558 THE SCIENTIFIC MONTHLY
a means of combating a long and diversified list of human ills, seems to be constantly and most disturbingly on the increase.
It is to be observed that there is no immunity from any of these ills for the multitude who (explicitly or tacitly) maintain tiiat eating should be entirely an esthetic performance, guided solely by refined and restrained sense gratification and adapted to encourage social inter- course; a performance, then, which can have as little concern with calories and protein, as has the music-lover's enjoyment of a beautifuUy taken high G, with a consideration of the wave-lengths of the vibrations which produced it. This attitude toward scientific nutrition has, needless to say, as little efficacy in warding off the physical ills resulting from dietetic errors, as has the behavior of the traditional ostrich toward the danger by which it is confronted.
Let ns undertake an analysis of the motives involved in the desire for food, as they commonly operate among the various classes of people of our own day and country.
1. Hunger. Beginning with the more fundamental physiological motives, we find that recent investigations^ seem to demonstrate con- clusively a fact which most of ns will be inclined to concede at once, or at least after a little refiection, viz., that hunger and appetite are distinctly different motives. Hunger is to be defined as an unpleasant sensation, referred by most people to the pit of the stomach or closely adjacent regions, not caused by the sight or thought of food, but by a certain lype of contractions of the stomach muscles which begin as soon as the stomach has been emptied, in normal individuals, and which continue until food is taken. The degree of hunger sensation or pang to which (presumably) these muscular contractions give rise, varies in different individuals, and also, of course, in the same indi- vidual at different times. Both the muscular performance and the sensation occur intermittently at first, or in periods of varying in- tensity, but at length these periods become continuous if no food is taken. In prolonged starvation or undernutrition, however, it seems that the hunger sensation (though not the contractions) gradually becomes weakened. Hunger pangs and contractions are almost in- stantly stopped by the entrance of food or palatable substances into the stomach, or even by fused taste and smell sensations unaccompanied by the swallowing of food. A few spoonfuls of hot soup, though they may contribute little or no nourishment to the body, go far toward alleviating hunger pangs for the moment; even a drink of water some- times helps; and this would be true even though the liquid were not swallowed, as was proved in case of Mr. V , Professor Carlson's
1 Cannon and Washbume, * * An Explanation of Hanger, ' ' American Journal , of Physiology, Vol. XXIX., p. 441. Carlson, Contributions to PliTsiologj of the Stomach," American Journal of Physiology, Vols. XXXT.-XXXIX. incL, also "Control of Hunger in Health and Disease," University of Chicago Press.
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