STUDIES OF FERTILIZATION 



575 



August 6 : This experiment was made up of a series of combinations 

 of blood A plus fertilizin-saturated blood B, Fertilizations made in 

 0.2 per cent sperm suspensions in each combination. 



TABLE 14 



(A) Filtered serum of males and females 



(B) 23 cc. A plus 11.5 cc. ripe eggs. Centrifuged after 10 min. and filtered; 

 sperm-agglutination test, 1/3200=9 sec. 



The protective action of the agglutinating substance gradually rises 

 up to nmnber 10 and then falls off, owing, presumably, to excess of 

 agglutinating substance. 



I have given a considerable number of the experiments because 

 the matter under consideration is of great significance. There 

 can be no question that some substance derived from the eggs 

 themselves protects against the inhibiting substance in the blood. 

 Until some method is devised for obtaining the agglutinating 

 substance pure, it is impossible to meet entirely the objection 

 that it may be some substance other than the agglutinating sub- 

 stance that protects against the inhibitor. The agglutinating 

 substance can, however, be demonstrated in high concentrations, 

 as the protocols of the experiments show. Until some reason for 

 a contrary assumption is shown, the neutralization of the inhibitor 



