The amount of solar ultraviolet radiation at a given point on the earth's surface is dependent on its geographic location and on certain climatic and physical variables. It has been demonstrated that vitamin D is created in the human or the animal body when the skin is exposed to ultraviolet radiation, either solar or artificial.1 Several investigators have reported that children's resistance to dental caries is increased when they are fed vitamin D.2 McBeath and Zucker2e and Erpf3 have reported that there is a seasonable rhythm in the incidence of caries. They found that the greatest freedom from new caries was in summer, when the most solar ultraviolet energy was available. Summer is also the season when the temperature permits the greatest exposure of the skin to sunshine.
In the study by McBeath and Zucker2e the experimental group of children were exposed to artificial ultraviolet