Self -Fertilization Induced by Artificial Means. 145 



Ether 15 min. 30 min. 



2. 45 o (only 3 eggs) 



I. 30 40 



Experiment VIII. The eggs and the sperm of one individual 

 were mixed in ether-solutions of 4, 3, 2, i, 0.7, 0.5 per cent., and 

 removed after 10, 20, 30, 60 minutes to sea-water. It was 

 noticed that the spermatozoa were very sluggish in sea-water, and 

 although somewhat more active in the ether solutions, yet their 

 activity was not marked. Of the eggs, which appeared to be in 

 excellent condition, only three segmented, two in the i per cent. 

 (20 minutes) and one in the 0.5 per cent. (20 minutes.) 



The eggs that had not segmented after the ether treatment 

 were fertilized, after they had stood 6 hours, with sperm from 

 another individual, and three quarters of an hour later nearly all 

 had divided normally into two cells. It was observed that the 

 spermatozoa of this second individual, used for cross-fertilization, 

 were also very inactive in their own fluid. They seemed to be 

 more active in the extract from the ovary of the first individual. 

 This ovary had also stood 6 hours in sea-water. 



At the same time another experiment was made in which the 

 eggs of another individual, that had been isolated for 24 hours, 

 were put into ether solutions of 3, 2, i per cent, for 10, 20, and 

 60 minutes, and then returned to sea-water. None of these eggs 

 divided, except one in the 3 per cent, solution (60 minutes). It 

 was observed in this case that the sperm was inactive even in the 

 ether-solutions, but nevertheless this same sperm, not in ether, 

 cross-fertilized the eggs of the other individual in the preceding 

 series, and also, as stated, appeared to be somewhat active in 

 the extract of the ovary of the other individual. 



Experiment IX. The eggs and sperm together were put into 

 ether-solutions of 5, 4, 0.7 per cent. The sperm were active 

 even in sea-water. The individual had been isolated for two days. 



Ether. 



5- 

 4- 

 0.7 



