After observing that of the two sexes amongst animals, the most vigorous and hottest constitution always prevails, and produces its kind; he adds, If this be applied to the inhabitants of Africa, it is evident that the men there, accustomed to polygamy, are enervated by the use of so many women, and therefore less vigorous; the women on the contrary, are of a hotter constitution, not only on account of their more irritable nerves, more sensitive organization, and more lively fancy; but likewise because they are deprived in their matrimony of that share of physical love which in a monogamous condition, would all be theirs; and thus for the above reasons, the generality of children are born females.