 digestion, the corresponding antibody, the cholera 

 antitoxins. 



On the contrary, in cases of the inclusion of 

 microbes by macrophages, as, for instance, in plague, 

 the blood acquires an antitoxic power by injection of 

 the microbes themselves and not by their toxins, as 

 was demonstrated by M. Roux and his collaborators. 

 The same fact was observed by Metchnikoff on the 

 alligator, in whom also microbes are digested by 

 macrophages. In those cases, when microbes and toxins 

 are digested by the same cells, the latter manufacture 

 antibodies against both. 



These facts rendered legitimate the supposition 

 of the macrophagic origin of antitoxins. 



In 1897 an International Congress took place in 

 Moscow. Metchnikoff read a paper on the phago- 

 cytic reaction against toxins and another dealing 

 with the whole of the knowledge acquired concerning 

 human plague. He ended this by a plea in favour of 

 Science, so often accused of having contributed 

 nothing to the solution of the most important human 

 problems, particularly ethical ones, and of having, 

 on the contrary, sanctioned the law of Might by 

 tabulating the laws of the struggle for existence. 

 MetchnikofE objected that, far from doing so, Science, 

 by revealing the laws of Nature, applied to humanity 

 the benefits derived from them, whilst striving to 

 counterbalance their cruel or harmful effects. The 

 struggle against plague and other diseases was a 



