Antirachitic Value of Winter Sunlight in the Latitude of 42° 21' (Boston)

Abstract

Authoritative data show conclusively that irradiation with ultraviolet light is of definite beneficial effect in preventing and in curing rickets. The antirachitic range of the solar spectrum, the wave lengths influencing the deposition of calcium in rickets, is from 290 to 313 millimicrons. That the ultraviolet rays of the sun's spectrum cannot be depended on, however, either to cure or to prevent the development of rickets in all latitudes and at all seasons of the year has also been established, as they vary in intensity during the different seasons of the year, the intensity being highest during the summer months and lowest during the winter months. The ultraviolet rays vary in intensity according to the geographic location, being more intense in the torrid zone than in the temperate zone and at high altitudes than at sea level. The intensity of the short rays is to a large extent dependent on the amount of moisture and dust particles in the air.In the latitude of 42°21' (Boston) under the usual winter condi¬ tions of housing and climate, the direct radiations which reach the growing baby, especially when properly clothed, do not suffice to prevent the development of rickets. On account of the cold and consequent loss of body heat during the winter months, direct exposure of naked infants to the sun's rays is not a practical or safe measure in the prevention or cure of this disease.One of the agents which has received attention in the prevention of rickets in the winter has been the ultraviolet transmitting glass. The types of ultraviolet transmitting glasses which have been more frequently used for this purpose are fused quartz glass, Vitaglass and Helioglass. Window panes made from fused quartz transmit ultraviolet light better than any other known product. The cost of producing it, however,

Skeleton of a Century

“…7 Ironically, the earliest English reference to rickets appeared exactly 300 years previously, in the Parish Clerk's Company Bill of Mortality of 1634. 26 Irradiation of foodstuffs, pioneered at the University of Wisconsin by Harry Steenbock in 1923, became the widely preferred method of treatment and prophylaxis. 9,10 The study of rickets was equally at the heart of a great success story of American pediatrics.…”