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being changed along with the body being nourished, and since a threefold purification and separation occurs according to the nourishment of each animal, it is altogether necessary that whatever is foreign to the animal's nourishment, as being unable to be assimilated, be destroyed and separated in its natural way or be changed into something else; and that the power of the nourishing body be agreeable and according to nature for the powers of the animal being nourished, and that this, having passed through its natural criteria and having been thoroughly purified by natural purifiers, become a most pure assimilation into substance; which indeed one, being true to the facts, would call the only true nourishment, as it casts off whatever is foreign and harmful to the constitution of the animal being nourished, and that great bulk introduced for the filling of the stomach and the satisfaction of the appetite. But no one would dispute that this is united with the body being nourished, being interwoven and molded around all its parts and particles; while that which is otherwise and against nature is quickly destroyed, if it mixes with a stronger power, but easily destroys that which is overcome and turns into corrupt humors and poisonous qualities, as bringing nothing kindred or friendly to the body being nourished. And the greatest proof of this is that for many of the animals being nourished pain or danger or death follows from these things, if because of a too-violent appetite it draws in along with its food something poisonous and against nature mixed in; which would indeed be altogether destructive of the body being nourished, if indeed things being nourished are nourished by what is kindred and according to nature, but are destroyed by their opposites. If, therefore, nourishment according to nature is divided according to the difference of animals differing in nature, and of this nourishment itself neither everything that the animal might take in nor any random part of it is assimilated into the body being nourished, but only that part which has been purified through all digestion and has been purely transformed for union with that kind of body and is well-suited to the parts being nourished, it is clear that nothing of what is against nature could ever be united with those things for which it is not a suitable and appropriate nourishment, but either it is separated in the belly itself, before it has generated some other raw and corrupt humor, or, having remained for a longer time, it produces a suffering or an incurable disease, which corrupts along with it also the natural nourishment or even the very flesh that needs the nourishment. But even if it is ever pushed away by some medicines or better foods, or having been conquered by the natural powers, it flowed out with no little harm, as bringing nothing peaceful to the things according to nature on account of its incompatibility with nature. But in general, even if someone should concede the nourishment that enters from these things

