A SEASONAL TIDE OF BLOOD PHOSPHATE IN INFANTS

Abstract

An investigation¹undertaken somewhat more than a year ago showed that in infants the inorganic phosphate of the blood could be raised to the normal level by means of frequent exposures to the sun's rays. It was shown later²that the same result can be accompushed by irradiation with the carbon arc lamp. It seemed probable that this striking phenomenon—chemical equilibrium brought about by the action of light— is due to the ultraviolet, rather than to the visible rays of the spectrum. As a matter of fact, subsequent investigation has confirmed the view that some ultraviolet radiations possess this biologic action, for when they are filtered out from the spectrum the rays lose this power.³As is well known, the composition of the rays of the sun is not at all times the same. There is a marked seasonal variation in its spectrum—in the temperate zone