74 



Horses 615 and 624. — Botli gave a serum with higher haemolytic 

 activity for mules than for horses. In 615 tlie haemolytic index for 

 mules increased. The haemolytic index of 615 was four times higher 

 tlian that of 624, whilst the amounts of injected blood were equal ; from 

 horse 615, however, five times more blood was taken than from 624. 



In 627, as in 612, iiaemolysines disappeared within two months. 



Comparative Table. 

 Horses Injected with Virulent Defibrinated Horse Blood. 



Conclusions. 



1. The most remarkable fact is that from eleven horses liyperim- 

 munised with defibrinated horse blood, the serum of 

 8 (= 72"7 ^) is undoubtedly more haemolytic for mules than 

 for horses. In one instance the haemolytic indices were 

 equal, and in the other two cases the haemolytic tests are not 

 satisfactory enough to make a definite statement. 



It appears, therefore, that the organism of horses " avoids" 

 or is incapable of reacting on the introduction of horse blood 

 by the production of anti-bodies exclusively specific for 

 horse blood. We cannot tell whether the isolysines arising 

 are the same for horses and mules, as the enumerated 

 experiments do not settle this point. It would have to be 

 carried out by specific absorption (according to Ehrlich and 

 Morgenroth). 



