OTTO GLASER. 



C. AGGLUTINATION. 



1. Iso-agglutination. That egg-secretion is capable of agglu- 

 tinating sperm has been fully described by Lillie ('I2 1 , 'I3 1 , T I3 2 ). 

 In this section I simply wish to add my testimony to his as to 

 the facts in the case namely that this phenomenon occurs; that 

 it is reversible; that its duration is brief and may be utilized as 

 a measure of concentration; and that sperm once agglutinated, 

 although capable of re-activation, do not agglutinate again. 



2. Hetero-agglutination. I have found that the Arbacia 

 secretion also agglutinates the sperm of Asterias, and that 

 Asterias secretion, besides agglutinating its own, has a similar 

 effect on the spermatozoa of Arbacia. Thus 



1. Arbacia sperm + Arbacia secretion = agglutination masses 



described by Lillie. 



2. Arbacia sperm + A sterias secretion = dense, angular masses. 



Reaction slower than I . 



3. Asterias sperm + Asterias secretion = masses smaller than I. 



Angular. 



4. Asterias sperm + Arbacia secretion = result similar to 3. 



At the time when these experiments were performed, the 

 material had practically disappeared, and in consequence the 

 question whether the above hetero-agglutinations are due to the 

 same substances as the iso-agglutinations, or whether each 

 secretion contains both an iso- as well as a hetero-agglutinin, 

 could not be decided. Since hetero-agglutination between 

 Arbacia and Nereis is not brought about by the same substance 

 ('I3 1 ) that causes the iso-agglutination, the same relations may 

 hold for Arbacia and Asterias. It will prove interesting to see 

 whether the agglutinin in Arbacia secretion that reacts with the 

 Nereis sperm is the same one that agglutinates Asterias sperma- 

 tozoa. If not, it becomes important to discover how many 

 agglutinins are present. In this connection I may refer to an 

 observation already published (i3 3 ), namely that the Arbacia 

 secretion agglutinates the larvse of Arenicola. 



3. Origin of the Agglutinin. Lillie has shown that the agglu- 

 tinin is chiefly located in the outer jelly of the Arbacia egg. I 

 have found the same thing to hold true of the Asterias ovum. 

 It was also proved by Lillie (i3 2 ) that if the outer jelly is removed 



