CHAPTER XVI. HOW EMBRYOS ARE NOURISHED, OR HOW THE INFANT IN THE BELLY RECEIVES ITS ALIMENT. Democritus and Epicurus say, that the embryos in the womb receive their aliment by the mouth, for we perceive, as soon as ever the infant is born, it applies its mouth to the breast; in the wombs of women (our understanding concludes) there are little dugs, and the embryos have small mouths by which they receive their nutriment. The Stoics, that by the secundines and navel they partake of aliment, and therefore the midwife instantly after their birth ties the navel, and opens the infant's mouth, that it may receive another sort of aliment. Alcmaeon, that they receive their nourishment from every part of the body; as a sponge sucks in water. CHAPTER XVII. WHAT PART OF THE BODY IS FIRST FORMED IN THE WOMB. The Stoics believe that the whole is formed at the same time. Aristotle, as the keel of a ship is first made, so the first part that is formed is the loins. Alcmaeon, the head, for that is the commanding and the principal part of the body. The physicians, the heart, in which are the veins and arteries. Some think the great toe is first formed; others affirm the navel. CHAPTER XVIII. WHENCE IS IT THAT INFANTS BORN IN THE SEVENTH MONTH ARE BORN ALIVE. Empedocles says, that when the human race took first its original from the earth, the sun was so slow in its motion that then one day in its length was equal to ten months, as now they are; in process of time one day became as long as seven months are; and there is the reason that those infants which are born at the end of seven months or ten months are born alive, the course of nature so disposing that the infant shall be brought to maturity in one day after that night in which it is begotten. Timaeus says, that we count not ten months but nine, by reason that we reckon the first conception from the stoppage of the menstruas; and so it may generally pass for seven months when really there are not seven; for it sometimes occurs that even after conception a woman is purged to some extent. Polybus, Diocles, and the Empirics, acknowledge that the eighth month gives a vital birth to the infant, though the life of it is more faint and languid; many therefore we see born in that month die out of mere weakness. Though we see many born in that month arrive at the state of man, yet (they affirm) if children be born in that month, none wish to rear them.