1. Since feeling and voluntary motion are peculiar to animals, whilst growth and nutrition are common to plants as well, we may look on the former as effects of the soul and the latter as effects of the nature. And if there be anyone who allows a share in soul to plants as well, and separates the two kinds of soul, naming the kind in question vegetative, and the other sensory, this person is not saying anything else, although his language is somewhat unusual. We, however, for our part, are convinced that the chief merit of language is clearness, and we know that nothing detracts so much from this as do unfamiliar terms; accordingly we employ those terms which the bulk of people are accustomed to use, and we say that animals are governed at once by their soul and by their nature, and plants by their nature alone, and that growth and nutrition are the effects of nature, not of soul.
1. ἐπειδὴ τὸ μὲν αἰσθάνεσθαί τε καὶ κινεῖσθαι κατὰ προαίρεσιν ἴδια τῶν ζῴων ἐστί, τὸ δʼ αὐξάνεσθαί τε καὶ τρέφεσθαι κοινὰ καὶ τοῖς φυτοῖς, εἴη ἂν τὰ μὲν πρότερα τῆς ψυχῆς, τὰ δὲ δεύτερα τῆς φύσεως ἔργα. εἰ δέ τις καὶ τοῖς φυτοῖς ψυχῆς μεταδίδωσι καὶ διαιρούμενος αὐτὰς ὀνομάζει φυτικὴν μὲν ταύτην, αἰσθητικὴν δὲ τὴν ἑτέραν, λέγει μὲν οὐδʼ οὗτος ἄλλα, τῇ λέξει δʼ οὐ πάνυ τῇ συνήθει κέχρηται. ἀλλʼ ἡμεῖς γε μεγίστην λέξεως ἀρετὴν σαφήνειαν εἶναι πεπεισμένοι καὶ ταύτην εἰδότες ὑπʼ οὐδενὸς οὕτως ὡς ὑπὸ τῶν ἀσυνήθων ὀνομάτων διαφθειρομένην, ὡς τοῖς πολλοῖς ἔθος, οὕτως ὀνομάζοντες ὑπὸ μὲν ψυχῆς θʼ ἅμα καὶ φύσεως τὰ ζῷα διοικεῖσθαί φαμεν, ὑπὸ δὲ φύσεως μόνης τὰ φυτὰ καὶ τό γʼ αὐξάνεσθαί τε καὶ τρέφεσθαι φύσεως ἔργα φαμέν, οὐ ψυχῆς.
2. Thus we shall enquire, in the course of this treatise, from what faculties these effects themselves, as well as any other effects of nature which there may be, take their origin. First, however, we must distinguish and explain clearly the various terms which we are going to use in this treatise, and to what things we apply them; and this will prove to be not merely an explanation of terms but at the same time a demonstration of the effects of nature. When, therefore, such and such a body undergoes no change from its existing state, we say that it is at rest; but, notwithstanding, if it departs from this in any respect we then say that in this respect it undergoes motion. Accordingly, when it departs in various ways from its preexisting state, it will be said to undergo various kinds of motion. Thus, if that which is white becomes black, or what is black becomes white, it undergoes motion in respect to colour; or if what was previously sweet now becomes bitter, or, conversely, from being bitter now becomes sweet, it will be said to undergo motion in respect to flavour; to both of these instances, as well as to those previously mentioned, we shall apply the term qualitative motion. And further, it is not only things which are altered in regard to colour and flavour which, we say, undergo motion; when a warm thing becomes cold, and a cold warm, here too we speak of its undergoing motion; similarly also when anything moist becomes dry, or dry moist. Now, the common term which we apply to all these cases is alteration. This is one kind of motion. But there is another kind which occurs in bodies which change their position, or as we say, pass from one place to another; the name of this is transference. These two kinds of motion, then, are simple and primary, while compounded from them we have growth and decay, as when a small thing becomes bigger, or a big thing smaller, each retaining at the same time its particular form. And two other kinds of motion are genesis and destruction, genesis being a coming into existence, and destruction being the opposite. Now, common to all kinds of motion is change from the preexisting state, while common to all conditions of rest is retention of the preexisting state. The Sophists, however, while allowing that bread in turning into blood becomes changed as regards sight, taste, and touch, will not agree that this change occurs in reality. Thus some of them hold that all such phenomena are tricks and illusions of our senses; the senses, they say, are affected now in one way, now in another, whereas the underlying substance does not admit of any of these changes to which the names are given. Others (such as Anaxagoras) will have it that the qualities do exist in it, but that they are unchangeable and immutable from eternity to eternity, and that these apparent alterations are brought about by separation and combination. Now, if I were to go out of my way to confute these people, my subsidiary task would be greater than my main one. Thus, if they do not know all that has been written, “On Complete Alteration of Substance” by Aristotle, and after him by Chrysippus, I must beg of them to make themselves familiar with these men's writings. If, however, they know these, and yet willingly prefer the worse views to the better, they will doubtless consider my arguments foolish also. I have shown elsewhere that these opinions were shared by Hippocrates, who lived much earlier than Aristotle. In fact, all those known to us who have been both physicians and philosophers Hippocrates was the first who took in hand to demonstrate that there are, in all, four mutually interacting qualities, and that to the operation of these is due the genesis and destruction of all things that come into and pass out of being. Nay, more; Hippocrates was also the first to recognise that all these qualities undergo an intimate mingling with one another; and at least the beginnings of the proofs to which Aristotle later set his hand are to be found first in the writings of Hippocrates. As to whether we are to suppose that the substances as well as their qualities undergo this intimate mingling, as Zeno of Citium afterwards declared, I do not think it necessary to go further into this question in the present treatise; for immediate purposes we only need to recognize the complete alteration of substance. In this way, nobody will suppose that bread represents a kind of meeting-place for bone, flesh, nerve, and all the other parts, and that each of these subsequently becomes separated in the body and goes to join its own kind; before any separation takes place, the whole of the bread obviously becomes blood; (at any rate, if a man takes no other food for a prolonged period, he will have blood enclosed in his veins all the same). And clearly this disproves the view of those who consider the elements unchangeable, as also, for that matter, does the oil which is entirely used up in the flame of the lamp, or the faggots which, in a somewhat longer time, turn into fire. I said, however, that I was not going to enter into an argument with these people, and it was only because the example was drawn from the subject-matter of medicine, and because I need it for the present treatise, that I have mentioned it. We shall then, as I said, renounce our controversy with them, since those who wish may get a good grasp of the views of the ancients from our own personal investigations into these matters. The discussion which follows we shall devote entirely, as we originally proposed, to an enquiry into the number and character of the faculties of Nature, and what is the effect which each naturally produces. Now, of course, I mean by an effect that which has already come into existence and has been completed by the activity of these faculties — for example, blood, flesh, or nerve. And activity is the name I give to the active change or motion, and the cause of this I call a faculty. Thus, when food turns into blood, the motion of the food is passive, and that of the vein active. Similarly, when the limbs have their position altered, it is the muscle which produces, and the bones which undergo the motion. In these cases I call the motion of the vein and of the muscle an activity, and that of the food and the bones a symptom or affection, since the first group undergoes alteration and the second group is merely transported. One might, therefore, also speak of the activity as an effect of Nature — for example, digestion, absorption, blood-production; one could not, however, in every case call the effect an activity; thus flesh is an effect of Nature, but it is, of course, not an activity. It is, therefore, clear that one of these terms is used in two senses, but not the other.
