THE CIRCULATING SYSTEM, 



431 



The lacteals end in the lower part of the thoracic duct. 



Lymphatic glands are scattered in various parts of the 

 body, but those most readily observed in man are the glands 

 in the arm-pit, the groin, and the sides of the neck. 



I 



FIG. 369. THE THORACIC DUCT. 



The Thoracic Duct occupies the middle of the figure. It lies upon the spinal 

 column, at the sides of which are seen portions of the ribs. At the bottom of 

 the' figure the psoas muscles appear. 



a, the receptacle of the chyle ; />, the trunk of the thoracic duct, opening at c into 

 the junction of the left jugular (/) and subclavian (g) veins as they unite into 

 the left innominate vein ; e. the right innominate vein formed by the union of 

 the left jugular and subclavian veins ; d, lymphatic glands placed in the lumbar 

 and intercostal regions ; h, /i, the cut oesophagus. Two veins are seen running 

 alongside the lower part of the thoracic duct, and, just above its middle,one (the 

 left) crosses under the duct and joins the other. These are the azygos veins. 



No part of the lymphatic system of man is rhythmically 

 contractile. 



13. In surveying this system by the light furnished by the 

 anatomy of other Vertebrates, we find that its condition may 



