The Antitoxins 129 



so adapted for union with them. Mineral substances and 

 alkaloidal substances have no such adaptations, but bacte- 

 rial products, the toxalbumins of various higher plants, 

 venoms, enzymes, and other proteid combinations have. 

 The possession of the haptophore groups determines whether 

 or not the cell can stimulate anti-body formation, and the 

 ability to produce anti-bodies 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 associated toxophore groups, as in the case of the 

 bacterio-toxins, but may not be discovered if there are no 

 toxophore groups. The combination of the toxin-hap- 

 tophores with the cell-haptophores 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 haptophores or receptors, loses its 

 further combining powers and fails to affect animals into 

 which it is subsequently injected. The increased formation 

 of receptors in consequence 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 haptophores of 

 the cells of the immunized membrane fix the poison so that 

 it is no longer able deleteriously to affect animals, while 

 no such effect takes place with the other membrane. 



The ability to stimulate the formation of anti-bodies is 

 entirely independent of any toxic action and is entirely the 

 work of the haptophores. This is best shown in the fact that 

 diphtheria toxin that has been heated or otherwise manip- 

 ulated until its toxic action is lost, still retains the power 

 of combining with antitoxin, or of producing anti-bodies. 



The cells furnishing the haptophore 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 which it is anchored, 



