Vitamin A determination, Relation between the biological, chemical, and physical methods of test. K. C. Lathbury. Biochem. Jour., Vol. 28, 1934, p. 2254.

This investigation, conducted in the Physiological Laboratories of The British Drug Houses, Ltd., was undertaken because of doubt cast by some investigators, notaby Coward et al, on the value of the Carr-Price color test, which is used by the British Drug Houses in describing the potency of their products. Six samples of crude liver oils or concentrates and a sample of the international standard were compared for their content of vitamin A by feeding experiments on rats, the Carr-Price test, and the spectrophotometric test.