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τῷ τρεφομένῳ σώματι συνεξαλλαττομένης, τριττῆς δὲ κατὰ τὴν ἑκάστου ζῴου τροφὴν γινομένης καθάρσεως καὶ διακρίσεως, δεῖ πάντως φθείρεσθαι μὲν καὶ διαχωρεῖν ᾗ πέφυκεν ἢ πρὸς ἕτερόν τι μεταβάλλειν πᾶν ὁπόσον ἀλλότριον εἰς τὴν τοῦ ζῴου τροφὴν ὡς συγκραθῆναι μὴ δυνάμενον, συμβαίνουσαν δὲ καὶ κατὰ φύσιν εἶναι τὴν τοῦ τρέφοντος σώματος δύναμιν ταῖς τοῦ τρεφομένου ζῴου δυνάμεσιν καὶ ταύτην ἐλθοῦσαν δι' ὧν πέφυκεν κριτηρίων καὶ καθαρθεῖσαν ἀκριβῶς τοῖς φυσικοῖς καθαρσίοις εἰλικρινεστάτην γενέσθαι πρόσληψιν εἰς οὐσίαν· ἣν δὴ καὶ μόνην ἐπαληθεύων ἄν τις τοῖς πράγμασιν ὀνομάσειεν τροφὴν ὡς ἀποβάλλουσαν πᾶν ὁπόσον ἀλλότριον καὶ βλαβερὸν εἰς τὴν τοῦ τρεφομένου ζῴου σύστασιν καὶ τὸν πολὺν ἐκεῖνον ὄγκον ἐπεισαχθέντα πρὸς τὴν τῆς γαστρὸς ἀποπλήρωσιν καὶ τὴν τῆς ὀρέξεως θεραπείαν. ἀλλὰ ταύτην μὲν οὐκ ἄν τις ἀμφισβητήσειεν ἑνοῦσθαι τῷ τρεφομένῳ σώματι συνδιαπλεκομένην τε καὶ περιπλαττομένην πᾶσι τοῖς τούτου μέρεσιν καὶ μορίοις· τὴν δ' ἑτέρως ἔχουσαν καὶ παρὰ φύσιν φθείρεσθαι μὲν ταχέως, ἢν ἐρρωμενεστέρᾳ συμμίξῃ δυνάμει, φθείρειν δὲ σὺν εὐμαρείᾳ τὴν κρατηθεῖσαν εἴς τε μοχθηροὺς ἐκτρέπεσθαι χυμοὺς καὶ φαρμακώδεις ποιότητας ὡς μηδὲν οἰκεῖον ἢ φίλον τῷ τρεφομένῳ σώματι φέρουσαν. καὶ τούτου τεκμήριον μέγιστον τὸ πολλοῖς τῶν τρεφομένων ζῴων ἐκ τούτων ἐπακολου- θεῖν ἄλγος ἢ κίνδυνον ἢ θάνατον, ἢν ὑπὸ σφοδροτέρας ὀρέξεως τῇ τροφῇ καταμεμιγμένον συνεφελκύσηταί τι φαρμακῶδες καὶ παρὰ φύσιν· ὃ δὴ καὶ πάντως φθαρτικὸν ἂν εἴη τοῦ τρεφομένου σώματος, εἴ γε τρέφεται μὲν τὰ τρεφόμενα τοῖς οἰκείοις καὶ κατὰ φύσιν, φθείρεται δὲ τοῖς ἐναντίοις. εἴπερ οὖν τῇ διαφορᾷ τῶν τῇ φύσει διαφερόντων ζῴων ἡ κατὰ φύσιν συνδιῄρηται τροφὴ καὶ ταύτης γε αὐτῆς οὔτε πᾶν ὅπερ ἂν προσενέγκηται τὸ ζῷον οὔτε τὸ τυχὸν ἐκ τούτου τὴν πρὸς τὸ τρεφόμενον σῶμα δέχεται σύγκρασιν, ἀλλ' αὐτὸ μόνον τὸ διὰ πάσης πέψεως κεκαθαρμένον καὶ μεταβεβληκὸς εἰλικρινῶς πρὸς τὴν τοῦ ποιοῦ σώματος ἕνωσιν καὶ τοῖς τρεφομένοις μέρεσιν εὐάρμοστον, εὔδηλον ὡς οὐδὲν τῶν παρὰ φύσιν ἑνωθείη ποτ' ἂν τούτοις οἷς οὔκ ἐστιν τροφὴ προσφυὴς καὶ κατάλληλος, ἀλλ' ἤτοι κατ' αὐτὴν τὴν κοιλίαν διαχωρεῖ πρὶν ἕτερόν τινα γεν- νῆσαι χυμὸν ὠμὸν καὶ διεφθαρμένον, ἢ συστὰν ἐπὶ πλεῖον τίκτει πάθος ἢ νόσον δυσίατον, συνδιαφθείρουσαν καὶ τὴν κατὰ φύσιν τροφὴν ἢ καὶ αὐτὴν τὴν τῆς τροφῆς δεομένην σάρκα. ἀλλὰ κἂν ἀπωσθῇ ποτε φαρμάκοις τισὶν ἢ σιτίοις βελτίοσιν ἢ ταῖς φυσικαῖς δυνάμεσι νικηθέν, μετ' οὐκ ὀλίγης ἐξερρύη τῆς βλάβης ὡς μηδὲν φέρον τοῖς κατὰ φύσιν εἰρηνικὸν διὰ τὸ πρὸς τὴν φύσιν ἀσύγ- κρατον. Ὅλως δὲ κἂν συγχωρήσῃ τις τὴν ἐκ τούτων εἰσιοῦσαν τροφὴν