in De morbis muliebribus, in which it is said that labor is
gravely interfered with when the infant is dead or apoplectic or
double. There is also a reference to monochorionic twins (which are by
modern teratologists regarded as monstrosities) in the treatise De
Superfoetatione, in which it is stated that "a woman, pregnant with
twins, gives birth to them both at the same time, just as she has
conceived them; the two infants are in a single chorion."

Ancient Explanations of Monstrosities.--From the time of Galen to the
sixteenth century many incredible reports of monsters are seen in
medical literature, but without a semblance of scientific truth. There
has been little improvement in the mode of explanation of monstrous
births until the present century, while in the Middle Ages the
superstitions were more ludicrous and observers more ignorant than
before the time of Galen. In his able article on the teratologic
records of Chaldea, Ballantyne makes the following trite statements:
"Credulity and superstition have never been the peculiar possession of
the lower types of civilization only, and the special beliefs that have
gathered round the occurrence of teratologic phenomena have been common
to the cultured Greek and Roman of the past, the ignorant peasant of
modern times, and the savage tribes of all ages. Classical writings,
the literature of the Middle Ages, and the popular beliefs of the
present day all contain views concerning teratologic subjects which so
closely resemble those of the Chaldean magi as to be indistinguishable
from them. Indeed, such works as those of Obsequens, Lycosthenes,
Licetus, and Ambroise Pare only repeat, but with less accuracy of
description and with greater freedom of imagination, the beliefs of
ancient Babylon. Even at the present time the most impossible cases of
so-called 'maternal impressions' are widely scattered through medical
literature; and it is not very long since I received a letter from a
distinguished member of the profession asking me whether, in my
opinion, I thought it possible for a woman to give birth to a dog. Of
course, I do not at all mean to infer that teratology has not made
immense advances within recent times, nor do I suggest that on such
subjects the knowledge of the magi can be compared with that of the
average medical student of the present; but what I wish to emphasize is
that, in the literature of ancient Babylonia, there are indications of
an acquaintance