Abstract
The distribution of vitamins A1 and A2 has been determined in the eye tissues and livers of a number of fishes. The vitamins were differentiated by means of the antimony chloride reaction, which yields with A1 a band at 615–620 mµ and with A2 a band at about 696 mµ. In the retina the presence of vitamin A1 is diagnostic of the operation of a rhodopsin, and vitamin A2 of a porphyropsin cycle.