He could not signal his approach to the sentinel, for he did not know what the signal was. But he had devised a way of surmounting this difficulty. As he came within hearing of the Navaho on guard, he began the utterance of heavy groans, and followed them with the motions of a person in a state of great bodily weakness. The sentinel heard the groans, and, springing to his feet, cocked his gun and waited for he knew not what. Soon a staggering form was outlined between the tree shadows. The sentinel let out a hissing sound, followed by the terrified squeak of a doomed squirrel. Buffalo Bill, in his disguise, did not answer in kind. He might make a mistake, and the mistake would be a fatal one. Instead, he redoubled his groans, giving to them the deeply guttural tones of the dead Crow-killer. The sentinel’s suspicions, if he had any, were dispelled. He stepped forward, and said in Navaho: “The great warrior of the Navahos, the brother of the favorite of the Great Spirit, Raven Feather, is in pain. Where is the pain?” “Here.” The false Crow-killer placed his hand on his heart, and at the same time began to cough violently. The sentinel was within a few feet of the disguised scout when his eyes fell on the horse. He started back, and his gun was raised in the twinkling of an eye. At that moment Buffalo Bill was very near death. In the confident belief that he had deceived the Indian, he had not made any demonstration with his rifle, which he carried loosely in his hand. He did not know that the pony had betrayed him. But he realized in a flash that the Indian had made an important discovery, and he acted with the celerity of lightning. But the Indian had the start, and a bullet would have reached Buffalo Bill’s heart if a tomahawk, thrown with a practiced hand, had not carved the Navaho’s skull at the very moment when he was about to press the trigger. The king of scouts saw the Indian fall, and knew that a friend had intervened, and in the nick of time. Wild Bill stepped from behind a tree. “I reckon you’ll forgive me for disobeying instructions,” he said in a whisper. “You see, I had a hunch that you’d taken the wrong pony, and, knowing how the Navahos regard such changes, I concluded to slip on behind you and see you through.” “You are forgiven,” returned Buffalo Bill huskily. “That’s another on me. I shan’t forget.” Wild Bill looked closely at the pony. Before, while on the way from the ravine, he paid no attention to the animal. “I am a fool,” he muttered, more to himself than to his old comrade. “The two ponies the Indians—Crow-killer and his partner—left behind when they sneaked for the flat were pintos. This pony is a plain muser. There was substitution after the Indians stole away from their ponies. Some one, a white man, sure, for on no other supposition can the conduct of this Navaho at my feet be accounted for, exchanged his own pony for that of Crow-killer. Why did he do it, and who was he?”