The Factors of Evolution 251 



Far back in the dim shadows of the past, primitive man is 

 represented as asking his Creator, "Am I my brother's 

 keeper?" And that question has come down to us through 

 all the ages, with ever-growing insistency. What measure of 

 responsibility do we bear for the well-being, not only of our 

 brothers of the present, but our children of the future ? Does 

 a man's conduct influence for weal or woe the lives of his 

 children? Alcoholism is a well recognized inherited trait. 

 But what is its origin? Can a man through indulgence in 

 the "cup that cheers" affect the inheritance of his children? 

 While abundant data are available from human inheritance 

 to show its inheritability, evidence regarding its origin can- 

 not be readily obtained here. And so the experimenter has 

 turned to the long-suffering guinea pig, the rat and the 

 chicken for an answer to his question. And here only indi- 

 rect evidence at best can be obtained. We cannot induce an 

 alcoholic tendency or fondness in a lower animal, or at least 

 it has not yet been done ; but we can determine whether sub- 

 jecting the parent to alcohol will in any way influence the 

 offspring, and whether such effects, if any, will persist in 

 future generations. 



Trial of several methods of subjecting animals to alcohol 

 has shown that the best method is to allow them to breathe 

 the fumes for stated periods daily, the length of the period 

 being determined by the ease with which the animal is in- 

 toxicated by the fumes. The method is objectionable because 

 of the tendency of the animals to become blind under the in- 

 fluence of the fumes. This does not however interfere with 

 their breeding, nor does it reappear in the offspring. Using 

 this method on guinea pigs Stockard has found that of one 

 hundred and three matings between parents, either one or 

 both of which had been treated with alcohol, forty-three were 

 either sterile or resulted in abortions; in fourteen matings 

 the young were stillborn, while in the forty-six matings pro- 

 ducing a total of eighty-nine young, thirty-seven of these 

 died soon after birth and only fifty-two survived, many of 

 which were undersized and nervous. 



MacDowell has carried out a long series of experiments to 

 test the effects of treating rats with alcohol upon the ability 

 of their young to learn a path through an intricate passage 

 or "maze," which indicate that the grandchildren of young 

 so treated learn less readily than do those of normal rats. 

 MacDowell has .also obtained a very definite effect upon 

 the rats so treated, their weight and fecundity being ma- 

 terially reduced. Pearl, in a similar series of experiments on 

 fowl, found that while the proportion of fertile eggs laid 

 by alcoholized parents was much lower than in those from 



