THEORIES EXPLAINING ACQUIRED IMMUNITY. 123 



tive function, but appear to be capable of combining with a 

 toxin by means of haptophorous bodies, the toxophile chains 

 in the cell, and the cytophile granules in the toxin molecule. 

 A second group of granules in the toxin molecule, called the 

 toxophot-e group of granules, destroys the cell if they are 

 present in sufficient quantity. If present in only a limited 

 quantity, they merely injure the cell, stimulating it to repair, 

 and the cell throws out new side-chains. The frequent intro- 

 duction into the body of toxins results in overstimulation of 

 the cell, and consequently it throws out for its protection 

 more side-chains than really are needed. This surplus or 

 overstock of side-chains is thrown into the circulating blood- 

 current, lymph, and other body-juices, and these constitute 

 the antitoxin, which during an infection combines with the 

 toxin and neutralizes it. The whole theory is based on the 

 chemistry of the cell, and the so-called " side-chains " simply 

 represent chemical formube. There is no experimental foun- 

 dation to this theory, but it is the most plausible of them 

 all, as all the changes in the body are merely chemical 

 changes. 