2. καὶ ζητήσομεν κατὰ τόνδε τὸν λόγον, ὑπὸ τίνων γίγνεται δυνάμεων αὐτὰ δὴ ταῦτα καὶ εἰ δή τι ἄλλο φύσεως ἔργον ἐστίν. ἀλλὰ πρότερόν γε διελέσθαι τε χρὴ καὶ μηνῦσαι σαφῶς ἕκαστον τῶν ὀνομάτων, οἷς χρησόμεθα κατὰ τόνδε τὸν λόγον, καὶ ἐφʼ ὅ τι φέρομεν πρᾶγμα. γενήσεται δὲ τοῦτʼ εὐθὺς ἔργων φυσικῶν διδασκαλία σὺν ταῖς τῶν ὀνομάτων ἐξηγήσεσιν. ὅταν οὖν τι σῶμα κατὰ μηδὲν ἐξαλλάττηται τῶν προϋπαρχόντων, ἡσυχάζειν αὐτό φαμεν· εἰ δʼ ἐξίσταιτό πῃ, κατʼ ἐκεῖνο κινεῖσθαι. καὶ τοίνυν ἐπεὶ πολυειδῶς ἐξίσταται, πολυειδῶς καὶ κινηθήσεται. καὶ γὰρ εἰ λευκὸν ὑπάρχον μελαίνοιτο καὶ εἰ μέλαν λευκαίνοιτο, κινεῖται κατὰ χρόαν, καὶ εἰ γλυκὺ τέως ὑπάρχον αὖθις αὐστηρὸν ἢ ἔμπαλιν ἐξ αὐστηροῦ γλυκὺ γένοιτο, καὶ τοῦτʼ ἂν κινεῖσθαι λέγοιτο κατὰ τὸν χυμόν. ἄμφω δε ταῦτά τε καὶ τὰ προειρημένα κατὰ τὴν ποιότητα κινεῖσθαι λεχθήσεται καὶ οὐ μόνον γε τὰ κατὰ τὴν χρόαν ἢ τὸν χυμὸν ἐξαλλαττόμενα κινεῖσθαί φαμεν, ἀλλὰ καὶ τὸ θερμότερον ἐκ ψυχροτέρου γενόμενον ἢ ψυχρότερον ἐκ θερμοτέρου κινεῖσθαι καὶ τοῦτο λέγομεν, ὥσπερ γε καὶ εἴ τι ξηρὸν ἐξ ὑγροῦ ἢ ὑγρὸν ἐκ ξηροῦ γίγνοιτο. κοινὸν δὲ κατὰ τούτων ἁπάντων ὄνομα φέρομεν τὴν ἀλλοίωσιν. ἕν τι τοῦτο γένος κινήσεως. ἕτερον δὲ γένος ἐπὶ τοῖς τὰς χώρας ἀμείβουσι σώμασι καὶ τόπον ἐκ τόπου μεταλλάττειν λεγομένοις, ὄνομα δὲ καὶ τούτῳ φορά. αὗται μὲν οὖν αἱ δύο κινήσεις ἁπλαῖ καὶ πρῶται, σύνθετοι δʼ ἐξ αὐτῶν αὔξησίς τε καὶ φθίσις, ὅταν ἐξ ἐλάττονός τι μεῖζον ἢ ἐκ μείζονος ἔλαττον γένηται φυλάττον τὸ οἰκεῖον εἶδος. ἕτεραι δὲ δύο κινήσεις γένεσις καὶ φθορά, γένεσις μὲν ἡ εἰς οὐσίαν ἀγωγή, φθορὰ δʼ ἡ ἐναντία. πάσαις δὲ ταῖς κινήσεσι κοινὸν ἐξάλλαξις τοῦ προϋπάρχοντος, ὥσπερ οὖν καὶ ταῖς ἡσυχίαις ἡ φυλακὴ τῶν προϋπαρχόντων. ἀλλʼ ὅτι μὲν ἐξαλλάττεται καὶ πρὸς τὴν ὄψιν καὶ πρὸς τὴν γεῦσιν καὶ πρὸς τὴν ἁφὴν αἷμα γιγνόμενα τὰ σιτία, συγχωροῦσιν· ὅτι δὲ καὶ κατʼ ἀλήθειαν, οὐκέτι τοῦθʼ ὁμολογοῦσιν οἱ σοφισταί. οἱ μὲν γάρ τινες αὐτῶν ἅπαντα τὰ τοιαῦτα τῶν ἡμετέρων αἰσθήσεων ἀπάτας τινὰς καὶ παραγωγὰς νομίζουσιν ἄλλοτʼ ἄλλως πασχουσῶν, τῆς ὑποκειμένης οὐσίας μηδὲν τούτων, οἷς ἐπονομάζεται, δεχομένης· οἱ δέ τινες εἶναι μὲν ἐν αὐτῇ βούλονται τὰς ποιότητας, ἀμεταβλήτους δὲ καὶ ἀτρέπτους ἐξ αἰῶνος εἰς αἰῶνα καὶ τὰς φαινομένας ταύτας ἀλλοιώσεις τῇ διακρίσει τε καὶ συγκρίσει γίγνεσθαί φασιν ὡς Ἀναξαγόρας. εἰ δὴ τούτους ἐκτραπόμενος ἐξελέγχοιμι, μεῖζον ἄν μοι τὸ πάρεργον τοῦ ἔργου γένοιτο. εἰ μὲν γὰρ οὐκ ἴσασιν, ὅσα περὶ τῆς καθʼ ὅλην τὴν οὐσίαν ἀλλοιώσεως Ἀριστοτέλει τε καὶ μετʼ αὐτὸν Χρυσίππῳ γέγραπται, παρακαλέσαι χρὴ τοῖς ἐκείνων αὐτοὺς ὁμιλῆσαι γράμμασιν· εἰ δὲ γιγνώσκοντες ἔπειθʼ ἑκόντες τὰ χείρω πρὸ τῶν βελτιόνων αἱροῦνται, μάταια δήπου καὶ τὰ ἡμέτερα νομιοῦσιν. ὅτι δὲ καὶ Ἱπποκράτης οὕτως ἐγίγνωσκεν Ἀριστοτέλους ἔτι πρότερος ὤν, ἐν ἑτέροις ἡμῖν ἀποδέδεικται. πρῶτος γὰρ οὗτος ἁπάντων ὧν ἴσμεν ἰατρῶν τε καὶ φιλοσόφων ἀποδεικνύειν ἐπεχείρησε τέτταρας εἶναι τὰς πάσας δραστικὰς εἰς ἀλλήλας ποιότητας, ὑφʼ ὧν γίγνεταί τε καὶ φθείρεται πάνθʼ, ὅσα γένεσίν τε καὶ φθορὰν ἐπιδέχεται. καὶ μέντοι καὶ τὸ κεράννυσθαι διʼ ἀλλήλων αὐτὰς ὅλας διʼ ὅλων Ἱπποκράτης ἁπάντων πρῶτος ἔγνω· καὶ τὰς ἀρχάς γε τῶν ἀποδείξεων, ὧν ὕστερον Ἀριστοτέλης μετεχειρίσατο, παρʼ ἐκείνῳ πρώτῳ γεγραμμένας ἔστιν εὑρεῖν. εἰ δʼ ὥσπερ τὰς ποιότητας οὕτω καὶ τὰς οὐσίας διʼ ὅλων κεράννυσθαι χρὴ νομίζειν, ὡς ὕστερον ἀπεφήνατο Ζήνων ὁ Κιττιεύς, οὐχ ἡγοῦμαι δεῖν ἔτι περὶ τούτου κατὰ τόνδε τὸν λόγον ἐπεξιέναι. μόνην γὰρ εἰς τὰ παρόντα δέομαι γιγνώσκεσθαι τὴν διʼ ὅλης τῆς οὐσίας ἀλλοίωσιν, ἵνα μή τις ὀστοῦ καὶ σαρκὸς καὶ νεύρου καὶ τῶν ἄλλων ἑκάστου μορίων οἱονεὶ μισγάγκειάν τινα τῷ ἄρτῳ νομίσῃ περιέχεσθαι κἄπειτʼ ἐν τῷ σώματι διακρινόμενον ὡς τὸ ὁμόφυλον ἕκαστον ἰέναι. καίτοι πρό γε τῆς διακρίσεως αἷμα φαίνεται γιγνόμενος ὁ πᾶς ἄρτος. εἰ γοῦν παμπόλλῳ τις χρόνῳ μηδὲν ἄλλʼ εἴη σιτίον προσφερόμενος, οὐδὲν ἧττον ἐν ταῖς φλεψὶν αἷμα περιεχόμενον ἕξει. καὶ φανερῶς τοῦτο τὴν τῶν ἀμετάβλητα τὰ στοιχεῖα τιθεμένων ἐξελέγχει δόξαν, ὥσπερ οἶμαι καὶ τοὔλαιον εἰς τὴν τοῦ λύχνου φλόγα καταναλισκόμενον ἅπαν καὶ τὰ ξύλα πῦρ μικρὸν ὕστερον γιγνόμενα. καίτοι τό γʼ ἀντιλέγειν αὐτοῖς ἠρνησάμην, ἀλλʼ ἐπεὶ τῆς ἰατρικῆς ὕλης ἦν τὸ παράδειγμα καὶ χρῄζω πρὸς τὸν παρόντα λόγον αὐτοῦ, διὰ τοῦτʼ ἐμνημόνευσα. καταλιπόντες οὖν, ὡς ἔφην, τὴν πρὸς τούτους ἀντιλογίαν, ἐνὸν τοῖς βουλομένοις τὰ τῶν παλαιῶν ἐκμανθάνειν κἀξ ὧν ἡμεῖς ἰδίᾳ περὶ αὐτῶν ἐπεσκέμμεθα. τὸν ἐφεξῆς λόγον ἅπαντα ποιησόμεθα ζητοῦντες ὑπὲρ ὧν ἐξ ἀρχῆς προὐθέμεθα, πόσαι τε καὶ τίνες εἰσὶν αἱ τῆς φύσεως δυνάμεις καὶ τί ποιεῖν ἔργον ἑκάστη πέφυκεν. ἔργον δὲ δηλονότι καλῶ τὸ γεγονὸς ἤδη καὶ συμπεπληρωμένον ὑπὸ τῆς ἐνεργείας αὐτῶν, οἷον τὸ αἷμα, τὴν σάρκα, τὸ νεῦρον· ἐνέργειαν δὲ τὴν δραστικὴν ὀνομάζω κίνησιν καὶ τὴν ταύτης αἰτίαν δύναμιν. ἐπεὶ γὰρ ἐν τῷ τὸ σιτίον αἷμα γίγνεσθαι παθητικὴ μὲν ἡ τοῦ σιτίου, δραστικὴ δʼ ἡ τῆς φλεβὸς γίγνεται κίνησις, ὡσαύτως δὲ κἀν τῷ μεταφέρειν τὰ κῶλα κινεῖ μὲν ὁ μῦς, κινεῖται δὲ τὰ ὀστᾶ, τὴν μὲν τῆς φλεβὸς καὶ τῶν μυῶν κίνησιν ἐνέργειαν εἶναί φημι, τὴν δὲ τῶν σιτίων τε καὶ τῶν ὀστῶν σύμπτωμά τε καὶ πάθημα· τὰ μὲν γὰρ ἀλλοιοῦται, τὰ δὲ φέρεται. τὴν μὲν οὖν ἐνέργειαν ἐγχωρεῖ καλεῖν καὶ ἔργον τῆς φύσεως, οἷον τὴν πέψιν, τὴν ἀνάδοσιν, τὴν αἱμάτωσιν, οὐ μὴν τό γʼ ἔργον ἐξ ἅπαντος ἐνέργειαν· ἡ γάρ τοι σὰρξ ἔργον μέν ἐστι τῆς φύσεως, οὐ μὴν ἐνέργειά γε. δῆλον οὖν, ὡς θάτερον μὲν τῶν ὀνομάτων διχῶς λέγεται, θάτερον δʼ οὔ.
