Now the music of the human instrument is a sort of compound of flute and lyre, sounding together in combination as in a concerted piece of music. For the breath, as it is forced up from the air-receiving vessels through the windpipe, when the speaker's impulse to utterance attunes the harmony to sound, and as it strikes against the internal protuberances which divide this flute-like passage in a circular arrangement, imitates in a way the sound uttered through a flute, being driven round and round by the membranous projections. But the palate receives the sound from below in its own concavity, and dividing the sound by the two passages that extend to the nostrils, and by the cartilages about the perforated bone, as it were by some scaly protuberance, makes its resonance louder; while the cheek, the tongue, the mechanism of the pharynx by which the chin is relaxed when drawn in, and tightened when extended to a point-all these in many different ways answer to the motion of the plectrum upon the strings, varying very quickly, as occasion requires, the arrangement of the tones; and the opening and closing of the lips has the same effect as players produce when they check the breath of the flute with their fingers according to the measure of the tune.

Σύμμικτος δέ τις ἡ μουσικὴ περὶ τὸ ἀνθρώπινον ὄργανον αὐλοῦ καὶ λύρας͵ ὥσπερ ἐν συνῳδίᾳ τινὶ κατὰ ταὐτὸν ἀλλήλοις συμφθεγγομένων. Τὸ μὲν γὰρ πνεῦμα διὰ τῆς ἀρτηρίας͵ ἀπὸ τῶν πνευματοδόχων ἀγγείων ἀνωθούμενον͵ ὅταν ἡ ὁρμὴ τοῦ φθεγγομένου πρὸς φωνὴν τονώσῃ τὸ μέρος͵ ταῖς ἔνδοθεν προσαρασσόμενον προσβολαῖς͵ αἳ κυκλοτερῶς τὸν αὐλοειδῆ τοῦτον διειλήφασι πόρον͵ μιμεῖταί πως τὴν διὰ τοῦ αὐλοῦ γινομένην φωνήν͵ ταῖς ὑμενώδεσιν ἐξοχαῖς ἐν κύκλῳ περιδονούμενον. Ὑπερῴα δὲ τὸν κάτωθεν φθόγγον ἐκδέχεται τῷ κατ' αὐτὴν κενώματι͵ διδύμοις αὐλοῖς τοῖς ἐπὶ τοὺς μυκτῆρας διήκουσι καὶ οἷον λεπίδων τισὶν ἐξοχαῖς τοῖς περὶ τὸν ἠθμὸν χόνδροις τὴν φωνὴν περισχίζουσα͵ γεγωνοτέραν τὴν ἠχὴν ἀπεργάζεται. Παρειὰ δὲ καὶ γλῶσσα καὶ ἡ περὶ τὸν φάρυγγα διασκευή͵ καθ' ἣν ὁ ἀνθερεὼν ὑποχαλᾶται κοιλαινόμενος καὶ ὀξυτονῶν ἐπιτείνεται· [152] ταῦτα πάντα τὴν ἐν ταῖς νευραῖς τοῦ πλήκτρου κίνησιν ὑποκρίνεται ποικίλως καὶ πολυτρόπως͵ ἐπὶ καιροῦ σὺν πολλῷ τῷ τάχει μεθαρμόζοντα πρὸς τὴν χρείαν τοὺς τόνους. Χειλέων δὲ διαστολὴ καὶ ἐπίμυσις ταὐτὸν ποιεῖ τοῖς διὰ τῶν δακτύλων ἐπιλαμβάνουσι τοῦ αὐλοῦ τὸ πνεῦμα καὶ τὴν ἁρμονίαν τοῦ μέλους.