They build very well arranged dwellings, although at first sight they look like mere piles of twigs, branches, and logs heaped in disorder on a small dome of mud. At the edge of a pond each raises his own lodge, and there is no work by the colony in common. If, however, there is a question of inhabiting the bank of a shallow stream, certain preliminary works become necessary. The rodents establish a dam, so that they may possess a large sheet of water which may be of fair depth, and above all constant, not at the mercy of the rise and fall of the stream. A sudden and excessive flood is the one danger likely to prove fatal to these dikes; but even our own constructions are threatened under such circumstances. When the beavers, tempted by abundance of willows and poplars, of which they eat the bark and utilize the wood in construction, have chosen a site, and have decided to establish a village on the edge of the water, there are several labors to be successively accomplished. Their first desire is to be in possession of a large number of felled trunks of trees. To obtain them they scatter themselves in the forest bordering the stream and attack saplings of from twenty to thirty centimetres in diameter. They are equipped for this purpose. With their powerful incisors, worked by strong jaws, they can soon gnaw through a tree of this size. But they are capable of attacking trees even more than 100 cm. in diameter and some forty metres in height with great skill and adaptability; “no better work could be accomplished by a most highly finished steel cutting tool, wielded by a muscular human arm” (Martin). They operate seated on their hindquarters, and they make their incision in the wood with a feather edge. It was once supposed that they always take care so to direct their wood-cutting task that the tree may fall on the water-side, but this is by no means the case, and appears to be simply due, as Martin points out, to the fact that trees by the water-side usually slope toward the water. The austerity of labor alternates, it may be added, with the pleasures of the table. From time to time the beavers remove the bark of the fallen trees and feed on it.