Feature

Malaria-Carrying Mosquito Now Being Battled in Brazil

Nature Ramblings: Bird Control

New World’s First Conquest Wars Were in Greenland

Sex Hormone Treatments Replacing Youth Operation

Double Blessed Event More Likely for Older Fathers

Derivative of Castor Oil Now Used in Fly Spray

Front Matter

New Electron Microscope May Some Day “See” Atoms

Franklin Medals Awarded to Compton and Baekeland

Germ-Killers in Soil Promise Conquest of All Bacteria

National Academy of Sciences 1940

Science Most International of All Human Activities