CIRCULATION OF THE BLOOD 



129 



duct returns the lymph from the entire body below the 



diaphragm, from the left arm, and from the left half of 



the chest, head, and face. It empties into the sub- 



clavian vein of the left arm. The right lymphatic duct 



is much smaller, returning the lymph 



from the right arm and from the right 



side of the chest, head, and face. It 



empties into the right subclavian vein. 



The lymph passes through lymph 



nodes found along the course of the 



lymphatic vessels. In these the lymph 



may undergo certain changes, and so 



become fitted for use in other parts of 



the body. 



The lymphatic vessels are very im- FlG bo ^ y ~ 

 portant. When they work properly all 

 of the wastes produced by the cells are 

 drained off into the blood and not per- 

 mitted to stagnate in the lymph spaces. 

 In this way the cells have new and fresh foods carried 

 to them as they need it, and the wastes removed as fast 

 as they are produced. Sometimes they do not work as 

 they should, and the lymph accumulates in the spaces 

 around the cells, causing a disease known as dropsy. 



The proper work of the lymphatics depends to a 

 large extent upon physical exercise. Muscular move- 

 ment serves as a natural massage for the lymphatics, 

 and pushes the lymph onward toward the heart. A 

 sufficient amount of -healthful exercise makes one feel 

 better, even in hot weather, because, when the lymph is 



drained by 

 each lymph trunk. 

 (Buchholz) : /4,the 

 left thoracic duct ; 

 B t the right lymph 

 trunk. 



