EGG SECRETIONS OF ARBACIA AND ASTERIAS 495 



In conclusion, I wish to express my gratitude to Dr. 0. C. 

 Glaser, who suggested this problem and directed the work; to 

 Dr. F. R. Lillie for the privileges of the Marine Biological Lab- 

 oratory, Woods Hole, and to the several colleagues who kindly 

 allowed me to demonstrate to them various reactions. 



IV. SUMMARY 



In confirmation of the work of Lillie and Glaser, it was found 

 that Asterias and Arbacia eggs secrete into the supernatant sea- 

 water a substance which causes the sperm of the same species 

 to be activated, aggregated, reversibly agglutinated, and 

 paralyzed. The secretion is also a parthenogenetic agent. 



Further study of its physiological properties brought out: 



1. That its presence is necessary for the fertilization of the 

 egg, since, 



a. Immature eggs of Asterias, which cannot be fertilized, pro- 

 duce a secretion with less than one-sixtieth the agglutinating 

 power of that produced by the same eggs when mature. 



h. Eggs from which the secretion has been washed do not de- 

 velop when inseminated. If, however, secretion be added before 

 insemination, they develop. 



c. Arbacia eggs which are 'resistant' to fertilization late in the 

 season, also produce little secretion. They fertilize normally if 

 secretion is added. 



2. That the secretion has a dual nature, as shown by the fol- 

 lowing facts : 



a. It reacts with both the sperm and the egg. 



h. Boiling destroys its value as a parthenogenetic agent, but 

 not as an agglutinin. 



c. Perivisceral fluid of the same species inhibits autopartheno-- 

 genesis, but not agglutination. 



A qualitative study of the chemical properties of the secre- 

 tion confirmed Glaser's observations, and indicated: 



1. That it does not dialyse through a collodion sac, and so is 

 probably colloidal. 



2. That it contains carbon and nitrogen, but gives no clear 

 response to protein tests. It gives a faint yellow color, in the 



