DIGESTION. 95 



part of the intestines, it excites the flow of a new digestive 

 fluid, which enters through a small tube, or duct, about 

 three inches below the stomach. It is formed by the union 

 of two distinct fluids the bile and the pancreatic juice. 

 The bile is secreted by the liver, which is the largest gland 

 of the body, and is situated on the right side and upper 

 part of the abdomen (Fig. 22). The bile is constantly 

 formed, but it flows most rapidly during digestion. Dur- 

 ing the intervals of digestion it is stored in the gall-bladder ', 

 a small membranous bag attached to the under side of the 

 liver. This fluid is of a greenish-yellow color, having a 

 peculiar smell, and a very bitter taste. 



34. The pancreatic juice is the product of a gland called 

 $\Q pancreas, situated behind the stomach. This fluid is col- 

 orless, viscid, and without odor. Like the digestive juices 

 previously described, it owes its solvent power to its pecu- 

 liar ferment principle, called pancreatin. By the joint 

 action of these fluids, the fatty parts of the food are pre- 

 pared for absorption. By previous steps of digestion the 

 fats are merely separated from the other components of the 

 food ; but here, within the intestines, they are reduced to a 

 state of minute division, or emulsion, resembling the con- 

 dition of butter in milk, before it has been churned. 

 There results from this action a white and milky fluid, 

 termed the chyle, which holds in solution the digestible 

 portions of the food, and is spread over the extensive 

 absorbent surface of the small intestines. 



35. The mucous membrane of the intestines, also, 

 secretes or produces, a digestive fluid by means of numer- 

 ous "follicles," or minute glands; this is called the in- 

 testinal juice. From experiments on the inferior animals, 

 it has been ascertained that this fluid exerts a solvent influ- 

 ence over each of the three organic food principles, and in 

 tins' way may supplement and complete the action of the 



34. The pancreatic juice ? The joint action of these fluids* ? 



35. The mucous membrane ? Experiments on inferior animals ? 



