§10.28Διὰ τί ἐν μὲν τοῖς ἄλλοις ζῴοις διαμένει ὁμοίως τὰ δίδυμα, θήλεος καὶ ἄρσενος ὄντος, ἐν δὲ τοῖς ἀνθρώποις οὔ;
Why is it that in other animals twins survive equally well when they are female and male, whereas in humans they do not?
ἢ διότι τούτῳ ἀσθενῆ μάλιστα τὰ δίδυμα· μονοτόκον γάρ ἐστιν.
Is it because twins are extremely weak in man; for man is uniparous.
ἐν δὲ τοῖς διδύμοις παρὰ φύσιν τὸ θῆλυ γίνεσθαι καὶ ἄρρεν, ὥστε ὃ μάλιστά ἐστι παρὰ φύσιν, τοῦτο καὶ ἀσθενέστατον.
And in twins, that a female and a male should be born is contrary to nature, so that what is most contrary to nature is also weakest.
§10.29Διὰ τί τοῖς μὲν ἵπποις καὶ τοῖς ὄνοις ἐκ τῶν οὐλῶν φύονται τρίχες, τοῖς δὲ ἀνθρώποις οὔ;
Why is it that in horses and asses hair grows from scars, but not in men?
ἢ διότι ἡ οὐλὴ κωλύει διὰ τὴν πύκνωσιν ἢ διὰ τὸ φθείρειν τὴν τροφήν;
Is it because the scar prevents it because of the condensation or because it corrupts the nourishment?
τοῖς μὲν οὖν ἀνθρώποις παντελῶς κωλύει διὰ τὴν ἀσθένειαν τῆς τριχός, τοῖς δὲ ἵπποις οὐκ ἐκώλυσεν, διέφθειρε δέ.
Thus in men it completely prevents it because of the weakness of the hair, whereas in horses it did not prevent it, but corrupted it.
§10.30Διὰ τί τοῖς ζῴοις ἄρτιοι πόδες;
Why do animals have an even number of feet?
ἢ ὅτι παντὸς μὲν τοῦ κινουμένου ἀνάγκη τι ἠρεμεῖν, συνέβαινεν δὲ περιττῶν ὄντων μὴ γίνεσθαι τοῦτο· ὅπερ κατὰ τὴν ἀντιστοιχίαν τῶν ποδῶν ἦν ἡ κίνησις.
Is it because for everything that moves it is necessary that something be at rest, but if they were odd, this would not happen; and this was the movement according to the alternation of the feet.
§10.31Διὰ τί ἐλάττω χρόνον τὰ ζῷα καθεύδει ἢ ἐγρήγορεν, οὐ συνεχῶς δέ;
Why do animals sleep for less time than they are awake, and not continuously?
ἢ διὰ τὸ μὴ ἅμα πᾶσαν πέττεσθαι τὴν περίττωσιν;
Is it because the residue is not all digested at once?
ἀλλ’ ὅταν τι πεφθῇ, κουφισθὲν διεγείρεται.
Rather, when a part is digested, they become lighter and wake up.
καὶ πλεονάκις δ’ ἐγείρονται, ὅσοις ψυχρὸς ὁ τόπος ὁ πέττων ἐστὶν τὴν περίττωσιν· ταχὺ γὰρ παύεται καὶ πολλάκις, ἡ δὲ διάπαυσις ἔγερσίς ἐστιν.
And those in whom the region that digests the residue is cold wake up more frequently; for the digestion stops quickly and often, and the pause is waking up.
ἡδὺ δέ, οὐδὲ εἰκός, διὰ τὸ ἀνάπαυσιν εἶναι φαίνεται.
And it seems pleasant—nor is this unreasonable—because it is a rest.
ἀλλ’ οὐδ’ ἐνταῦθα πλείω χρόνον ἡ ἀνάπαυσις γίνεται τῶν κατὰ φύσιν ἔργων· οὐδ’ εἰ τὸ ἐσθίειν ἥδιον τοῦ μή, ὅμως πλείω χρόνον ἐσθίουσιν ἢ ἀσιτοῦσιν.
But not even here does rest last for a longer time than natural activities; just as even if eating is more pleasant than not eating, they do not nevertheless eat for a longer time than they fast.
§10.32Διὰ τί τῶν ζῴων τὰ μὲν εὐθὺς ἀκολουθεῖ τοῖς γεννήσασι, τὰ δ’ ὀψέ, οἷον ἄνθρωπος, ἢ μόλις, ἢ οὐδέποτε;
Why is it that among animals, some immediately follow their parents, while others do so late (like man), or with difficulty, or never?
