The organic faculties of each species of animals are marvelously adapted to its peculiar mode of life, but only in the lower creatures the skilful exercise of those faculties appears to be an inborn gift. The young bee builds its first hexagon with mathematical precision. The young ant needs no instructor to aid her choice of proper building-material, of proper food to be stored for winter use or distributed in the nurseries of the larvæ. The young butterfly, an hour after issuing from the shell of the chrysalis, can use its wings as well as at the end of the summer, and displays the same skill in steering its way through the maze of a tangled forest. Young birds, on the other hand, have to acquire such accomplishments by long practice. Instead of driving them back to their nests, their parents encourage their attempts at longer and longer flights, and seem to know that occasional mishaps will prove a useful lesson for future emergencies. The mother fox carries half-crippled game to her burrow and sets her cubs a-scampering in pursuit, allowing the best runner to monopolize the tidbits. Young kittens practice mouse-catching by playing with balls; puppies run after grasshoppers, young squirrels play at nest-building by gathering handfuls of leaves and moss. A British naturalist, who had domesticated a young beaver, one day caught his pet building a dam across the floor of his study. The little engineer had dragged up a cartload of books, papers, sticks of wood, etc., and piled them up to best advantage, placing the heavier volumes in the bottom stratum and the lighter ones higher up, and filling out the interspaces with letters and journals. Every now and then he would “stand off” to scrutinize the solidity of the structure and return to mend a misarrangement here and there.