THE COMPOUND H^MOLYSINS 231 



lesser quantities of immune-body, the haemolysis is not so 

 great as this rule predicts, and this corresponds to the 

 behaviour of other lysins (cf. pp. 103 and 169), except that 

 the deviation from the rule in this case is evident 

 throughout the wide interval from o to 30 per cent, where 

 as for other lysins the deviation is observed only under 

 10 or 15 per cent. 



In the memoirs cited Morgenroth and Morgenroth and 

 Sachs employed, 1 among other hypotheses to explain their 

 observations, this also, that immune-body and alexin some- 

 times enter into a compound haemolysin or haemolysin 

 united with an erythrocyte, which is stable only in the pres- 

 ence of considerable quantities of the components. These 

 different substances participate, according to the Frankfort 

 school, in a chemical equilibrium. On the other hand, the 

 adherents of Bordet, among whom Metchnikoff, Gruber, 

 and Biltz may be cited, regard the haemolytic action as a 

 phenomenon of absorption. It seemed possible to decide 

 by means of quantitative experiments which of these two 

 ideas corresponds to the facts, and Ehrlich invited me to 

 undertake an investigation of this point in the laboratory 

 of the serum institute in Frankf ort-on-the-Main. These in- 

 vestigations led to the very certain conclusion that a chemi- 

 cal equilibrium governs the reaction of immune-body and 

 alexin, but the important reaction takes place within the 

 erythrocytes. It is very probable also that such an equi- 

 librium exists, even in the mixture of immune-body and 

 alexin, as is indicated by the diminution of the haemolytic 

 effect with increasing immune-body, as noted in some cases 



1 Morgenroth: Wiener klin. Wochenschrift, No. 43, p. 5 (1903); Mor- 

 genroth and Sachs: Berl klin. Wochcnschrift, No. 35, p. 8 (1902). 



