Ok I need help from a science fiction buff, on the name and author of this short story. There is a rat and scientist on an island, the story is written like a diary or journal, the scientist is found dead... and the reader discovers at the end that the rat wrote the journal entries. The rat was getting smarter and smarter each day. I think this short story was written before 1977 and was by a major writer. If you can help me solve this-- I would be forever greatful and might consider transfering 1 million dollars to your paypal account.