THE NATURE OF HUNGER 291 



A CONSIDERATION OF THE NATURE OF HUNGER 1 



By Professor W. B. CANNON 



LABORATORY OF PHYSIOLOGY IN THE HARVARD MEDICAL SCHOOL 



fc fc TTT HY do we eat ? " This question, presented to a group of 

 V V educated people, is likely to bring forth the answer, " We 

 eat to compensate for body waste, or to supply the body with fuel for 

 its labors." Although the body is in fact losing weight continuously 

 and drawing continuously on its store of energy, and although the body 

 must periodically be supplied with fresh material and energy in order 

 to keep a more or less even balance between the income and the outgo, 

 this maintenance of weight and strength is not the motive for taking 

 food. 



Primitive man, and the lower animals, may be regarded as quite 

 unacquainted with notions of the equilibrium of matter and energy in 

 the body, and yet they take food and have an efficient existence, in spite 

 of this ignorance. In nature, generally, important processes, such as 

 the preservation of the individual and the continuance of the race, are 

 not left to be determined by intellectual considerations, but are pro- 

 vided for in automatic devices. Natural desires and impulses arise in 

 consciousness, driving us to action; and only by analysis do we learn 

 their origin or divine their significance. Thus our primary reasons for 

 eating are to be found, not in convictions about metabolism, but in the 

 experiences of appetite and hunger. 



Appetite and Hunger 



The sensations of appetite and hunger are so complex and so inti- 

 mately interrelated that any discussion is sure to go astray unless at 

 the start there is clear understanding of the meanings of the terms. 

 The view has been propounded that appetite is the first degree of 

 hunger, the mild and pleasant stage, agreeable in character; and that 

 hunger itself is a more advanced condition, disagreeable and even pain- 

 ful — the unpleasant result of not satisfying the appetite. 2 On this 



1 Presented to the Harvey Society, New York City, December 16, 1911. The 

 results here stated were published in the American Journal of Physiology, 1912, 

 XXIX., pp. 41-454. 



2 Bardier, Richet's "Dictionnaire de Physiologie, " article "Faim," 1904, 

 VI., p. 1. See, also, Howell, "Text -book of Physiology," fourth edition, Phila- 

 delphia and London, 1911, p. 285. 