3. It appears to me, then, that the vein, as well as each of the other parts, functions in such and such a way according to the manner in which the four qualities are mixed. There are, however, a considerable number of not undistinguished men — philosophers and physicians — who refer action to the Warm and the Cold, and who subordinate to these, as passive, the Dry and the Moist; Aristotle, in fact, was the first who attempted to bring back the causes of the various special activities to these principles, and he was followed later by the Stoic school. These latter, of course, could logically make active principles of the Warm and Cold, since they refer the change of the elements themselves into one another to certain diffusions and condensations. This does not hold of Aristotle, however; seeing that he employed the four qualities to explain the genesis of the elements, he ought properly to have also referred the causes of all the special activities to these. How is it that he uses the four qualities in his book “On Genesis and Destruction,” whilst in his “Meteorology,” his “Problems,” and many other works he uses the uses the two only? Of course, if anyone were to maintain that in the case of animals and plants the Warm and Cold are more active, the Dry and Moist less so, he might perhaps have even Hippocrates on his side; but if he were to say that this happens in all cases, he would, I imagine, lack support, not merely from Hippocrates, but even from Aristotle himself — if, at least, Aristotle chose to remember what he himself taught us in his work “On Genesis and Destruction,” not as a matter of simple statement, but with an accompanying demonstration. I have, however, also investigated these questions, in so far as they are of value to a physician, in my work “On Temperaments.”
3. ἐμοὶ μὲν οὖν καὶ ἡ φλὲψ καὶ τῶν ἄλλων ἁπάντων ἕκαστον διὰ τὴν ἐκ τῶν τεττάρων ποιὰν κρᾶσιν ὡδί πως ἐνεργεῖν δοκεῖ. εἰσὶ δέ γε μὴν οὐκ ὀλίγοι τινὲς ἄνδρες οὐδʼ ἄδοξοι, φιλόσοφοί τε καὶ ἰατροί, τῷ μὲν θερμῷ καὶ τῷ ψυχρῷ τὸ δρᾶν ἀναφέροντες, ὑποβάλλοντες δʼ αὐτοῖς παθητικὰ τὸ ξηρόν τε καὶ τὸ ὑγρόν. καὶ πρῶτός γʼ Ἀριστοτέλης τὰς τῶν κατὰ μέρος ἁπάντων αἰτίας εἰς ταύτας ἀνάγειν πειρᾶται τὰς ἀρχάς, ἠκολούθησε δʼ ὕστερον αὐτῷ καὶ ὁ ἀπὸ τῆς στοᾶς χορός. καίτοι τούτοις μέν, ὡς ἂν καὶ αὐτῶν τῶν στοιχείων τὴν εἰς ἄλληλα μεταβολὴν χύσεσί τέ τισι καὶ πιλήσεσιν ἀναφέρουσιν, εὔλογον ἦν ἀρχὰς δραστικὰς ποιήσασθαι τὸ θερμὸν καὶ τὸ ψυχρόν, Ἀριστοτέλει δʼ οὐχ οὕτως, ἀλλὰ ταῖς τέτταρσι ποιότησιν εἰς τὴν τῶν στοιχείων γένεσιν χρωμένῳ βέλτιον ἦν καὶ τὰς τῶν κατὰ μέρος αἰτίας ἁπάσας εἰς ταύτας ἀνάγειν. τί δήποτʼ οὖν ἐν μὲν τοῖς περὶ γενέσεως καὶ φθορᾶς ταῖς τέτταρσι χρῆται, ἐν δὲ τοῖς μετεωρολογικοῖς καὶ τοῖς προβλήμασι καὶ ἄλλοθι πολλαχόθι ταῖς δύο μόναις; εἰ μὲν γὰρ ὡς ἐν τοῖς ζῴοις τε καὶ τοῖς φυτοῖς μᾶλλον μὲν δρᾷ τὸ θερμὸν καὶ τὸ ψυχρόν, ἧττον δὲ τὸ ζηρὸν καὶ τὸ ὑγρὸν ἀποφαίνοιτο τις, ἴσως ἂν ἔχοι καὶ τὸν Ἱπποκράτην σύμψηφον· εἰ δʼ ὡσαύτως ἐν ἅπασιν, οὐκέτʼ οἶμαι συγχωρήσειν τοῦτο μὴ ὅτι τὸν Ἱπποκράτην ἀλλὰ μηδʼ αὐτὸν τὸν Ἀριστοτέλην μεμνῆσθαί γε βουλόμενον ὧν ἐν τοῖς περὶ γενέσεως καὶ φθορᾶς οὐχ ἁπλῶς ἀλλὰ μετʼ ἀποδείξεως αὐτὸς ἡμᾶς ἐδίδαξεν. ἀλλὰ περὶ μὲν τούτων κἀν τοῖς περὶ κράσεων, εἰς ὅσον ἰατρῷ χρήσιμον, ἐπεσκεψάμεθα.
4. The so-called blood-making faculty in the veins, then, as well as all the other faculties, fall within the category of relative concepts; primarily because the faculty is the cause of the activity, but also, accidentally, because it is the cause of the effect. But, if the cause is relative to something — for it is the cause of what results from it, and of nothing else — it is obvious that the faculty also falls into the category of the relative; and so long as we are ignorant of the true essence of the cause which is operating, we call it a faculty. Thus we say that there exists in the veins a blood-making faculty, as also a digestive faculty in the stomach, a pulsatile faculty in the heart, and in each of the other parts a special faculty corresponding to the function or activity of that part. If, therefore, we are to investigate methodically the number and kinds of faculties, we must begin with the effects; for each of these effects comes from a certain activity, and each of these again is preceded by a cause.
4. ἡ δʼ οὖν δύναμις ἡ ἐν ταῖς φλεψὶν ἡ αἱματοποιητικὴ προσαγορευομένη καὶ πᾶσα δʼ ἄλλη δύναμις ἐν τῷ πρός τι νενόηται· πρώτως μὲν γὰρ τῆς ἐνεργείας αἰτία, ἤδη δὲ καὶ τοῦ ἔργου κατὰ συμβεβηκός. ἀλλʼ εἴπερ ἡ αἰτία πρός τι, τοῦ γὰρ ὑπʼ αὐτῆς γενομένου μόνου, τῶν δʼ ἄλλων οὐδενός, εὔδηλον, ὅτι καὶ ἡ δύναμις ἐν τῷ πρός τι. καὶ μέχρι γʼ ἂν ἀγνοῶμεν τὴν οὐσίαν τῆς ἐνεργούσης αἰτίας, δύναμιν αὐτὴν ὀνομάζομεν, εἶναί τινα λέγοντες ἐν ταῖς φλεψὶν αἱματοποιητικήν, ὡσαύτως δὲ κἀν τῇ κοιλίᾳ πεπτικὴν κἀν τῇ καρδίᾳ σφυγμικὴν καὶ καθʼ ἕκαστον τῶν ἄλλων ἰδίαν τινὰ τῆς κατὰ τὸ μόριον ἐνεργείας. εἴπερ οὖν μεθόδῳ μέλλοιμεν ἐξευρήσειν, ὁπόσαι τε καὶ ὁποῖαί τινες αἱ δυνάμεις εἰσίν, ἀπὸ τῶν ἔργων αὐτῶν ἀρκτέον· ἕκαστον γὰρ αὐτῶν ὑπό τινος ἐνεργείας γίγνεται καὶ τούτων ἑκάστης προηγεῖταί τις αἰτία.
5. The effects of Nature, then, while the animal is still being formed in the womb, are all the different parts of its body; and after it has been born, an effect in which all parts share is the progress of each to its full size, and thereafter its maintenance of itself as long as possible. The activities corresponding to the three effects mentioned are necessarily three—one to each— namely, Genesis, Growth, and Nutrition. Genesis, however, is not a simple activity of Nature, but is compounded of alteration and of shaping. That is to say, in order that bone, nerve, veins, and all other [tissues] may come into existence, the underlying substance from which the animal springs must be altered; and in order that the substance so altered may acquire its appropriate shape and position, its cavities, outgrowths, attachments, and so forth, it has to undergo a shaping or formative process. One would be justified in calling this substance which undergoes alteration the material of the animal, just as wood is the material of a ship, and wax of an image. Growth is an increase and expansion in length, breadth, and thickness of the solid parts of the animal (those which have been subjected to the moulding or shaping process). Nutrition is an addition to these, without expansion.
