Self -Fertilization Induced by Artificial Means. 151 



dividual produced poor sperm, yet It did fairly well In one case, 

 and In ether gave some results. 



E^i 5 ^. .^JE^IOOO^^E^ 80:;':^^ E" 100 E^ 70 



D- OriH-'DnOO^r D'^ lO(Ss) D^lOO D^ 30 



O; [^ 0100 0100 0100 C 100 



B^ 25Gtj,) B^c-) B^G-) B^ (,- ) B^ ( -j 



A^ 75 AMOO A<^100 A" 100 A^OO 



In the self-fertilized series no eggs segmented. The ether 

 series gave the following results : 



Ether A 



0.5 2 



1.0 50 (;Ss) 



The experiments recorded in Exp. XIII to XVI show that 

 the sperm is at fault when cross-fertilization does not take place. 

 In fact, eggs in the oviduct seem always to be capable of cross- 

 fertilization. It is also evident that it Is more difficult to get 

 results with ether when the sperm does not cross-fertilize well, 

 than when it does act well In this way. From this It seems to me 

 very probable that when the ether fails to bring about self- fer- 

 tilization the fault lies with the sperm. We may perhaps even 

 go further and conclude that the action of the ether in bringing 

 about the self-fertilization Is on the sperm alone, but I am not 

 In position to prove positively that the action of the ether on the 

 eggs may not also enter Into the result. 



In concluding my account of these experiments on Clona, I 

 should like to point out that I had constantly in mind the possi- 

 bility that the ether might produce parthenogenetic segmentation, 

 and that the sperm had in reality nothing to do with the result. 

 It was abundantly shown, however, that this was not the case, 

 and in the few experiments in which I put this view to the test, 

 by keeping eggs without sperm In ether - solutions of various 

 strengths, I got no results when the eggs were returned to water. 

 It should be noted in this connection that Lyon^ has recently 



1 American Journal of Physiology, IX, July, 1903. 



