172 ALIMENTATION. 



consideration naturally precedes the study of digestion, the process by which the articles 

 of food are prepared for absorption and appropriation by the circulating fluid. 



Hunger and Thirst. 



The term hunger may be applied to all degrees of that peculiar want felt by the sys- 

 tem which induces the ingestion of nutritive principles. Its first manifestations are, per- 

 haps, best expressed by the term appetite ; a sensation by no means disagreeable, and 

 one which may be excited by the sight, smell, or even the recollection 'of savory articles, 

 at times when it does not absolutely depend on a want in the system. In the ordinary 

 and moderate development of the appetite, it is impossible to say that the sensation is 

 referable to any distinct part or organ. It is influenced in some degree by habit ; in 

 many persons, the feeling being experienced at or near the hours when food is ordinarily 

 taken. If not soon gratified, the appetite is rapidly intensified until it becomes actual 

 hunger. Except when the quantity of food taken is unnecessarily large, the appetite 

 simply disappears on the introduction of food into the stomach and gives place to the 

 sense of satisfaction which accompanies the undisturbed and normal action of the diges- 

 tive organs ; or, in those who are in the habit of engaging in absorbing occupations at 

 that time, the only change experienced is the absence of desire for food. The sense of 

 oppression and fulness which attends over-distention of the stomach is simply superadded 

 to the feeling of satisfaction of the appetite, of which it is not a necessary part. 



In man, the appetite is usually manifested in a marked degree at least twice, and 

 generally three times in the twenty-four hours. In this country, food is commonly 

 taken three times daily. In childhood, when the system demands material, not only for 

 the repair of worn-out parts but for growth, food is generally taken oftener and in 

 larger relative quantity than in the adult. The infant should satisfy the appetite at least 

 six or seven times in the twenty-four hours ; and nothing has a more serious influence 

 upon the development of the growing child than bad quality or a restricted quantity of 

 food. 



It has been observed that children and old persons do not endure deprivation of food 

 so well as adults. This fact was noted by M. Savigny, in the case of the wreck of the 

 frigate Medusa. After the wreck, one hundred and fifty persons, of all ages, were 

 exposed on a raft for thirteen days with hardly any food. Out of this number only 

 fifteen survived, among them M. Savigny ; and the children, young persons, and the aged, 

 were the first to succumb. 



Important modifications in the appetite are due to temperature. In cold climates, 

 and during the winter season in all climates, the desire for food is notably increased, and 

 the tastes are somewhat modified. Animal food, and particularly fats, are more agree- 

 able at that time, and the quantity of nutriment which is demanded by the system is 

 then considerably greater. In many persons, the difference in the appetite in warm and 

 cold seasons is very marked. 



Exercise and occupation, both mental and physical, when not pushed to the point of 

 ex'i mstion, increase the desire for food and undoubtedly facilitate digestion. Certain 

 armies, especially the vegetable bitters, taken into the stomach immediately before the 

 time when food is habitually taken, frequently have the same effect; while other articles, 

 which do not satisfy the requirements of the system, have a tendency to diminish the 

 desire for food. Many articles of the materia medica, especially preparations of opium, 

 have, in some persons, a marked influence in diminishing the appetite. The abuse of 

 alcoholic stimulants will sometimes take away all desire for food. "When hunger is 

 pressing, it has been observed that tobacco, in those who are accustomed to its use, will 

 frequently allay the sensation for a time. When the system has been badly nourished 

 from any cause, as after prolonged abstinence or in recovery from an exhausting dis- 

 ease, hunger is generally pressing and almost constant; and this continues until the 

 organism has regained its normal condition. Under these circumstances, the ingestion 



