226 THE INCOME OF ENERGY 



enduring union with the haptophore group of a toxine, 

 this normal function is lost. Such a loss acts as a 

 physiological stimulus. 1 New side-chains are produced 

 by the cell, only to unite with fresh toxine. The pro- 

 duction and the loss of side-chains continue until all 

 the toxine in the blood is neutralized. By this time 

 the cell has become habituated to a more than normal 

 production of these special atom groups. The excess 

 is cast off like a secretion and circulates in the blood. 

 These free side-chains, possessing a special affinity for 

 one specific toxine, constitute the antitoxine of that 

 toxine. 



Their continued production after the neutralization 

 of all the toxine protects the animal against fresh 

 toxine, i. e. establishes continued immunity. 



It has already been stated that by special means the 

 toxophore group of a toxine may be weakened or 

 destroyed while its haptophore group is unchanged. 

 Such altered and non-poisonous toxines are termed 

 toxoids. As their affinity for the side-chains of the 

 cells remains unaltered, the toxoids by continuing to 

 unite with the side-chains of the cells may stimulate 

 :the production of such side-chains in excess, or, in 

 other words, may assist in making antitoxine and thus 

 establishing immunity. 



1 Weigert: Deutsche medicinische Wochenschrift, 1896. 



