"So much the better," said Jack, as he gave Socker a small sum of money. "I'll keep quiet about this, don't worry." "I hope you will," the janitor went on. "It's against the rules for me to do what I did, but I want to oblige you, and have you come out all right." "Which I think I will," Jack added. When he was alone he opened the bundle Socker had brought. It was a linen duster, and, as Jack saw several brown spots on it he uttered an exclamation of satisfaction. With his knife he scraped some substance from the garment, and placed the particles in a test tube. Then, taking this with him, he went to the laboratory, where he remained for some time. Late that afternoon Jack, who had avoided his chums, took a walk around the campus. As he came near a small building, where some of the students kept their motor cycles, one or two small automobile runabouts, and a few of the more well-to-do, their ponies, Jack assumed a slow and halting gait. He seemed to be limping from the effects of his sprained ankle. "I wonder if he's around," he muttered to himself. "Socker said he was going to take a spin this afternoon, and it's about time for him to start, by all accounts." As Jack neared the entrance to the combined garage and stable he saw a group of students approaching from an opposite direction. His limp became more decided than before. "He's there!" he said softly to himself. "Hello, Ranger!" exclaimed a number, as Jack passed them. He knew them fairly well, but was not intimate with them as they belonged to the "fast set," a good-enough crowd, but lads who had more spending money than was good for them. "Hello!" called Jack in reply. "What's the matter?" came several inquiries as the students noticed Jack's limp. "Turned on my ankle," was the reply. "A bit stiff yet." The crowd had nearly passed by this time, and, owing to the fact that Jack had the middle of the sidewalk, and did not turn to one side, the little group separated. Some went on one side, and some on the other. Just as Jack came opposite a tall, elaborately dressed youth, he seemed to stumble. To save himself from falling Jack threw out his hand and caught the tall student on the wrist. As he did so the well- dressed youth uttered a cry. "Clumsy! You hurt my sore wrist!" "I beg your pardon!" exclaimed Jack, struggling to recover his balance, but still keeping his hold of the other's hand. "Awfully careless of me!" There was quite a little jostling among the students, several trying to help Jack recover his balance. Then Jack straightened up. "I'm all right now," he said. "I bore down on it a little too hard." He limped on, thrusting one hand hurriedly into his pocket. As he did so, the tall student cried. "There! I've lost the rag off my sore wrist! I sprained it cranking my auto yesterday." Several of his companions began a search for it, but as Jack hurried on, as fast as he could, while still pretending to limp painfully he said to himself: