§2.7.17 Περὶ δ’ ἐγκεφάλου σχεδόν ἐστιν ἐχόμενον ει πολλοῖς γὰρ καὶ ὁ ἐγκέφαλος δοκεῖ μυελὸς εἶναι και ἀρχὴ τού μυελοῦ διὰ τὸ συνεχὴ τὸν ῥαχίτην αὐτῷ ὁρᾶν μυελόν.
7 It is almost continuous with this to speak of the brain; for to many the brain also seems to be marrow and the origin of marrow, because they see the spinal marrow continuous with it.
ἔστι δὲ πᾶν τοὐναντίον αὐτῷ τὴν φύσιν ὡς εἰπεῖν· ὁ μὲν γὰρ ἐγκέφαλος ψυχρότατον τῶν ἐν τῷ σήματι μορίων, ὁ δὲ μυελὸς θερμὸς τὴν φύσιν· δηλοῖ δʼ ἡ λιπαρότης αὐτοῦ καὶ τὸ πῖον.
But its nature is, so to speak, entirely opposite to it; for the brain is the coldest of the parts in the body, whereas the marrow is by nature hot, as is shown by its oiliness and fat.
διὸ καὶ συνεχὴς ὁ ῥαχίτης τῷ ἐγκεφάλῳ ἐστίν· ἀεὶ γὰρ ἡ φύσις μηχανἀται πρὸς τὴν ἑκάστου ὑπερβολὴν βοήθειαν τὴν τοῦ ἐναντίου παρεδρίαν, ἵνα ἀνισάζῃ τὴν θατέρου ὑπερβολὴν θάτερον.
Wherefore also the spinal marrow is continuous with the brain; for nature always devises a remedy against the excess of each thing by the presence of its opposite, so that the one may neutralize the excess of the other.
§2.7.2ὅτι μὲν οὖν ὁ 2 μυελὸς θερμόν ἐστι, δῆλον ἐκ πολλῶν.
2 That the marrow is hot, then, is clear from many things.
ἡ δὲ τοῦ ἐγκεφάλου ψυχρότης φανερὰ μὲν καὶ κατὰ τὴν θίξιν, ἔτι δʼ ἀναιμότατον τῶν ὑγρῶν τῶν ἐν τῷ σήματι πάντων (οὐδʼ ὁτιοῦν γὰρ αἵματος ἔχει ἐν αὑτῷ) καὶ αὐχμηρότατον.
But the coldness of the brain is manifest both to the touch, and because it is the most bloodless of all the liquids in the body (for it has not a single drop of blood in itself) and the most dry.
ἔστι δʼ οὔτε περίττωμα οὔτε τῶν συνεχῶν μορίων, ἀλλὰ ἴδιος ἡ φύσις, καὶ εὐλόγως τοιαύτη.
And it is neither a residue nor one of the continuous parts, but a unique nature, and reasonably of such a kind.
§2.7.3ὅτι μὲν οὖν οὐκ ἔχει συνέχειαν οὐδεμίαν 3 πρὸς τὰ αἰσθητικὰ μόρια, δῆλον μὲν καὶ διὰ τῆς ὄψεως, ἔτι δὲ μᾶλλον τ μηδεμίαν ποιεῖν αἴσθησιν θιγγανόμενος, ὥσπερ οὐδὲ τὸ αἷμα οὐδὲ τὸ περίττωμα τῶν ζῴων.
3 That it has no continuity indeed with the sensory parts is clear both to the sight, and still more because it produces no sensation when touched, just as neither the blood nor the residue of animals does.
ὑπάρχει δὲ τοῖς ξῴοις πρὸς τὴν τῆς φύσεως ὅλης σωτηρίαν.
But it exists in animals for the preservation of their whole nature.
οἱ μὲν γὰρ τού ζῴου τὴν ψυχὴν τιθέασι πῦρ ἠ τοιούτην τινὰ δύναμιν φορτικῶς τιθέντες· βέλτιον δʼ ἴσως φάναι ἐν τοιούτῳ τινὶ σώματι συνεστάναι.
For some assume the soul of the animal to be fire or some such power, making a crude assumption; but it is perhaps better to say that it is constituted in some such body.
τούτου δʼ αἴτιον ὅτι τοῖς τῆς ψυχῆς ἔργοις ὑπηρετικώτατον τῶν σωμάτων τὸ θερμόν ἐστιν· τὸ τρέφειν γὰρ καὶ κινεῖν ψυχῆς ἔργον ἐστί, ταῦτα δὲ διὰ ταύτης μάλιστα γίνεται τῆς δυνάμεως.
And the cause of this is that heat is the most subservient of bodies to the works of the soul; for nourishing and moving are the work of the soul, and these take place especially through this power.
