What is the orgin of the saying His name is mud?

There's an old story Dr. Samuel Mudd pitied John Wilkes Booth, who killed Abraham Lincoln. Mudd treated the broken ankle Booth suffered during his jump to the stage of Ford's Theater. Mud was later sentenced to life in federal prison. But Mudd isn't meant in "his name is mud." It first appeared in print in 1820, 45 years before Lincoln's death. Mud was English slang: an eighteenth century equivalent of "dope" or "dolt" and was used through the 1800s by union workers as a rough synonym of "scab." Hope that helped.