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potency of approximately 27 fig. per g. of the original liver powder. The chick thus appears to utilize the substance about four times as efficiently as L. casei, probably because of partial hydrolysis in the intestinal tract. The substance is readily adsorbed by charcoal a t pH 1 but riot a t pH 9 and only partially a t pH 4.5. It is slowly extractable by ether from strongly acid solutions and from preliminai y tests appears to be precipitated by lead acetate. It is stable a t pH 1 for a t least forty-eight hours a t 37 ’, but a sample lost i of its potency on autoclaving in 0 3 .\’ hvrlrocliloric acid for one hour a t 15 pounds pressurr. I t has been iound not only in liver, but also 111 yeast, vitab, cheese and eggs ’The amount present Varies from a trace to more than half of the origind total pantothenic acid activity Atteniptq t o isolatr. the whstanw are iii progress
Synthetic d,Z-a-tocopherol (Merck) was also converted to a solid but amorphous state. This note describes the method of crystallization and certain properties of the crystalline products. a-Tocopherol (0.5 g.) in methyl alcohol (20 cc.) was cooled to -35’ and scratched occasionally with a glass rod. After eight to ten days the tocopherol crystallized in transparent needles, m. p. 2.5-3.5’. The extinction coefficient of the crystals in ethyl alcohol 292 mp = i 1 J was slightly but not significantly lower than that uf uncrystallized a-tocopherol (E:?m 292 mp = 73.7).’ This provides additional evidence of the purity of the latter. Crystalline y-tocopherol, obtained by the same procedure, consisted of clumps of transparent needles which melted a t - 3 to -2’ and had 29% mp = 93.2. Uncrystallized y-tocopherol had E:?m 298 inp = 02.8.i Therefore, the extinction coefficient of y-tocopherol was also DEPARTMENT OF B I O C H E M I ~ I K \ COLLEGE OF AGRICULTLTF michanged significantly by crystallization. I’NIVERSITY O F W I S C ~ N ~ I X A L. NEAL Synthetic a-tocopherol (Merck) was obtained MADISON, A‘ISCONSIS 1’ h’f STRONC. Ktc~rr~ J Ln 19, 194:i
