Diocles the physician says that either no genital sperm is projected, or, if there be, it is in a less quantity than nature requires, or there is no prolific faculty in it; or there is a deficiency of a due proportion of heat, cold, moisture, and dryness; or there is a resolution of the generative parts. The Stoics attribute sterility to the obliquity of the yard, by which means it is not able to ejaculate in a due manner, or to the unproportionable magnitude of the parts, the matrix being so contracted as not to have a capacity to receive. Erasistratus assigns it to the womb's being more callous or more carneous, thinner or smaller, than nature does require.
CHAPTER X. WHENCE IT IS THAT ONE BIRTH GIVES TWO OR THREE CHILDREN.
Empedocles affirms, that the superabundance of sperm and the division of it causes the bringing forth of two or three infants. Asclepiades, that it is performed from the excellent quality of the sperm, after the manner that from the root of one barleycorn two or three stalks do grow; sperm that is of this quality is the most prolific. Erasistratus, that superfetation may happen to women as to irrational creatures; for, if the womb be well purged and very clean, then there can be divers births. The Stoics, that it ariseth from the various receptacles that are in the womb: when the seed illapses into the first and second of them at once, then there are conceptions upon conception; and so two or three infants are born.
CHAPTER XI. WHENCE IT IS THAT CHILDREN REPRESENT THEIR PARENTS AND PROGENITORS.
Empedocles says, that the similitude of children to their parents proceeds from the vigorous prevalency of the generating sperm; the dissimilitude from the evaporation of the natural heat it contains. Parmenides, that when the sperm falls on the right side of the womb, then the infant gives the resemblance of the father; if from the left, it is stamped with the similitude of the mother. The Stoics, that the whole body and soul give the sperm; and hence arise the likenesses in the characters and faces of the children, as a painter in his copy imitates the colors in a picture before him. Women have a concurrent emission of seed; if the feminine seed have the predominancy, the child resembles the mother; if the masculine, the father.
CHAPTER XII. HOW IT COMES TO PASS THAT CHILDREN HAVE A GREATER SIMILITUDE WITH STRANGERS THAN WITH THEIR PARENTS.
The greatest part of physicians affirm, that this happens casually and fortuitously; for, when the sperm of the man and woman is too much refrigerated, then children carry a dissimilitude to their parents. Empedocles, that a woman's imagination in conception impresses a shape upon the infant; for women have been enamoured with images and statues, and the children which were born of them gave their similitudes. The Stoics, that the resemblances flow from the sympathy and consent of minds, through the insertion of effluvias and rays, not of images or pictures.