50 



Scientific Proceedings (31). 



may be in no proportion to the immunity of the organism as a 

 whole. There must therefore be an additional factor, hypotheti- 

 cally designated by Behring as cytogenetic immunity. Of this 

 type of immunity there is the following experimental evidence. 

 In 1898, Kossel stated that if an animal were injected with eel 

 serum, its washed red cells manifested resistance to the hemolytic 

 action of the latter in vitro ; a fact confirmed by Camus and Gley, 

 and by Tshistovitch. In 1908, it was shown by Morawitz and 

 Pratt that in animals injected with phenylhydrazin, the red cells 

 became resistant to all hemolytic agents. This they showed to 

 be not an immune reaction, but the direct result of the chemical 

 action of the drug on the red cells. 



It was the object of the present series of experiments to deter- 

 mine whether it was possible to induce a specific resistance of the 

 red cells to poisons injected into the animal. Dogs and rabbits 

 were used. Among the hemolysins injected were : eel serum, and 

 dog serum ; saponin, and digitalin ; staphylolysin, tetanolysin, and 

 prodigiosus toxin ; and phenylhydrazin. Eel serum, saponin, 

 and phenylhydrazin were selected for routine experimentation. 

 All of these were found to induce a severe grade of anemia. The 

 animals were bled at intervals, and the resistance of the corpuscles, 

 after repeated washings in salt solution, tested against a variety of 

 destructive agents. Eel serum was found to induce occasionally 

 a marked change in the red cells ; saponin did so almost invariably, 

 in case the animal survived the treatment ; phenylhydrazin did so 

 without exception. In the early stage of treatment, the resistance 

 of the red cells to all hemolytic agents, including the injected 

 hemolysin, was diminished. In the later stages, it was increased in 

 a characteristic manner. The red cells of animals injected with 

 phenylhydrazin showed a marked increase of resistance to all types 

 of hemolysins. Animals injected with eel serum and with sapo- 

 nin came to possess a type of erythrocytes which were very resist- 

 ant to the specific injected hemolysin, but were almost invariably 

 more easily destroyed than normal control cells by all other hemo- 

 lytic agencies, including anisotonic salt solutions (demonstration). 

 In those animals injected with eel serum, which failed to develop a 

 specific resistance of the red cells, the serum showed marked anti- 

 hemolytic powers. It is evident, therefore, that the erythrocytes 

 have developed a specific immunity. 



