Rickets in Chicks

In 1923 Hart, Steenbock, Lepkovsky and Halpin1 reported that leg weakness in chicks was prevented by exposure to direct sunshine. The following year Murry, Little and Bovie2 obtained similar results by exposing chicks to the rays of a quartz mercury vapor arc. Hart stated in his report “from the limited data it appears that ½ hour’s daily exposure to direct sunlight was much more potent in furnishing the antirachitic equivalent than was 5 per cent of a synthetic ration fed as fresh green clover, calculated upon the basis of the dry weight of the clover.” Murry, Little and Bovie concluded as a result of Roentgen ray examination that “the leg bones of chickens treated by 15 minutes exposure daily to ultraviolet light are more mature than the leg bones of the chickens * * * * which were permitted to run out-of-doors in the sunlight.” These results were soon substantiated . . .