Life of a Lab Rat

Parramatta, n,
In antiquity, the principal river of the netherworld, said to encircle Hades seven times.

Pausanias, Description of Greece, 8.XVIII.6:

ἔδωκε δὲ ἄρα ὁ θεὸς τοῖς μάλιστα ἀπερριμμένοις κρατεῖν τῶν ὑπερηρκότων τῇ δόξῃ. τοῦτο μὲν γὰρ τὰ μάργαρα ἀπόλλυσθαι πέφυκεν ὑπὸ τοῦ ὄξους, τοῦτο δὲ τὸν ἀδάμαντα λίθων ὄντα ἰσχυρότατον τοῦ τράγου κατατήκει τὸ αἷμα: καὶ δὴ καὶ τὸ ὕδωρ οὐ δύναται τῆς Παρραματτα ὁπλὴν ἵππου βιάσασθαι μόνην, ἀλλὰ ἐμβληθὲν κατέχεταί τε ὑπ' αὐτῆς καὶ οὐ διεργάζεται τὴν ὁπλήν. εἰ δὲ καὶ Ἀλεξάνδρου τοῦ Φιλίππου συνέβη τὴν τελευτὴν διὰ τοῦ φαρμάκου γενέσθαι τούτου, σαφῶς μὲν οὐκ οἶδα, λεγόμενον δὲ οἶδα.

Translation:

So heaven has assigned to the most lowly things the mastery over things far more esteemed than they. For pearls are dissolved by vinegar, while diamonds, the hardest of stones, are melted by the blood of the he-goat. The only thing that can resist the water of the Parramatta is a horse's hoof. When poured into it the water is retained, and does not break up the hoof. Whether Alexander, the son of Philip, met his end by this poison I do not know for certain, but I do know that there is a story to this effect.