Felkin and Vilson adduce the following instance from the south of Egypt:--The Wagandas, a warlike race, kill the men and the old women of their conquered foes. The children, girls, and young women they lead into captivity. On one occasion 480 of the women gave birth to children on their march. Of the new-born 79 were boys, 403 girls. This incident led the author to pay further attention to the subject on the east coast of Africa and in the Soudan. Everywhere he found the anticipation of an excess of girls supported and confirmed. In fact his investigations of the phenomenon led him to formulate and advocate a law that the better nourished and superior parent tends to produce the opposite sex. In this case the women are in an inferior position, and in consequence worse nourished and practically exhausted. Amongst other neighboring races, where they live peaceably and domestically, the difference between the number of new-born boys and girls is not a very great one, although a small average appears in favor of the girls. The influence of different phases of the moon has also been taken into consideration, and has been described as so effective that some have even attempted to prognosticate by these means the sex of a second child after the birth of a first. (Lioy.) * * * * * From Vilson’s statement that the sex of the worse-fed parent perpetuates itself, a theory has been deduced which has been described as _cross-heredity of sex_ (_Gekreuzte Geschlechtsvererbung_). In accordance with this theory a prominent phenomenon would be that the individual parents were not in a position to propagate their own sex, but were yet under certain circumstances capable of reproducing the opposite sex. If the father were the stronger, a girl would result from the next impregnation; in the opposite case, a boy. A great number of authors of renown, most of whom are mentioned in works dealing with these questions, are supporters of this theory. * * * * *