372 OTTO GLASER. 



no means limited to the sperm. Thus, as I have pointed out 

 ('i3 3 ), egg-extract added to blastulse which have developed in 

 normal sea-water, slows their movements, and increases their 

 volume, indicating a change in permeability. R. S. Lillie has 

 emphasized on numerous occasions the great advantages of 

 Arenicola embryos ('i3 5 and earlier papers) as indicators of 

 permeability changes which may be registered by the outflow 

 of pigment. When the Arbacia secretion is added to the Aren-. 

 icola larvae, movement is slowed down, the pigment flows freely 

 into the water, indicating an increase in permeability, and a 

 slight and reversible agglutination occurs. Considering all the 

 facts at present available, it seems reasonable to suppose that 

 agglutination is the result of an increase in permeability, and we 

 may imagine that the exudation of material from the cells or 

 the changes that lead to the exudation, render them sticky. 

 Unless some other chemical reaction is involved, it seems to me 

 more likely that the occurrence of agglutination depends upon 

 the exudate. The sperm of Nereis, the blastula of Arbacia, 

 and the larvae of Arenicola appear to furnish us with three out 

 of four theoretically possible types of cases. 



D. PARALYSIS. 



The addition of egg-secretion to a sperm-suspension is followed 

 by activation, a chemotactic effect, and a reversible agglutination. 

 For some time after the agglutination masses have disappeared, 

 the sperm remain quite active, but the rate of their movements 

 decreases until finally they come to a standstill, and appear as 

 though paralyzed. As the re-activations show, this paralysis 

 is not an irreversible state, although the second period of activity 

 never lasts as long as the first, nor is the activity on the whole as 

 great while it lasts. The third activation may be almost mo- 

 mentary. Re-activated sperm are capable of fertilizing the eggs. 



II. QUALITATIVE CHEMICAL ANALYSIS OF THE EGG-SECRETION. 



Although the observations recorded are important for an 

 understanding of the nature of the egg-secretion, they have been 

 reported at this time and in this connection chiefly for the 

 interest they may have in relation to the factual basis of Lillie's 



