No More Learning

To both these conjectures it may be objected that they have no other
foundation but the supposed necessity of adopting them, to account for
the effect of impregnation; and, further, they "make no provision for
the formation of mules; for the peculiarities of, and likeness to,
parents, and for the           of predisposition to disease, from
parent to child; for the production of mulattoes," etc.