908 SPECIAL PHYSIOLOGY. 



distinction of the two classes of food is therefore, as previously stated, 

 inexact ; even the respiratory food is more or less assimilated, as it 

 enters the chyle and the blood, and both the blood and the chyle are 

 fluid parts of a tissue. Hence even respiratory food is plastic, as re- 

 gards those fluids. 



Effects, of Deprivation of Food. 



When an animal is entirely deprived of food, or when the quantity 

 supplied is insufficient to compensate for the waste of the tissues, the 

 weight of its body gradually diminishes, and it ultimately dies of 

 inanition or starvation. 



The phenomena attending this condition, have been best studied by 

 Chossat. 



The surface of the animal's body looks paler and withered, and the skin 

 seems wrinkled, owing to the disappearance of adipose tissue. The secretions 

 become more scanty and concentrated ; hence the mouth is parched, and the 

 digestive fluids wanting ; but the gall-bladder becomes distended with thick 

 tenacious bile. From the first, the urine is scanty and strongly acid. The 

 faeces are much reduced in quantity, are composed almost entirely of greenish 

 biliary matter, and, shortly before death, contain an excess both of water and 

 salts. 



Nutrition is interrupted or arrested. A warm-blooded animal becomes, 

 after a time, restless and excited, and continues so till the last day of life ; a 

 sudden fall in its temperature then occurs, and it passes into a state of almost 

 complete insensibility. Birds, in this condition, no longer attempt to fly ; 

 they sometimes gaze at surrounding objects, sometimes seem to be asleep. 

 The pulse and the respiration become gradually slower, and the limbs cold. 

 The general debility increases, until at length, being unable to stand, the ani- 

 mal falls over on one side, and does not again move. Diarrhoea always comes 

 on during the last twenty-four or forty-eight hours of life, and is attended with 

 a peculiar fetid odor of the body, a sign that decomposition is commencing. 

 The condition of stupor gradually becomes more profound, dilatation of the 

 pupil ensues, and the animal dies, death being sometimes ushered in by vio- 

 lent contractions of the muscles of the back, so that the body is drawn back- 

 wards, a condition known as opisthotonos. 



All the organs of the body suffer loss both in volume and weight, though 

 in very different degrees. Death usually occurs when the animal has lost 

 about T 4 , 7 ths of its weight. In many cases, however, the loss of weight is equal 

 to more than , and in others to only 4 th of that of the body. This appears to 

 be almost entirely dependent on the quantity of fatty tissue contained in the 

 body, before food is withheld, the loss of weight being greater the larger the 

 amount of fat previously in the system. 



In animals which had lost T 4 ,,ths of their weight, it was found that ^ths of the 

 fat had disappeared, T 7 ths of the spleen, T 5 ths of the liver and pancreas, T 4 ths 

 of the heart, muscles, and alimentary canal the latter at the same time having 

 undergone considerable shortening ^ths of the kidneys, -, z ths of the respira- 

 tory organs, th of the bones, y^th of the eyes, and only ^th of the nervous 

 substance. Of the adipose tissue, the fat-cells remain, the contents alone being 

 reabsorbed. The diminution in the quantity of the blood is very great, about 

 fths of it disappearing. Young and thin animals suffer much less loss of 

 weight, but they die sooner. 



The duration of life appears to be but little affected, whether the animal be 

 allowed to drink, or whether it be totally deprived of water. It has, however, 

 been shown that, if a dog be kept without water, the tissues and organs lose 

 weight, almost in the same proportion as if it had been deprived of solid food, 

 with one exception, for there is little diminution in the adipose tissue. Every 





