152 INFECTION AND RESISTANCE 



discoveries, the influence of this work upon the development of 

 immunology has been so important that it must be briefly reviewed 

 in order that controversial questions may be justly considered. 



The comparison of the action of hemolytic sera with that of fer- 

 ments, and the possibility of producing antiferments by the injection 

 of the ferments into animals, obviously suggests a similar induction 

 of antihemolysins by the treatment of animals with lysins. This, 

 we have seen, was the method employed by Ehrlich and Morgenroth 

 in their studies of the causes of the failure of autolysin formation 

 in goats. They extended this work with the purpose of ascertaining 

 whether or not there were differences in the structure of the cyto- 

 phile groups of the various amboceptors formed when various ani- 

 mals were injected with any given species of red blood cells. After 

 obtaining a strong hemolytic serum by injecting ox blood into a 

 rabbit, they treated a goat with the inactivated serum of this rabbit. 

 The result was that the serum of the goat so treated, when mixed 

 with ox blood cells and the hemolytic serum, prevented the sensiti- 

 zation of the cells by the hemolysin. They then measured the neu- 

 tralizing power of such an "aiiti-amboceptor" or a anti-sensitizer" 

 against a variety of hemolytic sera produced with ox blood in differ- 

 ent animals and found that, while this "anti-amboceptor" neutralized 

 the hemolytic action of an antiserum produced in rabbits, it had but 

 an indifferent or entirely ineffective neutralizing power upon sim- 

 ilar ox blood hemolysins derived from goats, geese, dogs, rats, or 

 guinea pigs. They concluded from this that, although these various 

 lysins had been produced in the different animals by the injection of 

 the same antigen, viz., ox blood, and possessed affinity for the ox 

 blood in consequence, they must necessarily differ from each other in 

 some way, since they were not equally neutralized by the same anti- 

 lysin. It seemed to them that the difference in such cases must 

 depend upon variations in the structure of the cytophile group of 

 the amboceptor, a conclusion which they based upon the foregoing 

 experiments and sought to support by the following reasoning: 

 When an animal is treated with sensitizers or amboceptors, they 

 reasoned, these bodies react with the tissue cells by means of the 

 cell-receptors. These receptors are then overproduced and extended 

 into the circulation as free atom-groups. 



They now act as "anti-amboceptor," free in the serum, but are 

 in structure merely overproduced cell receptors, identical with those 

 which originally united on the cell with the injected amboceptor. 



Ehrlich and Morgenroth, 39 therefore, believed that the neutral- 

 ization of the amboceptor by the antilysin depended upon a union of 

 the latter with the "cytophile" group of the former, preventing its 

 subsequent union with the red cells. And since one and the same 

 antilysin did not thus invalidate the action of all the amboceptors 



39 Ehrlich and Morgenroth. Berl kl Woch., No. 22, 1901, p. 600. 



