35 Remark by an SS leader at the Ordensburg Vogelsang in autumn 1937; quoted by Kogon, The Theory and Practice of Hell. See also Himmler's remarks on the Waffen SS reported by Kersten, Memoirs, which also contain numerous general principles and basic rules of selection. On the double function of the SS see also Reinhard Heydrich, Wandlungen unseres Kampfes (Munich, 1935).