In certain cases, notably in the bleeders, the inheritance is transmitted by the female alone, in other cases by the sexes equally, but there are no cases of transmission by the male line only.

It is evident that when the same malformation affects both the male and the female line the hereditary influence is much stronger.

A case has been related to me in which most of the inhabitants in a remote mountain valley in Virginia where there has been much intermarriage have one of the joints of the fingers missing.

There is a very prevalent idea that in close intermarriage in families variations and malformations often unfortunate for the individual are more common.

All experimental evidence obtained by interbreeding of animals shows that close interbreeding is not productive of variation, but that variations existing in the breed become accentuated.