With their pulses beating wildly and hearts thumping in accord, they watched the hazy streak on the horizon line ahead rapidly develop into the unmistakable rugged form of land.  As they drew closer, they could even see the glint of water on the other side, and knew without the shadow of doubt that what they were looking at was the long belt of earth connecting the two Americas--the Isthmus of Panama itself.  And down their backs ran a new thrill at the recognition.