Unlike the character he's portraying (Constable Crabtree), actor Jonny Harris is actually a popular, successful comedian.
The real W.C. Fields was 23 years old in 1902, when this episode takes place, and though his great fame as a comedian was still ahead of him, he was already a renowned juggler, and not at all the struggling and barely competent unknown this episode depicts. From the age of 19, in fact, he regularly billed himself as "the world's greatest juggler", and was very prominent in American vaudeville circles.
This episode takes place in 1902.