Feature

Artificial Radioelements for Medicine

Complete Huge Disc Intended for 200-Inch Telescope

Thymus Gland Treatment Hastens Growth of Rats

Front Matter

Annihilation of Matter Seen as Cause of Cosmic Rays

Study Electricity on Germs for New Light on Disease

Chromosome Structure Details Described by Russian

Scientists Study a Wingless Rooster

First Glances at New Books

In Science Fields

[Photograph]: Pavlov in His Laboratory

Nature Ramblings: On Their Own Roots