5. ἔργα τοίνυν τῆς φύσεως ἔτι μὲν κυουμένου τε καὶ διαπλαττομένου τοῦ ζῴου τὰ σύμπαντʼ ἐστὶ τοῦ σώματος μόρια, γεννηθέντος δὲ κοινὸν ἐφʼ ἅπασιν ἔργον ἡ εἰς τὸ τέλειον ἑκάστῳ μέγεθος ἀγωγὴ καὶ μετὰ ταῦθʼ ἡ μέχρι τοῦ δυνατοῦ διαμονή. ἐνέργειαι δʼ ἐπὶ τρισὶ τοῖς εἰρημένοις ἔργοις τρεῖς ἐξ ἀνάγκης, ἐφʼ ἑκάστῳ μία, γένεσίς τε καὶ αὔξησις καὶ θρέψις. ἀλλʼ ἡ μὲν γένεσις οὐχ ἁπλῆ τις ἐνέργεια τῆς φύσεως, ἀλλʼ ἐξ ἀλλοιώσεώς τε καὶ διαπλάσεώς ἐστι σύνθετος. ἵνα μὲν γὰρ ὀστοῦν γένηται καὶ νεῦρον καὶ φλὲψ καὶ τῶν ἄλλων ἕκαστον, ἀλλοιοῦσθαι χρὴ τὴν ὑποβεβλημένην οὐσίαν, ἐξ ἧς γίγνεται τὸ ζῷον· ἵνα δὲ καὶ σχῆμα τὸ δέον καὶ θέσιν καὶ κοιλότητάς τινας καὶ ἀποφύσεις καὶ συμφύσεις καὶ τἆλλα τὰ τοιαῦτα κτήσηται, διαπλάττεσθαι χρὴ τὴν ἀλλοιουμένην οὐσίαν, ἣν δὴ καὶ ὕλην τοῦ ζῴου καλῶν, ὡς τῆς νεὼς τὰ ξύλα καὶ τῆς εἰκόνος τὸν κηρόν, οὐκ ἂν ἁμάρτοις. ἡ δʼ αὔξησις ἐπίδοσίς ἐστι καὶ διάστασις κατὰ μῆκος καὶ πλάτος καὶ βάθος τῶν στερεῶν τοῦ ζῴου μορίων, ὧνπερ καὶ ἡ διάπλασις ἦν, ἡ δὲ θρέψις πρόσθεσις τοῖς αὐτοῖς ἄνευ διαστάσεως.
6. Let us speak then, in the first place, of Genesis, which, as we have said, results from alteration together with shaping. The seed having been cast into the womb or into the earth (for there is no difference), then, after a certain definite period, a great number of parts become constituted in the substance which is being generated; these differ as regards moisture, dryness, coldness and warmth, and in all the other qualities which naturally derive therefrom. These derivative qualities, you are acquainted with, if you have given any sort of scientific consideration to the question of genesis and destruction. For, first and foremost after the qualities mentioned come the other so-called tangible distinctions, and after them those which appeal to taste, smell, and sight. Now, tangible distinctions are hardness and softness, viscosity, friability, lightness, heaviness, density, rarity, smoothness, roughness, thickness and thinness; all of these have been duly mentioned by Aristotle. And of course you know those which appeal to taste, smell, and sight. Therefore, if you wish to know which alterative faculties are primary and elementary, they are moisture, dryness, coldness, and warmth, and if you wish to know which ones arise from the combination of these, they will be found to be in each animal of a number corresponding to its sensible elements. The name sensible elements is given to all the homogeneous parts of the body, and these are to be detected not by any system, but by personal observation of dissections. Now Nature constructs bone, cartilage, nerve, membrane, ligament, vein, and so forth, at the first stage of the animal's genesis, employing at this task a faculty which is, in general terms, generative and alterative, and, in more detail, warming, chilling, drying, or moistening; or such as spring from the blending of these, for example, the bone-producing, nerve-producing, and cartilage-producing faculties (since for the sake of clearness these names must be used as well). Now the peculiar flesh of the liver is of this kind as well, also that of the spleen, that of the kidneys, that of the lungs, and that of the heart; so also the proper substance of the brain, stomach, gullet, intestines, and uterus is a sensible element, of similar parts all through, simple, and uncompounded. That is to say, if you remove from each of the organs mentioned its arteries, veins, and nerves, the substance remaining in each organ is, from the point of view of the senses, simple and elementary. As regards those organs consisting of two dissimilar coats, of which each is simple, of these organs the coats are the are the elements — for example, the coats of the stomach, oesophagus, intestines, and arteries; each of these two coats has an alterative faculty peculiar to it, which has engendered it from the menstrual blood of the mother. Thus the special alterative faculties in each animal are of the same number as the elementary parts; and further, the activities must necessarily correspond each to one of the special parts, just as each part has its special use — for example, those ducts which extend from the kidneys into the bladder, and which are called ureters; for these are not arteries, since they do not pulsate nor do they consist of two coats; and they are not veins, since they neither contain blood, nor do their coats in any way resemble those of veins; from nerves they differ still more than from the structures mentioned. “What, then, are they?” someone asks — as though every part must necessarily be either an artery, a vein, a nerve, or a complex of these, and as though the truth were not what I am now stating, namely, that every one of the various organs has its own particular substance. For in fact the two bladders — that which receives the urine, and that which receives the yellow bile — not only differ from all other organs, but also from one another. Further, the ducts which spring out like kinds of conduits from the gall-bladder and which pass into the liver have no resemblance either to arteries, veins or nerves. But these parts have been treated at a greater length in my work “On the Anatomy of Hippocrates,” as well as elsewhere. As for the actual substance of the coats of the stomach, intestine, and uterus, each of these has been rendered what it is by a special alterative faculty of Nature; while the bringing of these together, the therewith of the structures which are inserted into them, the outgrowth into the intestine, the shape of the inner cavities, and the like, have all been determined by a faculty which we call the shaping or formative faculty; this faculty we also state to be artistic — nay, the best and highest art — doing everything for some purpose, so that there is nothing ineffective or superfluous, or capable of being better disposed. This, however, I shall demonstrate in my work “On the Use of Parts.”
