Thus the building faculty of the beaver is an instinct, for it acts spontaneously, and always in the same way. It is not a general faculty of building in all places and ways, but a special power of building houses of sticks, mud, and other materials, with the entrance under water and a dry place within. When beavers build on a running stream, they begin by making a dam across it, which preserves them from losing the water in a drought; but this also is a spontaneous and invariable act. The old stories of their driving piles, using their tails for trowels, and having well-planned houses with many chambers, have been found to be fictitious. That the beaver builds by instinct, though intelligence comes in to modify the instinct, appears from his wishing to build his house or his dam when it is not needed. Mr. Broderip, the English naturalist, had a pet beaver that manifested his building instinct by dragging together warming-pans, sweeping-brushes, boots, and sticks, which he would lay crosswise. He then would fill in his wall with clothes, bits of coal, turf, laying it very even. Finally, he made a nest for himself behind his wall with clothes, hay, and cotton. As this creature had been brought from America very young, all this procedure must have been instinctive. But his intelligence showed itself in his adapting his mode of building to his new circumstances. His instinct led him to build his wall, and to lay his sticks crosswise, and to fill in with what he could find, according to the universal and spontaneous procedure of all beavers. But his making use of a chest of drawers for one side of his wall, and taking brushes and boots instead of cutting down trees, were no doubt acts of intelligence. A large part of the wonderful procedure of bees is purely instinctive. Bees, from the beginning of the world, and in all countries of the earth, have lived in similar communities; have had their queen, to lay eggs for them: if their queen is lost, have developed a new one in the same way, by altering the conditions of existence in one of their larvæ; have constructed their hexagonal cells by the same mathematical law, so as to secure the most strength with the least outlay of material. All this is instinct--for it is spontaneous and not deliberate; it is universal and constant. But when the bee deflects his comb in order to avoid a stick thrust across the inside of the hive, and begins the variation before he reaches the stick, this can only be regarded as an act of intelligence.