INCOME OF MATTER 101 



small intestine, partly by the blood vessels, 

 and partly by special absorbents, the lacteals. 

 Covering the whole of the mucous membrane 

 of the small bowel there are innumerable 

 small finger-like processes, like the pile of 

 velvet. Each process is a little organ called 

 a villus. In the centre of each villus there is 

 a tube, the outer end of which communicates 

 with numerous minute channels ; this is the 

 commencement of the absorbent system. By 

 the confluence of the bases of these tubes a 

 network of fine tubes, running in the mesen- 

 tery (or web connecting the bowel with the 

 wall of the abdomen) is formed, and these 

 tubes, by confluence, form larger and larger 

 tubes until they reach certain gland-like 

 structures, the mesenteric glands. The ducts 

 of these glands, now called mesenteric lymph- 

 atic glands, pass to a special receptacle, the 

 receptaculum chyli, and from it a large 

 duct, the thoracic duct, runs up through 

 the thorax, and, at the root of the neck, 

 on the left side, opens obliquely into the 

 venous system, just at the confluence of 

 the internal jugular vein, carrying blood 



