Night Variations,” Radio Review, Aug. 1921; B. Van Der Pol, Jr., ‘ Over Electronenbewe- gungen in Trioden,” Physica, vol. 3, pt. 2 (1923). (3) W. E. Castle, Genetics and E. Griffiths (Pail. Trans., A, vol. 100, p. 555. 1037 tions of this spring to a terri- ble plague of typhus. In Sept. 1915 a new one. With increasing definiteness the Rockefeller Institute, New York, which at the end his