In April, an epidemic of influenza exploded in the Far East. Starting in Hong Kong, it spread thousands of miles in all directions in less than two months. As we watch it spread, we ask ourselves: Will this epidemic burn itself out—or is it the forerunner of a worldwide plague which may kill millions of people before it dies away?

Influenza, a disease of the respiratory tract, is spread from person to person by direct contact, through breathing, coughing, speaking, and sneezing. It is so highly infectious that many thousands of persons in a city may be attacked at…