6. περὶ πρώτης οὖν τῆς γενέσεως εἴπωμεν, ἣν ἐξ ἀλλοιώσεώς θʼ ἅμα καὶ διαπλάσεως ἐλέγομεν γίγνεσθαι. Καταβληθέντος δὴ τοῦ σπέρματος εἰς τὴν μήτραν εἰς τὴν γῆν, οὐδὲν γὰρ διαφέρει, χρόνοις τιοὶν ὡρισμένοις πάμπολλα συνίσταται μόρια τῆς γεννωμένης οὐσίας ὑγρότητι καὶ ξηρότητι καὶ ψυχρότητι καὶ θερμότητι καὶ τοῖς ἄλλοις ἅπασιν, ὅσα τούτοις ἕπεται, διαφέροντα. τὰ δʼ ἑπόμενα γιγνώσκεις, εἴπερ ὅλως ἐφιλοσόφησάς τι περὶ γενέσεως καὶ φθορᾶς· αἱ λοιπαὶ γὰρ τῶν ἁπτῶν ὀνομαζομένων διαφορῶν ταῖς εἰρημέναις ἕπονται πρῶται καὶ μάλιστα, μετὰ δὲ ταύτας αἱ γευσταί τε καὶ ὀσφρηταὶ καὶ ὁραταί. σκληρότης μὲν οὖν καὶ μαλακότης καὶ γλισχρότης καὶ κραυρότης καὶ κουφότης καὶ βαρύτης καὶ πυκνότης καὶ ἀραιότης καὶ λειότης καὶ τραχύτης καὶ παχύτης καὶ λεπτότης ἁπταὶ διαφοραὶ καὶ εἴρηται περὶ πασῶν Ἀριστοτέλει καλῶς. οἶσθα δὲ δήπου καὶ τὰς γευστάς τε καὶ ὀσφρητὰς καὶ ὁρατὰς διαφοράς. ὥστʼ, εἰ μὲν τὰς πρώτας τε καὶ στοιχειώδεις ἀλλοιωτικὰς δυνάμεις ζητοίης, ὑγρότης ἐστὶ καὶ ξηρότης καὶ ψυχρότης καὶ θερμότης· εἰ δὲ τὰς ἐκ τῆς τούτων κράσεως γενομένας, τοσαῦται καθʼ ἕκαστον ἔσονται ζῷον, ὅσαπερ ἂν αὐτοῦ τὰ αἰσθητὰ στοιχεῖα ὑπάρχῃ· καλεῖται δʼ αἰσθητὰ στοιχεῖα τὰ ὁμοιομερῆ πάντα τοῦ σώματος μόρια· καὶ ταῦτʼ οὐκ ἐκ μεθόδου τινὸς ἀλλʼ αὐτόπτην γενόμενον ἐκμαθεῖν χρὴ διὰ τῶν ἀνατομῶν. ὀστοῦν δὴ καὶ χόνδρον καὶ νεῦρον καὶ ὑμένα καὶ σύνδεσμον καὶ φλέβα καὶ πάνθʼ ὅσα τοιαῦτα κατὰ τὴν πρώτην τοῦ ζῴου γένεσιν ἡ φύσις ἀπεργάζεται δυνάμει χρωμένη καθόλου μὲν εἰπεῖν τῇ γεννητικῇ τε καὶ ἀλλοιωτικῇ, κατὰ μέρος δὲ θερμαντικῇ τε καὶ ψυκτικῇ καὶ ξηραντικῇ καὶ ὑγραντικῇ καὶ ταῖς ἐκ τῆς τούτων κράσεως γενομέναις, οἷον ὀστοποιητικῇ τε καὶ νευροποιητικῇ καὶ χονδροποιητικῇ· σαφηνείας γὰρ ἕνεκα καὶ τούτοις τοῖς ὀνόμασι χρηστέον. ἔστι γοῦν καὶ ἡ ἰδία σὰρξ τοῦ ἥπατος ἐκ τούτου τοῦ γένους καὶ ἡ τοῦ σπληνὸς καὶ ἡ τῶν νεφρῶν καὶ ἡ τοῦ πνεύμονος καὶ ἡ τῆς καρδίας οὕτω δὲ καὶ τοῦ ἐγκεφάλου τὸ ἴδιον σῶμα καὶ τῆς γαστρὸς καὶ τοῦ στομάχου καὶ τῶν ἐντέρων καὶ τῶν ὑστερῶν αἰσθητὸν στοιχεῖόν ἐστιν ὁμοιομερές τε καὶ ἁπλοῦν καὶ ἀσύνθετον· ἐὰν γὰρ ἐξέλῃς ἑκάστου τῶν εἰρημένων τὰς ἀρτηρίας τε καὶ τὰς φλέβας καὶ τὰ νεῦρα, τὸ ὑπόλοιπον σῶμα τὸ καθʼ ἕκαστον ὄργανον ἁπλοῦν ἐστι καὶ στοιχειῶδες ὡς πρὸς αἴσθησιν. ὅσα δὲ τῶν τοιούτων ὀργάνων ἐκ δυοῖν σύγκειται χιτώνων οὐχ ὁμοίων μὲν ἀλλήλοις, ἁπλοῦ δʼ ἑκατέρου, τούτων οἱ χιτῶνές εἰσι τὰ στοιχεῖα καθάπερ τῆς τε γαστρὸς καὶ τοῦ στομάχου καὶ τῶν ἐντέρων καὶ τῶν ἀρτηριῶν, καὶ καθʼ ἑκάτερόν γε τῶν χιτώνων ἴδιος ἡ ἀλλοιωτικὴ δύναμις ἡ ἐκ τοῦ παρὰ τῆς μητρὸς ἐπιμηνίου γεννήσασα τὸ μόριον, ὥστε τὰς κατὰ μέρος ἀλλοιωτικὰς δυνάμεις τοσαύτας εἶναι καθʼ ἕκαστον ζῷον, ὅσαπερ ἂν ἔχῃ τὰ στοιχειώδη μόρια. καὶ μέν γε καὶ τὰς ἐνεργείας ἰδίας ἑκάστῳ τῶν κατὰ μέρος ἀναγκαῖον ὑπάρχειν ὥσπερ καὶ τὰς χρείας, οἷον καὶ τῶν ἀπὸ τῶν νεφρῶν εἰς τὴν κύστιν διηκόντων πόρων, οἳ δὴ καὶ οὐρητῆρες καλοῦνται. οὗτοι γὰρ οὔτʼ ἀρτηρίαι εἰσίν, ὅτι μήτε σφύζουσι μήτʼ ἐκ δυοῖν χιτώνων συνεστήκασιν, οὔτε φλέβες, ὅτι μήθʼ αἷμα περιέχουσι μήτʼ ἔοικεν αὐτῶν ὁ χιτὼν κατά τι τῷ τῆς φλεβός· ἀλλὰ καὶ νεύρων ἐπὶ πλέον ἀφεστήκασιν ἢ τῶν εἰρημένων. τί ποτʼ οὖν εἰσιν; ἐρωτᾷ τις, ὥσπερ ἀναγκαῖον ὂν ἅπαν μόριον ἢ ἀρτηρίαν ἢ φλέβα ἢ νεῦρον ὑπάρχειν ἢ ἐκ τούτων πεπλέχθαι καὶ μὴ τοῦτʼ αὐτὸ τὸ νῦν λεγόμενον, ὡς ἴδιος ἑκάστῳ τῶν κατὰ μέρος ὀργάνων ἐστὶν ἡ οὐσία. καὶ γὰρ καὶ αἱ κύστεις ἑκάτεραι ἥ τε τὸ οὖρον ὑποδεχομένη καὶ ἡ τὴν ξανθὴν χολὴν οὐ μόνον τῶν ἄλλων ἁπάντων ἀλλὰ καὶ ἀλλήλων διαφέρουσι καὶ οἱ εἰς τὸ ἧπαρ ἀποφυόμενοι πόροι, καθάπερ στόμαχοί τινες ἀπὸ τῆς χοληδόχου κύστεως, οὐδὲν οὔτʼ ἀρτηρίαις οὔτε φλεψὶν οὔτε νεύροις ἐοίκασιν. ἀλλὰ περὶ μὲν τούτων ἐπὶ πλέον ἐν ἄλλοις τέ τισι κἀν τοῖς περὶ τῆς Ἱπποκράτους ἀνατομῆς εἴρηται. αἱ δὲ κατὰ μέρος ἅπασαι δυνάμεις τῆς φύσεως αἱ ἀλλοιωτικαὶ αὐτὴν μὲν τὴν οὐσίαν τῶν χιτώνων τῆς κοιλίας καὶ τῶν ἐντέρων καὶ τῶν ὑστερῶν ἀπετέλεσαν, οἵαπέρ ἐστι· τὴν δὲ σύνθεσιν αὐτῶν καὶ τὴν τῶν ἐμφυομένων πλοκὴν καὶ τὴν εἰς τὸ ἔντερον ἐκφυσιν καὶ τὴν τῆς ἔνδον κοιλότητος ἰδέαν καὶ τἆλλʼ ὅσα τοιαῦτα δύναμίς τις ἑτέρα διέπλασεν, ἣν διαπλαστικὴν ὀνομάζομεν, ἣν δὴ καὶ τεχνικὴν εἶναι λέγομεν, μᾶλλον δʼ ἀρίστην καὶ ἄκραν τέχνην καὶ πάντα τινὸς ἕνεκα ποιοῦσαν, ὡς μηδὲν ἀργὸν εἶναι μηδὲ περιττὸν μηδʼ ὅλως οὕτως ἔχον, ὡς δύνασθαι βέλτιον ἑτέρως ἔχειν. ἀλλὰ τοῦτο μὲν ἐν τοῖς περὶ χρείας μορίων ἀπδείξομεν.
7. Passing now to the faculty of Growth let us first mention that this, too, is present in the foetus in utero as is also the nutritive faculty, but that at that stage these two faculties are, as it were, handmaids to those already mentioned, and do not possess in themselves supreme authority. When, however, the animal has attained its complete size, then, during the whole period following its birth and until the acme is reached, the faculty of growth is predominant, while the alterative and nutritive faculties are accessory — in fact, act as its handmaids. What, then, is the property of this faculty of growth? To extend in every direction that which has already come into existence — that is to say, the solid parts of the body, the arteries, veins, nerves, bones, cartilages, membranes, ligaments, and the various coats which we have just called elementary, homogeneous, and simple. And I shall state in what way they gain this extension in every direction, first giving an illustration for the sake of clearness. Children take the bladders of pigs, fill them with air, and then rub them on ashes near the fire, so as to warm, but not to injure them. This is a common game in the district of Ionia, and among not a few other nations. As they rub, they sing songs, to a certain measure, time, and rhythm, and all their words are an exhortation to the bladder to increase in size. When it appears to them fairly well distended, they again blow air into it and expand it further; then they rub it again. This they do several times, until the bladder seems to them to have become large enough. Now, clearly, in these doings of the children, the more the interior cavity of the bladder increases in size, the thinner, necessarily, does its substance become. But, if the children were able to bring nourishment to this thin part, then they would make the bladder big in the same way that Nature does. As it is, however, they cannot do what Nature does, for to imitate this is beyond the power not only of children, but of any one soever; it is a property of Nature alone. It will now, therefore, be clear to you that nutrition is a necessity for growing things. For if such bodies were distended, but not at the same time nourished, they would take on a false appearance of growth, not a true growth. And further, to be distended in all directions belongs only to bodies whose growth is directed by Nature; for those which are distended by us undergo this distension in one direction but grow less in the others; it is impossible to find a body which will remain entire and not be torn through whilst we stretch it in the three dimensions. Thus Nature alone has the power to expand a body in all directions so that it remains unruptured and preserves completely its previous form. Such then is growth, and it cannot occur without the nutriment which flows to the part and is worked up into it.
