130 FRANK R. LILLIE. 



water began to fall off rapidly 'after two minutes; after four 

 minutes only 5 per cent, of the eggs fertilized. 



Eggs, on the other hand, show an effect of exposure to 1/500,000 

 copper chloride from 10 seconds exposure on, if transferred and 

 fertilized in sea-water. The effect is seen first in poor viability, 

 then in increase of polyspermy (after I minute exposure), but 







they may form membranes even after 8 minutes exposure. If 

 exposed to 1/25,000 copper, 50 per cent, will not fertilize at all 

 after I minute. The eggs in short are much more sensitive to 

 the copper than the sperm. 



Unfertilized eggs left in 1/500,000 copper chloride in sea- water 

 begin to show visible signs of injury after about two hours at 

 (approximately) 20 C. The surface of the egg beneath the 

 membrane first appears roughened, then by degrees a perivitelline 

 space appears containing a fluid stained red by escaping pigment; 

 a true cytolysis involving a "laking" effect due to destruction 

 of the plasma membrane has occurred. At this time, except for 

 the presence of pigment in the perivitelline fluid, the eggs look 

 as though they were provided with fertilization membranes. 

 Following this, cytoplasmic buds appear, the nucleus swells and 

 the egg disintegrates very gradually. 



4. Effect of Copper Chloride on Fertilized Eggs. 



(a) If eggs are fertilized in normal sea-water and transferred 

 to 1/500,000 copper chloride in sea- water two or more minutes 

 after insemination, they continue their development for several 

 hours, up to a late cleavage stage at least; but the copper acts 

 as a slow poison, so that the eggs rarely reach a swimming stage. 

 Eggs may segment in 1/250,000 and 1/125,000 copper chloride 

 if transferred 5 or more minutes after insemination in sea- water; 

 but their rate of death is naturally increasingly rapid. In 

 general the length of life of fertilized eggs is about the same in 

 any concentration used, whatever be the time of transfer before 

 cleavage. Successive stages of fertilization after the first five 

 minutes do not appear to vary notably in their sensitiveness to 

 CuCl 2 within the range explored. The effect of CuCl 2 on the 

 stages of fertilization after the first few minutes is thus a pro- 

 gressive poisoning varying in rate with concentration. 



