The Divine Institutes

It necessarily follows that I should begin to speak of the inward parts also, to which has been assigned not beauty, because they are concealed from view, but incredible utility, since it was necessary that this earthly body should be nourished with some moisture from food and drink, as the earth itself is by showers and frosts. The most provident Artificer placed in the middle of it a receptacle for articles of food, by means of which, when digested and liquefied, it might distribute the vital juices to all the members. But since man is composed of body and soul, that receptacle of which I have spoken above affords nourishment only to the body; to the soul, in truth, He has given another abode. For He has made a kind of intestines soft and thin, which we call the lungs, into which the breath might pass by an alternate interchange; and He did not form this after the fashion of the uterus, lest the breath should all at once be poured forth, or at once inflate it. And on this account He did not make it a full intestine, but capable of being inflated, and admitting the air, so that it might gradually receive the breath; while the vital air is spread through that thinness, and might again gradually give it back, while it spreads itself forth from it: for the very alternation of blowing and breathing, and the process of respiration, support life in the body.

Since, therefore, there are in man two receptacles,—one of the air which nourishes the soul, the other of the food which nourishes the body,—there must be two tubes through the neck for food, and for breath, the upper of which leads from the mouth to the belly, the lower from the nostrils to the lungs. And the plan and nature of these are different: for the passage which is from the mouth has been made soft, and which when closed always adheres to itself, as the month itself; since drink and food, being corporeal, make for themselves a space for passage, by moving aside and opening the gullet. The breath, on the other hand, which is incorporeal and thin, because it was unable to make for itself a space, has received an open way, which is called the windpipe. This is composed of flexible and soft bones, as though of rings fitted together after the manner of a hemlock stalk, and adhering together; and this passage is always open. For the breath can have no cessation in passing; because it, which is always passing to and fro, is checked as by a kind of obstacle through means of a portion of a member usefully sent down from the brain, and which is called the uvula, lest, drawn by pestilential air, it should come with impetuosity and spoil the slightness of its abode, or bring the whole violence of the injury upon the inner receptacles. And on this account also the nostrils are slightly open, which are therefore so named, because either smell or breath does not cease to flow through these, which are, as it were, the doors of this tube. Yet this breathing-tube lies open not only to the nostrils, but also to the mouth in the extreme regions of the palate, where the risings of the jaws, looking towards the uvula, begin to raise themselves into a swelling. And the reason of this arrangement is not obscure: for we should not have the power of speaking if the windpipe were open to the nostrils only, as the path of the gullet is to the mouth only; nor could the breath proceeding from it cause the voice, without the service of the tongue.

Therefore the divine skill opened a way for the voice from that breathing-tube, so that the tongue might be able to discharge its office, and by its strokes divide into words the even course of the voice itself. And this passage, if by any means it is intercepted, must necessarily cause dumbness. For he is assuredly mistaken, whoever thinks that there is any other cause why men are dumb. For they are not tongue-tied, as is commonly believed; but they pour forth that vocal breath through the nostrils, as though bellowing, because there is either no passage at all for the voice to the mouth, or it is not so open as to be able to send forth the full voice. And this generally comes to pass by nature; sometimes also it happens by accident that this entrance is blocked up and does not transmit the voice to the tongue, and thus makes those who can speak dumb. And when this happens, the hearing also must necessarily be blocked up; so that because it cannot emit the voice, it is also incapable of admitting it. Therefore this passage has been opened for the purpose of speaking. It also affords this advantage, that in frequenting the bath, because the nostrils are not able to endure the heat, the hot air is taken in by the mouth; also, if phlegm contracted by cold shall have happened to stop up the breathing pores of the nostrils, we may be able to draw the air through the mouth, lest, if the passage should be obstructed, the breath should be stifled. But the food being received into the stomach, and mixed with the moisture of the drink, when it has now been digested by the heat, its juice, being in an indescribable manner diffused through the limbs, bedews and invigorates the whole body.

The manifold coils also of the intestines, and their length rolled together on themselves, and yet fastened with one band, are a wonderful work of God. For when the stomach has sent forth from itself the food softened, it is gradually thrust forth through those windings of the intestines, so that whatever of the moisture by which the body is nourished is in them, is divided to all the members. And yet, lest in any place it should happen to adhere and remain fixed, which might have taken place on account of the turnings of the coils, which often turn back to themselves, and which could not have happened without injury, He has spread over these from within a thicker juice, that the secretions of the belly might more easily work their way through the slippery substance to their outlets. It is also a most skilful arrangement, that the bladder, which birds do not use, though it is separated from the intestines, and has no tube by which it may draw the urine from them, is nevertheless filled and distended with moisture. And it is not difficult to see how this comes to pass. For the parts of the intestines which receive the food and drink from the belly are more open than the other coils, and much more delicate. These entwine themselves around and encompass the bladder; and when the meat and the drink have arrived at these parts in a mixed state, the excrement becomes more solid, and passes through, but all the moisture is strained through those tender parts, and the bladder, the membrane of which is equally fine and delicate, absorbs and collects it, so as to send it forth where nature has opened an outlet.