FOODS AND DIET. 215 



into this organ. It may, therefore, be said that the sensation of hunger 

 is caused both by a want in the system generally, and also by the condi- 

 tion of the stomach itself, by which condition, of course, its own nerves 

 are more directly affected. 



The sensation of thirst, indicating the want of fluid, is referred to 

 the fauces, although, as in hunger, this is, in great part, only the local 

 declaration of a general condition. For thirst is relieved for only a very 

 short time by moistening the dry fauces ; but may be relieved completely 

 by the introduction of liquids into the blood, either through the stomach, 

 by injections into the blood-vessels, or by absorption from the surface of 

 the skin or the intestines. The sensation of thirst is perceived most 

 naturally whenever there is a disproportionately small quantity of water 

 in the blood : as well, therefore, when water has been abstracted from 

 the blood, as when saline or any solid matters have been abundantly 

 added to it. And the cases of hunger and thirst are not the only ones 

 in which the mind derives, from certain organs, a peculiar predominant 

 sensation of some condition affecting the whole body. Thus, the sensa- 

 tion of the " necessity of breathing," is referred especially to the air- 

 passages ; but, as Volkmann's experiments show, it depends on the con- 

 dition of the blood which circulates everywhere, and is felt even after 

 the lungs of animals are removed ; for they continue, even then, to gasp 

 and manifest the sensation of want of breath. 



Starvation. The effects of total deprivation of food have been made 

 the subject of experiments on the lower animals, and have been but too 

 frequently illustrated in man. (1) One of the most notable effects of 

 starvation, as might be expected, is loss of weight ; the loss being great- 

 est at first, as a rule, but afterwards not varying very much, day by day, 

 until death ensues. Chossat found that the ultimate proportional loss 

 was, in different animals experimented on, almost exactly the same ; 

 death occurring when the body had lost two-fifths (forty per cent) of its 

 original weight. Different parts of the body lose weight in very differ- 

 ent proportions. The following results are taken, in round numbers, 

 from the table given by M. Chossat : 



Fat loses, .... 93 per cent. 



Blood, 75 " " 



Spleen, .... 71 " " 



Pancreas, .... 64 " " 



Stomach loses, . . 39 " " 



Pharynx, (Esophagus, 34 " " 



Skin, 33 " " 



Kidneys lose, . . 31 " " 



(2.) The effect of starvation on the temperature of the various ani- 

 mals experimented on by Chossat was very marked. For some time the 

 variation in the daily temperature was more marked than its absolute 

 and continuous diminution, the daily fluctuation amounting to 5 or 6 



Liver loses, ... 52 per cent. 



Heart, 44 " " 



Intestines, . . . 42 " " 

 Muscles of locomotion, 42 " " 

 Respiratory apparatuses " " 



Bones, 16 " " 



Eyes, 10 " " 



Nervous System, . . 2 (nearly.) 



