pi are said to do (Blumenbach on Generation, Cadel,
London); since in that case one embryon, or living filament, must have
begun to form one part first, and the other another part first. But such
monstrous conformations become less difficult to comprehend, when they are
considered as an effect of the imagination, as before explained, on the
living filament at the time of its secretion; and that such duplicature of
limbs were produced by accretion of new parts, in consequence of
propensities, or animal appetencies thus acquired from the male parent.

For instance, I can conceive, if a turkey-cock should behold a rabbit, or a
frog, at the time of procreation, that it might happen, that a forcible or
even a pleasurable idea of the form of a quadruped might so occupy his
imagination, as to cause a tendency in the nascent filament to resemble
such a form, by the apposition of a duplicature of limbs. Experiments on
the production of mules and monsters would be worthy the attention of a
Spallanzani, and might throw much light upon this subject, which at present
must be explained by conjectural analogies.

The wonderful effect of imagination, both in the male and female parent, is
shewn in the production of a kind of milk in the crops both of the male and
female pigeons after the birth of their young, as observed by Mr. Hunter,
and mentioned before. To this should be added, that there are some
instances of men having had milk secreted in their breasts, and who have
given suck to children, as recorded by Mr. Buffon. This effect of
imagination, of both the male and female parent, seems to have been
attended to in very early times; Jacob is said not only to have placed rods
of trees, in part stripped of their bark, so as to appear spotted, but also
to have placed spotted lambs before the flocks, at the time of their
copulation. Genesis, chap. xxx. verse 40.

5. In respect to the imagination of the mother, it is difficult to
comprehend, how this can produce any alteration in the fetus, except by
affecting the nutriment laid up for its first reception, as described in
No. V. 2. of this section, or by affecting the nourishment or oxygenation
with which she supplies it afterwards. Perpetual anxiety may probably
affect the secretion of the liquor amnii into the uterus, as it enfeebles
the whole system; and sudden fear is a frequent cause of miscarriage; for
fear, contrary to joy, decreases for a time the action of the extremities
of t