"After him!" spluttered Rattleton. "He may not be able to get away! We'll try to capture him!" But the effort was vain. The eavesdropper had made good his escape. After a little time the boys all came back to Diamond's room. They found Jack examining the piece of cloth, which he had taken from the bulldog with no small difficulty. "It is from somebody's trousers," said Jack, seriously. "Whoever the sneak was, he'll have to buy a new pair. He hit Prince a frightful blow behind the ear, but the good old fellow held fast to this trophy." "If we'd nabbed the fellow, we wouldn't have done a thing to him--not a thing!" cried Griswold. "See if any of you fellows recognize this piece of cloth as belonging to the clothing of any chap you know," invited Diamond. They all examined it. "If I mistake not," said Dismal Jones, "this came from a certain section of a certain individual's trousers, and the section to which I refer is located about eight inches south of the back strap." "And the fellow," exclaimed Robinson, "the fellow is----" "Roland Ditson!" finished Rattleton. "In that case," said Diamond, "Merriwell's enemies have received a good tip concerning his fondness for Nemo. You will have to be doubly careful about that horse after this, Frank." CHAPTER VII. THE PLOT. If Roland Ditson was the person from whose trousers the piece of cloth had been torn he took good care to destroy what he had retained of the breeches without delay, for they were never again seen in his possession. The figure on the cloth was not pronounced enough to distinguish it in a manner to make it absolute proof that it came from a garment owned by Roland. Nevertheless Diamond accused Ditson of listening at his door, but Roll vigorously denied that he had done so. Diamond told him he was a natural-born prevaricator, and let it go at that. But Ditson was watched like a hawk by the boy from Virginia, for Jack felt sure the fellow was up to crookedness. Frank Merriwell knew that if Ditson had been listening to the conversation that was taking place in that room his enemies must know in what light he regarded Nemo. This caused Frank to caution both Toots and Grody to redouble their vigilance in watching over and caring for the splendid creature. "Don' yo' worry about me, Marser Frank," assured the darky lad. "Dat's de fines' hawse dat dis chile ebber seen, an' I'se gwan ter watch ober heem lek he wus de apple ob mah eye." "I have decided to enter Nemo in the Mystic Park races at Bethany, Toots," Merriwell declared, "and I think I'll let you ride him, my boy." Toots showed two rows of gleaming ivories and beamed with the greatest delight. "If yer done dat, Marser Frank, I'se gwan ter win on dat hawse jes ez shore ez yeh bawn, sar!" he cried. "I'se done rid dat critter enough teh know he's a wondah, sar. Dat hawse is wuf a forchune, sar!" "If you win, Toots, I may give you a chance to ride him in some races later in the season."