EGG SECRETIONS OF ARBACIA AND ASTERIAS 



483 



TABLE 11 



Inhibition of cleavage by purple x 



mechanical]}^ by entrapping the sperm. The egg itself also 

 appears swollen, and hence maj^ be so changed that it cannot 

 develop. It will be noted in the following experiments (table 11) 

 that boiled Arbacia sperm blocks fertilization only when 'purple 

 x' is present. This inhibitor (Woodward, '15) appears to be 

 derived from testicular or ovarian tissue. 



Boiling the sperm or egg secretion of Asterias produces a 

 salmon-colored substance, ^salmon x,' which also acts as an in- 

 hibitor with both Asterias and Arbacia eggs. The color of the 

 boiled Asterias sperm suspension was not always noted. The 

 inconsistent results shown in the second line of table 12 arouse 

 the suspicion that in some cases the inhibitor, and perhaps the 

 salmon-colored compound, was not present. 



TABLE 12 

 Inhibition of cleavage by salmon x 



TREATMENT OF EGGS 



Asterias eggs + sperm 



Asterias eggs + boiled Asterias sperm + sperm. . . . 

 Asterias eggs + boiled Asterias fertilizin + sperm. . 



Arbacia eggs + sperm 



Arbacia eggs + boiled Asterias sperm + Arbacia 



sperm 



Arbacia eggs + boiled Asterias fertilizin + Arbacia 



sperm 



28 

 21 



