“If a dog bites a man,” editors used to instruct cub reporters, “that’s an ordinary occurrence. But when a man bites a dog, that’s news.” The advice and the saying man bites dog can be traced back to Oliver Goldsmith’s poem “Elegy on the Death of a Mad Dog,” about a dog that “went mad and bit a man,“ which concludes with the lines:
The man recover’d of the bite,
The dog it was that died.
According to Eric Partridge, this touching poem passed into
folklore in a number of versions, possibly including a funny one where a man did
bite a dog, and finally became the journalistic advice.