28 IMMUNE SERA. 



chickens and oxen and specific bactericidal bodies 

 against cholera and typhoid bacilli, etc., and as we 

 shall see, still other groups of anti-bodies. 



Multiplicity of Complements. Under these circum- 

 stances an important question presents itself: 

 Is there in normal serum one single complement 

 which completes the action of all these various 

 immune bodies, one, for example, which in the 

 above illustration will fit all the haemolytic im- 

 mune bodies as well as all the bactericidal ones, or 

 are there a great many different complements? 

 Ehrlich, as a result of his experimental work with 

 Morgenroth, claims that the latter is the case; 

 namely, that it takes a different complement to fit 

 the immune body specifically haemolytic for guinea- 

 pig blood than it does to fit that specific for 

 chicken blood. 



Bordet, on the other hand, assuming that the 

 immune body plays the role of mordant, believes, 

 as does also Buchner, that there is but one single 

 complement in the serum. According to him, 

 this complement is able to dissolve blood-cells as 

 well as bacteria after these have been sensitized 

 by their specific immune body. Each of these 

 authors supports his claims by means of ingenious 

 experiments, for the details of which, however, 

 we must refer to the original articles, as they re- 

 quire the knowledge of a specialist for their com- 

 prehension. As a result of my own work I accept 

 Ehrlich's view, that of the multiplicity of the com- 



