The primary amino acid deficiency of sesame protein is lysine, Almquist and Grau (1944). Casein, gelatin and zein were tested for lysine content by feeding as supplements to a sesame meal ration by Grau and Almquist (1944). Good growth was obtained by feeding casein or gelatin while zein, a protein deficient in lysine, gave only a small response. The feeding of 0.5 percent lysine gave a rate of gain per day which was similar to the gain made by the casein supplemented group.The White Leghorn chicks used during the experiments conducted by Almquist and Grau (1944) and Grau and Almquist (1944) were fed a practical ration during the first 10 days of their life after which they were fed the lysine deficient sesame meal ration. The possibility of this 10 day conditioning period on the practical ration in supplying certain growth promoting factor (s) in amounts which could have …