Attempt to thwart the nesting-instinct in a bird and see how persistent it is, and how blind! One spring a pair of English sparrows tried to build a nest on the plate that upholds the roof of my porch. They were apparently attracted by an opening about an inch wide in the top of the plate, that ran the whole length of it. The pair were busy nearly the whole month of April in carrying nesting-material to various points on that plate. That big crack or opening which was not large enough to admit their bodies seemed to have a powerful fascination for them. They carried straws and weed stalks and filled up one portion of it, and then another and another, till the crack was packed with rubbish from one end of the porch to the other, and the indignant broom of the housekeeper grew tired of sweeping up the litter. The birds could not effect an entrance into the interior of the plate, but they could thrust in their nesting-material, and so they persisted week after week, stimulated by the presence of a cavity beyond their reach. The case is a good illustration of the blind working of instinct. Animals have keen perceptions,--keener in many respects than our own,--but they form no conceptions, have no powers of comparing one thing with another. They live entirely in and through their senses. It is as if the psychic world were divided into two planes, one above the other,--the plane of sense and the plane of spirit. In the plane of sense live the lower animals, only now and then just breaking for a moment into the higher plane. In the world of sense man is immersed also--this is his start and foundation; but he rises into the plane of spirit, and here lives his proper life. He is emancipated from sense in a way that beasts are not.