naturalists now confirm the belief that the young of certain birds—the swallow has been particularly instanced—are _taught_ to fly by the parent birds; whilst any one who has trained a dog will know how such a trick as “begging” for food may become so habitual as to appear instinctive. So much for general definition; I come now to the point which marks the differentiation of man from the animal world, and which is first clearly evidenced in the use of the reasoning, intellectual powers of inhibition. Now it is evident that in the earlier stages of man’s development, the inhibition of the subconscious animal powers was frequently a source of danger and of death. Reason, not as yet sufficiently instructed and far-seeing, was an inefficient pilot, and sometimes laid the ship aback when she would have kept before the wind if left to herself. To abandon the metaphor, the control was imperfect, it wavered between two alternatives, and by rejecting the guidance of instinct it suffered, it may be, destruction. But the necessity for conscious control grew as the conditions of life came to differ ever more and more from those of the wild state. This, plainly, was due to many causes, but chiefly to the limitations enforced by the social habit which grew out of the need for co-operation. This point must be briefly elaborated, for it marks the birth of inhibition in its application to everyday life, and in so doing it demonstrates the growth of the principle of conscious control which, after countless thousands of years, we are but now beginning to appreciate and understand. It is true that we have evidence of conscious inhibition in a pure state of nature. The wild cat stalking its quarry inhibits the desire to spring prematurely, and controls to a deliberate end its eagerness for the instant gratification of a natural appetite. But in this, and in the many other similar instances, such instinctive acts of inhibition have been developed through long ages of necessity. The domestic kitten of a few weeks old, which has never been dependent on its own efforts for a single meal, will exhibit the same instinct. In animals the inherited power is there; in man also the power is there as a matter of physical inheritance, but with what added possibilities due to the accumulated experience gained from the conscious use of this wonderful force.