260 RAYMOND PEARL 



In other words, there is no evidence that the abihty of the off- 

 spring to hve was in any way adversely affected by the fact that 

 one or both parents had been systematically alcoholized (or 

 etherized) . 



2. This result takes on added significance in view of the fact 

 that the chick mortahty on the Station poultry plant was, in 

 general, verj^ unusually high in the season of 1915. This came 

 about from the fact that the rearing of the chicks was put in the 

 hands of a man who had had no previous experience in this sort 

 of work. In the process of learning to feed and brood chicks 

 properly he managed to kill an extraordinarily large number. 

 It required a chick of highly vigorous constitution to survive. 

 All weaklings of low vitality and defectives were quickly elimi- 

 nated by this drastic natural selection. This fact is abundantly 

 evident from the first two lines of table 6. 



3. Offspring of the ethyl male showed the highest average 

 percentage chick mortality. The ether male gave a mortality 

 about 5 per cent lower. The offspring of the methyl male 

 exhibited a very low rate of mortality, both absolutely and 

 relatively. The latter fact, probably means no more than that 

 his chickens were exceptionally strong, vigorous specimens, 

 totally uninfluenced by the parental treatment. It will be 

 recalled that this same male gave the lowest percentage of 

 mortality in the shell before hatching (cf. table 1). This bears 

 out the general fact that there is a tendency in poultry towards 

 a distinct positive correlation between the prenatal and post- 

 natal mortality. 



4. In every group the offspring of treated females (treated cf) 

 showed a lower average percentage of chick mortaUty than did 

 the offspring of normal untreated females mated to the same 

 males. Proportionally about half as many chicks of the former 

 sort died as of the latter. Again this parallels the facts regard- 

 ing prenatal mortality brought out in table 1. 



5. Out of the 39 offspring of treated parents which M^ent into 

 winter quarters only 4, or approximately 10 per cent died before 

 February 1, 1916. This is a smaller adult mortality than is 

 shown by any of the control lots except the second. 



