But I shall proceed to the cause of their Generation.

The Natural Cause of Generation of Monsters, according to the Ancients,
is either in the Matter, or in the Agent; in the Seed or in the Womb:
The Matter may be unable to perform its Office two ways; by Defect, or
by Excess: By Defect, when a Child hath but one Arm, or one Leg, &c.
and by Excess, when it hath three Hands or two Heads. The Agent or Womb
may be in Fault several ways, as in the forming Faculty, which may be
too strong or too weak, by which a deprav'd Figure is oftentimes
produc'd, the ill Conformation of the place of Conception will cause a
Monstrous Birth; and the imaginative Power at the time of Conception, is
so forcible, that it stamps a Character of the thing upon the Child; so
that the Child of an Adulteress, by the strength of Imagination may have
a nearer resemblance of her Husband, than of the Person who begat it.
And some Histories mention, that through this Imaginative Faculty, a
Woman at the time of Conception, beholding the Picture of a Blackamoor,
produc'd a Child resembling an Æthiopian.

Monsters are sometimes Engender'd by unseasonable amorous Embraces, as
when a Man enters on the Pleasures of Venus at a time as the monthly
Flowings are upon his Wife; For this being against Nature, it is no
wonder that it should produce an unnatural Offspring. If therefore a
Man's desire be never so great for Copulation at such a time, yet the
Woman ought not to admit of his Embraces; the issue of those unclean
Embraces proving often Monstrous, or dull and heavy, and Defective in
their Understandings.

Sometimes by a corruption of Seed, Monstrous Shapes are form'd, which by
some is ascrib'd to the bad Influence of the Planets, that were
predominant at the time of Conception; and sometimes the straightness of