ABSORPTION. 121 



though the number varies in different portions of the lymphatic 

 system. As the lymph flows through the lymphatic gland it receives 

 a large addition of corpuscles. Lymph-corpuscles are granular in 

 structure, and measure %$$ ^ an i ncn i n diameter. When with- 

 drawn from the vessels, lymph undergoes a spontaneous coagulation 

 similar to that of blood, after which it separates in serum and clot. 



Origin and Functions of Lymph. Though the blood is the com- 

 mon reservoir of all nutritive materials, they are not available for 

 nutritive purposes as long as they are confined within the blood- 

 vessels. But owing to the character of the wall of the capillary 

 blood-vessel, some of the constituents of the blood-plasma pass 

 through it and are received by the tissue-spaces in which they come 

 into contact with the tissue-cells. To the sum total of these materials 

 the term lymph is given. Its function becomes apparent from its 

 origin and composition, its situation and relation to the tissues. It 

 is to furnish the tissue-cells with those nutritive materials which 

 are necessary for their growth, repair and functional activity. It 

 also receives all waste products that arise from their activity prior 

 to their removal by the blood- and lymph-vessels. 



Absorption of Lymph. From the fact that lymph is being dis- 

 charged more or less continuously from the thoracic duct, it is 

 evident that lymph is being absorbed from the intercellular spaces ; 

 from which it may be inferred that more lymph is passing from 

 the blood into the tissue-spaces than is necessary for the immediate 

 needs of the tissues. To prevent an accumulation and an inter- 

 ference through pressure with the activities of the tissues, the excess 

 is absorbed by the lymph-vessels and returned to the blood stream 

 by way of the thoracic duct. It is likely that some of the con- 

 stituents are absorbed by the blood-vessels. 



Chyle. Chyle is the fluid found in the lymph vessels, coming 

 from the small intestine after the digestion of a -neal containing 

 fat. In the intervals of digestion the fluid of thebe lymphatics is 

 identical in all respects with the lymph found in all other regions 

 of the body. As soon as the emulsified fat passes into the lymph 

 vessels and mingles with the lymph it becomes milky white in color, 

 and the vessels which previously were invisible become visible, and 

 resemble white threads running between the layers of the mesentery. 

 Chyle has a composition similar to that of lymph, but it contains, 



