1. Jacques Barzun, Romanticism and the Modern Ego (Boston, Little, Brown & Co., 1944), pp. 76-7.
2. Herbert Collins, 'The Fabulous Races' in E. T. Thompson and E. C. Hughes (eds.), Race: Individual and Collective Behavior (New York, Free Press of Glencoe, 1965), pp. 238-243.
3. Charles C. Gillispie, Genesis and Geology (New York, Harper, 1959), passim. Jean Rostand, 'The Development of Biology' in G. Métraux and F. Crouzet, The Nineteenth-Century World (New York, Mentor, 1963 ), pp. 177-192.