The bones and flesh, and other similar parts of us, were made as follows. The first principle of all of them was the generation of the marrow. For the bonds of life which unite the soul with the body are made fast there, and they are the root and foundation of the human race. The marrow itself is created out of other materials: God took such of the primary triangles as were straight and smooth, and were adapted by their perfection to produce fire and water, and air and earth-these, I say, he separated from their kinds, and mingling them in due proportions with one another, made the marrow out of them to be a universal seed of the whole race of mankind; and in this seed he then planted and enclosed the souls, and in the original distribution gave to the marrow as many and various forms as the different kinds of souls were hereafter to receive. That which, like a field, was to receive the divine seed, he made round every way, and called that portion of the marrow, brain, intending that, when an animal was perfected, the vessel containing this substance should be the head; but that which was intended to contain the remaining and mortal part of the soul he distributed into figures at once around and elongated, and he called them all by the name "marrow"; and to these, as to anchors, fastening the bonds of the whole soul, he proceeded to fashion around them the entire framework of our body, constructing for the marrow, first of all a complete covering of bone.

[73b] Τὸ δὲ ὀστῶν καὶ σαρκῶν καὶ τῆς τοιαύτης φύσεως πέρι πάσης ὧδε ἔσχεν. τούτοις σύμπασιν ἀρχὴ μὲν ἡ τοῦ μυελοῦ γένεσις· οἱ γὰρ τοῦ βίου δεσμοί͵ τῆς ψυχῆς τῷ σώματι συνδουμένης͵ ἐν τούτῳ διαδούμενοι κατερρίζουν τὸ θνητὸν γένος· αὐτὸς δὲ ὁ μυελὸς γέγονεν ἐξ ἄλλων. τῶν γὰρ τριγώνων ὅσα πρῶτα ἀστραβῆ καὶ λεῖα ὄντα πῦρ τε καὶ ὕδωρ καὶ ἀέρα καὶ γῆν δι΄ ἀκριβείας μάλιστα ἦν παρασχεῖν δυνατά͵ ταῦτα ὁ θεὸς ἀπὸ τῶν ἑαυτῶν ἕκαστα γενῶν χωρὶς ἀποκρίνων͵ [73c] μειγνὺς δὲ ἀλλήλοις σύμμετρα͵ πανσπερμίαν παντὶ θνητῷ γένει μηχανώμενος͵ τὸν μυελὸν ἐξ αὐτῶν ἀπηργάσατο͵ καὶ μετὰ ταῦτα δὴ φυτεύων ἐν αὐτῷ κατέδει τὰ τῶν ψυχῶν γένη͵ σχημάτων τε ὅσα ἔμελλεν αὖ σχήσειν οἷά τε καθ΄ ἕκαστα εἴδη͵ τὸν μυελὸν αὐτὸν τοσαῦτα καὶ τοιαῦτα διῃρεῖτο σχήματα εὐθὺς ἐν τῇ διανομῇ τῇ κατ΄ ἀρχάς. καὶ τὴν μὲν τὸ θεῖον σπέρμα οἷον ἄρουραν μέλλουσαν ἕξειν ἐν αὑτῇ περιφερῆ πανταχῇ πλάσας ἐπωνόμασεν τοῦ μυελοῦ ταύτην τὴν μοῖραν ἐγκέφαλον͵ [73d] ὡς ἀποτελεσθέντος ἑκάστου ζῴου τὸ περὶ τοῦτ΄ ἀγγεῖον κεφαλὴν γενησόμενον· ὃ δ΄ αὖ τὸ λοιπὸν καὶ θνητὸν τῆς ψυχῆς ἔμελλε καθέξειν͵ ἅμα στρογγύλα καὶ προμήκη διῃρεῖτο σχήματα͵ μυελὸν δὲ πάντα ἐπεφήμισεν͵ καὶ καθάπερ ἐξ ἀγκυρῶν βαλλόμενος ἐκ τούτων πάσης ψυχῆς δεσμοὺς περὶ τοῦτο σύμπαν ἤδη τὸ σῶμα ἡμῶν ἀπηργάζετο͵ στέγασμα μὲν αὐτῷ πρῶτον συμπηγνὺς περὶ ὅλον ὀστέινον.