336 RALPH S. LILLIE. 



the spontaneous post-maturational cytolysis; i. e., they undergo 

 complete coagulation within eighteen hours or less, precisely as 

 do normal eggs. Whether the resistance to cytolysis by salt 

 solutions is also decreased I have not yet determined; but the 

 decrease in the resistance to the post-maturational cytolysis 

 a change supposedly due to the action of certain protoplasmic 

 oxidation products upon the plasma membrane 1 is clear evidence 

 that the membrane has been brought into a condition more 

 nearly approaching the normal . The experiments to be described 

 show that a return of the normal responsiveness to the spermato- 

 zoon is closely correlated with a return of the normal behavior 

 with respect to this spontaneous oxidative cytolysis. In other 

 words, the plasma membranes of the ether-treated "reju- 

 venated" eggs undergo breakdown in the manner and at the 

 time characteristic of normal eggs. 



The following record gives the description of two typical 

 experiments. 



July 6, 1911. Eggs were removed at 11:00 A.M. from two lots of starfish, A 

 and B. In both lots a good proportion of eggs underwent apparently normal mat- 

 uration. Eggs from each lot were divided into two portions. One portion re- 

 mained in sea-water; and about four hours after removal from the animals part of 

 these eggs were fertilized; the rest remained unfertilized. The other portion was 

 transferred, two hours after removal, to sea-water containing 0.3 vol. per cent, 

 ether; in this solution they remained for one hour and thirty-five minutes; they were 

 then returned to sea-water; to part of these eggs spermatozoa were added, the rest 

 remained unfertilized. The ether-treated and the untreated eggs were fertilized 

 at the same time. The two lots -4 and B were treated alike so far as possible. The 

 results of these experiments were as follows: 



LOT A. The following was the condition of the eggs ca. 22 hours after removal: 



1. Untreated Eggs, (a) Unfertilized. Most mature eggs are coagulated hut 

 to a varying degree; some are only slightly darkened, and in a fair proportion the 

 protoplasm remains semi-translucent. 



(b) Fertilized. All of the mature eggs have formed membranes and most have 

 undergone cleavage or irregular fragmentation; but many remain uncleaved; no 

 blastulae are present. 



2. Ether-treated Eggs. (In 0.3 vol. per cent, ether from i.oo to 2.35 P.M.) 



(a) Unfertilized. All mature eggs are completely and uniformly coagulated; 

 there are no partly coagulated or semi-translucent eggs. 



(b) Fertilized. Decided contrast to ib. Most eggs are dead, but among these 

 there are no uncleaved eggs; numerous blastulae and gastrulse are present, many 

 swimming at the surface. 



LOT B. (The condition of the eggs ca. 22 hours after removal.) 



1 Since the change is greatly retarded in oxygen-free or cyanide-containing sea- 

 water. Cf. J. Loeb, Archiv fur die gesammte Physiologic, 1902, loc. , it. 



