In truth the power which animals as well as men possess, of conforming themselves to new situations and forming new habits adapted to new circumstances is proof of a capability of improvement. The wild dogs in the plains of La Plata, burrow, because there is no security for them above ground against stronger beasts of prey. In the same country owls make their nests in the ground, because there are neither trees nor buildings to afford them concealment. A clergyman in Iceland by sowing angelica upon a Lake-island some miles from the sea, not only attracted gulls and wild ducks to breed there, but brought about an alliance between those birds, who are not upon neighbourly terms elsewhere. Both perceived that the new plants afforded better shelter from wind and rain, than any thing which they had seen before; there was room enough for both; and neighbourhood produced so much good will, that the gulls protected the weaker birds not only against the ravens who are common enemies, but against another species of gull also which attacks the duck's nest. A change more remarkable than either of these, is that which the common hearth-cricket has undergone in its very constitution as well as in all its ways of life, since men built houses and inhabited cold climates. The field-cricket in North America, which buries itself during the winter ten inches deep and there lies torpid, began about an hundred years ago to avail itself of the work of man and take up its abode in the chimnies. This insect even likes man for a bed-fellow, not with any such felonious intentions as are put in execution by smaller and viler vermin, but for the sake of warmth. The Swedish traveller, Kalm, says that when he and his companions were forced to sleep in uninhabited places, the crickets got into the folds of their garments, so that they were obliged to make some tarriance every morning, and search carefully before they could get rid of them. Two species of Swallows have domesticated themselves with man. We have only that which builds under the eaves in England, but in North America they have both the house swallow and the chimney swallow; the chimnies not being made use of in summer, they take possession, and keep it sometimes in spite of the smoke if the fire is not very great. Each feather in this bird's tail ends in a stiff point, like the end of an awl; they apply the tail to the side of the wall, and it assists in keeping them up, while they hold on with their feet. “They make a great thundering noise all day long by flying up and down in the chimnies;” now as the Indians had not so much as a hearth made of masonry, it is an obvious question, says Kalm, where did these swallows build before the Europeans came, and erected houses with chimnies? Probably, it is supposed, in hollow trees, but certainly where they could; and it is thus shown that they took the first opportunity of improving their own condition.