CONCERNING ILUMOLYSINS. 13 



of the centrifuge, and they showed by their behavior that they had 

 combined with the immune body. They did not dissolve on the 

 addition of physiological salt solution, but dissolved when addiment 

 in the form of normal goat serum was added. In contrast to this, 

 both components combined with the sheep blood-cells when the 

 mixture was kept at room temperature (about 20 C.) even for only 

 eight minutes. The blood-cells, separated by centrifuge and washed 

 with physiological salt solution to free them from traces of serum, 

 were mixed with more salt solution and placed in an incubator, 

 where they dissolved in considerable quantity. 



These new and stronger immune sera therefore exhibited proper- 

 ties in relation to the sheep blood-cells entirely analogous to those 

 of the serum previously described by us. On the other hand in cer- 

 tain respects their behavior was entirely different. 



The serum described by Bordet, as well as that of our goats, 1 lost 

 its haBinolytic power when heated for half an hour to 56 C. This has 

 been shown by Buchner to be true of all normal hsemolytic sera. 

 The sera of our two bucks even when heated for three-quarters of an 

 hour to 56 C. showed only a scarcely appreciable diminution of their 

 solvent action on sheep blood, while their normal solvent action on guinea- 

 pig blood and rabbit blood was entirely destroyed. Even when the serum 

 was heated to 56 C. for three hours or when, after mixing with equal 

 parts of water, it was heated for one and one-half hours to 65 C., 

 it showed merely a reduction in its solvent action for sheep blood, 

 but not a destruction of this action. 



Our preliminary experiments on the combining relations had 

 shown us that the action of these hsemolysins was due to the pres- 

 ence in the serum of a specific immune body and an addiment. It was 

 therefore clear that we were here dealing with an addiment of a very 

 peculiar kind, which was distinguished from the addiments of 

 all hsemolysins heretofore known by its extraordinary resistance 

 to thermic influences. This property must pertain to the addi- 

 ment itself and cannot be ascribed to the presence of another sub- 

 stance in the serum increasing its resistance, for such a substance 

 would have served to protect the haemolytic bodies normally present. 



In order, however, to analyze these phenomena completely, it 

 was absolutely essential to obtain the two components of the complex 



1 This refers to the female goats. The male goat is always designated 

 "buck" by Ehrlich and Morgenroth. [Translator.] 



