PART SIXTH. 

 DIGESTIVE SYSTEM. 



I. OBJECT OF DIGESTION. INANITION. FOOD. 



THE aim of the digestive functions is to transform the 

 substances borrowed from without, so us to enable them to 

 pass into the system, to be absorbed and carried into the 

 current of the circulation, in order to renew the organs, and 

 keep up their functions. 



These reconstructive substances are food. 



By privation of food, animals are reduced to a state of 

 inanition: the inevitable consequences of prolonged inani- 

 tion are gradual loss of weight, cold, and death ; animals die 

 when they have lost -j* ff of their original weight (Chossat.) 1 



This loss of weight is produced sooner in some animals 

 than in others : cold-blooded animals will endure privation 

 of food thirty times longer than the warm-blooded, and some- 

 times, even, for an almost incredible space of time : thus Cl. 

 Bernard has known frogs go entirely without food for nearly 

 three years, while a small bird dies of hunger after two or 

 three days. 



Inanition, as observed in persons subjected to a strict diet, 

 not only affects the general temperature, but also the daily 

 variations in temperature: even when there is no fever, this 

 may vary 3. This fact should be taken into account, in esti- 

 mating the temperature of persons suffering from intermittent 

 fever, who have long been on a low diet. 



Some of the alimentary substances, intended to repair the 

 incessant waste of the system, are immediately absorbed ; 

 while others, which are deposited on the surface of the 



1 Chossat, * ' Recherches Experimeiitalcs sur 1'Inanition. ' ' Paris, 

 1843, in 4to. 



