156 T. H. Morgan. 



with their own sperm, segmented. Another similar experiment 

 with two other individuals gave the following results : 



A BO 



A^' B" 



A" 50 B' r^'^^T) 



In another set the ether appears to have been too strong, yet 

 50 per cent, of A'' divided. 



In another experiment, 10 per cent, of the self-fertilized eggs 

 in ether segmented, and 50 per cent, of the crossed. 



In another, 5 per cent, of the self-fertilized eggs in ether seg- 

 mented, and 75 of the crossed. 



The next set is more instructive : 



A BO 



A^' 100 B*^ 



A^ 2 B^ 4 



It is clear that the ether had a marked effect in A"*, making all 

 of the eggs self-fertilize. This is all the more interesting be- 

 cause none of the eggs without ether self-fertilized. Both eggs 

 and sperm of the B- set appear to have been in poor condition, so 

 that the sperm did not cross-fertilize, or the eggs become cross- 

 fertilized, to any extent. 



In searching for other substances that might act on the sperma- 

 tozoa as does tht ether, I tried, amongst other things, a solution 

 of ammonia in sea-water, and this I found made the spermatozoa 

 even more active than the ether. Dilute solutions of alcohol 

 from I to 10 per cent, also excite the spermatozoa to greater ac- 

 tivity. Certain salt-solutions, ammonium chloride (i, ^, ^ per 

 cent.), magnesium chloride (2 per cent.), and sodium chloride (i 

 per cent.) appeared also to act on the sperm, but much less ef- 

 fectively than does ether, alcohol, or ammonia. In the alcohol 

 series of i, 3, 5, 6, 10 per cent., it was found that i per cent, made 

 the sperm very little more active; 3 per cent, more so; 5 per cent, 

 most active; 6 per cent, less; 8 per cent, no effect; 10 per cent., no 

 effect. The last two solutions undoubtedly injured the sperm. 

 In another series, 7 per cent, gave the best results. 



