368 STUDIES IN IMMUNITY 



The important factor that Ehrlich and Morgenroth neglect is 

 that each alexin has a definite toxic property of its own for a given 

 corpuscle. It is quite evident that the hemolytic or bacteriolytic 

 power of serum will vary in different animal species as their alexins 

 differ in intensity. 



There is, however, one experiment reported by Ehrlich and 

 Sachs* which, if the interpretation they give to it were correct, 

 would prove indisputably that the alexin really unites with the 

 sensitizer. It would actually seem in the experiment in question 

 as if the sensitizer does unite with the corpuscles subsequent to its 

 union with the alexin. 



This alexin-sensitizer union would seem to be so indispensable 

 that, if the alexin were destroyed, a real paralysis of the sensitizer 

 would result, so that its affinity for the corpuscle would be destroyed 

 or at least inhibited; in other words, the cytophilic group would 

 seem to react with the corpuscle only after the complementophilic 

 group, uniting with the alexin, is satisfied. 



It remains to be seen, however, whether Ehrlich and Sachs have 

 not entirely misinterpreted their own experiment. The sensitizer 

 in question is present in inactivated (56 degrees) normal bovine 

 serum, the corpuscles affected are from the guinea-pig, and the 

 alexin employed is in the form of fresh horse serum. 



We may first of all summarize the facts that Ehrlich and Sachs 

 have noted. Bovine serum, inactivated at 56 degrees, naturally 

 does not hemolyze guinea-pig corpuscles, as its alexin has been 

 destroyed. Fresh (alexic) horse serum also has only the slightest 

 hemolytic effect on these cells. The heated ox serum, however, 

 apparently sensitizes the corpuscles so that they are hemolyzed when 

 fresh horse serum is added. Strong hemolysis (Experiment I) is 

 evident when guinea-pig corpuscles, heated bovine serum and fresh 

 horse serum are mixed together in suitable doses, t So far there is 



plus 0.1 of a cubic centimeter of guinea-pig serum, and to tube "d " 0.4 of a cubic 

 centimeter of rabbit serum plus 0.1 of a cubic centimeter of guinea-pig serum. 

 Resultant hemolysis. Complete in one-half hour in "d"; complete in one hour 

 in "c." There is only a trace of hemolysis in "a" and none in "b" in an hour. 



* Ehrlich and Sachs, Studies on Immunity, Ehrlich-Bolduan, John Wiley & 

 Sons, p. 209. 



f For example, 1 c.c. of a 5 per cent suspension of guinea-pig blood plus 0.3 of 

 a cubic centimeter of bovine serum (56 degrees) plus 0.5 of a cubic centimeter of 

 fresh horse serum. 



