“…Richter (29) developed a method based on the refractive index of the fat extract. This avenue of approach has been followed by Wesson (34), Coleman and Fellows (6), Demikovskil (7), Ermakov (8), Basse and Bake (13), Leithe (22), Leithe and Heinz (23), Bielefeldt (4), Stanley (32), and Brüchner (5).…”