DIGESTION. 



69 



being also largest at its commencement. At the point of 

 union, the two tubes do not form a continuous straight 

 passage, but the smaller one opens into the larger on its 

 inner side, something after the manner in which a small 

 pipe leads off from the side of 

 a larger. The large intestine is 

 here closed at its lowest part, 

 forming a pouch. 



A magnifying glass shows the 

 inner surface of the small intes- 

 tine to be covered with minute 

 elevations. These are known as 

 villi. The size of each villus is 

 from one-fiftieth to one-thirty- 

 second of an inch in length. 

 They are so thickly placed as to 

 give the lining the appearance 

 of the pile on velvet. It is these 

 tiny projections that give to tripe 

 its peculiar appearance. In each 

 villus is a branch, sometimes 

 double, of the lymphatic system. 

 These branches are .known as 

 the lacteals, so called because, 



during digestion, they contain a ^ ^^ Alimentary Canal 

 milky fluid, the chyle, which they low the gullet: i, stomach; 2, 3, 4, 

 have sucked up from the con- 

 tents of the intestine. Follow- 

 ing the chyle on through the lacteals, we find the tubes 

 become larger, and finally pour their contents into a sac at 

 the back of the loins, called the receptacle of the chyle. Trom 

 this sac, the thoracic duct ascends through the back part 

 of the thoracic cavity, and eventually opens into a large vein 



small intestines; 6-11, large intestine; 

 5, closed pouch of large intestine. 



