The Antitoxins 129 



under normal conditions engaged in maintaining the proper nutrition 

 of the cell; under abnormal conditions (as when preempted by the 

 inert or injurious haptophores of the bacterial products) are obliged 

 to increase in number to compensate for the damage done the cell. 

 Antibody formation can be induced only by antigens or bodies that 

 bear a resemblance to the normal nutrient substances absorbed 

 by the cells in that they are provided with haptophore groups 

 corresponding with the haptophile groups of the cells and so adapted 

 for union with them. Mineral and alkaloidal substances have 

 no such adaptations, but bacterial products, the toxalbumins of 

 various higher plantSj venoms,- enzymes, and other protein com- 

 binations have. The possession of the haptophile groups determines 

 whether or not the cell can stimulate antibody formation, and the 

 ability to produce antibodies shows the existence of the haptophore 

 groups. 



The attachment of the haptophore groups to the cells is usually 

 shown by morbid action of the cells in cases where there are as- 

 sociated toxophore and toxophile groups, as in the case of the bacterio- 

 toxins, but may not be discovered if there are none. The combina- 

 tion of the toxin-haptophores with the cell-haptophiles can be 

 demonstrated in the test-tube by crushing the cerebral substance of 

 a rabbit, and adding tetanus toxin. The toxin becomes -fixed by 

 combination with the cell haptophiles or receptors, loses its further 

 combining powers and fails to affect animals into which it is sub- 

 sequently injected. The increased formation of receptors in con- 

 sequence of repeated stimulation has been shown by the effect of 

 abrin upon the conjunctiva. If dropped into one eye until the 

 conjunctiva is thoroughly immune against its action, the cells of 

 this eye develop a greatly increased capacity for absorbing — i.e., 

 fixing — the abrin as compared with those of the other eye. Thus if 

 the two conjunctival membranes be dissected out and a certain 

 quantity of abrin triturated with each, the haptophiles of the cells 

 of the immunized membrane fix the poison so that it is no longer able 

 deleteriously to affeict animals, while no such effect takes place with 

 the other membrane. 



The abihty to stimulate the formation of antibodies is entirely 

 . independent of any toxic action and is entirely the work of the hap- 

 tophiles. This is best shown in the fact that diphtheria toxin that 

 has been heated or otherwise manipulated until its toxic action is 

 lost, still retains the power of combining with antitoxin, or of 

 producing antibodies. 



The cells furnishing the haptophile groups, or receptors, whose 

 presence in the blood gives it its antitoxic quality vary in number or 

 quality in different animals. Thus, in the warm-blooded animals 

 the rapidity with which tetanus toxin is anchored to the cells of 

 the central nervous system seems to indicate that those cells, if 

 not the only cells in the body passing the adapted receptors by 



