When the nuthatch carries a fragment of a hickory-nut to a tree and wedges it into a crevice in the bark, the bird is not showing an individual act of intelligence: all nuthatches do this; it is a race instinct. The act shows intelligence,--that is, it adapts means to an end,--but it is not like human or individual intelligence, which adapts new means to old ends, or old means to new ends, and which springs up on the occasion. Jays and chickadees hold the nut or seed they would peck under the foot, but the nuthatch makes a vise to hold it of the bark of the tree, and one act is just as intelligent as the other; both are the promptings of instinct. But when man makes a vise, or a wedge, or a bootjack, he uses his individual intelligence. When the jay carries away the corn you put out in winter and hides it in old worms' nests and knot-holes and crevices in trees, he is obeying the instinct of all his tribe to pilfer and hide things,--an instinct that plays its part in the economy of nature, as by its means many acorns and chestnuts get planted and large seeds widely disseminated. By this greed of the jay the wingless nuts take flight, oaks are planted amid the pines, and chestnuts amid the hemlocks. Speaking of nuts reminds me of an incident I read of the deer or white-footed mouse--an incident that throws light on the limitation of animal intelligence. The writer gave the mouse hickory-nuts, which it attempted to carry through a crack between the laths in the kitchen wall. The nuts were too large to go through the crack. The mouse would try to push them through; failing in that, he would go through and then try to pull them after him. All night he or his companion seems to have kept up this futile attempt, fumbling and dropping the nut every few minutes. It never occurred to the mouse to gnaw the hole larger, as it would instantly have done had the hole been too small to admit its own body. It could not project its mind thus far; it could not get out of itself sufficiently to regard the nut in its relation to the hole, and it is doubtful if any four-footed animal is capable of that degree of reflection and comparison. Nothing in its own life or in the life of its ancestors had prepared it to meet that kind of a difficulty with nuts. And yet the writer who made the above observation says that when confined in a box, the sides of which are of unequal thickness, the deer mouse, on attempting to gnaw out, almost invariably attacks the thinnest side. How does he know which is the thinnest side? Probably by a delicate and trained sense of feeling or hearing. In gnawing through obstructions from within, or from without, he and his kind have had ample experience.