292 TEE POPULAR SCIENCE MO NT ELY 



basis appetite and hunger would differ only quantitatively. Another 

 view, which seems more justifiable, is that the two experiences are fun- 

 damentally different. 



Careful observation indicates that appetite is related to previous sen- 

 sations of taste and smell of food. Delightful or disgusting tastes and 

 odors, associated with this or that edible substance, determine the appe- 

 tite. It has therefore important psychic elements in its composition, 

 as the studies by Pawlow and his collaborators have so clearly shown. 

 Thus, by taking thought, we can anticipate the odor of a delicious beef- 

 steak or the taste of peaches and cream, and in that imagination we can 

 find pleasure. In the realization, direct effects in the senses of taste 

 and smell give still further delight. We now know from observations 

 on experimental animals and on human beings, that the pleasures of 

 both anticipation and realization^ by stimulating the flow of saliva and 

 gastric juice, play a highly significant role in the initiation of digestive 

 processes. 3 



Among prosperous people, supplied with abundance of food, the 

 appetite seems sufficient to ensure for bodily needs a proper supply of 

 nutriment. We eat because dinner is announced, because by eating we 

 avoid unpleasant consequences, and because food is placed before us in 

 delectable form and with tempting tastes and odors. Under less easy 

 circumstances, however, the body needs are supplied through the much 

 stronger and more insistent demands of hunger. 



The sensation of hunger is difficult to describe, but almost every 

 one from childhood has felt at times that dull ache or gnawing pain 

 referred to the lower mid-chest region and the epigastrium, which may 

 take imperious control of human actions. As Sternberg has pointed 

 out, hunger may be sufficiently insistent to force the taking of food 

 which is so distasteful that it not only fails to rouse appetite, but may 

 even produce nausea. The hungry being gulps his food with a rush. 

 The pleasures of appetite are not for him — he wants quantity rather 

 than quality, and he wants it at once. 



Hunger and appetite are, therefore, widely different — in physiolog- 

 ical basis, in localization and in psychic elements. Hunger may be 

 satisfied while the appetite still calls. Who is still hungry when the 

 tempting dessert is served, and yet are there any who refuse it, pleading 

 they no longer need it? On the other hand, appetite may be in abey- 

 ance while hunger is goading. 4 What ravenous boy is critical of his 

 food ? Do we not all know that " hunger is the best sauce " ? Although 

 the two sensations may thus exist separately, they, nevertheless, have 



3 Pawlow, "The Work of the Digestive Glands," London, 1902, pp. 50, 71. 



* See Sternberg, Zentralblatt fur Physiologie, 1909, XXII., p. 653. Similar 

 views were expressed by Bayle in a thesis presented to the Faculty of Medicine 

 in Paris in 1816. 



