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the providence of the Creator for us, come, let us lead you again to the heart itself. This then, being the most important part, and entrusted with the governance of the body, He fences in from all sides like a king, and places around it a strong enclosure, the thorax, so that nothing falling upon it from the outside may easily harm it. And since it moves continually (for it is the source of the arteries), underneath He has spread for it a kind of soft mattress, the porous and spongy and many-pored and arterial body of the lung; and from above, He both made its cone-like shape strong, and has placed around it a tunic that is membranous, yet waterproof and strong. And He supplies it with the matter of nourishment, not only the pneuma, but also the blood; and it draws this, as through a kind of channel of the vena cava, from the parts of the liver. But the liver draws up this matter from the stomach. And the stomach, through the esophagus, draws in the nourishment that has been cut by the teeth and ground down and smoothed by the molars; and having drawn it in, it first holds and turns it into chyle, and alters it, and changes it, and makes it like itself; then, when it has been well digested and altered, it justly separates it, and on the one hand allows the liver to filter and draw the pure part of this, but the excess it pushes away and sends on to the intestines, using the propulsive faculty as a helper. Thus the liver, having received the pure part of the nourishment, is not content with the purification and separation that has occurred, but as if with certain filters again, it divides and purifies it, and the sediment-like and thickest dregs, the spleen, drawing them for certain reasons, makes this its nourishment; while that which has been concocted beyond measure, and has taken on a bilious quality, and has changed into a yellowish substance, the gall bladder receives; and the watery and very thin part, and devoid of nourishment, goes into the receptacle of the liquid superfluities. Thus that nourishment, having become purely clean, and having been assimilated to the liver, and having passed into the nature of blood, the vena cava, having received it, supplies the need to the heart, and goes upward, and being split into many veins, it nourishes the thorax, and nourishes the shoulders, and hands, and reaches to the fingernails, it is entwined about the neck, it takes possession of the head, it goes down to the buttocks, and thighs, and knees, and shanks, and feet, and in a word, it travels around