Just a thought -- Justin Kaplan, author of the great biography Mr. Clemens and Mark Twain, is I believe married to writer Anne Bernays. She is the grandniece of Sigmund Freud. I do not know how to contact Mr. Kaplan, except perhaps through his publisher. I'm thinking that he lives in Cambridge, Massachusetts. But it would not be a surprise to me if he came across whatever material there is concerning Freud and Twain as he did the research for his book. I would also imagine he would have more than a passing interest in exploring it as well, if for no other reason than the family connection. But that's only a supposition on my part. Good luck in your search! Roger Durrett