356 AGRICULTURE ON THE PACIFIC SLOPE 



pours a juice which not only digests fats, but also any 

 albumin and starch which has not already been made 

 liquid. Now all the food is in liquid form ready to 

 be taken up into the blood. 



How is the liquid food absorbed? We have seen 

 (page 12) that the plant must have a large surface to 

 absorb its liquid food, and this surface is greatly in- 

 creased by small hairlike bodies (the root hairs). It 

 is much the same with the animal. A large surface is 

 made by the great length of the intestine. The small 

 intestine in man is over twenty feet long; this surface 

 is increased by ridges on the inside of the tube and 

 furthermore by hairlike bodies so thickly placed that 

 they give the surface the appearance of velvet, as you 

 can easily see, if you put a piece of the small intestine 

 of a sheep in water. 



From the small intestine, the food passes into the 

 large intestine, which in man is about six feet long. 

 Here the last of the liquid food is absorbed, and the 

 part which has not been made liquid then leaves the 

 body. 



How other animals digest food. The digestive sys- 

 tem of birds differs from ours, because birds have no 

 teeth. When a chicken is being dressed, you may easily 

 see all the digestive apparatus. The food passes down 

 the throat into a sort of sac called the crop, in which 

 it becomes softened, and then it goes into the stomach, 

 the hinder part of which is called the gizzard. The, 



