Of Those Sentiments Concerning Nature with Which Philosophers Were Delighted by Plutarch

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 be in a capacity to receive. Erasistratus assigns it to the womb's being more callous or more carneous, thinner or smaller, than nature does require.