276 CARL R. MOORE. 



present paper to take up for discussion the disputed points of 

 the fertilizin theory 1 nor to discuss the way in which fertilizin 

 acts or its role in the process of fertilization, but it is perhaps 

 desirable to add another instance of the existing parallelism 

 between the presence of a detectable amount of this agglutinating 

 substance and the capacity for fertilization. Professor Lillie 

 and the writer have previously shown this parallelism to exist 

 in all cases thus far tested : (i) Normal, ripe Arbacia eggs liberate 

 this substance into the sea-water as long as they are capable 

 of fertilization; eggs whose germinal vesicles have not broken 

 down do not liberate fertilizin in detectable quantities and they 

 cannot be fertilized. (2) If Arbacia eggs have been exposed 

 to the optimum concentration of butyric acid and full mem- 

 branes were produced, no fertilizin was detectable and the eggs 

 could not be fertilized. (3) If eggs are over-exposed to the 

 same concentration of butyric acid (i to 3 mins.) the eggs can 

 be, at least, partially fertilized and fertilizin is readily detected. 

 (4) If they are exposed for two hours to this same concentration 

 of butyric acid (50 c.c. sea-water + 2.8 c.c. N/io butyric acid) 

 they cannot be fertilized and fertilizin is not liberated in de- 

 tectable quantities. (5) If eggs are exposed to heated sea-water 

 of 35 C. for 10 minutes they could not be fertilized nor could 

 fertilizin be detected; and finally to be added from these experi- 

 ments. (6) If eggs are exposed to a hypertonic sea-water solu- 

 tion for one to one and one-half hours, sometimes some of the 

 eggs are still fertilizable to a limited extent but always such 

 conditions have been accompanied by a detectable amount of 

 fertilizin ; but in conditions where the eggs are not capable of 

 fertilization no fertilizin has ever been detected. Only one 

 experiment will be given in detail to show this parallelism (see 

 Table II.). 



From microscopical examination at 5:00 P.M., August 15, 

 one could see that many eggs of the X lot were apparently normal 

 in appearance; they were well rounded, and seemed to possess 

 practically the normal amount of pigment, but upon insemina- 

 tion they did not produce fertilization membranes and the 

 blastomeres after segmentation were not held together, and not 

 one of them developed to the swimming blastula stage. 



1 See Lillie, '14, Moore, '16. 



