FUNCTIONS OF THE INTERCELLULAR LYMPH 229 



Production of Lymph. This is still under discussion, 

 various theories being advanced, but none are abso- 

 lutely definite, nor is any accepted by physiologists as 

 the correct one. It is supposed to be formed by the 

 plasma of the blood passing through the thin-walled 

 capillaries into the small lymph spaces which exist 

 between the cells of the adjacent tissues; and another 

 theory is that this transudation is aided by an active 

 secretory action on the part of the endothelial cells 

 composing the capillary walls. 



This passing or transudation of the nutritive material 

 and the white cells through the walls of the capillaries 

 is necessary in order to have the tissues receive the 

 elements essential for their nourishment, and to 

 combat, with the contained lymphocytes, any invading 

 germ, or to neutralize any toxin within the spaces. 

 The passage of the plasma or liquid nutritive element 

 of the blood through the capillary walls is based on 

 three factors: namely, osmosis, diffusion, and filtration. 

 (See standard works on physiology.) 



The Functions of the Intercellular Lymph. The 

 intimate contact of the lymph with the tissue cells 

 of the body denotes that its function is to furnish 

 those cells with nutritive elements essential to their 

 growth, repair, and functional activity, and to receive 

 from those cells the products resulting from disintegra- 

 tion or tissue waste as a result of body metabolism. 



In order to have the lymph in relation with the 

 tissue cells retain a certain composition, which is con- 

 stantly being reduced by the absorption of the waste 

 products into the lymph vessels and blood, it is 

 necessary that the lymph be renewed as rapidly as 

 consumed, and the waste material removed as pro- 

 duced. Should one of these conditions fail the nutri- 

 tive elements of the lymph would be reduced, and 

 consequently destroy the vitality of the tissues. 



The formation of lymph is a continuous phenomena 

 and more is formed than is essential to the needs of 



