He knew that if he could excite the hound and induce him to give tongue, the rest of the pack would be on the ground in two minutes' time; and as they were all young dogs (Carlo was shut up in the barn every night to do guard duty there), they would not be likely to take hold of the boys, if left to themselves.
They would not permit them to escape, either.

They would surround them and keep them there until morning, and that was what Dan wanted.
He could not afford to watch the cabin every night, and he thought it would be a good plan to give Bob and his friend a lesson they would not forget.
That the prowlers had come there to force an entrance into the cabin, was quickly made plain to even Dan's dull comprehension.

He saw them try the door, and then go around to the other side of the building and attempt to pry off the planks that covered the window.

Dan heard something crack as Bob laid out his strength on the lever he was using, and believing that the thieves were on the point of accomplishing their object, he uttered a loud whistle to let the rest of the pack know that they were wanted, and shouted: "Here they be! Take 'em, fellers! Take 'em down!" Bose, who had been growing more and more impatient every moment, was quite ready to obey.

Uttering a loud yelp, which was almost immediately answered by the rest of the pack, he raised himself upon his hind legs, and struggled so furiously to escape that Dan was obliged to drop his rifle and seize him with both hands.