HEREDITY 35 



species, an inhibitory mechanism by which the expected reaction may 

 be stopped. The inhibitory mechanism (aside from its usefulness to 

 the individual) is a device for protecting the community from reactions 

 that, however favorable originally to the individual, are antisocial. 

 Children at birth have the inhibitors undeveloped, but they have a 

 marvelous capacity for acquiring them in some or all forms. Many a 

 person, however, unfortunately for himself and society, is incapable of 

 acquiring the full complement of them; he tends constantly or period- 

 ically, throughout life and despite the best training, to react directly 

 to the stimulus that falls upon him, antisocial though the reaction may 

 be. Such a person may have perfect " society manners " and be faithful 

 in conjugal relations but on occasion will take from shops articles for 

 which she has no need ; or another is regarded as a valuable member of 

 his community, a leading member of the bar and a pillar of the church, 

 but about once a year consumes a nearly lethal quantity of alcoholic 

 drinks; or another is an agreeable, generous, affectionate young fellow 

 who, about once a month, secretly sets fire to buildings in order to feed 

 an irresistible love of the excitement produced by the flames; or a 

 young girl who does well at school starts out from a comfortable home 

 ostensibly to go to Sunday School, but makes it a practise of spending 

 the afternoon in the rooms of some marines; or a lad of refined home, 

 beloved of his parents and loving them, slips out of doors instead of 

 going to bed at night and sleeps in entry ways or wanders out into the 

 country and spends the night in a barn. These are examples, among 

 hundreds that could be cited, of a lack of specific inhibitions. The 

 stimulus can not be shunted off; it must lead to the specific response. 

 Just as the amoeba throws out its pseudopods along the path of the 

 incident ray and so moves from the source of light; as the moth flies 

 towards the candle; as the carrion fly is directed in its movements by 

 the scent wafted to it from afar, so such persons perform their unsocial 

 acts as part of their necessary reactions. 



In another set of cases every reaction to a stimulus is of a socially 

 desirable sort. All desires for the property of others, all inclinations 

 to avenge insult by violence, all tastes and appetites, including the sex 

 instinct, are readily inhibited — are under perfect control. And why 

 are they under control ? Because, first, the person who has the inhibit- 

 ors came from a fertilized egg that carried the determiners for them; 

 and, secondly, was surrounded by influences that were favorable to their 

 development. In what sense can these people be held to be equal before 

 the law with those considered in the preceding paragraph? 



Even in numerous elements of mood and behavior the influence of 

 the hereditary make-up is striking. One person is prevailingly elated, 

 jovial, irrepressible; another quiet, depressed, melancholic; another, 

 still, alternates in these moods and when elated he believes he can do 



