A species of earth of a yellowish-grey colour, found in the island of Lemnos, said to cure the bites of serpents and other wounds. It was called terra sigillata, because it was sealed by the priest before being vended. Philoctetes was left at Lemnos when wounded in the foot by Hercules.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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