Page - 939 - in The Complete Aristotle

passes through the nostrils passes through the windpipe out of the chest as well, and without the latter the nostrils cannot act. Again, when animals are bereft of respiration through the nostrils, no detrimental result ensues, but, when prevented from breathing through the windpipe, they die. Nature employs respiration through the nostrils as a secondary function in certain animals in order to enable them to smell. But the reason why it exists in some only is that though almost all animals are endowed with the sense of smell, the sense-organ is not the same in all. A more precise account has been given about this elsewhere. Empedocles, however, explains the passage inwards and outwards of the breath, by the theory that there are certain blood-vessels, which, while containing blood, are not filled by it, but have passages leading to the outer air, the calibre of which is fine in contrast to the size of the solid particles, but large relatively to those in the air. Hence, since it is the nature of the blood to move upwards and downwards, when it moves down the air rushes in and inspiration occurs; when the blood rises, the air is forced out and the outward motion of the breath results. He compares this process to what occurs in a clepsydra. < div class=“quote”> Thus all things outwards breathe and in;—their flesh has tubes Bloodless, that stretch towards the body’s outmost edge, Which, at their mouths, full many frequent channels pierce, Cleaving the extreme nostrils through; thus, while the gore Lies hid, for air is cut a thoroughfare most plain. And thence, whenever shrinks away the tender blood, Enters the blustering wind with swelling billow wild. But when the blood leaps up, backward it breathes. As when With water-clock of polished bronze a maiden sporting, Sets on her comely hand the narrow of the tube And dips it in the frail-formed water’s silvery sheen; Not then the flood the vessel enters, but the air, Until she frees the crowded stream. But then indeed Upon the escape runs in the water meet. So also when within the vessel’s deeps the water Remains, the opening by the hand of flesh being closed, The outer air that entrance craves restrains the flood At the gates of the sounding narrow, upon the surface pressing, Until the maid withdraws her hand. But then in contrariwise Once more the air comes in and water meet flows out. 939