Man An Adaptive Mechanism

ans of which a given stimulus causes different effects in different brains? Why will one man run away and another attack on receipt of identical stimuli ? We postulate that the adaptive reactions of the organism are executed by mechanisms, each of which, like a wireless station, awaits the arrival of the specific impulse which is to awaken it to specific response. Between the ceptor organs of the eye, the ear, the nose, the sensory nerve endings in the skin and the nerves governing muscles and glands there intervenes an intricate network of action patterns. As over the same copper wire may be transmitted the voice, a telegraph message, a dynamic charge of electricity for firing a mine, lighting a concert hall or driving an engine, ? so over the same nerve or group of nerves may be transmitted impulses destined for the production of terror, of sudden flight or of the reactions of eating or drinking. Thus during consciousness thebraiir is the seat of a continual flow of opposing, assisting, crossing and interfering impulses, the amount of fatigue produced being proportional to the number and strength of stimuli that evoke responses, whether these responses be those of gross activity or of mere perception. It is not as difficult as it seems at first to conceive how the most complex reactions have been built out Fio. 77. ? Cross-section Of Leaf And Hair Of Venus' Fly-trap. Drawing showing the cellular mechanism which corresponds to the nerve path in ani...