158 PHYSIOLOGY. 



The proteids present are fibrinogen, serum-globulin, and serum- 

 albumin. The three proteids in the blood are diminished in the 

 lymph, especially the fibrinogen. 



The extractives in lymph are urea, fat, lecithin, cholesterin, and 

 sugar, with the inorganic salts. The quantity of salts in the lymph 

 and the blood is the same. The lymphocytes contain glycogen. 



The apparently transparent lymph is found to contain cor- 

 puscles when examined under the microscope; to them the name 

 lymphocytes has been applied. They have a large nucleus with com- 

 paratively little protoplasm. In some places the thoracic duct, for 

 example a few colored blood-corpuscles are found and are believed 

 to have found their way into this distinct system by reason of 



spaces 



^ -Secreting 

 cells. 



- Blood 

 capillary 



Basement 

 membrane 



Fig. 44. Diagram to Show Relation of the Secreting Cell of a Gland 

 to the Blood and Lymph-supply. (STABLING.) 



diapedesis. The regular lymphocytes find their way into the blood- 

 stream, where they multiply and are known as leucocytes. 



The real manufactories of these lymphocytes are the lymphatic 

 glands, whose alveoli contain adenoid tissue. The number of lym- 

 phocytes is much greater in the lymph after it has passed through 

 a gland, and we find that lymph collected from regions where there 

 are few glands, as the lower extremities, is always poorer in albumin 

 and richer in water than the lymph in the large lymphatic vessels. 



For purposes of analysis, lymph can be obtained from the limbs, 

 thoracic duct, and serous cavities. Accidental lymphatic fistulae in 

 man, as well as experimental ones in animals, have been the source 

 of much lymph for analytical purposes. 



The pericardial fluid and aqueous humor are forms of lymph 

 which are not coagulable except upon the addition of fibrin-ferment. 