ὅμοιον οὖν τὸ τὴν ψυχὴν εἶναι φάναι πῦρ, η τρύπανον τὸν τέκτονα ἤ τὴν τεκτοκαὶ τὸ πρί τὸ ἔργον περαίνεται ἐγγὺς ἀλλήλων οὗσιν.
To say, then, that the soul is fire is like saying that the saw or the drill is the carpenter or the art of carpentry; for there too the work is accomplished by their being near to one another.
νιχ μεν οὖν θερμότητος τὰ ζῷα μετέχειν ἀναγκαῖον, §2.7.44 δἦλον ἐκ τούτων·
That animals must therefore participate in heat is clear from these things.
ἐπεὶ δʼ ἅμαντα δεῖται τὴς ἐναντίας ῥοπῆς, ἵνα τυγχάνῃ τοῦ μετρίου καὶ τού μέσου (τὴν γὰρ οὐσίαν ἔχει τοῦτο καὶ τὸν λόγον, τῶν δʼ ἄκρων ἑκάτερον οὐκ ἔχει χωρίς), διὰ ταύτην τὴν αἰτίαν πρὸς τὸν της καρδίας τόπον καὶ τὴν ἐν αὐτῇ θερμότητα μεμηχάνηται τὸν ἐγκέφαλον ἡ φύσις, καὶ τούτου χαέριν ὑπάρχει τοῦτο τὸ μόριον τοῖς ζῴοις, τὴν φύσιν ἔχον κοινὴν ὕδατος καὶ γῆς, καὶ διὰ τοῦτο τὰ ἔναιμα ἔχει πάντα ἐγκέφαλον, τῶν δʼ ἄλλων οὐδὲν ὡς εἰπεῖν, πλὴν ὅτι κατὰ τὸ ἀνάλογον, οἷον ὁ πολύπους·
4 But since everything needs the opposite counterpoise, in order that it may attain the moderate and the mean (for this possesses the substance and the definition, whereas neither of the extremes has it separately), for this reason nature has devised the brain against the region of the heart and the heat in it, and it is for this sake that this part exists in animals, having a nature common to water and earth.
ὀλιγόθερμα γὰρ πάντα διὰ τὴν ἀναιμίαν.
And because of this, all blooded animals have a brain, but virtually none of the others do, except for something analogous, such as the octopus; for they are all deficient in heat because of their bloodlessness.
§2.7.55 ὁ μὲν οὖν ἐγκέφαλος εὔκρατον ποιεῖ τὴν ἐν τῇ καρδίᾳ θερμότητα καὶ ζέσιν· ῦνα δὲ καὶ τοῦτο τὸ μὸριον τυγχάένῃ μετρίας θερμότητος, ἀφʼ ἑκατέρας τὴς φλεβὸς, τῆς τε μεγάλης καὶ τῆς καλουμένης ἀορτῆς, τελευτῶσιν αἱ φλέβες εἰς τὴν μήνιγγα τὴν περὶ τὸν ἐγκέφαλον.
5 The brain, then, tempers the heat and boiling in the heart; and in order that this part also may obtain a moderate heat, from each of the two vessels, both the great vein and that which is called the aorta, the vessels terminate in the membrane around the brain.
πρὸς δὲ τὸ τῇ θερμὸτητι μὴ βλάπτειν, ἀντὶ μὲν μεγάλων ὀλίγων πυκναὶ καὶ λεπταὶ φλέβες περιέχουσιν αὑτόν, ἀντὶ δὲ πολλοῦ καὶ παχέος αἵματος λεπτὸν καὶ καθαρὸν.
And so as not to cause harm by the heat, instead of a few large vessels, dense and thin vessels surround it, and instead of much and thick blood, thin and pure blood flows.
διὸ καὶ τὰ ῥεύματα τοῖς σώμασιν ἐκ τῆς κεφαλῆς ἐστὶ τὴν ἀρχὴν, ὅσοις ἄν ᾖ τὰ περὶ τὸν ἐγκέφαλον ψυχρότερα τῆς συμμέτρου κράσεως· ἀναθυμιωμένης γὰρ διἀ τῶν φλεβῶν ἄνω τῆς τροφῆς τὸ περίττωμα ψυχόμενον διὰ τὴν τού τόπου τούτου δύναμιν ῥεύματα ποιεῖ φλέγματος καὶ ίχῶρος.
Wherefore also the fluxes in bodies have their origin from the head in all those whose region around the brain is colder than the proportionate temperament; for when the food is evaporated upwards through the vessels, the residue, being cooled by the power of this place, produces fluxes of phlegm and ichor.