§5.5Τοῖς δ᾽ ἄλλοις ζῴοις τοῦ μὴ γίνεσθαι διὰ τὴν ἡλικίαν ταύτην τὴν μεταβολὴν ἐπιδήλως τὸ αὐτὸ αἴτιον ὅπερ εἴρηταται καὶ ἐπὶ τῆς φαλακρότητος· ὀλίγον γὰρ ἔχουσι καὶ ἧττον ὑγρὸν τὸν ἐγκέφαλον, ὥστε μὴ ἐξαδυνατεῖν τὸ θερμὸν πρὸς τὴν πέψιν.
In other animals, the cause of this change not occurring conspicuously due to age is exactly the same cause that has been stated in the case of baldness; for they have a small and less moist brain, so that the heat does not completely fail for concoction.
τοῖς δ᾽ ἵπποις [αὐτῶν] ἐπισημαίνει μάλιστα ὧν ἴσμεν ζῴων, ὅτι λεπτότατον τὸ ὀστοῦν ὡς κατὰ μέγεθος ἔχουσι περὶ τὸν ἐγκέφαλον τῶν ἄλλων.
On the other hand, in horses, of the animals we know, this is most clearly indicated, because they have, in proportion to their size, the thinnest bone around the brain compared to other animals.
τεκμήριον δ᾽ ὅτι καίριος ἡ πληγὴ ἡ εἰς τὸν τόπον τοῦτον γίνεται αὐτοῖς· διὸ καὶ Ὅμηρος οὕτως ἐποίησεν "ἵνα τε πρῶται τρίχες ἵππων κρανίῳ ἐμπεφύασι, μάλιστα δὲ καίριόν ἐστιν. "ῥᾳδίως οὖν ἐπιρρεούσης τῆς ὑγρότητος διὰ τὴν λεπτότητα τοῦ ὀστοῦ, τῆς δὲ θερμότητος ἐλλειπούσης διὰ τὴν ἡλικίαν, ἐπιπολιοῦνται αἱ τρίχες αὗται.
And the proof is that a blow to this place is fatal to them; therefore, Homer also wrote: "Where the first hairs of horses grow on the skull, and it is most fatal." Therefore, since the moisture easily flows in due to the thinness of the bone, and the heat is deficient due to age, these hairs become gray.
καὶ αἱ πυρραὶ δὲ θᾶττον πολιοῦνται τρίχες τῶν μελαινῶν· ἔστι γὰρ καὶ ἡ πυρρότης ὥσπερ ἀρρωστία τριχός, τὰ δ᾽ ἀσθενῆ γηράσκει πάντα θᾶττον.
Also, red hairs become gray faster than black ones; for redness is, as it were, a disease of the hair, and all weak things age faster.
μελαντέρας δὲ γίνεσθαι γηρασκούσας λέγεται τὰς γεράνους.
But cranes are said to become blacker as they grow old.
αἴτιον δ᾽ ἂν εἴη τοῦ πάθους τὸ φύσει λευκοτέραν αὐτῶν εἶναι τὴν τῶν πτερῶν φύσιν, πλέον τε γηρασκόντων εἶναι τὸ ὑγρὸν ἐν τοῖς πτεροῖς ἢ ὥστε εὐσηπτότερον εἶναι.
And the cause of this condition would be that the nature of their feathers is naturally whiter, and that as they grow old, the moisture in their feathers is more than what would make them easily corrupted (i.e., too much to be easily corrupted).
ὅτι δὲ γίγνεται ἡ πολιὰ σήψει τινί, καὶ ὅτι οὐκ ἔστιν, ὥσπερ οἴονταί τινες, αὔανσις, σημεῖον τοῦ προτέρου ῥηθέντος τὸ τὰς σκεπαζομένας τρίχας πίλοις ἢ καλύμμασι πολιοῦσθαι θᾶττον (τὰ γὰρ πνεύματα κωλύει τὴν σῆψιν, ἡ δὲ σκέπη ἄπνοιαν ποιεῖ), καὶ τὸ βοηθεῖν τὴν ἄλειψιν τὴν τοῦ ὕδατος καὶ τοῦ ἐλαίου μιγνυμένων.
