§ Rabbi Samlai taught: To what is a fetus in its mother’s womb comparable? To a folded notebook [lefinkas]. And it rests with its hands on its two sides of its head, at the temples, its two arms [atzilav] on its two knees, and its two heels on its two buttocks, and its head rests between its knees, and its mouth is closed, and its umbilicus is open. And it eats from what its mother eats, and it drinks from what its mother drinks, and it does not emit excrement lest it kill its mother. But once it emerges into the airspace of the world, the closed limb, i.e., its mouth, opens, and the open limb, its umbilicus, closes, as otherwise it cannot live for even one hour.