, and cannot therefore be ascribed to
the imagination of either of the parents.

Dr. Thunberg observes, in his Journey to the Cape of Good Hope, that there
are some families, which have descended from blacks in the female line for
three generations. The first generation proceeding from an European, who
married a tawny slave, remains tawny, but approaches to a white complexion;
but the children of the third generation, mixed with Europeans, become
quite white, and are often remarkably beautiful. V. i. p. 112.

When the embryon has produced a placenta, and furnished itself with vessels
for selection of nutritious particles, and for oxygenation of them, no
great change in its form or colour is likely to be produced by the
particles of sustenance it now takes from the fluid, in which it is
immersed; because it has now acquired organs to alter or new combine them.
Hence it continues to grow, whether this fluid, in which it swims, be
formed by the uterus or by any other cavity of the body, as in
extra-uterine gestation; and which would seem to be produced by the
stimulus of the fetus on the sides of the cavity, where it is found, as
mentioned before. And thirdly, there is still less reason to expect any
unnatural change to happen to the child after its birth from the difference
of the milk it now takes; because it has acquired a stomach, and lungs, and
glands, of sufficient power to decompose and recombine the milk; and thus
to prepare from it the various kinds of nutritious particles, which the
appetencies of the various fibrils or nerves may require.

From all this reasoning I would conclude, that though the imagination of
the female may be supposed to affect the embryon by producing a difference
in its early nutriment; yet that no such power can affect it after it has
obtained a placenta, and other organs; which may select or change the food,
which is presented to it either in the liquor amnii, or in the milk. Now as
the eggs in pullets, like the seeds in vegetables, are produced gradually,
long before they are impregnated, it does not appear how any sudden effect
of imagination of the mother at the time of impregnation can produce any
considerable change in the nutriment already thus laid up for the expected
or desired embryon. And that hence any changes of the embryon, except those
uniform ones in the production of mules and mulattoes, more probably depend
on the imagination of the male parent. At the same time it seems