Film historian Jonathan Froes has uploaded this trailer for the 1939 Universal monsters classic "Son of Frankenstein". According to Indiewire, this particular trailer was thought to be lost due to the fact that it shot on nitrate film. That film stock proved to be highly flammable, causing studios to ends its use and destroy countless prints of feature films and trailers. Indiewire says that horror film enthusiasts consider this to be a real find because it contains alternate takes and snippets of scenes not included in the final cut of the film, which featured a stellar cast: Basil Rathbone, Boris Karloff, Bela Lugosi and Lionel Atwill. For more click here