A Further Report on Imparting Antirachitic Properties to Inert Substances by Ultra- Violet Irradiation

In a series of communications (1) we have reported experiments which show that antirachitic properties can be imparted to various inert fluids by means of ultra-violet irradiations. In the first report, presented in June, it was recorded that this held true for vegetable oils, such as cottonseed oil. Subsequent to irradiation 0.1 cc. of this oil was sufficient to protect young rats which had been fed on a low phosphorus rickets-producing diet. Later it was found that the same effect could be brought about in growing wheat or in green lettuce leaves-vegetables which possess insignificant protective qualities when they have not been irradiated. Similar results have been reported by Steenbock (2) and his collaborators in regard to vegetable oils and other foods. These investigators used the growth-promoting and bone-calcifying properties of the irradiated food as a criterion of rickets. If growth was brought about on a diet which was complete in all respects excepting for the antirachitic factor it was assumed that the food under investigation possessed antirachitic properties. Throughout our investigations we have taken roentgenologic pictures of the epiphyses and made histologic examinations of the bones, and based our conclusions on these examinations. Since publishing these reports our investigation has been extended in various directions. It has been found that green wheat which had been irradiated was able to retain its antirachitic power even after it had been stored at ordinary room temperature for a period of 2 weeks. When rats were given 10