CHAPTER IX. 



ABSORPTION. 



Lymph. 

 The methods b}< which the lymph in the body passes out 

 of the bloodvessels into the tissues, are generally considered 

 in conjunction with the physical process of the diffusion 

 and filtration of fluids. It is more than probable that 

 these may assist in the passage of fluid from the blood into 

 the tissues, yet neither of such purely physical processes 

 is capable of wholly explaining the many facts in connec- 

 tion with lymph formation, and it is therefore more in 

 agreement with advanced physiological thought to attribute 

 its formation to changes in the walls of the capillary blood- 

 vessels, the epithelium of which is probably as intimately 

 concerned in the production of lymph from the blood, as 

 the other cells of the body are concerned in the manufac- 

 ture of secretions. 



The tissues are bathed in lymph, which is contained in 

 the lymphatic spaces which exist between the capillary 

 bloodvessels and capillary lymph- vessels. There is a con- 

 stant passage of material from the blood into the tissues, 

 and from here through the capillary lymphatics into the 

 main lymphatics, and thence through the thoracic duct 

 into the venous system. 



The largest lymph-spaces in the body are the pleural 

 and peritoneal cavities ; both these communicate with 

 lymphatic vessels, many of which are in the diaphragm. 



Lymph may be regarded as the material by which the 

 tissues are directly nourished ; but besides this it may be 

 looked upon as a means by which effete material is col 



