This establishment contained fifty or sixty white mice—from the venerable grandfather and grandmother down to the little juveniles two weeks old, to say nothing of sundry little ones which had not appeared on the "grand parade," and which looked like bits of beef, or more like pieces of a large fish worm. Other establishments on the wall contained smaller numbers; and, though it was impossible to count them, there were not less than a hundred and fifty white mice in the basement.

When Leo conducted the visitors to the cellar, all the tribes of mice were in the highest enjoyment of colonial and domestic bliss. Though most of them scampered to their lairs when the gentlemen appeared, they returned in a moment, looked at the strangers, snuffed and stared, and then went to work upon the buckwheat and canary seed, which Leo gave them as a special treat. Squatting on their hind legs, they picked up grains or seeds, and holding them in their fore paws, like squirrels, picked out the kernels.

LEO'S WORKSHOP.—Page 76.

In other houses, they were chasing each other along the galleries, performing various gymnastics on the apparatus provided for the purpose, or revolving in the whirligigs that some of the cages contained. It was after dark; and, having reposed during the day, they were full of life and spirit at night. The detective was delighted, and even Mr. Checkynshaw for a few moments forgot that his valuable papers had been stolen. Both of them gazed with interest at the cunning movements and the agile performances of the little creatures.

"I see why you remained down cellar so long," said the detective, with a smile.

"I was at work on that mouse-house," replied Leo, pointing to the bench.

The palace in process of construction was somewhat different from the others. Instead of being open in front of the "grand parade," it had a glass door, so that the occupants of the establishment could be seen, but could not fall out.

"What is that one for?" asked Mr. Clapp.

"I'm making that for Mr. Stropmore," answered Leo. "I gave him one lot, but his cat killed them all. The cat can't get at them in this house, and they can't fall out."