XVII. CONCERNING ALEXIN ACTION. 1 



By Dr. HANS SACHS, Assistant at the Institute. 



AFTER the fundamental studies of Bordet, and of Ehrlich & 

 Morgenroth had shown that the haemolysins produced in serum by 

 immunization with blood-cells owed their effect to the combined 

 action of two substances (amboceptor and complement) it seemed 

 very natural to suppose that the hsemolysins of normal sera, which 

 had been known for some time, were also of a complex nature. 

 Buchner, who was the first to recognize the significance of the bac- 

 tericidal and globulicidal properties of blood serum, had conceived 

 these actions from a Unitarian standpoint and referred them to the 

 " alexin ' of each particular serum. Recent investigations, how- 

 ever, have shown that Buchner 's alexin is not a single simple sub- 

 stance, but the sum of an infinite number of combinations, whose more 

 thorough analysis has been rendered possible only by the methods 

 of the newer hsemolysin investigations. 



' The credit of applying the experiences gained with the haemoly- 

 sins artificially produced to the study of hsemolysins of normal 

 serum, belongs to Ehrlich and Morgenroth. They made use of a 

 method which they had already employed in the analysis of hsemolytic 

 immune sera, the separation by means of cold. This depends on the 

 fact that at under favorable circumstances only the interbody, 

 and not the complement, is bound by the blood-cells. Accordingly 

 by appropriate treatment it could be shown that the serum had 

 lost part of its power, but that it could be regenerated by the addi- 

 tion of the same kind of serum previously inactivated by heat. This 

 confirmed their view of the complex nature of normal hsemolysins. 

 They were further able to activate inactive hsemolytic normal sera 

 by the addition of other kinds of sera which served as complements, 

 and which by themselves did not dissolve the particular blood-cells 



1 Reprint from the Berl. klin. Wochen. 1902, Nos. 9 and 10. 



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