246 EAYMOND PEARL 



The ether cf has two records of perfect fertihty with untreated 

 females (matings 2104 and 2111). With an ether 9 he gave, 

 in mating 2106, only 4 eggs infertile out of a total of 25 set. 



2. Considering totals and averages it is clearly evident that 

 the inhalation treatment of the females seriously reduces the 

 proportion of fertile eggs which they are capable of producing. 

 Taking grand totals 59.2 per cent of all eggs set were infertile 

 when the mating was of the type ''treated cf X treated 9," 

 as against 25.2 per cent infertile for matings of the type ''treated 

 cT X normal, untreated 9 ," and 23.2 per cent for matings of 

 the type "normal, untreated cf X normal, untreated 9." It 

 thus appears that the treated females gave rather more than 

 twice as many in fertile eggs as untreated females in the same 

 season and under the same conditions except for the alcoholic 

 treatment. Calculating the correlation coefficient between germ 

 dosage index and percentage of eggs infertile we get 



r = +0.316 ±0.136 



This is a relatively large coefficient and almost certainly signifi- 

 cant. It means that the higher the germ dosage the greater the 

 proportionate failure of the germ cells to form zygotes. This 

 defect in the percentage of fertility in treated females' eggs 

 might, on a priori grounds, conceivably be due to any one of 

 three general sets of causes, viz., (a) that the oviduct of the 

 treated females formed a less favorable environment for the 

 sperm than the oviduct of the normal female, or (b) that the 

 eggs of the treated females were themselves adversely affected 

 by the alcohol, so that in respect either of their chemical or 

 physical condition or both they were less capable of being fer- 

 tilized than the eggs of normal untreated females, and at the 

 same time the sperm of treated males was less capable of fer- 

 tilizing, or (c) that there was an assortative mating operating 

 against treated females, and in favor of normal, untreated females 

 in the same breeding pen. There appears to be no doubt that 

 the principal cause of the reduced fertility is the second one 

 mentioned (b). The correlation between germ dosage and infer- 

 tility indicates that a certain proportion of the germ cells which 



