Robert Campbell
Campbell was born in 1896 and had one shortened arm nearly to the elbow which sported a single finger.
He started in the business in about 1915, and supposedly once travelled with Barnum & Bailey Circus.
In 1925 he was discovered dead in his room in New York City at 133 East 114th Street at age 29, apparently from a suicide, as gas from his stove filled the room when his body was discovered.