TIME Magazine content is available exclusively for TIME subscribers.

Current subscribers for full access. Not a TIME subscriber? .

JONAS SALK: Virologist

How many cases make an epidemic? Survivors of the great polio plagues of the 1940s and '50s will never believe that in the U.S. the average toll in those years was "only" 1 victim out of every 5,000 people. Was that really all it took to scare the nation out of its wits, sending families scurrying in all directions--to the mountains, to the desert, to Europe--in vain hope of sanctuary.

Perhaps polio's other name, infantile paralysis, had something to do with it. Images of babies in wheelchairs and tots on crutches tend to skew one's perception. And just in case...

Time.com on Digg

POWERED BY digg

For use in rail of Articles page or Section Fronts pages. Duplicate and change name as necesssary to distinguish.