Swan realized this and looked wearily across the swamp they had just covered. It was all his work. A narrow mound of solid earth ran back as far as eye could reach, and on it two shining steel rails glittered in the blazing sun. On either side lay wet, poisonous ground covered with deadly growths and exuding fearful odors and devitalizing forces which even the heat could not dissipate. In that noonday light which burned and burned and made no impression on the moisture, Swan's face was wilted like a white flower which is dead and turning yellow. His eyes, too, were like things once living and now dead. The muscles around his mouth twitched like electric wire. "It isn't possible for me to finish it alone," he told himself. He knew that he could finish the job by working both night and day, but could he stand the strain? Had he, after all, a stronger physique than any other white man had ever had before? He leaned far back as if he were trying to fold himself up, and then bent forward in the same manner, trying, with a desperation like death, to relieve the weakness that was numbing his limbs. He suddenly felt dizzy as he looked at the hot distance where some big leaves were waving--dizzy as he knew that he must fail. "By God!" he exclaimed, striking the pile of dirt. "By God! I'll do it!" Pilchard put on his hat and smiled. He had been waiting for this. "If you say you will, I bet you will!" he told Swan. "That's why you'll always come out ahead." As he said this he looked intently at Swan, who was still sitting on the pile of dirt. He noticed for the first time the peculiar look in his eyes and the trembling of his whole body. Swan sat silent. He saw the dark perspiring bodies of the Indians who were laying ties, and his lifelong ambition to be a great engineer suddenly presented itself to him in the old strong unemotional way. "For science is a cruel mistress. She exacts her yearly tribute of flesh and blood like the dragons of ancient pagan mythology." This had been said by an eminent scientist who had addressed his graduating class. Swan had heard it then and remembered it now. He clearly remembered that hot June morning ten years ago. Some young maple leaves had made a lovely pattern on the blue northern sky outside the uncurtained windows of the lecture-hall. He remembered that he had looked through the window and vowed that he would never give up.