250 FRANK R. LILLIE. 



be superficial in position and easily detached as proved by its 

 effectiveness before the spermatozoon penetrates. Extracts of 

 the entire spermatozoon must contain numerous other substances 

 which may neutralize its effectiveness. 



The difficulty of the investigation as shown by my experiments 

 is that it is liberated only very slowly in concentrated suspensions 

 and that its amount in dilute suspensions would presumably be 

 too slight to be effective. Some means can probably be devised 

 for liberating it in concentrated sperm suspensions and freeing it 

 of the spermatozoa for testing. 



Finally I may point out that the conclusion that spermatozoa 

 lose a substance necessary for the exercise of their fertilizing 

 power is consistent with my own point of view of the mechanism 

 of fertilization as well as with Loeb's. From my point of view 

 the spermatozoon loses its receptors, viz., the substance that 

 activates the fertilizin of the egg; from Loeb's point of view the 

 spermatozoon loses its lysin, the substance that corrodes (cy- 

 tolyzes) the egg. 



My previous experiments had shown that eggs produce a 

 certain substance in sea-water (fertilizin) which is necessary 

 for their fertilization; fertilized eggs no longer produce this 

 substance and are incapable of fertilization. Both eggs and 

 spermatozoa therefore contain substances, more or less liable 

 to loss, which are necessary for fertilization. The mechanism 

 of fertilization cannot possibly, therefore, be regarded in the 

 simple manner postulated by Loeb's theory. The existence of 

 parthenogenesis demonstrates the efficacy under given condi- 

 tions of the egg-substance alone; we must therefore regard the 

 spermatic substance essentially as an activator of the fertilizin 

 of the egg. 



LITERATURE. 

 Gemmill, James F. 



'oo On the Vitality of the Ova and Spermatozoa of Certain Animals. Journ. 



of Anat. and Physiol., Vol. 34 (N. S., Vol. 14), pp. 163-181. 

 Glaser, Otto. 



'13 On Inducing Development in the Sea-urchin, together with Considerations 



on the Initiatory Effect of Fertilization. Science, N. S., Vol. XXXVIII, 



pp. 446-450. 

 '14 The Change in Volume of Arbacia and Asterias Eggs at Fertilization. Biol. 



Bull., Vol. XXVI., pp. 84-91. 



