544 FRANK R. LILLIE 



thus colorless, non-filterable, non-dialyzable, very thermo-stable 

 and apparently non-protein in its character. 



The stability of the substance is also evidenced in its lasting 

 qualities. Filtrates from egg-suspensions were kept and tested 

 after various intervals of time. Thus the filtrate from a 33 per 

 cent egg-suspension of June 21, was of 1600 agglutinating power; 

 on August 26 it was of 100 agglutinating power. Similarly, the 

 filtrate from a 33 per cent egg-suspension of June 20 was of 1600 

 agglutinating power; on August 26 it was of 100 agglutinating 

 power. On the other hand, an agglutinating solution of June 30, 

 of 800 agglutinating power was practically negative on August 26. 

 In this tube there was more evidence of bacterial action than in 

 the other two. Again, a distilled water extract kept from Sep- 

 tember, 1912, was of 16 agglutinating power on July 7, 1913. 



In Study V, I also noted that its production is confined entirely 

 to the eggs. It is not contained in the blood, and could not be 

 extracted from other tissues. 



6. ANTI-FERTILIZIN 



We have noted the extreme avidity of the spermatozoa for the 

 fertilizin produced by the eggs. Neither the blood nor tissues 

 appears to contain any substance capable of uniting with the 

 spermophile side-chain which causes agglutination of the sper- 

 matozoa, or of neutralizing its action. However, such a substance 

 is contained within the egg itself, and its discovery is one of the 

 most interesting points in the mechanism of fertilization, because 

 it would appear from the facts considered in section 7 that it 

 is the occupancy of the spermophile side-chain of the fertiUzin 

 by this substance, which I propose to call anti-fertilizin, that pre- 

 vents polyspermy, or refertilization of eggs. 



Its presence can be demonstrated in the test-tube by methods 

 which extract the internal substance of the eggs. But as the 

 jelly surrounding the eggs contains an immense excess of fertilizin, 

 complete neutralization of sperm agglutinating power can be 

 obtained only after the jelly is removed, and still better if the 

 eggs have been repeatedly washed until their fertilizin production 

 is greatly reduced. 



