The many studies on the relation between the intensity of radiation and the magnitude of the biological reaction indicate that in a majority of cases high intensities and brief exposures are more effective than low intensities and correspondingly long exposures; and that single doses are more effective from the biological point of view than divided doses. The opinion is sometimes expressed or implied that experimental results which point to an opposite conclusion are probably wrong. In the literature, reviewed by Griffith and Zimmer (7) Pack and Quimby (16), and Schreiber (20), may be found many instances of experiments in which the same test objects and technic were used and yet the results were contradictory. Ascaris eggs, exposed in air, are reported to be less affected by divided doses than by a single massive dose (13, 8), and again to be more affected (23). Exposed in an atmosphere deprived of its oxygen, these eggs show a simple cumulative effect of repeated doses (8); that this treatment may produce a greater reaction than that which follows a single dose is also claimed (11).