With the holiday season approaching, why not check in with Galen for some shopping advice? Here is what he tells his friends to do to get the best drugs from the rhôpopôlai, the street vendors at the market (I’ve posted about them here). As a bonus, Galen tells us what he takes to be his own innovation in quantifying the active powers in drugs, even throwing in a bit of epistemology and some critical remarks against hair-splitting logicians.

Happy holidays ✨🎄⚗

Galen has just talked about where to keep drugs in the house and he’s reminded us not to keep them near the food…

I encourage my friends to copy me in the following way, too, at least if they want to produce their medical products well. You see, every year, in order that those damned hucksters sell me the very best drugs from all over the world, I thoroughly harass them. Maybe it would be better to complain not only to them, but rather to their wholesalers, and even more to the root-cutters themselves—that’s what they’re called, even though they import from the mountains and into the city not just roots, but also saps, juices, fruits, flowers and blossoms. These people are the first of all to adulterate the drugs.

Therefore, whoever wants to get their hands on remedies from anywhere easily needs to acquire experience with every material derived from plants, and every material derived from both animals and metals, and all those earthy bodies distinct from metals which we bring in for medical use, so that one can discern which of them are real and which are fake. After that, one needs to train following my book in which I wrote about the capacities of simple drugs. For if one turns to what is useful in these notebooks without having prepared, while he may go as far as a rational understanding with respect to the method, he won’t produce anything worthy of it.

For suppose someone knows the things which we mentioned before about tendon injuries, but, because of their ignorance, introduces adulterated drugs into the compounds, or doesn’t even know their capacities precisely from the start. Won’t it be necessary that they will more often go wrong than right? To me it seems completely obvious, but precisely knowing the capacities differs a great deal from knowing them. For merely knowing them means recognizing whether the drug naturally dries, moistens, cools or heats us, while precisely knowing means also recognizing, in addition to this, the quantity of the capacity. For some drugs have a capacity such that, when they come into contact with our bodies, it produces a warm heat, while others produce a moderate one only a little bit stronger than the former; and others even boil so strongly that they can burn. Accordingly, the doctor needs to aim to recognize not only the quality of the condition, but also, one might say, the quantity in it.

For, while quantity is clearly not properly said to be something in [the category of] quality,* it is said to be all the same, in the way a fever, too, is said to be big or small. And the practice of speaking in this way is so common that already these terms have the force of proper speech, like [the words] ‘boxwood,’ ‘coppersmith,’ ‘animal-drawer,’ ‘oakcutter,’ and, in short, like terms that started off as instances of what grammarians call catachresis, but ended up being taken to be said properly. I’ve said these things for the people who want to get into discussions about logic at inappropriate times, but what I was saying when they interrupted me is this: what needs to be heated does not simply need to be heated, but heated with an appropriate measure.

*i.e., quality is not predicated of quantity, e.g., three is no more a kind of heat than it is a shade of red.

τοὺς δ’ ἑταίρους προτρέπω καὶ κατὰ τοῦτο μιμήσεσθαί με βουλομένους γε καλῶς ἐργάζεσθαι τὰ τῆς τέχνης ἔργα. γιγνώσκετε γὰρ, ὅπως ἐξ ἑκάστου τῶν ἐθνῶν τὰ κάλλιστά μοι διακομίζεται καθ’ ἕκαστον ἔτος φάρμακα διὰ τὸ τοὺς ἐπιτρίπτους ῥωποπώλας, παντοίως αὐτοῖς λυμαίνεσθαι. βέλτιον δ’ ἴσως οὐ τούτους μόνους, ἀλλὰ πολὺ μᾶλλον αὐτῶν τοὺς κομίζοντας ἐμπόρους μέμφεσθαι, κᾀκείνων ἔτι μᾶλλον αὐτοὺς τοὺς ῥιζοτόμους μὲν ὀνομαζομένους, οὐδὲνδ’ ἧττον τῶν ῥιζῶν ὀπούς τε καὶ χυλοὺς καὶ καρποὺς, ἄνθη τε καὶ βλάστας ἐκ τῶν ὀρῶν κατακομίζοντας εἰς τὰς πόλεις· οὗτοι γάρ εἰσιν οἱ πρῶτοι πάντων εἰς αὐτὰ πανουργοῦντες.

