HEMOLYTIC SERA AND THEIR ANTITOXINS. 191 



sensitized corpuscles is the important fact that Ehrlich and Morgen- 

 roth were the first to show experimentally.* This fact would 

 seem to be a remarkable confirmation of the idea that we established 

 several years ago, namely, that under the influence of a suitable 

 sensitizing substance (preventive substance) the animal body 

 directs this bactericidal (or cellulicidal) power particularly against 

 a given cell. 



Normal rabbit corpuscles remain intact when mixed with fresh 

 normal guinea-pig serum and the alexin is not absorbed. If we 

 subsequently add sensitized cholera vibrios to this mixture, they soon 

 show a granular transformation, which proves that the fluid con- 

 tains free alexin. But if in another tube we mix normal guinea- 

 pig serum with rabbit corpuscles treated with a hemosensitizing 

 substance, they are destroyed, absorb the alexin, and sensitized 

 vibrios subsequently added remain normal and show no transfor- 

 mation. 



EXPERIMENT. An emulsion of cholera vibrios is made by suspending an agar 

 culture in 10 cc. of salt solution. About a third of this volume of cholera serum 

 from the rabbit, heated to 55 degrees for half an hour, is then added. This forms 

 an emulsion of sensitized vibrios. The blood used is washed rabbit blood. 



Mixture A. 0.3 of a cubic centimeter of rabbit blood plus 0.6 of a cubic 

 centimeter of hemolytic serum (55 degrees) plus 0.3 c.c. normal guinea-pig serum. 

 Complete and rapid hemolysis occurs. 



Mixture B. Identical with A with the exception that 0.6 of a cubic centimeter 

 of normal guinea-pig serum (55 degrees) is used instead of a specific serum. No 

 hemolysis. 



Mixture C. Identical with A but with guinea-pig blood, 0.3 of a cubic centi- 

 meter, replacing the rabbit blood. In this mixture there is no hemolysis, as the 

 guinea-pig corpuscles are not affected by fresh guinea-pig serum and heated 

 hemolytic serum. 



In 1 to 2 hours 0.1 of a cubic centimeter of the emulsion of sensitized 

 vibrios is added to each mixture. The mixtures are then placed in the incubator 

 for an hour with the following results: in mixture A, where hemolysis took place, 

 the vibrios undergo no transformation. There is complete granular transforma- 

 tion in mixtures B and C, in which the corpuscles were intact. 



3. The fixation by corpuscles of the active substances of hemolytic 

 serum. The action of the stromata. 



Rabbit corpuscles when mixed with our hemolytic serum pre- 

 viously heated to 55 degrees remain intact, with the exception of 

 being agglutinated. Under these conditions they fix the sensitizing 



* See "Collected Studies on Immunity," Ehrlich-Bolduan, Wiley & Co., p. 1. 



