The ancient physicians and philosophers say that since these two principles out of which the body of man is made, and which renders the child like the parents, and by one or other of the sex, viz., seed common to both sexes and menstrual blood, proper to the woman only; the similitude, say they, must needs consist in the force of virtue of the male or female, so that it proves like the one or the other, according to the quantity afforded by either, but that the difference of sex is not referred to the seed, but to the menstrual blood, which is proper to the woman, is apparent; for, were that force altogether retained in the seed, the male seed being of the hottest quality, male children would abound and few of the female be propagated; wherefore, the sex is attributed to the temperament or to the active qualities, which consists in heat and cold and the nature of the matter under them--that is, the flowing of the menstruous blood. But now, the seed, say they, affords both force to procreate and to form the child, as well as matter for its generation; and in the menstruous blood there is both matter and force, for as the seed most helps the maternal principle, so also does the menstrual blood the potential seed, which is, says Galen, blood well concocted by the vessels which contain it. So that the blood is not only the matter of generating the child, but also seed, it being impossible that menstrual blood has both principles. The ancients also say that the seed is the stronger efficient, the matter of it being very little in quantity, but the potential quality of it is very strong; wherefore, if these principles of generation, according to which the sex is made were only, say they, in the menstrual blood, then would the children be all mostly females; as were the efficient force in the seed they would be all males; but since both have operation in menstrual blood, matter predominates in quantity and in the seed force and virtue. And, therefore, Galen thinks that the child receives its sex rather from the mother than the father, for though his seed contributes a little to the natural principle, yet it is more weakly. But for likeliness it is referred rather to the father than to the mother. Yet the woman's seed receiving strength from the menstrual blood for the space of nine months, overpowers the man's in that particular, for the menstrual blood rather cherishes the one than the other; from which it is plain the woman affords both matter to make and force and virtue to perfect the conception; though the female's be fit nutriment for the male's by reason of the thinness of it, being more adapted to make up conception thereby. For as of soft wax or moist clay, the artificer can frame what he intends, so, say they, the man's seed mixing with the woman's and also with the menstrual blood, helps to make the form and perfect part of man.