Chemistry, and General Chemistry, University of

rations of radio-active materials, so it seems desirable to take the opportunity of studying their action on vitamins. A number of workers have studied the action of rays of short wave length on these substances, and it is clear that at least one of them, vitamin A, is quite labile. Ziiva (1) exposed milk fat to the rays from a quartz mercury arc, and ob served that it was bleached, acquired the odor of tallow, and became un palatable. Vitamin A was destroyed. In a later study (2) he concluded the destruction of the vitamin was due to ozone, for if the exposure were con ducted in an atmosphere of carbon dioxide there was no loss of vitamin activity. Spinka (3) subjected milk to a similar procedure, and concluded that toxic substances developed which killed the experimental animals, but vitamin A was not destroyed. Zilva (4) remained convinced, however, that in his experiments destruction of the vitamin had occurred. Titus, Hughes, Hinshaw, and Fitch (5) exposed milk to the rays of a quartz-mercury arc, and observed destruction of vitamin A. Supplee and Dow (6) irradiated milk for very short periods, a few seconds up to 3 J ^ minutes, but were not able to detect any destruction of the vitamin. Steenbock and Coward (7) regarded vitamin A as remarkably stable to ultra-violet rays. The effect of rays of still greater frequency has apparently received little attention. As to the effect of rays of short wave length on the water-soluble vita mins there is at present no unanimity of opinion. Hogan and Hunter (8) reviewed the earlier literature on this topic, and reported that one of the factors in the vitamin B complex, stable to heat, is destroyed by ultra violet irradiation. No attempt was made to determine whether the de struction was complete, or whether partial destruction of other factors occurred. Chick and Roscoe (9) confirmed this report in its essentials, an