7. Ἐπὶ δὲ τὴν αὐξητικὴν ἤδη μεταβάντες δύναμιν αὐτὸ τοῦθʼ ὑπομνήσωμεν πρῶτον, ὡς ὑπάρχει μὲν καὶ αὐτὴ τοῖς κυουμένοις ὥσπερ καὶ ἡ θρεπτική· ἀλλʼ οἶον ὑπηρέτιδές τινές εἰσι τηνικαῦτα τῶν προειρημένων δυνάμεων, οὐκ ἐν αὑταῖς ἔχουσαι τὸ πᾶν κῦρος. ἐπειδὰν δὲ τὸ τέλειον ἀπολάβῃ μέγεθος τὸ ζῷον, ἐν τῷ μετὰ τὴν ἀποκύησιν χρόνῳ παντὶ μέχρι τῆς ἀκμῆς ἡ μὲν αὐξητικὴ τηνικαῦτα κρατεῖ· βοηθοὶ δʼ αὐτῆς καὶ οἷον ὑπηρέτιδες ἥ τʼ ἀλλοιωτικὴ δύναμίς ἐστι καὶ ἡ θρεπτική. τί οὖν τὸ ἴδιόν ἐστι τῆς αὐξητικῆς δυνάμεως; εἰς πᾶν μέρος ἐκτεῖναι τὰ πεφυκότα. καλεῖται δʼ οὕτω τὰ στερεὰ μόρια τοῦ σώματος, ἀρτηρίαι καὶ φλέβες καὶ νεῦρα καὶ ὀστᾶ καὶ χόνδροι καὶ ὑμένες καὶ σύνδεσμοι καὶ οἱ χιτῶνες ἅπαντες, οὓς στοιχειώδεις τε καὶ ὁμοιομερεῖς καὶ ἁπλοῦς ὀλίγον ἔμπροσθεν ἐκαλοῦμεν. ὅτῳ δὲ τρόπῳ τὴν εἰς πᾶν μέρος ἔκτασιν ἴσχουσιν, ἐγὼ φράσω παράδειγμά τι πρότερον εἰπὼν ἕνεκα τοῦ σαφοῦς. Τὰς κύστεις τῶν ὑῶν λαβόντες οἱ παῖδες πληροῦσί τε πνεύματος καὶ τρίβουσιν ἐπὶ τῆς τέφρας πλησίον τοῦ πυρός, ὡς ἀλεαίνεσθαι μέν, βλάπτεσθαι δὲ μηδέν· καὶ πολλή γʼ αὕτη ἡ παιδιὰ περί τε τὴν Ἰωνίαν καὶ ἐν ἄλλοις ἔθνεσιν οὐκ ὀλίγοις ἐστίν. ἐπιλέγουσι δὲ δὴ καί τινʼ ἔπη τρίβοντες ἐν μέτρῳ τέ τινι καὶ μέλει καὶ Ῥυθμῷ καὶ ἔστι πάντα τὰ Ῥήματα ταῦτα παρακέλευσις τῇ κύστει πρὸς τὴν αὔξησιν. ἐπειδὰν δʼ ἱκανῶς αὐτοῖς διατετάσθαι δοκῇ, πάλιν ἐμφυσῶσί τε καὶ ἐπιδιατείνουσι καὶ αὖθις τρίβουσι καὶ τοῦτο πλεονάκις ποιοῦσιν, ἄχρις ἂν αὐτοῖς ἡ κύστις ἱκανῶς ἔχειν δοκῇ τῆς αὐξήσεως. ἀλλʼ ἐν τούτοις γε τοῖς ἔργοις τῶν παίδων ἐναργῶς, ὅσον εἰς μέγεθος ἐπιδίδωσιν ἡ ἐντὸς εὐρυχωρία τῆς κύστεως, τοσοῦτον ἀναγκαῖον εἰς λεπτότητα καθαιρεῖσθαι τὸ σῶμα καὶ εἴ γε τὴν λεπτότητα ταύτην ἀνατρέφειν οἷοί τʼ ἦσαν οἱ παῖδες, ὁμοίως ἂν τῇ φύσει τὴν κύστιν ἐκ μικρᾶς μεγάλην ἀπειργάζοντο. νυνὶ δὲ τοῦτʼ αὐτοῖς ἐνδεῖ τὸ ἔργον οὐδὲ καθʼ ἕνα τρόπον εἰς μίμησιν ἐνδεχόμενον ἀχθῆναι μὴ ὅτι τοῖς παισὶν ἀλλʼ οὐδʼ ἄλλῳ τινί· μόνης γὰρ τῆς φύσεως ἴδιόν ἐστιν. ὥστʼ ἤδη σοι δῆλον, ὡς ἀναγκαία τοῖς αὐξανομένοις ἡ θρέψις. εἰ γὰρ διατείνοιτο μέν, ἀνατρέφοιτο δὲ μή, φαντασίαν ψευδῆ μᾶλλον, οὐκ αὔξησιν ἀληθῆ τὰ τοιαῦτα σώματα κτήσεται. καίτοι καὶ τὸ διατείνεσθαι πάντη μόνοις τοῖς ὑπὸ φύσεως αὐξανομένοις ὑπάρχει. τὰ γὰρ ὑφʼ ἡμῶν διατεινόμενα σώματα κατὰ μίαν τινὰ διάστασιν τοῦτο πάσχοντα μειοῦται ταῖς λοιπαῖς, οὐδʼ ἔστιν εὑρεῖν οὐδέν, ὃ συνεχὲς ἔτι μένον καὶ ἀδιάσπαστον εἰς τὰς τρεῖς διαστάσεις ἐπεκτεῖναι δυνάμεθα. μόνης οὖν τῆς φύσεως τὸ πάντη διιστάναι συνεχὲς ἑαυτῷ μένον ἔτι καὶ τὴν ἀρχαίαν ἅπασαν ἰδέαν φυλάττον τὸ σῶμα. καὶ τοῦτʼ ἔστιν ἡ αὔξησις ἄνευ τῆς ἐπιρρεούσης τε καὶ προσπλαττομένης τροφῆς μὴ δυναμένη γενέσθαι.
8. We have, then, it seems, arrived at the subject of Nutrition, which is the third and remaining consideration which we proposed at the outset. For, when the matter which flows to each part of the body in the form of nutriment is being worked up into it, this activity is nutrition, and its cause is the nutritive faculty. Of course, the kind of activity here involved is also an alteration, but not an alteration like that occurring at the stage of genesis. For in the latter case something comes into existence which did not exist previously, while in nutrition the inflowing material becomes assimilated to that which has already come into existence. Therefore, the former kind of alteration has with reason been termed genesis, and the latter, assimilation.
8. καὶ τοίνυν ὁ λόγος ἥκειν ἔοικεν ὁ περὶ τῆς θρέψεως, ὃς δὴ λοιπός ἐστι καὶ τρίτος ὧν ἐξ ἀρχῆς προὐθέμεθα. τοῦ γὰρ ἐπιρρέοντος ἐν εἴδει τροφῆς παντὶ μορίῳ τοῦ τρεφομένου σώματος προσπλαττομένου θρέψις μὲν ἡ ἐνέργεια, θρεπτικὴ δὲ δύναμις ἡ αἰτία. ἀλλοίωσις μὲν δὴ κἀνταῦθα τὸ γένος τῆς ἐνεργείας, ἀλλʼ οὐχ οἵαπερ ἡ ἐν τῇ γενέσει. ἐκεῖ μὲν γὰρ οὐκ ὂν πρότερον ὕστερον ἐγένετο, κατὰ δὲ τὴν θρέψιν τῷ ἤδη γεγονότι συνεξομοιοῦται τὸ ἐπιρρέον καὶ διὰ τοῦτʼ εὐλόγως ἐκείνην μὲν τὴν ἀλλοίωσιν γένεσιν, ταύτην δʼ ἐξομοίωσιν ὠνόμασαν.
9. Now, since the three faculties of Nature have been exhaustively dealt with, and the animal would appear not to need any others (being possessed of the means for growing, for attaining completion, and for maintaining itself as long a time as possible), this treatise might seem to be already complete, and to constitute an exposition of all the faculties of Nature. If, however, one considers that it has not yet touched upon any of the parts of the animal (I mean the stomach, intestines, liver, and the like), and that it has not dealt with the faculties resident in these, it will seem as though merely a kind of introduction had been given to the practical parts of our teaching. For the whole matter is as follows: Genesis, growth, and nutrition are the first, and, so to say, the principal effects of Nature; similarly also the faculties which produce these effects — the first faculties — are three in number, and are the most dominating of all. But as has already been shown, these need the service both of each other, and of yet different faculties. Now, these which the faculties of generation and growth require have been stated. I shall now say what ones the nutritive faculty requires.
9. ἐπειδὴ δὲ περὶ τῶν τριῶν δυνάμεων τῆς φύσεως αὐτάρκως εἴρηται καὶ φαίνεται μηδεμιᾶς ἄλλης προσδεῖσθαι τὸ ζῷον, ἔχον γε καὶ ὅπως αὐξηθῇ καὶ ὅπως τελειωθῇ καὶ ὅπως ἕως πλείστου διαφυλαχθῇ, δόξειε μὲν ἂν ἴσως ἱκανῶς ἔχειν ὁ λόγος οὗτος ἤδη καὶ πάσας ἐξηγεῖσθαι τὰς τῆς φύσεως δυνάμεις. ἀλλʼ εἴ τις πάλιν ἐννοήσειεν, ὡς οὐδενὸς οὐδέπω τῶν τοῦ ζῴου μορίων ἐφήψατο, κοιλίας λέγω καὶ ἐντέρων καὶ ἥπατος καὶ τῶν ὁμοίων, οὐδʼ ἐξηγήσατο τὰς ἐν αὐτοῖς δυνάμεις, αὖθις δόξειεν ἂν οἷον προοίμιόν τι μόνον εἰρῆσθαι τῆς χρησίμου διδασκαλίας. τὸ γὰρ σύμπαν ὧδʼ ἔχει. γένεσις καὶ αὔξησις καὶ θρέψις τὰ πρῶτα καὶ οἷον κεφάλαια τῶν ἔργων ἐστὶ τῆς φύσεως· ὥστε καὶ αἱ τούτων ἐργαστικαὶ δυνάμεις αἱ πρῶται τρεῖς εἰσι καὶ κυριώταται· δέονται δʼ εἰς ὑπηρεσίαν, ὡς ἤδη δέδεικται, καὶ ἀλλήλων καὶ ἄλλων. τίνων μὲν οὖν ἡ γεννητική τε καὶ αὐξητικὴ δέονται, εἴρηται, τίνων δʼ ἡ θρεπτική, νῦν εἰρήσεται.
