BACTERICIDAL PROPERTIES OF BLOOD SERUM 145 



in contact with beef blood corpuscles for 15 minutes at 40 C., and 

 then separated the cells from the supernatant fluid by centrifuga- 

 tion. To the blood cells they then added a little normal goat serum 

 (by itself not hemolytic for beef blood) and found that complete 

 hemolysis occurred. The addition of normal goat serum and beef 

 blood cells to the supernatant fluid, however, resulted in no change. 

 In the following diagram we have tried to represent this basic 

 experiment, giving the facts only of the experiment without using 

 any of the usual symbols which imply agreement with a theory. 



EXPERIMENT TO SHOW THAT THE ANTIGEN (iN THIS CASE RED BLOOD CELLS) 

 ABSORBS THE SPECIFIC HEAT STABLE ANTIBODY OUT OF THE IMMUNE SERUM. 



f 4 c. c. of 5 per cent, emulsion of washed beef blood. 



In a test tube \ 1 c. c. of inactivated blood serum of a goat treated with beef 

 i blood. 



These substances are left together at 37.5 C. for one hour and 

 then centrifugalized into: 



I II 



Sediment of Corpuscles. To this are Supernatant Fluid Containing the Serum 



added 4 c. c. salt solution and 0.8 c. c. and Salt Solution. To this are added 



fresh normal goat serum, by itself washed beef corpuscles and 0.8 c. c. 



not hemolytic for beef corpuscles. fresh normal goat serum. 



Result = Complete hemolysis. Result = No hemolysis. 



Summarized, together with the facts we have already outlined, 

 this basic experiment has the following significance : the fresh serum 

 of the goat, previously injected ("immunized") with the beef blood, 

 possessed the property of dissolving the hemoglobin out of beef cor- 

 puscles, viz., hemolyzing them. Heating this serum to 56 C. for 

 20 minutes, as Bordet has shown, deprives the serum of all hemolytic 

 power, i. e., inactivates it. The addition of a little fresh goat serum, 

 in itself inactive, completely reactivates the hemolytic properties of 

 the heated immune serum. So far, as we have already seen, this 

 shows that hemolysis is a dual process in which a heat-sensitive 

 and a heat-stable substance co-operate, neither of them capable of 

 producing lysis by itself. The heat-sensitive ingredient, correspond- 

 ing to Buchner's "alexin," is present in normal serum, and, as Bor- 

 det 19 and von Dungern 20 had shown, is not increased in the process 

 of immunization, and is apparently not specific. The heat-stable 

 substance, therefore specific and increased in immunization, must 

 represent the receptors, overproduced and cast off into the circula- 

 tion. And, as Ehrlich and Morgenroth have now shown in the ex- 

 periment just described, this heat-stable element is actually bound 

 to the red corpuscles, and renders them susceptible to the action of 



19 Bordet. Ann. de I'Inst. Past., Vol. 12, 1898. 



20 v. Dungern. Mimch. med. Woch., No. 20, 1900, p. 677. 



