SUBSTANCES WHICH ACTIVATE COBRA VENOM. 

 TABLE I 



445 



TABLE II. 



In like manner the complementing property of the serum is de- 

 stroyed by appropriate digestion with hydrochloric acid and with 

 soda lye, in which again the serum differs from lecithin. 



We felt that the discovery of agents which would exert an inhibit- 

 ing effect in the hsemolytic action of only one of the two factors (either 

 on that of the serum or of the lecithin) would be most valuable for 

 a positive differentiation of serum complement and lecithin. We 

 therefore next immunized rabbits and chickens with guinea-pig serum, 

 seeking in that way to produce anticomplements. By the natural 

 production of an antibody we could thus prove the complement 

 nature of the serum activator. These experiments, however, en- 

 countered certain difficulties, for, as we have already mentioned 



