268 INFECTION AND IMMUNITY 



process become overstocked and cast them off to circulate freely 

 in the blood. These freely circulating receptors atom-groups with 

 specific affinity for the toxins used in their production represent 

 the antitoxins. These, by uniting with the poison before it can reach 

 the sensitive cells, prevent its deleterious action. 



The theory of Ehrlich, in brief, then, depends upon the assump- 

 tions that toxin and antitoxin enter into chemical union, that each 

 toxin possesses a specific atom-group by means of which it is bound 

 to a pre-existing side chain of the affected cell, and that these side 

 chains, in accordance with Weigert's law, under the influence of 

 repeated toxin stimulation, are eventually overproduced and cast off 

 by the cell into the circulation. 



It stands to reason that this theoretical conception would be 

 vastly strengthened were it possible to show that such receptors or 

 toxin-binding atom-groups actually pre-existed in the animal body, 

 and such support was indeed given by the experiments of Wasser- 

 mann and Takaki. 25 These observers succeeded in showing that 

 tetanus toxin could be rendered innocuous if, before injection into 

 animals, it was thoroughly mixed with a sufficient quantity of the 

 fresh brain substance of guinea-pigs. Similar observations were in- 

 dependently made by Asakawa, 26 and variously confirmed. Kempner 

 and Schepilewsky 27 showed a similar relation to exist between brain 

 tissue and botulismus toxin, and Myers 28 brought proof of analogous 

 conditions in the case of suprarenal tissue and cobra poison. 



25 Wassermann und Takaki, Berl. klin. Woch., 1898. 

 M Asakawa, Cent. f. Bakt,, 1898. 



27 Kempner und Schepileivsky, Zeit. f . Hyg., 1898. 



28 Myers, Cent, f . Bakt., i, 1899. 



