The Effect of a Small Dose of Roentgen Rays upon the Human Body as Revealed by the Method of Electric Flicker

The method of electric flicker which is serviceable for measuring the effect of oxygen lack and fatigue was shown to be useful for detection of the effect of a small dose of Roentgen rays, too. 1. The threshold value of Roentgen rays to produce a noticeable increase of the electric flicker value was within a range from 0.1 to 0.4 r. 2. The effect of a Roentgen irradiation appeared with a latency of a few minutes, and attained a maximum in about 20-30 minutes to dis-appear in about 50 minutes. 3. As no sensation of light was elicited by such a small dose of Roentgen rays in a light-adapted state of the retina, the phenomenon under consideration is not a secondary effect of visual excitation. 4. When any other parts of the body were exposed to Roentgen rays of higher doses, a very slight effect, if any, could be observed, and this effect could be accounted for in terms of the direct effect of scattered Roentgen rays upon the eyes.