114 



THE HUMAN BODY. 



Aorta> 



The lymphatic vessels are much more delicate and 

 slender than the blood-vessels. 



3. When a farmer has a wet field, he frequently lays 

 pipes in it made of burned clay, called tile. The standing 

 water soaks into these pipes, and is carried off; and so 

 the field is dried. 



The lymphatics are the drain-pipes of the body. They 

 assist the blood-vessels in taking up the fluids which are 

 standing in all parts, and carrying them away to be 

 delivered up to the blood-stream at the proper place. 



4, The lacteals comprise that portion of the lym- 



phatic vessels that 

 begins in the walls 

 of the small intes- 

 tine. When diges- 

 tion is not going on, 

 they are drain-pipes, 

 like the rest. As 

 soon as digestion 

 begins, they begin 

 to look white and 

 milky. They are 

 then engaged in 

 their special work of 

 taking up the fat 

 from the intestine. 

 They are found in 

 all the villi. 



Thoracic 

 \ duct. 



Lymphatic 

 glands. 



Small 

 intestine. 



Lacteal*. 



Fig. 46. 

 LYMPHATICS OP THE INTESTINE. 



SECTION IV. 1. The process of digestion is not under 

 control of the will. In health it takes care of itself, and 

 we give no thought to it. But, when the digestive appa- 