ὅστις οὖν βούλεται πανταχόθεν βοηθημάτων εὐπορεῖν, ἔμπειρος γενέσθω πάσης μὲν τῆς ἀπὸ τῶν φυτῶν ὕλης, πάσης δὲ τῆς ἀπὸ τῶν ζώων τε καὶ μετάλλων, ὅσα τε γεώδη σώματα χωρὶς μεταλλείας εἰς ἰατρικὴν χρῆσιν ἄγομεν, ὡς διαγινώσκειν αὐτῶν τά τε ἀκριβῆ καὶ τὰ νόθα, καὶ μετὰ τοῦτο γυμνασάσθω κατὰ τὴν ἐμὴν πραγματείαν, ἐν ᾗ περὶ τῆς δυνάμεως ἔγραψα τῶν ἁπλῶν φαρμάκων. εἰ μὴ γὰρ οὕτως παρεσκευασμένος ἥκει πρὸς τὴν ἐκ τῶνδε τῶν ὑπομνημάτων ὠφέλειαν, ἄχρι λόγου μὲν εἴσεται τὴν μέθοδον, ἔργον δ’ οὐδὲν ἄξιον αὐτῆς ἐργάσεται.

φέρε γὰρ αὐτὰ μὲν ἃ προείρηκα περὶ τῶν νευροτρώτων ἐπίστασθαί τινα, δεδολωμένα δὲ φάρμακα δι’ ἄγνοιαν ἐμβάλλειν τοῖς συντιθεμένοις, ἢ μηδὲ τὴν ἀρχὴν ἐπίστασθαι τὰς δυνάμεις ἀκριβῶς αὐτῶν, ἆρα οὐκ ἀναγκαῖον ἔσται πλεονάκις τοῦτον διαμαρτάνειν ἢ κατορθοῦν; ἐμοὶ μὲν καὶ πάνυ δοκεῖ. τὸ δὲ ἀκριβῶς ἐπίστασθαι τὰς δυνάμεις τοῦ μὲν ἐπίστασθαι διαφέρει πάμπολυ. τὸ μὲν γὰρ μόνον ἐπίστασθαι γινώσκειν ἐστὶν, εἰ ξηραίνειν τὸ φάρμακον ἢ ὑγραίνειν ἢ ψύχειν ἢ θερμαίνειν ἡμᾶς πέφυκε. τὸ δ’ ἀκριβῶς ἐπίστασθαι πρὸς τούτῳ καὶ τὸ ποσὸν τῆς δυνάμεώς ἐστιν ἐγνωκέναι. τινὰ μὲν γὰρ φάρμακα δύναμιν ἔχει χλιαρᾶς θερμασίας γεννητικὴν, ὅταν ὁμιλήσῃ τοῖς σώμασιν ἡμῶν, ἔνια δὲ συμμέτρου, καθάπερ ἄλλα βραχὺ ταύτης ἰσχυρότερα, ἕτερα δ’ ἤδη ζεούσης οὕτως ἰσχυρῶς, ὡς καίειν δύνασθαι. χρὴ τοίνυν τὸν ἰατρὸν ἐστοχάσθαι, μὴ μόνον τοῦ ποιοῦ τῆς διαθέσεως, ἀλλὰ καὶ τοῦ κατ’ αὐτὴν ὡς ἂν εἴποι τις ποσοῦ.

λέγεται μὲν γὰρ οὐ πάνυ τι κυρίως τὸ ποσὸν ἐν τῇ ποιότητι. λέγεται δ' οὖν ὅμως, ὅπως καὶ πυρετὸς μέγας καὶ μικρός. καὶ τοσαύτη γε χρῆσίς ἐστι τῶν οὕτω λεγομένων, ὥστ' ἤδη κυρίου δύναμιν ἔχειν αὐτὰ παραπλησίως πυξίδι καὶ χαλκεῖ καὶ ζωγράφῳ καὶ δρυοτόμῳ καὶ συνελόντι φάναι τοῖς ἀρξαμένοις μὲν ἐκ τῆς ὑπὸ τῶν γραμματικῶν ὀνομαζομένης καταχρήσεως, ὕστερον δὲ κυρίοις λέγεσθαι πεπιστευμένοις. ταῦτα μὲν εἴρηταί μοι διὰ τοὺς οὐκ ἐν καιρῷ διαλεκτικευομένους. ὃ δὲ λέγων ἀπέλιπεν ἔστι τοιόνδε, ὅτι τὸ ξηραίνεσθαι δεόμενον οὐχ ἁπλῶς δεῖται τοῦ ξηραίνοντος, ἀλλὰ σὺν τῷ προσήκοντι μέτρῳ.

Galen, On Compound Drugs by Kind (Comp. Med. Gen.) 3.2, 13.570–573 K.