36 E. E. JUST. 



Farthermore, the studies of Lillie have shown that like the 

 fertilized egg, the egg induced to development artificially no 

 longer produces fertilizin. Moore's ('16, '17) studies confirm 

 and extend those of Lillie. 



The presence of fertilizin in Echinarachnius , Arbacia and 

 Nereis is indicated by its power to agglutinate specific sperm. 

 But this very agglutination of the sperm is held as an argument 

 against the fertilizin theory because it is held to "inhibit the 

 fertilizing effect of the spermatozoa instead of enhancing it 

 since the cluster formation prevents the sperm from reaching 

 the egg. Even from a teleological viewpoint it is difficult to 

 understand why a substance which only prevents the fertilizing 

 action of the sperm should be a necessary link in such action" 

 (Loeb, '14). First, however, it should be recalled that this 

 agglutination is a reversible process where specific sperm are 

 employed, the clumping lasting from ten to twenty seconds for 

 average egg-water dilution. Second, while Lillie found that 

 agglutination reduces the per cent, of fertilization, Fuchs ob- 

 served the contrary to be the case. Finally, we should note these 

 agglutinations are made in the laboratory with fairly thick sperm 

 suspension and that not only the motility of the sperm but the 

 density of the suspension are functions in the agglutination 

 reaction. Agglutination would scarcely take place in the sea 

 where the conditions are not those in a drop of water on a slide. 

 As a matter of fact agglutination rarely takes place during in- 

 semination in a finger-bowl because we very carefully use thin 

 sperm suspensions to avoid polyspermy. The sperm are thus 

 too widely separated to clump; instead, they stick to the eggs. 

 I, therefore, heartly agree with Loeb when he states that he is 

 "inclined to believe that the cluster formation or agglutination 

 of sperm does not occur when fertilization takes place under 

 natural conditions." But this in no wise invalidates the claims 

 of the fertilizin theory. 



Concerning the sperm agglutination by egg-water of another 

 form, hetero-agglutination, it seems to me that it would be neces- 

 sary to know the nature of the agglutination; this demands the 

 microscopic method of studying the agglutination. Thus, 

 Arbacia egg-water agglutinates Nereis sperm, but this is a toxic 



