Whether the embryo is nourished before its formation.
Consideration must be given to the accidents by which [the members] are diversified," etc. In this nineteenth book, first one inquires whether the embryo is nourished before its formation.
1. It seems not. For nothing is nourished unless it is alive. What is not alive in act, but solely in potency, is not nourished in act. But the embryo is like this before its formation.
2. In addition, the nutritive power has organs designated for it, but the embryo does not have organs before its formation. Therefore, etc.
3. In addition, the last nutriment or food of the members is blood, according to the Philosopher. But there is no generation of blood in the embryo before its formation. Therefore, etc.
To the contrary. Nutrition precedes growth. But the embryo grows before its organization. Therefore, it is nourished, since growth does not occur without nourishment.
To this, one must reply that the semen is digested after its reception in the womb, and what is suited to the fetus is separated from what is not, and is converted into a certain fleshy mass, in which there is a regulative power [virtus regitiva] and natural heat. Therefore, just as a seed that falls to the ground receives, by its own power, nutriment from the ground, so too does the fetus's matter receive nutriment by its own power from the womb or from what is contained in the womb.
Nevertheless, it is nourished in different ways before and after its organization, because before its organization it is nourished only by a power derived from its father, but after its organization it is nourished by a power of its own soul.
1. On to the arguments. To the first, one must reply that nothing is nourished unless it is alive in act or has the power of living. Now, however, although the embryo does not have life in act before its formation, it still has a power of life derived from the father.
2. To the second argument one must reply that after its formation the embryo is nourished by means of organs, but before its formation it is nourished due to its spongy nature [spongiositas]. It is analogous to whatever is committed to the ground, since it grows in different ways before and after its formation, because before its formation it exists as a seed [ frumentum]. In the seed there are compacted earthy parts, and the intrinsic heat extends these earthy parts and spreads them out. This is the right way to understand the embryo. This is why, etc.
3. To the third argument one must reply that menstrual blood, which nourishes the embryo, is not generated in the embryo but in the womb; etc.
Whether the embryo emits superfluities in the womb.
Further one inquires whether the embryo emits superfluities in the womb.
And it seems that this is so after its formation. For the formed embryo is nourished by the menstrual blood. But this blood is not entirely uniform. Therefore, it has some impurity.
In addition, everything that can take in food beyond its own capacity has something superfluous in it. But the embryo can do this. Therefore, etc.
To the contrary. A superfluity is generated from what enters through the mouth into the stomach. But this does not occur in the embryo, and therefore, etc.
One must reply that there are three types of superfluity (that is, what it does not need), namely, excrement, urine, and sweat. The first superfluity precedes the generation of blood; the second superfluity is generated with blood, because it is strained from blood; and the third is generated in the individual members, after blood. The first one does not exist in the embryo, since it is not nourished on crude or earthy things or through a mouth, but is nourished by the mother's menstrual blood. Therefore, that superfluity, which is the excrement, exists in the mother but not in the embryo.
Similarly, if urine is properly understood to be a moisture that is separated from the blood in the liver, before the blood is relegated to the members then, taken this way, urine does not exist in an embryo, because the embryo is nourished through the umbilical cord, at which the veins converge, and before the nutriment arrives at the umbilical cord it is purified in the mother's liver by separating out the urine. But if urine is understood to be a moisture which flows with the blood and is separated out by the members and emitted internally, then, taken this way, urine is in the embryo since this very same moisture is called "sweat" if it is expelled through the skin's pores. Therefore, the third superfluity, properly speaking, does exist in the embryo but not the first or the second digestion, because the first and second digestions occur in the mother, but the third occurs in the fetus.
With this, a solution to the arguments is clear. For they prove that some superfluity exists in the embryo, and this we concede. means "construction," or "framework." One MSS variant reads complexionem, "complexion." Our translation of "capacity" is a compromise between meaning and a possible textual corruption whereby compactionem derived from an original capacitatem, perhaps through abbreviation.
-  "Spongy nature": The plural spongiositates is quite odd, "spongiosities." Based on context, what is implied is that the matter of the fetus is less dense at this stage, and, lacking formal organs for the reception of nourishment, it relies on a sort of wicking action to draw nourishment into itself.
-  "Capacity": the printed text of ultra compactionemis difficult since the word