"under the wisely altered name of Boris Karloff"

Boris Karloff (1887-1969) emigrated to Canada in the 1910s and is best known for playing Frankenstein's monster in Frankenstein (1931), Bride of Frankenstein (1935) and Son of Frankenstein (1939).  Born in London, he attended both Uppingham and the Merchant Taylors' School. He was successful as an actor despite his lisp.