Note 78 — ARRIAN ON COURSING.
William Dansey translation
The ancients cleansed their hands with the soft crumb of bread after meals, and threw it to their dogs. These pieces of bread were called ἀπομαγδαλίαι: the μειλίγματα of the Homeric simile:
Homer. Odyss. x. 216.
ὡς δ’ ὅταν ἀμφὶ ἄνακτα κύνες δαίτηθεν ἰόντα σαίνωσ’, (αἰεὶ γάρ τε φέρει μειλίγματα θυμοῦ).
Hence probably Juvenal’s “sordes farris mordere canini.”