ALCOHOL AND HEREDITY 125 



employed on the guinea pigs, and naturally we should 

 expect to get similar results. In one respect there is 

 complete agreement. The proportion of fertile eggs 

 was reduced by subjecting the parents to alcohol ; the 

 higher the dosage the smaller the number of zygotes 

 formed. On the other hand, the number of embryos 

 which after being formed died before hatching, and the 

 number of individuals dying after hatching, was actu- 

 ally less among the offspring of alcoholized than un- 

 treated birds. When both parents were alcoholized, 

 the average weight of the offspring at hatching was 

 greater than when one or neither received treatment. 

 The superiority of the offspring of fowls subjected to 

 alcohol was maintained during their subsequent de-' 

 velopment, and they showed no greater proportion of 

 abnormalities than the controls. 



9. How can such contradictory results be explained ? Explanation 

 Dr. Pearl supposes that the essential facts are about as 

 follows : The gametes or germ cells vary in their vitality, 

 and are not equally affected by any deleterious agent. 

 Consequently, on treating the parents with alcohol or 

 any similar substance which reaches the germ plasm, 

 we may expect to find three classes of effects : 



a. Some cells will be destroyed, or so injured that 



they are incapable of forming viable zygotes. 



b. Some cells will be injured, but will form zygotes 



which are capable of living, though variously 

 imperfect or pathological. 



c. Some cells will not be appreciably affected. 



It will be seen that this situation parallels the effects 

 of disease on adults. . In the presence of some acute 

 bacterial diseases, some will die, others will live but 

 suffer injury, still others will escape unharmed. In the 

 case of bacterial disease, there is little or no evidence 



