Theses medicae de divina et admiranda hominis in utero formatione

and the conjunction of similar ones (for there is no faculty given that could accomplish this; furthermore, if everything were gathered together, for example, all the bony parts, only one large bone would be made, and so on for the other particles), but because each particle of the seed has this power and faculty within itself, so that it can produce this and not another thing from itself. This very faculty is brought into action once the beginning of motion has occurred.

XXIX.

Thus, various movements arise in this work, according to the aptitude of the parts of the seed to receive the forms of different parts, all of which proceed from that generative faculty using its instruments in various ways.

XXX.

The faculty itself, which the plasmē formation/molding uses as a servant, produces the temperament of similar parts through heat or cold: but the structure of the organic parts is produced primarily and by itself through diachysis plasmē diffusion of the molding.

XXXI.

Galen divides the entire gestation of the fetus into four periods. The first is that in which the form of the seed still prevails, which Hippocrates calls gonon seed, kyēma embryo/product of conception, or gonēn. The second is when the substance of the conception represents not seed, but flesh, and this is called kyēma by Hippocrates. The third is that in which one can clearly see three principles, and the lineaments of the remaining parts have an outlined configuration: this constitution of a living thing Hippocrates names embryon embryo. The fourth is when all the limbs are already articulated, and the embryo begins to move like an animal, which Hippocrates calls paidion child and embryon.

XXXII.

Galen holds that upon the seed being received in the uterus, first of all three membranes are formed, which envelop the fetus and receive its excrement within themselves, once the thicker parts of the seed have been dried like a crust by the surrounding heat of the uterus: The first and outermost is the chorion outer membrane, which envelops the entire fetus and consists of two membranes, between which many small veins and arteries are carried to nourish the fetus. The middle one is the thin, weak, and narrow amnion fetal membrane, which surrounds the fetus in the middle like a bandage. It is also said to consist of two tunics, within which the fetus's urine is contained. The third is the allantoeidē allantois, closest to the fetus, which envelops it entirely from the crown to the tips of the feet: within this and the fetus, sweat and other impurities are said to be collected.

XXXIII.

But it does not seem probable that the membranes are formed first, since