PhantomXCI wrote:

THE CAT CREEPS, THE GORILLA, THE TERROR and THE CHINESE PARROT are all lost.  They were also all remade as talkies by different companies.  Although I have no proof to back up my theory, I suspect that all of these films were deliberately destroyed by their producers, as a requirement of the purchase of the film rights by competing producers. THE CAT AND THE CANARY survived because it had already been released on 16mm via the Show-at-Home division.
Up until the end of the 30s, the general the Motion Picture Producers and Distributors agreement for properties remade by another studio or producer was that all copyright would transfer to the remake's studio and the original copyright holder was required to destroy all prints in their ownership with the option of retaining a single print for "archival purposes". Some studios and producers saw no value in retaining an archival print for a film property they no longer held rights in, so many silent films transferred under this agreement did not survive if they were not widely distributed non-theatrically. Early talkies transferred under these same industry agreements were better served by their successor studios who saw some value in theatrical reissues. For example, MGM exploited the Frederick March version of Jekyll and Hyde it inherited from Paramount and Warners reissued a code friendly version of A Farewell to Arms after their remake failed. But in these cases the successor studio took control of the original films elements as well as the copyrights. The end of the 30s was the point were the practice was changed to taking control of both stock and copyrights decreasing the instances of original studios left with "worthless" elements to films they could no longer exploit commercially.