SECTION II 

 THE METABOLISM DURING STARVATION 



IT will tend to simplify our task if we deal first with the results of the 

 experiments which have been made on the metabolic exchanges of animals 

 during starvation, i.e. during a period when the whole energy involved in the 

 maintenance of the movements of respiration and circulation, and in the 

 maintenance of the body temperature, &c., is derived from the animal's 

 own tissues. It must be remembered that the tissues of an animal comprise 

 two distinct classes. In the first class must be placed the living machinery 

 of the body, generally composed of proteins or their near allies. In the 

 second class are the fatty tissues of the body, which form no part of the 

 ordinary machinery, but function simply as a storehouse of material which 

 can be utilised for the production of energy. In addition to the store of fat 

 there is, in a well-fed animal, a certain reserve of carbohydrate in the form 

 of glycogen, deposited in the liver and muscles of the body. This store of 

 glycogen is drawn upon to a large extent at the beginning of a period 

 of starvation. The total amount of glycogen present at any time is so 

 small in comparison with the possible amount of fat that it cannot 

 provide the energy necessary for the prolonged period during which the 

 maintenance of life is possible in a complete state of inanition, although 

 it plays an important part during the first one or two days of a period 

 of starvation. 



Contrary to general belief, the condition of an animal which is completely 

 deprived of food is not a painful one. For this statement we have not only 

 such evidence as can be derived from inspection of animals placed in this 

 condition, but also evidence derived from men who have voluntarily or 

 involuntarily been deprived of food for considerable periods. Especially 

 instructive in this connection are the cases of the so-called professional 

 ' fasting men,' two of whom, Succi and Cetti, have been subjected to complete 

 metabolic investigation during the period of their starvation. During the 

 first day or two there is a craving for food at meal-times. This, however, 

 passes off, and during the later portions of the experiment even the desire for 

 food may be entirely absent. As might be expected, the restriction of food 

 is followed by a diminution in the amount of water required by the animal. 

 The essential characteristic of the state of inanition is an ever-increasing 

 weakness, accompanied by a strong disinclination to undertake any mental 

 or physical exertion whatsoever. The animal passes its time in a state of 



624 



