The Effect of Light on Creatinine and Creatine Excretion and Basal Metabolism.*

Thus far, Hoogenhuyze and Best (1) have been the only investigators foundwho haveworked on the influence of light on the formation of creatinine. The light which they used was from 88 incandescent lamps of 16 candle power each, placed along the four sides of a wooden cabinet lined with zinc. The subject was placed in the cabinet for $ hour with only his head out of the opening at the top. The temperature of the interior of the cabinet, whenclosed, variedfrom40-50°C. but could bereducedto35” or 36°C. by opening one of the sides and fanning the air vigorously. Light exposures for ?J hour with and without heat increased the creatinine excretion, but when the light was intercepted by sheets of asbestos, the temperature remaining the same, the creatinine was either not increased at all or increased to only a slight extent. Averages of their figures show an excretion before light exposure of 1.488 gm. of creatinine, apparently for the 24 hours, as compared with 1.767 gm. with light at a temperature of 50°C. Without light, but with the same temperature, 5O”C., the excretion became 1.550 gm. per 24 houn’s as against 1.807 gm. with cooled light. It is to be regretted that they did not give more details of their work. In the above experiments the whole body was exposed to the light rays, but later these same workers sought to find whether there was any influence