166 ALIMENTATION. 



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 exhaustion, increase the desire for food and undoubtedly facili- 

 tate digestion. Certain articles, especially the vegetable bitters, taken into 

 the stomach immediately before the time when food is habitually taken, fre- 

 quently 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. 



If food be not taken in obedience to the demands of the system as ex- 

 pressed by the appetite, the sensation of hunger becomes most distressing. 

 It is then manifested by a peculiar and indescribable sensation in the stom- 

 ach, which soon becomes developed into actual pain. This is generally accom- 

 panied with intense pain in the head and a feeling of general distress, which 

 soon render the satisfaction of this imperative demand on the part of the 

 system the absorbing idea of existence. Furious delirium frequently super- 

 venes after a few days of complete abstinence; and this is generally the 

 immediate precursor of death. It is unnecessary to cite the many instances 

 in which murder and cannibalism have been resorted to when starvation is 

 imminent ; suffice it to say, that the extremity of hunger or of thirst, like 

 the sense of impending suffocation, is a demand on the part of the system so 

 imperative, that it must be satisfied if within the range of possibility. 



The question of the seat of the sense of hunger is one of considerable 

 physiological interest. Saying that it is instinctively referred to the stomach, 

 is simply expressing the fact that the sensation is of a nature to demand 

 the introduction of food in the usual way. When the system is suffering 

 from defective nutrition, as after prolonged abstinence or during recovery 

 from diseases which have been accompanied by a lack of assimilation, the 

 mere filling of the stomach produces a sensation of repletion of this organ, 

 but the sense of hunger is not relieved ; but if, on the other hand, the nutri- 

 tion be active and sufficient, the stomach is frequently entirely empty for a 

 considerable time without the development of the sense of hunger. The 

 appetite is preserved and hunger is felt by persons who suffer from extensive 

 organic disease of the stomach, and the sensation has been occasionally 

 relieved by nutritious enernata or by injections into the veins. It is certain 

 that the appetite and the sense of hunger are expressions of a want on the 

 part of the organism, referred by the sensations to the stomach, but really 

 existing in the general system. This can be completely satisfied only by the 

 absorption of digested alimentary matters by the blood and their assimilation 

 by the tissues. 



The sense of hunger is undoubtedly appreciated by the cerebrum, and it 

 has been a question whether there be any special nerves which convey this 



