And if the desire for alcohol were due to a longing for excitement, life, tension, movement, this longing would seem to be well satisfied by the conditions in modern American cities without recourse to 2.,000 million gallons of alcoholic liquors yearly.
Any satisfactory theory of the alcohol impulse must not only take account of the facts to be explained, some of which we have mentioned above, but it must also be grounded on an accurate knowledge of the whole life history of man, particularly his mental development and the corresponding development of the brain. It would be necessary, furthermore, for such a theory that we should have an accurate knowledge of the action of alcohol on the human brain. Neither psychology nor physiology is able as yet to furnish this knowledge completely, so that any theory of the alcohol motive must be tentative, awaiting further scientific advance. The following observations, therefore, although for brevity's sake put in somewhat dogmatic form, may be considered as suggestions toward such a theory.
Human progress seems to be in a certain definite direction and to involve the development of certain definite mental powers and of the corresponding higher cerebral centers. The chief of these powers is that of voluntary, sustained attention, which differentiates man sharply from the lower animals and likewise distinguishes civilized man from the savage. Progress has been possible because man has been able to narrow the field of attention, to concentrate or focus his powers, to live under mental stress, strain and effort and to hold his attention on a definite object. The word "tension" may perhaps express both psychologically and physiologically the subjective correlate of progress. It is characteristic of the savage as compared with the lower animals, of civilized man as compared with the savage, of northern races as compared with southern, and of the male as compared with the female. As concentration, sustained attention and abstraction, it issues among civilized man in science and invention. Whether the product be Newton's Principia or Edison's talking machine, or even the long-sustained working-day of the common laborer, it presupposes the above-mentioned powers and involves the constant enlargement of the higher cortical centers of the brain. There is something, whether it be the "will to live," or a "vital impulse," or the cosmic consciousness, or only natural selection, that is eternally driving us on in this direction.
Now the higher and newer the brain centers, the more subject they are to fatigue and the greater is their need of rest. During sleep these centers enjoy almost perfect rest, our dream activity taking the form of passive revery. But eight hours of sleep are not sufficient for this part of the brain. Sixteen hours of sustained attention would probably result in immediate insanity, if such an act were possible. Nature seems to demand some form of activity which shall allow the higher brain centers to rest while providing employment for the lower ones. To such a condition of mind and body we apply the name relaxation
