I have kept various kinds of animals for several years, in order to observe them and try experiments at my convenience.  I have suddenly inserted an unfamiliar object in the various cages in which I have kept birds, rabbits, moles, and other animals.  At first sight the animal is always surprised, timid, curious, or suspicious, and often retreats from it.  By degrees his confidence returns, and after keeping out of the way for some time, he becomes accustomed to it, and resumes his usual habits.  If then, by a simple arrangement of strings already prepared, I move the object to and fro, without showing myself, the animal scuttles about and is much less easily reconciled to its appearance.  I have tried this experiment with various animals, and the result is almost always the same.

In the cage of a very tame thrush, I made a movable bottom to his feeding trough, so arranged that by suddenly pulling a cord, the food which it contained could be raised or lowered.  When everything remained stationary in its place the thrush ate with lively readiness, but as soon as I raised the food he nearly always flew off in alarm.  When the experiment had been often repeated, he did not like to come near the feeding trough, and—­which is a still stronger proof that he imagined the food itself to be endowed with life—­he often refused to approach, or only approached in fear the sopped bread which was placed outside the trough.  I tried the same experiment with other birds, and nearly always with the same result.

On another occasion I repeatedly waved a white handkerchief before a spirited horse, bringing it close to his eyes; at first he looked at it suspiciously and shied a little, but without being much discomposed, and I continued the experiment until he became accustomed to its ordinary appearance.  One day I and a friend went out driving with this horse, and I directed a man, while we were passing at a moderate pace, to wave the same handkerchief, attached to a stick, in such a way that his person on the other side of the hedge was invisible.  The horse was scared and shied violently, and even in the stable he could not see the handkerchief without trembling, and it was difficult to reconcile him to the sight of it.  I repeated the experiment with slight variations on other horses, and the issue was always more or less the same.

Again, I placed a scarecrow or bogey in a parti-coloured dress in the spacious kennel of a hound while he was absent from it.  When the dog wished to return to his kennel, he drew back at the sight of it, and barked for a long while.  After going backwards and forwards, snuffing suspiciously, he decided to enter, but he remained on the threshold of the kennel, anxiously inspecting the bogey.  In a few days, however, he became accustomed to it, and was indifferent to its presence.  I ought to add that I had taught him on the first day, by punishment and admonition, that he must not destroy the bogey.  One day when the dog was lying down I violently moved the puppet’s arms by a cord, and he jumped up and ran barking out of the kennel, soon returning to bark as he had done at first.  Finally, he again became accustomed to it, but whenever I repeated the movement with greater violence, it took a long while for him to become reconciled to it.