Professor Cielo Allenson, better known at the Military Academy as the "Old Guard," was a venerable man past seventy. He had a highly intellectual countenance and his silvery white hair and patriarchal beard gave him a noble dignity which commanded respect. His strenuous virility and inexhaustible energy was ever a lesson and a rebuke to the many indolent youths who came in contact with him. He was a philosopher of the first rank and an intense lover of nature. Imbued with the deeper knowledge of the subtle workings of natural phenomena, "he could not draw a line," he would say, "between the manifestations of human, animal and vegetable kingdoms." "Halt you d----d old cur! I demand no apology, but satisfaction," snarled Don Seville abruptly, his face livid with anger. For a second the Professor was taken aback. But in that very second, through his intuitive and resourceful mind flashed the fact that he was "cornered." He was not a man easily frightened, for as a Major of Volunteers during the Panama and Columbian trouble, and while in his teens, he had led on his handful of men up the hills against the ramparts of the enemy. But a problem which required instantaneous solution was now presented to him by Carlos Don Seville. It was a problem which neither diplomacy, moral persuasion nor flight of oratory could solve. He realized in that very second that the only way out of this difficulty was to take the coward at his word. It was to be a fistic encounter to the finish. "Apology, I have none to offer you sir, and am ready to give you such satisfaction as you desire," replied the old man with a dignified firmness. A remarkable change had taken place in the person of Cielo Allenson. That venerable and spirituelle individual had been transformed in a twinkling of an eye, into a grim and determined looking animal, and like an expert gladiator of the fistic arena, he took the attitude of self-defense. The "ring" constituted the platform of the wooden bridge, the side rails of which served as the partial ropes. There were no seconds to goad their favorites into action, no referee to decide the doubtful or unlawful blows, no gong to mark the rounds, nor time-keeper to count the defeated out of action. In the languorous glow of the twilight their shadows, reflected in black silhouettes in the placid waters below, were the only silent witnesses of this remarkable encounter.