The following instance of sagacity deserves to be recorded. "During the great flood of the 4th of September, 1829, when the river Tyne was at it height, a number of people were assembled on its margin. A swan appeared with a black spot upon its plumage, which on its nearer approach proved to be a live rat. It is probable, that the latter had been borne into the water by some object, and observing the swan, had taken refuge on its back for safety. As soon as the swan reached the land, the rat leaped off and ran away." Two ladies, friends of a near relative of my own, from whom I received an account of the circumstance, were walking in Regent-street, and were accosted by a man who requested them to buy a beautiful little dog, covered with long, white hair, which he carried in his arms. Such things are not uncommon in that part of London, and the ladies passed on without heeding him. He followed, and repeated his entreaties, stating, that as it was the last he had to sell, they should have it at a reasonable price. They looked at the animal; it was really an exquisite little creature, and they were at last persuaded. The man took it home for them, received his money, and left the dog in the arms of one of the ladies. A short time elapsed, and the dog, which had been very quiet, in spite of a restless, bright eye, began to show symptoms of uneasiness, and as he ran about the room, exhibited some unusual movements, which rather alarmed the fair purchasers. At last, to their great dismay, the new dog ran squeaking up one of the window curtains, so that when the gentleman of the house returned home a few minutes after, he found the ladies in consternation, and right glad to have his assistance. He vigorously seized the animal, took out his penknife, cut off its covering, and displayed a large rat to their astonished eyes, and, of course to its own destruction. MICE. The round, yet delicate form of the Mouse, and the better expression of its countenance, make it an object much more worthy of admiration than the rat, of which it is but a diminished representative. It has the same destructive propensities, assembles also in vast numbers, and is equally carnivorous; but with all these, it is a more tamable and lovable animal. There is a white variety which is often nurtured as a pet. Mr. Darwin says, that with other small Rodents, numbers live together in nearly desert places, as long as there are a few blades of vegetation left; and that they swarm on the borders of salt-lakes, where not a drop of fresh water can be procured. Some of them lay up stores of food, especially those which inhabit northern countries.