618 COLLECTED STUDIES IN IMMUNITY. 



by Klein, 1 who found that horse serum, through digestion with 

 guinea-pig blood, loses its complementing power for the combina- 

 tion " guinea-pig blood inactive ox serum." Finding that the horse 

 serum suffered a loss of its agglutinin at the same time, Klein ad- 

 vanced the view that the complement was destroyed by the pro- 

 cess of cleglutination. This view was combated by Browning, 2 

 who showed that the complements of horse serum remain unaffected 

 if the guinea-pig blood-cells are digested with the serum at low 

 temperatures (0 C.), although optimum conditions for the agglu- 

 tinating action and for the binding of agglutinin are thus presented. 

 Browning believes that the reason for the disappearance of com- 

 plement through digestion at higher temperatures, lies in the fact 

 that horse serum contains amboceptors for guinea-pig blood, which 

 amboceptors serve to bind the complement only at higher tem- 

 peratures. That amboceptors for guinea-pig blood exist in horse 

 serum was demonstrated by Morgenroth and Sachs, 3 who show 

 that horse serum plus active guinea-pig serum was able to produce 

 haemolysis of guinea-pig blood-cells. 



These authors demonstrated further that horse serum alone, 

 even in large doses, only rarely dissolved guinea-pig blood-cells, 

 This showed that horse serum usually did not contain the suitable 

 "dominant" complement fitting its own amboceptor for guinea- 

 pig blood. It is well known that an amboceptor which has been 

 anchored to a cell is able to rob an active serum of all its comple- 

 ment functions. Furthermore, according to Ehrlich and Sachs, 4 

 under certain conditions even "non-dominant" complements 

 may be anchored while "dominant" complements remain in solu- 

 tion. Hence the explanation offered by Browning presented no 

 difficulties. Browning assumed that the horse serum complement, 

 dominant for the ox amboceptor but not dominant for the horse 

 amboceptor, is absorbed by guinea-pig blood through the agency 

 of the serum's own amboceptor. The loss of complement described 

 by Klein was thus readily explained on the basis of the ambo- 



1 Klein, Wiener klin. Wochenschr., No. 48, 1905. 



2 Browning, Wiener klin. Wochenschr., No. 15, 1906. 



3 Morgenroth and Sachs, Berliner klin. Wochenschr., No. 27, 1902. See 

 also page 233. 



4 Ehrlich and Sachs, Berliner kiin. Wochenschr. 1902, Nos/14 and 15. See 

 also this volume, page 195. 



