News just in.... from Legislature of the Province of Ontario 1908 vol 5
"And here I would say that I am indebted for the most of the information that I can give, respecting Bertolotto and his Fleas, to D. Jewell, Esq., broker, who was intimately acquainted with Bertolotto, Lt. Col, Gray of H. M. Customs, who was a member of the Stadacona Club during the time of Bertolotto's stewardship, and the Rev. E. A. W. King, M.A., Rector of St Peter's who witnessed on of Bertolotto's exhibitions in Boston. Mass."
This is another tantalising snippet that I found from google books when searching for "exhibit of trained fleas", I'll try to track down if there is more of this article. Apparently my nearest copies are in the USA or Canada.