192 



FUNCTIONS OF NUTRITION. 



FIG. 33. 



emulsifying action on fats is also quite secondary in importance, and its 

 power of digesting albumenoid substances doubtful or imperfect. Its 

 most important property is perhaps the simple one of lubricating the 



mucous membrane, and facilita- 

 ting the passage of alimentary 

 materials through the intestine. 

 Digestion in the Intestine. 

 The digestive process, which 

 commences in the stomach under 

 the influence of the gastric juice, 

 is continued and completed dur- 

 ing the passage of the food 

 through the small intestine. Its 

 details may be examined in suc- 

 cessive parts of the alimentary 

 canal, in animals killed while 

 digestion is going on. After 

 a meal, consisting of muscu- 

 lar flesh and adipose tissue, 

 the stomach contains (Fig. 

 33) masses of softened meat, 

 smeared with gastric juice, and 

 a moderate quantity of grayish 

 grumous fluid with an acid reaction. This fluid contains isolated mus- 

 cular fibres, more or less reduced to fragments. The fat vesicles of 



CONTENTS OF STOMACH DURING DIGESTION OF MEAT, 

 from the Dog. a. Fat Vesicle, filled with opaque, 

 solid, granular fat. 6, 6. Partially disintegrated 

 muscular fibre, c. Oil globules. 



FIG. 34. 



FIG. 35. 



FROM DUODENUM OF DOG DURING DIGESTION 

 OF MEAT. a. Fat vesicle, with its contents 

 diminishing. The vesicle is beginning to 

 shrivel and the fat breaking up. 6, 6. Disinte- 

 grated muscular fibre, c, c. Oil globules. 



FROM MIDDLE OF SMALL INTESTINE. a, a. Fat 

 vesicles, nearly emptied of their contents. 



beef are but little altered, and there are only a few free oil globules in 

 the mixed fluids of the stomach. In the duodenum the muscular fibres 



