Sufficient data are now available to show conclusively that irradiation with ultraviolet light is of positive benefit in the treatment of rickets. Frequently it is desirable to use sunlight as a source of ultraviolet rays, but in winter months, in this latitude, it is often necessary to use sunlight that has passed through glass. Accordingly, an investigation was undertaken to determine the extent to which ultraviolet light passed through different types of glass readily obtainable on the open market. The investigation was conducted along two lines: A study was made with rachitic children to determine the therapeutic value of sunlight that passed through different types of glass, and a second study was made with albino rats to secure additional data concerning the pathologic condition of the bones and their mineral content.
The results obtained by treating rachitic children with sunlight which had passed through different types of glass formed the