On the other hand, that grayness is produced by a certain corruption, and is not, as some think, a drying up, is proved by the former statement, namely, that hairs covered with hats or coverings become gray faster (for winds prevent corruption, but covering causes a lack of wind), and that the application of a mixture of water and oil is helpful.
τὸ μὲν γὰρ ὕδωρ ψύχει, τὸ δ᾽ ἔλαιον μιγνύμενον κωλύει ξηραίνεσθαι ταχέως· τὸ γὰρ ὕδωρ εὐξήραντον.
For the water cools, and the oil mixed with it prevents it from drying quickly; for water is easily dried.
ὅτι δ᾽ οὐκ ἔστιν αὔανσις, οὐδ᾽ ὥσπερ ἡ πόα αὐαινομένη λευκαίνεται, οὕτω καὶ ἡ θρίξ, σημεῖον ὅτι φύονται εὐθέως ἔνιοι πολιοί· αὖον δ᾽ οὐθὲν φύεται.
On the other hand, that it is not a drying up, nor does the hair become white in the same way as grass drying up becomes white, is proved by the fact that some hairs grow gray from the very start; for nothing dry grows.
λευκαίνονται δὲ καὶ ἐπ᾽ ἄκρου πολλαί· ἐν γὰρ τοῖς ἐσχάτοις καὶ λεπτοτάτοις ἐλαχίστη θερμότης ἐγγίνεται.
Also, many hairs become white at the tip; for in the outermost and thinnest parts, the least heat is generated.
τοῖς δ᾽ ἄλλοις ζῴοις ὅσοις γίνονται λευκαὶ αἱ τρίχες, φύσει ἀλλ᾽ οὐ πάθει συμβαίνει γίνεσθαι τοῦτο.
In other animals in which the hairs become white, this happens by nature and not by disease.
αἴτιον δὲ τῶν χρωμάτων τὸ δέρμα τοῖς ἄλλοις· τῶν μὲν γὰρ λευκῶν λευκὸν τὸ δέρμα, τῶν δὲ μελάνων μέλαν, τῶν δὲ ποικίλων καὶ γιγνομένων ἐκ συμμίζεως τῇ μὲν λευκὸν τῇ δὲ μέλαν φαίνεται ὅν.
On the other hand, the skin is the cause of colors in other animals; for the skin of white ones is white, of black ones black, and of variegated ones and those produced by mixing, it appears white in one part and black in another.
ἐπὶ δὲ τῶν ἀνθρώπων οὐθὲν αἴτιον τὸ δέρμα· καὶ γὰρ οἱ λευκοὶ σφόδρα μελαίνας ἔχουσιν.
But in humans, the skin is not the cause at all; for indeed, extremely white people have very black hairs.
αἴτιον δ᾽ ὅτι λεπτότατον πάντων δέρμα ἄνθρωπος ἔχει ὡς κατὰ μέγεθος, διόπερ οὐθὲν ἰσχύει πρὸς τὴν τῶν τριχῶν μεταβολήν, ἀλλὰ διὰ τὴν ἀσθένειαν τὸ δέρμα καὶ μεταβάλλει αὐτὸ τὴν χρόαν, καὶ γίνεται ὑπὸ ἡλίων καὶ πνευμάτων μελάντερον· αἱ δὲ τρίχες ὀθὲν συμμεταβάλλουσιν.
And the cause is that human has the thinnest skin of all animals in proportion to size; therefore, it has no power to change the hairs, but due to its weakness, the skin itself changes its color and becomes blacker under the sun and winds; but the hairs do not change along with it at all.
ἐν δὲ τοῖς ἄλλοις τὸ δέρμα χώρας ἔχει δύναμιν διὰ τὸ πάχος· διὸ αἱ μὲν τρίχες κατὰ τὰ δέρματα μεταβάλλουσι, τὰ δὲ δέρματα οὐθὲν κατὰ τὰ πνεύματα καὶ τὸν ἥλιον.
On the other hand, in other animals, the skin has the power of a soil due to its thickness; therefore, the hairs change according to the skins, but the skins do not change at all according to the winds and the sun.