4. Although not a consciously purposed action, instinct nevertheless involves consciousness. In sucking, for instance, sensation accompanies both the discomfort of the organism giving rise to the movements and also the instinctive act itself. In this respect it differs from such automatic actions as breathing, the circulation of the blood, and the beating of the heart.
=Origin of Instinct.=--The various instinctive movements with which an organism is endowed, not being a result of experience or education, a question at once arises as to their source, or origin. Instinct has its origin in the fact that certain movements which have proved beneficial in the ancestral experience of the race have become established as permanent modes of reaction, and are transmitted to each succeeding generation. The explanation of this transmission of tendencies is, that beneficial movements are retained as permanent modifications of the nervous system of the animal, and are transmitted to the offspring as a _reactive tendency_ toward definite stimuli. The partridge family, for instance, has preserved its offspring from the attacks of foxes, dogs, and other enemies only by the male taking flight and dragging itself along the ground, thus attracting the enemy away from the direction of the nest. The complex movements involved in such an act, becoming established as permanent motor connections within the system, are transmitted to the offspring as predispositions. Instinct would thus seem a physiological habit, or hereditary tendency, within the nervous system to react in a fixed manner under certain conditions. In many respects, however, instincts seem to depend more largely upon bodily development than upon nervous structure. While the babe will at first instinctively suck; yet as soon as teeth appear, the sucking at once gives way to the biting instinct. The sucking instinct then disappears so completely that only a process of education will re-establish it later. Birds also show no instinctive tendency to fly until their wings are developed, while the young of even the fiercest animals will flee from danger, until such time as their bodily organism is properly developed for attack. From this it would seem that instinctive action depends even more upon general bodily structure and development than upon fixed co-ordinations within the nervous system.