ἢ διότι τὰ μὲν ταχὺ ἀπολαμβάνει τὸ γνωρίζειν, τὰ δ’ ὀψέ;
Is it because some quickly acquire the power of recognition, while others do so late?
καὶ τὰ μὲν ἀναίσθητα τοῦ ὠφελοῦντος, τὰ δὲ ἔχει αἴσθησιν.
And some are insensitive to what is beneficial, while others have perception of it.
ὅσα μὲν οὖν ἄμφω ἔχει ταῦτα (λέγω δ’ οἷον καὶ αἴσθησιν τοῦ ὠφελοῦντος καὶ ἐπιτέλεσιν τοῦ σώματος), ἀκολουθεῖ, τὰ δὲ μὴ ἄμφω οὐ ποιεῖ τοῦτο· δεῖ γὰρ δύνασθαι καὶ διαισθάνεσθαι.
Those, therefore, which have both of these (I mean both perception of what is beneficial and the completion of the body) follow, whereas those that do not have both do not do so; for they must have both the physical power and the clear perception.
§10.33Διὰ τί λεύκη οὐ γίνεται τοῖς ἄλλοις ζῴοις;
Why does vitiligo not occur in other animals?
πότερον ὅτι τοῖς μὲν ἄλλοις νόσημα, τοῖς δὲ ἀνθρώποις γίνεται διάλευκα τὰ δέρματα καὶ αἱ τρίχες αὐτῶν;
Is it because in other animals it is a disease, but in humans their skins and hairs become white-spotted?
ἀλλ’ ὅμως ἀπορήσειεν ἄν τις διὰ τί ὕστερον οὐ γίνεται, ἀλλ’ ἐκ γενετῆς ἡ ποικιλία.
Yet one might wonder why it does not occur later in life in them, but the variegation is present from birth.
ἢ ὅτι τὰ δέρματα τῶν ἄλλων ζῴων σκληρά, ἄνθρωπος δὲ φύσει λεπτοδερμότατον;
Is it because the skins of other animals are hard, whereas man by nature has the thinnest skin?
ἡ δὲ λεύκη πνεύματός ἐστιν ἔκκρισις, ὃ κωλύεται διὰ τὴν πυκνότητα ἐξιέναι τοῖς ἄλλοις ζῴοις τοῦ δέρματος.
And vitiligo is an excretion of breath, which is prevented from escaping in other animals because of the density of their skin.
§10.34Διὰ τί δὲ ἐν μὲν τῇ λεύκῃ πολιαὶ γίνονται, ὅπου δὲ πολιαί, οὐκ ἀεὶ λεύκη;
And why is it that in vitiligo white hairs are produced, but where there are white hairs, there is not always vitiligo?
ἢ διότι αἱ τρίχες ἐκ τοῦ δέρματός εἰσιν, ἡ δὲ πολιὰ ὥσπερ σαπρότης τις τῶν τριχῶν ἐστιν.
Is it because the hairs come from the skin, and white hair is like a sort of decay of the hairs?
ὅταν μὲν οὖν τὸ δέρμα κάμνῃ, ἀνάγκη καὶ τὴν τρίχα ἐξ ἐκείνου οὖσαν κάμνειν· ὅταν δὲ ἡ θρίξ, οὐκ ἀνάγκη τὸ δέρμα.
Therefore, when the skin suffers, the hair which comes from it must also suffer; but when the hair suffers, the skin does not necessarily suffer.
§10.35Διὰ τί τῶν ζῴων τὰ μὲν χαλεπά ἐστι μετὰ τὸν τόκον, οἷον κύων καὶ ὗς, τὰ δὲ οὐδὲν ἐπιδήλως, οἷον γυνή, πρόβατον;
Why is it that among animals, some are fierce after giving birth, like the dog and the sow, while others are not noticeably so, like a woman and a sheep?
ἢ ὅτι ὅσα μὲν περιττωματικὰ πραέα;
Is it because those that have much residue are gentle?
ἀπέρχεται γὰρ ἐν τῷ τόκῳ τὰ λυποῦντα.
For the things that cause distress are removed in birth.
ὅσοις δὲ ἀπὸ τῶν εὖ ἐχόντων γίνεται ἡ ἀφαίρεσις,. . . ὥστε ἡ ἰσχνότης ποιεῖ διὰ τὴν ἕξιν τὴν ὀργήν, ὥσπερ καὶ αἱ ἀλεκτορίδες οὐ τεκοῦσαι χαλεπαί, ἀλλ’ ἐπῳάζουσαι, διὰ τὴν ἀσιτίαν.
But in those from whom the removal is made from their healthy parts,... so that their emaciation, owing to their condition, produces anger, just as hens are fierce not when they have laid eggs, but when they are brooding, because of fasting.