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The Evolution of the Physicist's Picture of Nature

An account of how physical theory has developed in the past and how, in the light of this development, it can perhaps be expected to develop in the future

By P. A. M. Dirac

Moiré Patterns

They are produced when figures with periodic rulings are made to overlap. A study of their basic properties reveals that they can illuminate many problems of scientific interest

By Gerald Oster and Yasunori Nishijima

The Lysosome

This small particle acts as the digestive tract of the living cell. Its enzymes dissolve the substances ingested by the cell and under certain circumstances can dissolve the cell itself

By Christian de Duve

Radiation Belts

It has been five years since these rings of trapped particles were discovered. Presenting a review of present knowledge of the belts, with special reference to particles injected by nuclear explosions

By Brian J. O'Brien


A pheromone is a substance secreted by an animal that influences the behavior of other animals of the same species. Recent studies indicate that such chemical communication is surprisingly common

By Edward O. Wilson

Early Man in the Andes

A rich assemblage of obsidian tools has been discovered at El Inga, high in the mountains of Ecuador. It may provide a Long-sought link between the prehistoric men of the U.S. and those of South America

By William J. Mayer-Oakes

The Measurement of Motivation

A basic human attribute that has long resisted investigation can now be measured with the help of a simple device. The key to the measured with is what happens when the subject is given a short rest

By H. J. Eysenek

The Cultivation of Tilapia

This prolific fish has been introduced into many less developed areas as a cheap source of protein-rich human food. A new method for making it grow larger in ponds may enhance its usefulness

By Charles F. Hickling


  • 50 and 100 Years Ago: May 1963

  • Science and the Citizen: May 1963

  • Letters

    Letters to the Editors, May 1963

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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Introducing Scientific American Health & Medicine

Introducing Scientific American Health & Medicine