The almost universal use of roentgen-ray therapy has prompted numerous chemical examinations of the blood with the purpose of demonstrating any regular changes induced by such treatment and especially with the hope of establishing some variation that might serve to explain the roentgen-ray sickness so frequently observed in patients following treatment. Hall and Whipple1have reviewed the various theories advanced to explain this roentgen-ray illness, but few of them have a substantial scientific basis and some are quite hypothetic. Lange2suggests that roentgenray sickness results from an acidosis caused by cellular degeneration or from increased catabolic cellular activity. The work of Denis, Aldrich and Martin3supports this idea, for they observed an acidosis in rabbits, when some portion of the intestinal canal is included within the irradiated area. Golden,4from observations on patients treated and on dogs exposed experimentally to roentgen rays, finds no diminution of