220 LECTURES ON IMMUNITY 



throcytes. For if these have been shaken for an hour 

 with alexin and have thereafter been separated from the 

 fluid, they remain intact on the addition of immune-body. 



Ehrlich and Morgenroth have performed experiments 

 on the binding of immune-body and alexin that have 

 caused a great deal of discussion, but have not been ex- 

 plained in a satisfactory manner. 1 If the hsemolytic mix- 

 ture of the two substances is shaken with the specific 

 erythrocytes at low temperature (0-3 C.) for an hour, the 

 immune-body (from goat-serum) is absorbed by the ery- 

 throcytes (of sheep), the alexin remaining alone in the 

 solution. The experiment succeeds even at 40 if the 

 time of contact between .solution and corpuscles is re- 

 stricted to ten minutes. If the corpuscles are then sus- 

 pended in physiological salt-solution a moderate haemolysis 

 is observed, which is augmented if alexin (normal goat- 

 serum) be added. 



Evidently we here observe a case of velocity of reaction, 

 in which the immune-body plays nearly the same r61e as 

 cholesterin in Ransom's experiments with saponin. A 

 difference is that the immune-body is very rapidly and 

 strongly absorbed by the erythrocytes, which is evidently 

 not the case with cholesterin. At low temperatures the 

 velocity of reaction between immune-body and alexin is 

 imperceptible. Therefore no measurable part of the alexin 

 (which to a slight degree is taken up by the blood-corpus- 

 cles) becomes bound by the immune-body. But at higher 

 temperatures a sufficient quantity of haemolysin is formed 



1 Ehrlich and Morgenroth: BerL klin. Wochenschrift, No. I (1899); 

 Gruber: Munch, med. Wochemchrift, Nos. 48-49 (1901), No. 2 (1904); Mor- 

 genroth: Wiener klin. Wochenschrift> No. 43 (1903), No. 5 (1904). 



