234 PSYCHOTHERAPY : SCIENTIFIC AND RELIGIOUS chap.
haviourism, the most superficial view of all, would root personality in the complex co-ordination of bodily reaction mechanisms by which behaviour is regulated in accordance with environmental stimuli. It would eliminate consciousness altogether, and do away with the will in any intelligible sense of the word. A great contribution to this school of thought was made by Pavlov,174 the Russian physiologist, who formulated the conditioned reflex theory which is one of its leading ideas. Soon after 1900, while working on the physiology of digestion, Pavlov noticed a peculiar fact in the behaviour of the dog that he was using as subject. He had arranged apparatus for collecting the dog's saliva directly from one of the salivary glands, and was giving the animal food to arouse the flow. He noticed that the saliva began to flow in an experienced dog before the food was actually placed in his mouth, at the sight of the dish containing the food, at the approach of the attendant who customarily brought it, or even at the sound of the attendant's footsteps in the adjoining room. Now, while food in the mouth is undoubtedly a natural stimulus to the flow of saliva that is an innate reflex the sight of the person or the sound of his footsteps could hardly be expected to produce this response, but must have become attached to the response in the course of the prolonged experiment, so as to serve as a preliminary signal. Pavlov saw that the capacity for acquiring such signals must be very important in the development of an individual animal's adaptation to its particular environment. He saw also that he had struck a promising lead toward the experimental study of the higher brain functions, and proceeded to turn the energies of his laboratory in that direction. He coined the term, ' conditioned reflex \ to stand for a reflex in which the response had become attached to some sub-