348 INFECTION AND IMMUNITY. 



sumption was made that if one could force all the 

 receptors of erythrocytes, for example, to take up 

 the specific amboceptors, such corpuscles should 

 lose their power to cause the formation of a hemo- 

 lytic serum when injected into a suitable animal. 

 This would follow logically, for the receptors of 

 the corpuscles, being already bound, would not be 

 free to unite with receptors of the immunized ani- 

 mal. Antibodies were not formed under these cir- 

 cumstances, from which it is concluded that the 

 receptors of the erythrocytes had united chemi- 

 cally with the antibodies of the serum (Sachs). 

 In order to completely occupy all the receptors of 

 the vibrio of cholera Pfeiffer used 3,000,000 to 

 4,000,000 times the dissolving amount of the anti- 

 cholera serum. Although the mere absorption of 

 agglutinins and amboceptors by the homologous 

 cells is cited in favor of the chemical hypothesis, 

 we may bear in mind the contention of certain in- 

 vestigators that this absorption is physical rather 

 than chemical. 



chemical Na- Second tenet : What evidence have we that tox- 

 ins and other antigenous substances enter into 

 chemical union with receptors in the cells of the 

 ceii Re f <^p- immunized animal ? It is probable that no ob- 

 servation speaks more strongly in favor of such 

 union than a famous experiment of Wassermann's 

 in which the central nervous system of guinea- 

 pigs was ground up with tetanus toxin, the mix- 

 ture allowed to stand for a short time and then 

 injected into mice. The mixture was found to be 

 non-toxic, and further experiments showed that 

 the neutralizing power resides in the solid tissue 

 in the emulsion. - It is claimed by Ehrlich that 



