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 anyone wasn’t scared enough, the National Foundation for Infantile Paralysis hammered the nightmare home with photos that seemed to show up everywhere of sad-looking children in leg braces. “Please give to the March of Dimes.” Oh yes, indeed, five times at the same movie–or so it sometimes felt. It was inevitable that whoever was first to allay such fears would become a national hero. “The Man Who Saved the Children” should be good for a statue in every town in the world. And since the odds of a microbiologist’s becoming even a little bit famous are a lot worse than 5,000 to 1, it was perhaps inevitable that this hero’s achievements would immediately be disputed. In a scientific field so heavily manned, findings routinely crisscross and even minor discoveries can leave a trail of claims and counterclaims, not to mention envy and acrimony, that are truly incurable. Thus a monument to the conquest of polio faithful to the facts would consist of not one man in a white lab coat but two of them glaring at each other. Both Drs. Jonas Salk and Albert Sabin could and did make convincing cases for themselves and pretty good ones against each other too. But since the public usually prefers one hero to two, and since Salk did get there first, he got the monument. Between occasional shouts of “Eureka!” even the heroes of science tend to have quiet careers. But Salk’s career stands out in at least two respects: the sheer speed with which he outraced all the other tortoises in the field and the honors he did not receive for doing so. How could the Man Who Saved the Children be denied a Nobel Prize? Or summarily be turned down for membership in the National Academy of Sciences? What was it about Salk that so annoyed his fellow scientists? That he was fast, there was no doubt. And hungry too. After taking brilliant advantage of the amazing public education available to New Yorkers in the first half of this century, this son of Orthodox Polish-Jewish immigrants whizzed through his medical training to fetch up at the University of Michigan an enviable fellowship to study virology under the distinguished Dr. Thomas Francis–who, incidentally, would remain in Salk’s corner for life, politics or no politics. Salk’s major patron at Michigan, however, proved to be no one man but the whole U.S. Army, which needed a flu vaccine at once to help win World War II and was happy to complete Salk’s education in speed under pressure. After that, it was a snap for him to set up his own peacetime lab at the University of Pittsburgh and equip it to the gills for the Great Crusade–the one that every immunologist in the world then had his eye on–against the Great White Whale itself, poliomyelitis.