Hair Of The Dog Meaning

Example : 1818, Sir Walter Scott, Rob Roy, ch. 12:  But with the morning cool repentance came. I felt, in the keenest manner, the violence and absurdity of my conduct, and was obliged to confess that wine and passion had lowered my intellects. . . . I descended to the breakfast hall, like a criminal to receive sentence. . . . [H]e poured out a large bumper of brandy, exhorting me to swallow "a hair of the dog that had bit me."1841, Charles Dickens, Barnaby Rudge, ch. 52:  Ha ha! Put a good face upon it, and drink again. Another hair of the dog that bit you, captain!