every part of the body, and deprives none of the living members of this irrigation. For the veins are like certain channels and conduits, entrusted to irrigate the body; for which reason they have a thin and porous tunic, so that the adjacent parts might easily draw nourishment from them; but the arteries have not only waterproof, but also double tunics; for they are receptacles of pneuma, not of blood; and the pneuma flows out finely and easily. Observe, therefore, here also the providence of the Maker. For the veins, since they carry blood to the parts of the body, He has made from thin membranes, and has placed around them a kind of porous covering with its opening. For the blood is thick, and requiring large pores for its secretion. Therefore, so that it might not all flow out, and might provide a kind of moisture to the adjacent parts, He has made the nature of the vessels to be such. But the arteries, which carry the pneuma everywhere (and this is fine and easily dissipated), and is easily secreted through the smallest parts; the Molder did not weave these in the same way, nor did He make them from only one tunic, but from two waterproof and very dense ones. And He placed the arteries beside the veins, so that by the motion of the warm pneuma the blood, being spurred on, might run everywhere. For stillness is known to produce coagulation. For this reason in certain parts He implanted them in each other through certain very small pores, so that the blood also might partake of some small amount of pneuma,

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περὶ ἡμᾶς τοῦ πεποιηκότος κηδεμονίαν, δεῦρο, πάλιν πρὸς αὐτήν σε τὴν καρδίαν ἀγάγωμεν. 83.593 Ταύτην τοίνυν κυριώτατον οὖσαν μόριον, καὶ τὴν ἡγεμονίαν τοῦ σώματος πεπιστευμένην, καθάπερ τινὰ βασιλέα πάντοθεν περιφράττει, καὶ περίβολον αὐτῇ ἰσχυρὸν τὸν θώρακα περιτίθησιν, ἵνα μηδὲν αὐτὴν ῥᾳδίως τῶν ἔξωθεν προσπιπτόντων λυπῇ. Ἐπειδὴ δὲ διηνεκῶς κινεῖται (ἀρτηριῶν γὰρ αὕτη πηγὴ), κάτωθεν μὲν ὑπέστρωσεν αὐτῇ οἷόν τινα στρωμνὴν μαλακὴν, τὸ μανὸν καὶ σπογγοειδὲς καὶ πολύπορον καὶ ἀρτηριῶδες τοῦ πνεύμονος σῶμα· ἄνωθεν δὲ, τό τε κωνοειδὲς αὐτῆς ἰσχυρὸν ἀπειργά σατο, καὶ χιτῶνα ὑμενώδη μὲν, στεγανὸν δὲ καὶ ἰσχυρὸν περιτέθεικεν. Ὕλην δὲ τροφῆς αὐτῇ χορη γεῖ, οὐ τὸ πνεῦμα μόνον, ἀλλὰ καὶ τὸ αἷμα· ἕλκει δὲ τοῦτο, οἷον διά τινος ὁλκοῦ τῆς κοίλης φλεβὸς, ἀπὸ τῶν τοῦ ἥπατος μορίων. Τὸ δὲ ἧπαρ ἐκ τῆς γαστρὸς ταύτην ἀνιμᾶται τὴν ὕλην. Ἡ δὲ γαστὴρ, διὰ τοῦ στομάχου τὴν ὑπὸ τῶν ὀδόντων τεμνομένην, καὶ ὑπὸ τῶν μυλῶν λεπτυνομένην τε καὶ λεαινομέ νην ἕλκει τροφήν· ἕλκουσα δὲ, πρότερον κατ έχει καὶ χυλοῖ, καὶ ἀλλοιοῖ, καὶ μεταβάλλει, καὶ πρὸς ἑαυτὴν ὁμοιοῖ· εἶτα διαπεφθεῖσαν καλῶς καὶ ἀλλοιω θεῖσαν, ἀποκρίνει δικαίως, καὶ παραχωρεῖ μὲν τῷ ἥπατι διηθεῖν καὶ ἕλκειν ταύτης τὸ καθαρὸν, τὸ δὲ περιττὸν ἀπωθεῖται, καὶ τοῖς ἐντέροις παραπέμπει, τῇ προωστικῇ δυνάμει συνεργῷ κεχρημένη. Οὕτω τὸ ἧπαρ τὸ καθαρὸν τῆς τροφῆς ὑποδεξάμενον, οὐκ ἀρκεῖται τῇ γενομένῃ καθάρσει καὶ διακρίσει, ἀλλ' οἷόν τισι πάλιν ἠθμοῖς, ταύτην διαιρεῖ καὶ κα θαίρει, καὶ τὴν μὲν οἷον ὑποστάθμην καὶ παχυτάτην τρύγα, διά τινων αἰτιῶν ἕλκων ὁ σπλὴν, ταύτην ποιεῖται τροφήν· τὸ δὲ πέρα τοῦ μέτρου πεφθὲν, καὶ τὴν χολώδη μεταλαβὸν ποιότητα, καὶ εἰς τὸ ὠχρὸν μεταπεσὸν σῶμα, λαμβάνει τὸ χοληδόχον ἀγ γεῖον· τὸ δὲ ῥοῶδες καὶ λίαν λεπτὸν, καὶ τροφῆς ἄμοιρον, εἰς τὸ τῶν ὑγρῶν περιττωμάτων δοχεῖον χωρεῖ. Οὕτως ἀκραιφνῶς καθαρὰν τὴν τροφὴν ἐκεί νην γενομένην, καὶ ὁμοιωθεῖσαν τῷ ἥπατι, καὶ εἰς αἵματος μεταβᾶσαν φύσιν, ἡ κοίλη παραλαβοῦσα φλὲψ, χορηγεῖ μὲν τῇ καρδίᾳ τὴν χρείαν, ἄνεισι δὲ ἄνω, καὶ εἰς πολλὰς διασχιζομένη φλέβας, τρέφει μὲν τὸν θώρακα, τρέφει δὲ ὤμους, καὶ χεῖρας, ἀφ ικνεῖται δὲ μέχρις ὀνύχων, περιπλέκεται τῷ τραχήλῳ, καταλαμβάνει τὴν κεφαλὴν, κάτεισιν εἰς γλουτοὺς, καὶ μηροὺς, καὶ γόνατα, καὶ σκέλη, καὶ πόδας, καὶ ἁπαξαπλῶς, ἅπαν τὸ τοῦ σώματος περινοστεῖ μό ριον, καὶ οὐδὲν τῶν ζώντων μελῶν ταύτης ἀποστερεῖ τῆς ἀρδείας. Ὁλκοῖς γάρ τισι καὶ ὀχετοῖς ἐοίκασιν αἱ φλέβες, ἄρδειν τὸ σῶμα πεπιστευμέναι· διὸ καὶ λεπτὸν καὶ μανὸν ἔχουσι τὸν χιτῶνα, ὥστε ῥᾳδίως τὰ παρακείμενα μόρια τὴν τροφὴν ἐκεῖθεν ἀρύεσθαι· αἱ δ' ἀρτηρίαι, οὐ στεγανοὺς μόνον, ἀλλὰ καὶ δι πλοῦς ἔχουσι τοὺς χιτῶνας· πνεύματος γὰρ, ἀλλ' οὐχ αἵματός εἰσι δοχεῖα· λεπτομερῶς δὲ καὶ ῥᾳδίως ἐκρέει τὸ πνεῦμα. Βλέπε τοιγαροῦν κἀνταῦθα τοῦ Ποιητοῦ τὴν προμήθειαν. Τὰς μὲν γὰρ φλέβας, ἅτε δὴ αἷμα τοῖς μορίοις τοῦ σώματος κομιζούσας, ἀπὸ λεπτῶν ὑμένων πεποίηκε, καὶ οἷον ἀραιά τινα τῇ 83.596 τρυμαλιᾷ αὐτῇ περιβόλαια περιτέθεικε. Παχυμερὲς γὰρ τὸ αἷμα, καὶ μεγάλων εἰς ἔκκρισιν δεόμενον πόρων. Ἵνα τοίνυν καὶ μὴ ἅπαν ἐκρέῃ, καὶ οἷόν τινα νοτίδα τοῖς παρακειμένοις παρέχῃ μορίοις, τοιαύτην τοῖς ἀγγείοις τὴν φύσιν πεποίηκε. Τὰς δὲ ἀρτηρίας τὸ πνεῦμα πανταχοῦ κομιζούσας (λεπτομερὲς δὲ τοῦτο, καὶ ῥᾳδίως φροῦδον γινόμενον), καὶ διὰ τῶν σμικροτάτων μερῶν εὐπετῶς ἐκκρινόμενον· οὐ κέθ' ὁμοίως ὁ Πλάστης ἐξύφηνεν, οὐδὲ ἐξ ἑνὸς αὐτὰς μόνου χιτῶνος ἐποίησεν, ἀλλ' ἐκ δύο στεγανῶν καὶ λίαν συχνῶν. Παρέθηκε δὲ ταῖς φλεψὶ τὰς ἀρτηρίας, ἵνα τῇ κινήσει τοῦ θερμοῦ πνεύματος τὸ αἷμα νυττό μενον, πανταχοῦ διατρέχῃ. Οἶδε γὰρ ἡ στάσις τὴν πῆξιν ἐργάσασθαι. Τούτου χάριν ἔν τισι μορίοις ἐν έφυσε ταύτας ἀλλήλαις διὰ σμικροτάτων τινῶν πόρων, ὅπως καὶ τὸ αἷμα βραχέος τινὸς μεταλαμβάνῃ πνεύ ματος,