Recalls mutual friends, Georges Cuvier and Mary Somerville. Gratitude for JP's kindness in Rome to JH's daughter, Margaret Louisa, now deceased. Asks JP to assist newlyweds David and Mary Power, who are caught in Rome by David's failing health and need advice on medical treatment. [Annotation by Constance Anne (Herschel) Lubbock identifies couple as David Power and bride Mary Lipscompe. David died soon after, and his widow married JH's son John.]