followeth of course, viz., the emission of seed into the womb in the act of copulation. For the woman having received this prolific seed into her womb, and retained it there, the womb thereupon becomes depressed, and embraces the seed so closely, that being closed the point of a needle cannot enter into it without violence. And now the woman may be said to have conceived, having reduced by her heat from power into action, the several faculties which are contained in the seed, making use of the spirits with which the seed abounds, and which are the instruments which begin to trace out the first lineaments of the parts, and which afterwards, by making use of the menstruous blood flowing to it, give it, in time, growth and final perfection. And thus much shall suffice to explain what conception is. I shall next proceed to show SECT. II.--_How a Woman ought to order herself after Conception._ My design in this treatise being brevity, I shall bring forward a little of what the learned have said of the causes of twins, and whether there be any such things as superfoetations, or a second conception in a woman (which is yet common enough), and as to twins, I shall have occasion to speak of them when I come to show you how the midwife ought to proceed in the delivery of the women that are pregnant with them. But having already spoken of conception, I think it now necessary to show how such as have conceived ought to order themselves during their pregnancy, that they may avoid those inconveniences, which often endanger the life of the child and many times their own.