144 T. H. Morgan. 



It Is Interesting to note In this case, In which so large a per- 

 centage of the eggs were self-fertUIzed In ether, that of several 

 hundred eggs of the same Individual, to which sperm was added, 

 but which were kept In sea-water, not one segmented. It was 

 also found, and will be referred to again later, that when the 

 sperm alone was put into a 2 per cent, soluton, of ether for five 

 minutes, and was then added to eggs of the same individual In 

 sea-water, 70 per cent, of the eggs segmented. 



Experiment VI. In this experiment the eggs and the sperm 

 were put into ether-solutions of 2 and of 0.5 per cent, and 

 removed after ten minutes. In one lot the eggs were self-fertil- 

 ized, in the other they were cross-fertilized. 



Self-fert. Cross-fert. 



• Ether 10 min. 10 min. 



2. o 100 



0.5 o 100 



In this case although no self-fertihzation took place, all the 

 crossed eggs which had also been In the ether-solution developed, 

 showing that the solutions have no baneful effect on cross-fertiliza- 

 tion. The lack of self-fertilization shows that the sperm were 

 not sufficiently acted upon by the ether-solutions employed to effect 

 self-fertilization. 



Experiment VII. This experiment shows how slight a differ- 

 ence in the conditions may cause great differences In the result. 

 The Individuals had been Isolated 48 hours. One lot of self- 

 fertilized eggs was kept in water and allowed to stand there 20 

 minutes. The eggs with the surrounding sperm were then put 

 Into ether-solutions of 2, i and 0.5 per cent, for 20 minutes, and 

 then returned to sea-water. None of these segmented. Another 

 lot of eggs from this individual were mixed with sperm of the 

 same individual and put into a 2 per cent, ether-solution for 

 ten minutes and then carried back to sea-water. Here 95 per 

 cent, of the eggs segmented. On the other hand some of these 

 same eggs taken from the ether after 5 minutes did not divide. 

 The following experiments were also carried out with other self- 

 fertilized eggs of the same individual. 



