126 SOCIAL EVOLUTION 



ill-conditioned, or immoral parentages are markedly 

 detrimental to the children's eye-sight; (2) No sufficient 

 or definite evidence that school environment has a 

 deleterious effect on the eye-sight of children; (3) 

 Ample evidence that refraction and keenness of vision 

 are inherited characters. ' When it is considered that 

 this study was undertaken in anticipation of finding that 

 inheritance and environment factors would be far more 

 comparable in magnitude, it is evident that the investi- 

 gation was pursued without bias. A second study, of 

 the influence of defective physique and unfavorable home 

 environment on the intelligence of school children, 

 showed that there was ''no sign of an environmental 

 condition producing an effect on the mentality of the 

 child at all comparable with the known influences of 

 heredity. " ^'^ This investigation also appears to have 

 been undertaken with an open mind. Finally, the con- 

 troversial "Study of the Influence of Parental Alcoholism 

 on the Physique and Ability of the Offspring," ^^ ap- 

 peared to show that there was no marked relation be- 

 tween intelligence, physique or disease of the offspring 

 and parental alcoholism in any of the categories investi- 

 gated. For example, the study showed that the average 

 weight and height of the children of alcoholic parents 

 was slightly in excess of that of children of sober parents ; 

 the general health of the children of alcoholic parents ap- 

 peared to be slightly better than the health of children of 

 sober parents. However completely subsequent investi- 

 gations may correct or confirm the conclusions of the 

 London eugenists, certain it is that in the present stage 

 of our knowledge we can make no dogmatic statements 



10 Eugenics Lahoratory Memoirs, VIII, p. 00. 



11 Eugenics Lahoratory Memoirs, X. 



