Vaudeville became the home of jugglers in the early 1900's. The circus was another popular site for jugglers to perform. Because they no longer had to be a one man show, they were able to specialize and their tricks became more complex.
This is a picture of Bobby May, known as "America's Greatest Juggler". He performed during the 20's and 30's, and could bounce-juggle 5 balls while balanced on his head!