THE BLOOD 207 



individual cell elements. These spaces in the tissues open 

 into vessels the lymph vessels in which the lymph flows 

 and is conducted through lymph glands and back to the 

 blood through the thoracic duct. (See Fig. 105, p. 209.) 



Lymph varies in character according to the situation from 

 which it is taken and according to the condition of the 

 animal. 



Lymph taken from the lymph spaces e.g. the pericar- 

 dium, pleura or peritoneum is a clear, straw-coloured fluid. 

 It has little or no tendency to coagulate. Microscopic 

 examination shows that it contains few or no cells any 

 cells which may exist being lymphocytes. In reaction it 

 is alkaline. The specific gravity varies according to its 

 source. 



Apparently the cause of the non-coagulation of such lymph 

 is the absence of cells from which thrombin may be set free. 

 If blood or white corpuscles be added to it, a loose coagulum 

 forms. 



If the lymph be taken from lymphatic vessels after these 

 have passed through lymphatic glands, it is found to contain 

 a number of lymphocytes, and it coagulates readily. 



Chemically, lymph resembles blood plasma in which the 

 proteids are in smaller amount, but the inorganic salts in 

 the same proportion as in the blood. The amount of solids 

 varies in lymph from different organs. 



Lymph of Proteids. 



Limbs 2-3 per cent. 



Intestines .... 4-6 

 Liver 6-8 



In the lymphatics coming from the alimentary canal during 

 starvation, the lymph has the characters above described. 

 But after a meal it has a milky appearance and is called 

 chyle. This milky appearance is due to the presence of fats 

 in a very fine state of division, forming what is called the 

 molecular basis of the chyle. 



Lymph in various diseases tends to accumulate as serous 

 effusions in the large lymph spaces e.g. the pleura, peri- 

 toneum, pericardium and these effusions behave differently 



