THE 



AMERICAN NATURALIST 



Vol. XLVIII December 1914 No. 576 



THE FAILURE OF ETHER TO PRODUCE MUTA- 

 TIONS IN DROSOPHILA 



PROFESSOR T. H. MORGAN 

 Columbia University 



The many mutants of Drosophila ampelophUa that have 

 appeared " under domestication" have raised the question 

 as to the cause or causes that have brought about the re- 

 sult. Since every fly that has passed through our hands 

 has been etherized once in its life, usually before it begins 

 to lay its eggs if a female or before mating if a male, it 

 might appear that this recurring condition was respon- 

 sible for the mutations. At any rate it seemed worth 

 while to put this view to a test, if for no other reason 

 than to remove from one's mind the suspicion that ether 

 "did it." 



Preliminary trials showed that two drops of ether (on a 

 piece of cotton > in a quart milk bottle, tightly stoppered 

 with a cotton plug, would not noticeably affect the flies in 

 half an hour, three drops made them slightly "stupid," 

 four drops more so, and five drops quieted them. It was 

 found that they would for the most part recover even 

 after 6, 7 and 8 drops of ether. If etherized twice daily 

 the flies were so far weakened that they generally died 

 without laying any eggs. Therefore in the later experi- 

 ments the flies were etherized only once a day or once in 

 two days. 



The larvae (beginning two days after the eggs were laid, 

 705 