10. For I believe that I shall prove that the organs which have to do with the disposal of the nutriment, as also their faculties, exist for the sake of this nutritive faculty. For since the action of this faculty is assimilation, and it is impossible for anything to be assimilated by, and to change into anything else unless they already possess a certain community and affinity in their qualities, therefore, in the first place, any animal cannot naturally derive nourishment from any kind of food, and secondly, even in the case of those from which it can do so, it cannot do this at once. Therefore, by reason of this law, every animal needs several organs for altering the nutriment. For in order that the yellow may become red, and the red yellow, one simple process of alteration is required, but in order that the white may become black, and the black white, all the intermediate stages are needed. So also, a thing which is very soft cannot all at once become very hard, nor vice versa; nor, similarly can anything which has a very bad smell suddenly become quite fragrant, nor again, can the converse happen. How, then, could blood ever turn into bone, without having first become, as far as possible, thickened and white? And how could bread turn into blood without having gradually parted with its whiteness and gradually acquired redness? Thus it is quite easy for blood to become flesh; for, if Nature thicken it to such an extent that it acquires a certain consistency and ceases to be fluid, it thus becomes original newly-formed flesh; but in order that blood may turn into bone, much time is needed and much elaboration and transformation of the blood. Further, it is quite clear that bread, and, more particularly lettuce, beet, and the like, require a great deal of alteration, in order to become blood. This, then, is one reason why there are so many organs concerned in the alteration of food. A second reason is the nature of the superfluities. For, as we are unable to draw any nourishment from grass, although this is possible for cattle, similarly we can derive nourishment from radishes, albeit not to the same extent as from meat; for almost the whole of the latter is mastered by our natures; it is transformed and altered and constituted useful blood; but, not withstanding, in the radish, what is appropriate and capable of being altered (and that only with difficulty, and with much labour) is the very smallest part; almost the whole of it is surplus matter, and passes through the digestive organs, only a very little being taken up into the veins as blood — nor is this itself entirely utilisable blood. Nature, therefore, had need of a second process of separation for the superfluities in the veins. Moreover, these superfluities need, on the one hand, certain fresh routes to conduct them to the outlets, so that they may not spoil the useful substances, and they also need certain reservoirs, as it were, in which they are collected till they reach a sufficient quantity, and are then discharged. Thus, then, you have discovered bodily parts of a second kind, consecrated in this case to the [removal of the] superfluities of the food. There is, however, also a third kind, for carrying the pabulum in every direction; these are like a number of roads intersecting the whole body. Thus there is one entrance — that through the mouth — for all the various articles of food. What receives nourishment, however, is not one single part, but a great many parts, and these widely separated; do not be surprised, therefore, at the abundance of organs which Nature has created for the purpose of nutrition. For those of them which have to do with alteration prepare the nutriment suitable for each part; others separate out the superfluities; some pass these along, others store them up, others excrete them; some, again, are paths for the transit in all directions of the utilisable juices. So, if you wish to gain a thorough acquaintance with all the faculties of Nature, you will have consider each one of these organs. Now in giving an account of these we must begin with those effects of Nature, together with their corresponding parts and faculties, which are closely connected with the purpose to be achieved.
10. δοκῶ γάρ μοι δείξειν τὰ περὶ τὴν τῆς τροφῆς οἰκονομίαν ὄργανά τε καὶ τὰς δυνάμεις αὐτῶν διὰ ταύτην γεγονότα. ἐπειδὴ γὰρ ἡ ἐνέργεια ταύτης τῆς δυνάμεως ἐξομοίωσίς ἐστιν, ὁμοιοῦσθαι δὲ καὶ μεταβάλλειν εἰς ἄλληλα πᾶσι τοῖς οὖσιν ἀδύνατον, εἰ μή τινα ἔχοι κοινωνίαν ἤδη καὶ συγγένειαν ἐν ταῖς ποιότησι, διὰ τοῦτο πρῶτον μὲν οὐκ ἐκ πάντων ἐδεσμάτων πᾶν ζῷον τρέφεσθαι πέφυκεν, ἔπειτα δʼ οὐδʼ ἐξ ὧν οἷόν τʼ ἐστὶν οὐδʼ ἐκ τούτων παραχρῆμα, καὶ διὰ ταύτην τὴν ἀνάγκην πλειόνων ὀργάνων ἀλλοιωτικῶν τῆς τροφῆς ἕκαστον τῶν ζῴων χρῄζει. ἵνα μὲν γὰρ τὸ ξανθὸν ἐρυθρὸν γένηται καὶ τὸ ἐρυθρὸν ξανθόν, ἁπλῆς καὶ μιᾶς δεῖται τῆς ἀλλοιώσεως· ἵνα δὲ τὸ λευκὸν μέλαν καὶ τὸ μέλαν λευκόν, ἁπασῶν τῶν μεταξύ. καὶ τοίνυν καὶ τὸ μαλακώτατον οὐκ ἂν ἀθρόως σκληρότατον καὶ τὸ σκληρότατον οὐκ ἂν ἀθρόως μαλακώτατον γένοιτο, ὥσπερ οὐδὲ τὸ δυσωδέστατον εὐωδέστατον οὐδʼ ἔμπαλιν τὸ εὐωδέστατον δυσωδέστατον ἐξαίφνης γένοιτʼ ἄν. πῶς οὖν ἐξ αἵματος ὀστοῦν ἄν ποτε γένοιτο μὴ παχυνθέντος γε πρότερον ἐπὶ πλεῖστον αὐτοῦ καὶ λευκανθέντος ἢ πῶς ἐξ ἄρτου τὸ αἷμα μὴ κατὰ βραχὺ μὲν ἀποθεμένου τὴν λευκότητα, κατὰ βραχὺ δὲ λαμβάνοντος τὴν ἐρυθρότητα; σάρκα μὲν γὰρ ἐξ αἵματος γενέσθαι Ῥᾷστον· εἰ γὰρ εἰς τοσοῦτον αὐτὸ παχύνειεν ἡ φύσις, ὡς σύστασίν τινα σχεῖν καὶ μηκέτʼ εἶναι Ῥυτόν, ἡ πρώτη καὶ νεοπαγὴς οὕτως ἂν εἴη σάρξ· ὀστοῦν δʼ ἵνα γένηται, πολλοῦ μὲν δεῖται χρόνου, πολλῆς δʼ ἐργασίας καὶ μεταβολῆς τῷ αἵματι. ὅτι δὲ καὶ τῷ ἄρτῳ καὶ πολὺ μᾶλλον θριδακίνῃ καὶ τεύτλῳ καὶ τοῖς ὁμοίοις παμπόλλης δεῖται τῆς ἀλλοιώσεως εἰς αἵματος γένεσιν, οὐδὲ τοῦτʼ ἄδηλον. Ν̔ μὲν δὴ τοῦτʼ αἴτιον τοῦ πολλὰ γενέσθαι τὰ περὶ τὴν τῆς τροφῆς ἀλλοίωσιν ὄργανα. δεύτερον δʼ ἡ τῶν περιττωμάτων φύσις. ὡς γὰρ ὑπὸ βοτανῶν οὐδʼ ὅλως δυνάμεθα τρέφεσθαι, καίτοι τῶν βοσκημάτων τρεφομένων, οὕτως ὑπὸ Ῥαφανίδος τρεφόμεθα μέν, ἀλλʼ οὐχ ὡς ὑπὸ τῶν κρεῶν. τούτων μὲν γὰρ ὀλίγου δεῖν ὅλων ἡ φύσις ἡμῶν κρατεῖ καὶ μεταβάλλει καὶ ἀλλοιοῖ καὶ χρηστὸν ἐξ αὐτῶν αἷμα συνίστησιν· ἐν δὲ τῇ Ῥαφανίδι τὸ μὲν οἰκεῖόν τε καὶ μεταβληθῆναι δυνάμενον, μόγις καὶ τοῦτο καὶ σὺν πολλῇ τῇ κατεργασίᾳ, παντάπασιν ἐλάχιστον· ὅλη δʼ ὀλίγου δεῖν ἐστι περιττωματικὴ καὶ διεξέρχεται τὰ τῆς πέψεως ὄργανα, βραχέος ἐξ αὐτῆς εἰς τὰς φλέβας ἀναληφθέντος αἵματος καὶ οὐδὲ τούτου τελέως χρηστοῦ. δευτέρας οὖν αὖθις ἐδέησε διακρίσεως τῇ φύσει τῶν ἐν ταῖς φλεψὶ περιττωμάτων. καὶ χρεία καὶ τούτοις ὁδῶν τέ τινων ἑτέρων ἐπὶ τὰς ἐκκρίσεις αὐτὰ παραγουσῶν, ὡς μὴ λυμαίνοιτο τοῖς χρηστοῖς, ὑποδοχῶν τέ τινων οἷον δεξαμενῶν, ἐν αἷς ὅταν εἰς ἱκανὸν πλῆθος ἀφίκηται, τηνικαῦτʼ ἐκκριθήσεται. δεύτερον δή σοι καὶ τοῦτο τὸ γένος τῶν ἐν τῷ σώματι μορίων ἐξεύρηται τοῖς περιττώμασι τῆς τροφῆς ἀνακείμενον. ἄλλο δὲ τρίτον ὑπὲρ τοῦ πάντη φέρεσθαι, καθάπερ τινὲς ὁδοὶ πολλαὶ διὰ τοῦ σώματος ὅλου κατατετμημέναι. μία μὲν γὰρ εἴσοδος ἡ διὰ τοῦ στόματος ἅπασι τοῖς σιτίοις, οὐχ ἓν δὲ τὸ τρεφόμενον ἀλλὰ πάμπολλά τε καὶ πάμπολυ διεστῶτα. μὴ τοίνυν θαύμαζε τὸ πλῆθος τῶν ὀργάνων, ὅσα θρέψεως ἕνεκεν ἡ φύσις ἐδημιούργησε. τὰ μὲν γὰρ ἀλλοιοῦντα προπαρασκευάζει τὴν ἐπιτήδειον ἑκάστῳ μορίῳ τροφήν, τὰ δὲ διακρίνει τὰ περιττώματα, τὰ δὲ παραπέμπει, τὰ δʼ ὑποδέχεται, τὰ δʼ ἐκκρίνει, τὰ δʼ ὁδοὶ τῆς πάντη φορᾶς εἰσι τῶν χρηστῶν χυμῶν, ὥστʼ, εἴπερ βούλει τὰς δυνάμεις τῆς φύσεως ἁπάσας ἐκμαθεῖν, ὑπὲρ ἑκάστου τούτων ἂν εἴη σοι τῶν ὀργάνων ἐπισκεπτέον. Ἀρχὴ δʼ αὐτῶν τῆς διδασκαλίας, ὅσα τοῦ τέλους ἐγγὺς ἔργα τε τῆς φύσεώς ἐστι καὶ μόρια καὶ δυνάμεις αὐτῶν.
