See, for instance, A.F. Tredgold, Mental Deficiency, 1908.

The investigation of Bezzola showing that the maxima in the conception of idiots occur at carnival time, and especially at the vintage, has been held (especially by Forel) to indicate that alcoholism of the parents at conception causes idiocy in the offspring. It may be so. But it may also be that the licence of these periods enables the defective members of the community to secure an amount of sexual activity which they would be debarred from under normal conditions. In that case the alcoholism would merely liberate, and not create, the idiocy-producing mechanism.

Godden, Eugenics Review, April, 1911.

Feeble-mindedness and the other allied variations are not always exactly repeated in inheritance. They may be transmuted in passing from father to son, an epileptic father, for instance, having a feeble-minded child. These relationships of feeble-mindedness have been clearly brought out in an important investigation by Davenport and Weeks (Journal of Nervous and Mental Disease, November, 1911), who have for the first time succeeded in obtaining a large number of really thorough and precise pedigrees of such cases.