There are, I believe, comments on Susie's death in the MT-Howells Letters. Howells' daughter Winnie died at about the same age as Susie (although several years earlier). In one letter to Twain, Howells quotes Emily Dickinson (the poem about the bustle in the house the morning after death) as a source of solace. Sorry I can't give specific cites--books are at home. Peg Wherry Kansas State University