562 FRANK R. LILLIE 



the agglutination does not take place, except in high concen- 

 trations. (3) The fertihzin of Arbacia eggs does not com- 

 bine with Nereis sperm. (4) A substance, which I have named 

 anti-fertilizin, may be extracted from Arbacia eggs, by breaking 

 them up or by extracting them in distilled water, which has the 

 property of combining with the spermophile group of the fertilizin. 

 It is present in sufficient amount to neutralize all the fertilizin 

 contained in the eggs, excluding the jelly. (5) When the fertilizin 

 is extracted from the eggs by repeated washings, they are no longer 

 capable of fertilization. (6) Fertilized eggs produce no more 

 fertilizin; that present at the moment of fertilization is neutra- 

 lized by anti-fertilizin. (7) Eggs with membranes formed by 

 butyric acid become incapable of fertilization, and they contain 

 no free fertilizin. 



III. THE OVOPHILE SIDE-CHAIX 

 INTRODUCTION 



Having shown then, that the union of the agglutinating sub- 

 stance with the spermatozoon enters in some significant way 

 into the process of fertilization, the problem was to ascertain in 

 what way. The simplest idea (viz., that the union is itself the 

 fertilization process) was soon shown to be untenable, for the 

 reason that the perivisceral fluid (blood) of the sea-urchin espe- 

 cially of ripe males and females, often contains a substance which 

 absolutely inhibits fertilization in the presence of any quantity 

 of sperm, but which has no inhibiting effect at all upon the sperm- 

 agglutinating reaction. It does not enter into combination with 

 the spermophile side-chain. In other words, the binding of the 

 agglutinating substance by the sperm may be complete, but in 

 the presence of an inhibitor contained in the blood none of the 

 usual effects of insemination, mo matter how heavy, follow. 



The next suggestion was fairly obvious, viz., that the substance 

 which we have been calling the agglutinating substance on ac- 

 count of its effect on the spermatozoa, in reality possesses two 

 side-chains active in fertilization, viz., a spermophile and an 

 ovophile side-chain; the binding of the sperm activates the ovo- 



