Among the bronzed, broad-shouldered young men who turned up for the National A.A.U. swimming championships in Seattle last week, slender, mild-mannered John Birnie Marshall was easy to overlook. But there was no missing Australian-born John Marshall when he uncoiled for the mile race. For 20 minutes, the biggest splash in U.S. swimming since Johnny Weissmuller had spectators, officials and competitors watching hardly anybody else.
Churning through the water with the ease of a porpoise, Marshall soon left most of the others well behind. Lap after lap, over the 55-yd. pool, he kept reaching for the water, hand open and fingers outstretched like...