De ventriculi natura, et affectibus

9. We call chyle a certain uniform juice, and in a way ὁμοιομερῆ, a substance suited for nourishing the animal and having acquired its quality.

10. For the performing of χυλωσιν, the stomach was endowed by nature with suitable substance, shape, and faculties.

11. For by an innate power it attracts, retains, and concocts the foods; and it expels the perfect and finished chyle.

12. Its somewhat globular shape serves this purpose: that it might be able to contain a great quantity of food (as much, namely, as is necessary for nourishing the human body). The fibrous tunics, which are easily dilated in every direction, serve this necessity.

13. Hunger sharpens the attraction of foods, as does the appetite for food arising from a sense of want, namely while the excessively emptied tunics collapse upon themselves and nip the mouth of the stomach by pulling it downward.

14. It seems to contribute not a little to retention that the tunics can easily be constricted, and that both orifices are located in a higher position.

15. Indeed, it performs concoction—that is, the conversion of foods into the specific quality of that which is nourished, which is its principal function—both by the primary quality of the innate heat and by a certain specific property of it.

16. The heat of the neighboring parts—the liver, spleen, omentum, vena cava, diaphragm, etc.—assists the heat of the stomach not a little, like fire placed under a cauldron.

17. Moreover, that χύλωσις is completed not only by the primary quality of the innate heat, but also by a hidden property of the same, the ostrich concocting iron, the quail hellebore, the stork snakes, and many other animals seem to convince us.

18. Furthermore, the stomach seizes the portion of the already completed chyle most congenial to itself and stores it within its own tunics by absorption.

19. Whether it is truly nourished by this, however, is not sufficiently agreed upon among the authorities of the medical art, some affirming it, others on the contrary asserting that it is nourished by blood alone.

20. In this diversity of opinions, a middle view pleases us: that of those who think the inner tunic of the stomach is nourished by chyle, but the outer by blood.

21. The stomach, satisfied with the portion of chyle seized, [sends forth] the rest just as [a burden]