Many of Kaufmann's clients used his services as a guide on repeated occasions. Freeman Allen (1870-1930), for example, climbed with Kaufmann in the Canadian Rockies (e.g., Mt. Victoria), the Bernese Oberland (e.g., Jungfrau and Mönch in June1908, with Christian's brother Fritz Kaufmann), and the seven weeks (from June 20 to August 10, 1909) in the Valais, ascending 9 peaks, including Monte Rosa, Lyskamm, and Aigille du Grépon. Allen, grandson of Harriet Beecher Stowe, was one of the foremost authorities on the use of anesthetics and worked in Cuba with General Leonard Wood on the causes and prevention of yellow fever. J. Duke Smith, a fellow Alpine enthusiast from Boston, often join Allen and Kaufmann (e.g., Matterhorn, Rothorn, and the High-level Route from Chamonix to Zermatt). He comments that whatever I have learned about the mountains I owe to Christian. The Sanders family—Harry, Jack, Cathi, and Helen—from London made rigorous climbs with Kaufmann in 1908 and 1909. On June 26, 1908, Ethel Reddan (Hampstead, London), a member of the Ladies Alpine Club, climbed the Wetterhorn as well as the Little and Big Schreckhorn with Kaufmann.