<span>Mr.Nuttel is staying in the country in order to take a "rest cure." He is suffering from a nervous disorder and, as he tells Mrs. Sappleton, "The doctors agree in ordering me complete rest, an absence of mental excitement, and avoidance of anything in that can exhaust him.</span>
If this is from "The Bet", then it would have been because the lawyer is writing this as a final notice before his escape.
