The rule of selection-“the survival of the fittest”-is the one by which man has himself arrived on the scene.He,being one of the most adaptable creatures the earth has yet produced,may last longer than most.Some creatures,certain small animals,insects and birds,will almost certainly outlast man,for they seem even more adaptable.You may take it as another rule that when ,at last,man shows signs of dying out ,no other creature will extend a paw to postpone his departure. On the contrary,he will be hurried out;for Nature,though fair,is a hardhearted mistress.She had no favorites.