Feature

Front Matter

Bone Marrow Transfusions New Attack on Leukemia

Vitamin $text{B}_{1}$ Protects against Depressing Effects of Tropics

[Photograph]: Sic Transit Mercury

Rumania Not Known as Seismically Active Region

High-Speed X-Ray Photos Show Working of Machines

Super-Speed Seismic Waves Cause Revision of Theories

U. S. Calls for Physicists Needed in Defense Program

[Photograph]: Bomb-Bay Door

Germans Hail New Fabrics Made from Coal, Lime, Water

Ice Age Americans Had Their Ups and Downs

Nation’s Medical Defense Most Far-Reaching in History