368 OTTO GLASER. 



spermatozoa are almost motionless. The suspensions I worked 

 with showed only isolated spermatozoa executing occasional 

 spasmodic movements. Upon the addition of the secretion from 

 its corresponding egg, the Asterias sperm are thrown into violent 

 activity contrasting sharply with their original state of quiescence. 



2. Hetero- Activation. Essentially the same phenomenon de- 

 scribed under the head of iso-activation can be observed if 

 Asterias sperm are treated with Arbacia secretion, and Arbacia 

 sperm with that from Asterias eggs. As might be expected the 

 phenomenon is more marked with the Asterias sperm on account 

 of their original inactivity, although the Arbacia sperm are also 

 noticeably accelerated. I have made no experiments capable of 

 deciding whether the activation of the two kinds of spermatozoa 

 is due to the existence in the secretions from the two kinds of eggs 

 of the same substance or of specifically different substances. 



3. Re- Activation. Activation is a temporary state, and after 

 certain other reactions have occurred, the spermatozoa are 

 found to be quite immotile. Such spermatozoa, although chem- 

 ically different (I3 1 ) from fresh ones which have never been 

 subjected to the secretions, are nevertheless capable of re-activa- 

 tion. This is shown by the following experiments, in which 

 Arbacia sperm-suspensions prepared in each case from a single 

 male were divided into lots, activated by the addition of secretion, 

 observed at intervals, and treated with more secretion as well as 

 fresh eggs. The degrees of activation, reactivation, or movement 

 are given as great, moderate, slight, or zero. In the instances 

 in which eggs were added, fertilizations always took place, but 

 the proportion of eggs that divided varied inversely with the 

 length of exposure of the sperm to the secretion (p. 369). 



B. CHEMOTAXIS. 



The chemotactic effect of the egg-secretion has been studied 

 very carefully by Lillie, and both methods and results have been 

 described by him at length ('I3 1 )- I have verified the most 

 essential results on Arbacia and have extended them to Asterias. 

 The injected-drop method as well as the distribution of sperm 

 about groups of eggs were used as indicators. As Lillie suggests, 

 such results do not make clear the role of chemotaxis in normal 



