The belief that sunlight exerts a beneficial effect on health is at present exceedingly popular. Its general endorsement by the public is visible during the summer months at the beaches and summer resorts. The growing tendency to continue "sun bathing" throughout the year is indicated by the increasing numbers of "sun lamps" available on the open market and the rather large numbers of these devices purchased by the American people for use in their homes. But what is the scientific knowledge regarding the effects of sunlight and of ultraviolet rays on health? Does such information indicate a need for excessive basking in the sun's rays or does it suggest that this practice is unnecessary or perhaps even undesirable? Laurens1 has recently reviewed the available knowledge in this field.
First, which of the sun's rays actually pass through the outer layer of the skin into the deeper strata? Studies have