Nessus, a Centaur who, for attempting to carry off Dejanira, Hercules' wife, was shot by Hercules with an arrow dipped in the blood of the Hydra (q.v.), and who in dying handed to Dejanira his mantle, dipped in his poisoned blood, as a charm to regain her husband's affections should he at any time prove unfaithful. See Hercules.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Nesselrode, Count von * Nessus' Shirt