11. Let us once more, then, recall the actual purpose for which Nature has constructed all these parts. Its name, as previously stated, is nutrition, and the definition corresponding to the name is: an assimilation of that which nourishes to that which receives nourishment. And in order that this may come about, we must assume a preliminary process of adhesion, and for that, again, one of presentation. For whenever the juice which is destined to nourish any of the parts of the animal is emitted from the vessels, it is in the first place dispersed all through this part, next it is presented, and next it adheres, and becomes completely assimilated. The so-called white [leprosy] shows the difference between assimilation and adhesion, in the same way that the kind of dropsy which some people call anasarca clearly distinguishes presentation from adhesion. For, of course, the genesis of such a dropsy does not come about as do some of the conditions of atrophy and wasting, from an insufficient supply of moisture; the flesh is obviously moist enough, — in fact it is thoroughly saturated, — and each of the solid parts of the body is in a similar condition. While, however, the nutriment conveyed to the part does undergo presentation, it is still too watery, and is not properly transformed into a juice, nor has it acquired that viscous and agglutinative quality which results from the operation of innate heat; therefore, adhesion cannot come about, since, owing to this abundance of thin, crude liquid, the pabulum runs off and easily slips away from the solid parts of the body. In white [leprosy], again, there is adhesion of the nutriment but no real assimilation. From this it is clear that what I have just said is correct, namely, that in that part which is to be nourished there must first occur presentation, next adhesion, and finally assimilation proper. Strictly speaking, then, nutriment is that which is actually nourishing, while the quasi-nutriment which is not yet nourishing (e.g. matter which is undergoing adhesion or presentation) is not, strictly speaking, nutriment, but is so called only by an equivocation. Also, that which is still contained in the veins, and still more, that which is in the stomach, from the fact that it is destined to nourish if properly elaborated, has been called “nutriment.” Similarly we call the various kinds of food “nutriment,” not because they are already nourishing the animal, nor because they exist in the same state as the material which actually is nourishing it, but because they are able and destined to nourish it if they be properly elaborated. This was also what Hippocrates said, viz., “Nutriment is what is engaged in nourishing, as also is quasi-nutriment, and what is destined to be nutriment.” For to that which is already being assimilated he gave the name of nutriment; to the similar material which is being presented or becoming adherent, the name of quasi-nutriment; and to everything else — that is, contained in the stomach and veins — the name of destined nutriment.
11. αὐτοῦ δὲ δὴ πάλιν ἀναμνηστέον ἡμῖν τοῦ τέλους, οὗπερ ἕνεκα τοσαῦτά τε καὶ τοιαῦτα τῇ φύσει δεδημιούργηται μόρια. τὸ μὲν οὖν ὄνομα τοῦ πράγματος, ὥσπερ καὶ πρότερον εἴρηται, θρέψις· ὁ δὲ κατὰ τοὔνομα λόγος ὁμοίωσις τοῦ τρέφοντος τῷ τρεφομένῳ. ἵνα δʼ αὕτη γένηται, προηγήσασθαι χρὴ πρόσφυσιν, ἵνα δʼ ἐκείνη, πρόσθεσιν. ἐπειδὰν γὰρ ἐκπέσῃ τῶν ἀγγείων ὁ μέλλων θρέψειν ὁτιοῦν τῶν τοῦ ζῴου μορίων χυμός, εἰς ἅπαν αὐτὸ διασπείρεται πρῶτον, ἔπειτα προστίθεται κἄπειτα προσφύεται καὶ τελέως ὁμοιοῦται. δηλοῦσι δʼ αἱ καλούμεναι λεῦκαι τὴν διαφορὰν ὁμοιώσεώς τε καὶ προσφύσεως, ὥσπερ τὸ γένος ἐκεῖνο τῶν ὑδέρων, ὅ τινες ὀνομάζουσιν ἀνὰ σάρκα, διορίζει σαφῶς πρόσθεσιν προσφύσεως. οὐ γὰρ ἐνδείᾳ δήπου τῆς ἐπιρρεούσης ὑγρότητος, ὡς ἔνιαι τῶν ἀτροφιῶν τε καὶ φθίσεων, ἡ τοῦ τοιούτου γένεσις ὑδέρου συντελεῖται. φαίνεται γὰρ ἱκανῶς ἥ τε σὰρξ ὑγρὰ καὶ διάβροχος ἕκαστόν τε τῶν στερεῶν τοῦ σώματος μορίων ὡσαύτως διακείμενον. ἀλλὰ πρόσθεσις μέν τις γίγνεται τῆς ἐπιφερομένης τροφῆς, ἅτε δʼ ὑδατωδεστέρας οὔσης ἔτι καὶ μὴ πάνυ τι κεχυμωμένης μηδὲ τὸ γλίσχρον ἐκεῖνο καὶ κολλῶδες, ὃ δὴ τῆς ἐμφύτου θερμασίας οἰκονομίᾳ προσγίγνεται, κεκτημένης ἡ πρόσφυσις ἀδύνατός ἐστιν ἐπιτελεῖσθαι πλήθει λεπτῆς ὑγρότητος ἀπέπτου διαρρεούσης τε καὶ Ῥᾳδίως ὀλισθαινούσης ἀπὸ τῶν στερεῶν τοῦ σωματος μορίων τῆς τροφῆς. ἐν δὲ ταῖς λεύκαις πρόσφυσις μέν τις γίγνεται τῆς τροφῆς, οὐ μὴν ἐξομοίωσίς γε. καὶ δῆλον ἐν τῷδε τὸ μικρῷ πρόσθεν Ῥηθὲν ὡς ὀρθῶς ἐλέγετο τὸ δεῖν πρόσθεσιν μὲν πρῶτον, ἐφεξῆς δὲ πρόσφύσιν, ἔπειτʼ ἐξομοίωσιν γενέσθαι τῷ μέλλοντι τρέφεσθαι. κυρίως μὲν οὖν τὸ τρέφον ἤδη τροφή, τὸ δʼ οἷον μὲν τροφή, οὔπω δὲ τρέφον, ὁποῖόν ἐστι τὸ προσφυόμενον ἢ προστιθέμενον, τροφὴ μὲν οὐ κυρίως, ὁμωνύμως δὲ τροφή· τὸ δʼ ἐν ταῖς φλεψὶν ἔτι περιεχόμενον καὶ τούτου μᾶλλον ἔτι τὸ κατὰ τὴν γαστέρα τῷ μέλλειν ποτὲ θρέψειν, εἰ καλῶς κατεργασθείη, κέκληται τροφή. κατὰ ταὐτὰ δὲ καὶ τῶν ἐδεσμάτων ἕκαστον τροφὴν ὀνομάζομεν οὔτε τῷ τρέφειν ἤδη τὸ ζῷον οὔτε τῷ τοιοῦτον ὑπάρχειν οἷον τὸ τρέφον, ἀλλὰ τῷ δύνασθαί τε καὶ μέλλειν τρέφειν, εἰ καλῶς κατεργασθείη. τοῦτο γὰρ ἦν καὶ τὸ πρὸς Ἱπποκράτους λεγόμενον· "Τροφὴ δὲ τὸ τρέφον, τροφὴ καὶ τὸ οἷον τροφὴ καὶ τὸ μέλλον." τὸ μὲν γὰρ ὁμοιούενον ἤδη τροφὴν ὠνόμασε, τὸ δʼ οἷον μὲν ἐκεῖνο προστιθέμενον ἢ προσφνόμενον οἷον τροφήν· τὸ δʼ ἄλλο πᾶν, ὅσον ἐν τῇ γαστρὶ καὶ ταῖς φλεψὶ περιέχεται, μέλλον.