(St.). Patron of those afflicted with the plague, because he devoted his life to their service, and is said to intercede for them in his exaltation. He is depicted in a pilgrim's habit, lifting his dress to display a plague-spot on his thigh, which an angel is touching that he may cure it. Sometimes he is accompanied by a dog bringing bread in his month, in allusion to the legend that a hound brought him bread daily while he was perishing in a forest of pestilence.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894