Abstract
That skeletal muscle may vary in color, not only from species to species but within the same animal, has long been known. (1) In 1865, Kuhne (2) examined extracts of blood-free muscle and observed that the extract from the pale muscle was colorless, that from the dark muscle was red. He examined the absorption spectra of the red extract, and of thin strips of red muscle, and concluded that the pigment was hemoglobin. | Later, Lankester (3) suggested that red pigmentation is found in muscles from which the most persistent and prolonged activity is required. A general survey of the animal kingdom bears out this view; in lower animals, nearly all the muscles (except the constantly acting heart which is always pigmented) are colorless, but in mammals all the muscles except a few are red. Ranvier (4) in 1873, was the first to bring definite experimental evidence of the different behaviour of the two types of muscle. He showed that a higher rate of stimulation was necessary to produce a smooth continuous contraction with white muscle than with red. He inferred that the twitch movement was a slower process in the red muscle than in the white.