THE COMPOUND H^EMOLYSINS 247 



body or antialexin, Ehrlich and Morgenroth proceeded in 

 the following manner. Immune-body is added to the anti- 

 body, and if this is an antialexin, it leaves the immune-body 

 free, which thereafter may be extracted with erythrocytes, 

 that may afterward be haemolysed through treatment with 

 alexin. If it be an anti-immune-body, it binds the immune- 

 body present, which thereafter cannot be extracted by 

 erythrocytes. 



Evidently the antihsemolysm, if such an antibody exists, 

 behaves in this case as the antialexin. The specificity is 

 not very prominent. Normal serum contains anti-immune- 

 bodies and antialexins, and after its injection into animals 

 these produce antialexins. According to Ehrlich and 

 Morgenroth, inactivated serum heated to 56 C., which 

 ought not to contain alexin, still gives an antialexin after 

 injection. (The antialexins resist a temperature of 55- 

 60 C. ; usually they are heated before using in order 

 to free them of perturbations through the presence of 

 alexins.) Another peculiarity was found by Ehrlich and 

 Morgenroth, namely, that serum from a goat previously 

 injected with serum from a rabbit contains an antialexin, 

 not only against the alexin in rabbit-serum, but also 

 against the alexin contained in guinea-pig-serum. The 

 same antialexin is even contained in the serum of a goat 

 treated by injections of horse-serum. 



The antialexins have been regarded as especially im- 

 portant because they bind the alexins, which are 

 according to the views of Bordet as well as of Ehrlich 

 the effective parts of the haemolysins. Therefore the 

 chief part of the work on the antihaemolytic substances 

 has been concerned with investigations of antialexins, 



