142 T. H. Morgan. 



Experiment I. The eggs were removed from an individual that 

 had been isolated 20 hours. The sperm was also taken out, and, 

 together with the eggs, was put into ether-solutions, 5, 2, i, 0.7, 

 0.5 per cent, in sea-water. After 5 minutes, and again after 10 

 minutes, the eggs were removed to pure sea-water. The eggs 

 were injured by the ether in the strongest solution, but neverthe- 

 less one segmented. In all of the other solutions about 80 per 

 cent, of the eggs divided; the most in the weaker solutions. 



Experiment II. In this experiment the eggs and the sperm 

 were put together into ether solutions of 5, 2, i, 0.7, 0.5 per cent. 

 Some of the eggs were transferred to water after 5 and 10 min- 

 utes, but others were left in the solutions. In the strongest solu- 

 tion the eggs w^ere killed. In the others the following results were 

 obtained: 



Eggs segmented Eggs segmented. 



Ether 5 minutes in ether. 10 minutes in ether. 



2. percent. 20 per cent. 25 per cent. 



I. " 5 " 75 " 



0.7 " 2 " 2 



0.5 " 10 " 5 



.J't is clear that the stronger solutions gave the best results, and 

 that ten minutes immersion was better than five minutes. None 

 of the eggs that were left in the ether-solutions segmented. This 

 does not mean that they were not fertilized, but that the ether so 

 injured the eggs after a long immersion, that they failed to de- 

 velop. Several check experiments were also made in this case. 

 In one the eggs were not self-fertilized but were put into a 5 

 per cent, ether-solution, and transferred after ten minutes to 

 sea-water. They did not segment, nor did a few that were left 

 behind in the ether solution. In another check series the eggs 

 were not fertilized, and were left in sea-water. None segmented, 

 which shows clearly that the ether in the preceding experiment 

 was in some way responsible for the self-fertilization of the eggs. 

 It should also be recorded that tadpoles developed from all the 

 fertihzed eggs that had been in the ether-solutions. 



Experiment III. The eggs and sperm of the same individual 



