The trial-and-error method which serves to establish the efficient modes of behaviour observed in animals is so far reaching in its possibilities that one might be tempted to regard it as accounting for the existence of Magic and of Religion. Were this theory tenable, the origin of the three modes of human behaviour would have been brought back to one method of learning, the unreasoning, trial-and-error method. But even a superficial consideration discovers insuperable obstacles in the way of this enticingly simple explanation, and compels the admission that magical art and Religion involve the operation of mental powers not required for the establishment of the mechanical, and of the non-religious anthropopathic behaviours. The first of the two differences I intend to bring out, is that if a particular action is to be learned by an animal, the gratification of the actuating desire must follow immediately, or nearly so, upon the performance of the successful act, and be frequently repeated at short intervals; whereas in man, as far as Magic and Religion are concerned, the results may follow quite irregularly upon the performance, often only long after, and, not infrequently, not at all. Had not the door opened every time the cat pressed the latch, but, let us say, only once every ten times, or, if every time, one week after the movement, he would never have learned to make his escape. No more would he have acquired the trick, had he not been placed in the cage repeatedly and at short intervals. An interesting instance of the gradual undoing of a habit in consequence of the absence of the sensory results for the sake and under the guidance of which the action had been learned, is reported by Lloyd Morgan.[8] He had brought up in his study a brood of ducks. They had had a bath every morning in a tin tray. After a while, the tray was placed empty in its accustomed place. The ducks got into it and went through all their ordinary ablutions. The next day, they again enjoyed the missing water, but not as long as on the first day. On the third day they gave up the useless practice of bathing in an empty tray.