150 



Ether A B C D E 



0.5 00 o o 10 (only ten eggs.) 



i.o o o ? 2 50 



It becomes evident from this result that the frequent failure 

 of the sperm and eggs (mixed together) to self-fertilize in ether 

 is due to the poor quality of the sperm. The poor sperm does 

 not cross-fertilize, and presumably for the same cause it can not 

 always be made to self-fertilize even in the ether. That sperm 

 that is too poor to cross-fertilize may sometimes self-fertilize with 

 the help of ether I hold to be possible. I regret that I did not at- 

 tempt to determine whether poor sperm, that will not cross-fer- 

 tilize, can be made to do so by means of ether, but other experi- 

 ments lead me to think that it would often do so. 



Experiment XV. In the following experiment all of the sperm 

 appears to have been good except that of A, whose eggs, how- 

 ever, were in excellent condition. 



It is clear that the a-sperm was poor, although it did well 

 In C"" in which 70 per cent, of the eggs divided. 



There was also a self-fertilized series in which none of the 

 eggs segmented, except 5 per cent. In B. (In C, 90 per cent, of 

 the eggs divided, but this may have been due to accidental con- 

 tamination.) In the ether series the following results were ob- 



In this case although the spermatozoa of B, C, D, E were capa- 

 ble of crossing, they self-fertilized In ether very poorly, except In 

 C, where good results followed. 



Experiment XVI. In this experiment again only the first in- 



