471 b ἀποθνήσκουσι καὶ φαίνονται ἀσπαρίζοντα ὥσπερ τὰ πνιγόμενα, εἴπερ ἀναπνέουσιν; οὐ γὰρ δὴ 15τροφῆς γε ἐνδείᾳ τοῦτο πάσχουσιν. ἣν γὰρ λέγει Διογένης αἰτίαν, εὐήθης· φησὶ γὰρ ὅτι τὸν ἀέρα πολὺν ἕλκουσι λίαν ἐν τῷ ἀέρι, ἐν δὲ τῷ ὕδατι μέτριον, καὶ διὰ τοῦτ᾿ ἀποθνήσκειν. καὶ γὰρ ἐπὶ τῶν πεζῶν ἔδει δυνατὸν εἶναι τοῦτο συμβαίνειν· νῦν δ᾿ οὐδὲν τῷ σφόδρα ἀναπνεῦσαι ἀποπνίγεται 20πεζὸν ζῷον. ἔτι δ᾿ εἰ πάντα ἀναπνεῖ, δῆλον ὅτι καὶ τὰ ἔντομα τῶν ζῴων ἀναπνεῖ· φαίνεται δ᾿ αὐτῶν πολλὰ διατεμνόμενα ζῆν, οὐ μόνον εἰς δύο μέρη ἀλλὰ καὶ εἰς πλείω, οἷον αἱ καλούμεναι σκολόπενδραι· ἃ πῶς ἢ τίνι ἐνδέχεται ἀναπνεῖν; αἴτιον δὲ μάλιστα τοῦ μὴ λέγεσθαι περὶ αὐτῶν καλῶς 25τό τε τῶν μορίων ἀπείρους εἶναι τῶν ἐντός, καὶ τὸ1 μὴ λαμβάνειν ἕνεκά τινος τὴν φύσιν πάντα ποιεῖν· ζητοῦντες γὰρ τίνος ἕνεκα ἡ ἀναπνοὴ τοῖς ζῴοις ὑπάρχει, καὶ ἐπὶ τῶν μορίων τοῦτ᾿ ἐπισκοποῦντες, οἷον ἐπὶ βραγχίων καὶ πλεύμονος, εὗρον ἂν θᾶττον τὴν αἰτίαν.
30IV. Δημόκριτος δ᾿ ὅτι μὲν ἐκ τῆς ἀναπνοῆς συμβαίνει τι τοῖς ἀναπνέουσι λέγει, φάσκων κωλύειν 472 aἐκθλίβεσθαι τὴν ψυχήν· οὐ μέντοι ὡς τούτου γ᾿ ἕνεκα ποιήσασαν τοῦτο τὴν φύσιν οὐθὲν εἴρηκεν· ὅλως γὰρ ὥσπερ καὶ οἱ ἄλλοι φυσικοί, καὶ οὗτος οὐθὲν ἅπτεται τῆς τοιαύτης αἰτίας. λέγει δ᾿ ὡς ἡ ψυχὴ καὶ τὸ θερμὸν ταὐτὸν τὰ πρῶτα σχήματα 5τῶν σφαιροειδῶν. συγκρινομένων οὖν αὐτῶν ὑπὸ τοῦ περιέχοντος ἐκθλίβοντος, βοήθειαν γίνεσθαι τὴν ἀναπνοήν φησιν. ἐν γὰρ τῷ ἀέρι πολὺν
fishes die in the air, and are seen to gasp convulsively as if they were choking, if they respire? For their symptoms are not due to lack of food. The explanation which Diogenes gives is childish; he says that in the air they draw in too much air, but in the water only a moderate quantity, and that this is why they die. But in that case it ought to be possible for this to happen to land animals, but in point of fact no land animal is ever choked by excessive respiration. Again, if every living creature respires, it is obvious that insects as well as other animals respire; but many of them clearly continue living even when severed, not merely into two parts but into more, for instance the so-called centipedes; how and with what organ can they respire? The real reason why men have given a false account of them is that they are ignorant of their internal anatomy, and do not realize that Nature does everything with some end in view; for if they had inquired why respiration is characteristic of animals, and had considered the question in respect of their organs, for instance the gills and lungs, they would have discovered the reason more easily.
IV. Democritus states that respiration serves aWhy do creatures breathe? certain purpose in animals that respire; he alleges that it prevents the soul from being crushed out; but he never says that this is why nature evolvedRefutation of Democritus. respiration; for, generally speaking, he, like other natural philosophers, never touches upon any reason of this kind. But he does identify the soul with the hot, as primary shapes of his spherical particles. So he contends that when these particles are being forced together by the pressure of the surrounding air, breathing intervenes to help them. For in the