Whether the period for generation among men lasts longer than does the period for conception in women.
Further one inquires whether the period for generation among men lasts longer than does the period for conception in women.
And it seems not, because the power of the man is weakened while generating since he emits something outside himself. But during conception the woman does not emit anything outside herself. Therefore, since whatever is more weakened fails more quickly, a man will cease to generate more quickly than a woman.
The Philosopher says the opposite.
One must respond that the nobler something is, the more slowly does it acquire its perfection. For it is clear that a human fetus moves on its own later than does the fetus of another, and the more perfect something is, the more it preserves its own perfection. That is why a perfect animal has a longer lifespan than an imperfect animal. Since, then, a man is more perfect than a woman, a man acquires the complete power for generating more slowly and conserves it longer. Therefore, in a woman it begins after the second seven-year period, and ends about the fiftieth year, but in a man it begins at the end of the third seven-year period and ends about the seventieth year.
There even may be other causes, because a man emits semen alone whereas a woman emits semen and the menses. And the woman is likewise more burdened with giving birth to and nourishing the fetus. Therefore, it often happens that she loses an appetite for intercourse, as a result of the pain of childbirth, and ceases to subject herself to it.
One must reply to the argument that although a woman does not emit seed during intercourse, nevertheless she admits something that is outside the womb, which is the matter for the fetus, into the womb.
Whether a male grows more slowly outside the uterus than a woman does.
Further one inquires whether a male grows more slowly outside the uterus than a woman does.
1. And it seems not, because heat is the principle of growth. But heat is greater in a man than in a woman. Therefore, etc.
2. In addition, a male grows more quickly in the uterus than a female. Therefore, the same is true outside the uterus.
The Philosopher says the opposite.
One must reply that the male grows more quickly within the uterus, but more slowly outside it. And the reason for this is that temperate heat is the active principle of growth, and temperate moisture is the passive principle. But the heat is greater in the male than in the female, as reason proves. Since, then, there is sufficient moisture in the uterus and sufficient heat in the male, he therefore grows more quickly in the uterus. But outside the uterus the heat is increased, but the moisture is diminished because the heat consumes the moisture, and this is why he grows more slowly, owing to the dryness of the members, a dryness that opposes the moisture's growth. But in the female the heat is not powerful enough to consume the moisture, and this is why the woman grows more quickly outside the uterus, whereas she grows more slowly within the uterus owing to the weakness of her heat, while outside her moisture may grow and is obedient and her heat is strong, etc.
1. To the arguments one must reply that the heat is greater in the man, but in the uterus he has proportionate moisture, and outside of it he consumes this moisture, and this is why he grows more quickly inside the uterus but more slowly outside of it.
2. In the same way a solution is evident for the second argument.
Whether the menses are necessary for generation after impregnation.
Further one inquires whether the menses are necessary for generation after impregnation.
1. It seems not. For the agent introduces form and disposes the matter, but the thing that is made conserves itself. For although "nothing generates itself, each thing preserves itself," as is said in the second book of On the Soul? But the menses are neither form nor matter for the fetus. Therefore, they are not necessary.
2. In addition, some woman are masculine-like [viragines] who conceive and yet do not suffer menstruation, as is said in the text. Therefore, etc.
To the contrary. Just as flowers exist for the production of the fruit, so the menses relate to the production of the fetus. But flowers are necessary for the sake of the generation of the fruits, and therefore, etc.
One must reply that the menses are necessary in women for several reasons. Because one part of them becomes the radical spermatic members, like the heart, the brain, and ones such as these. And it is from another part of them that the empty spaces [vacuitates] in the embryo's members are filled in, namely, the spaces between the nerves and the veins and things of this sort, and these parts are necessary for the production of the fetus. A third part is delegated for the breasts and is converted into milk. A fourth part is enclosed in the womb and in the stomach and makes the stomach swell and softens the membranes [ pelliculas] and the opening of the womb so that it may stretch out better at the time of birth, and it then exits after the birth. And a fifth part flows from the individual members in a given month, although in a modest amount, and sometimes it exits imperceptibly with the urine in pregnant women, and this is not necessary for the sake of the fetus but only for the sake of cleansing the woman.
1. To the first argument one must reply that things are different for animate and inanimate things. For animate things are not preserved without nourishment, and this is why it is necessary for the fetus to be nourished in the uterus. But its nourishment while it is in the uterus is the menses, by which the fetus is nourished through the umbilical cord. Therefore, form, matter, and nutriment are required for the fetus's production, and it is preserved by this.
2. To the second argument one must reply that in a warm region the moistures that become the menses in other regions are consumed, and this is why the women there do not menstruate. This also makes clear why poor women or women who work hard and do not live a delicate life do not undergo menstruation, because whatever they assume as nutriment is barely adequate to sustain nature and this is why they rarely suffer menstruation, or hardly at all. And it is the same for masculine like women, because the menses are consumed in them by the strength of their heat. This is why, etc.