1. On the Action of the Mother in the Formation of Our Bodies

38. To understand this one needs to know that in the formation of our body there is first a local motion from the place of the body to be corrupted to a place fitted for the generation from it of an organic body. This local motion is followed by a shaping of that changed body, and the shaping is not without local motion. Third there follows a condensing of the body to be corrupted, and this is an alteration that precedes the generation of a denser body from the less dense body, and this alteration is not without change of place, by which is not acquired a new place but a smaller space is occupied. In the last instant of this alteration the form is induced, by which the body is completely organized, whether the form is, according to some, the intellective soul or, according to others, some other form preceding it [cf. infra 4 d.11 q.3] - and this, according to both of them, whether the form is single for the whole organic body and the heterogeneous parts, or whether the form of the whole is different from those that are the proper and substantial forms of the heterogeneous parts, or whether still in a third way there is no form for the whole organic body different from the partial forms of the heterogeneous parts; and according to this third option, a body’s being completely organized would be for all the partial forms to be completely induced. And although, according to this third option among these, one could posit that not all the partial forms are induced simultaneously but one is induced first, for which a shorter alteration would suffice, and another later, on which a longer alteration would follow further - yet, according to all three, there is something in the last instant which was not there before and without which the body is not completely organized.