176 A Manual of Veterinary Physiology. 



lected from the tissues and taken back into the blood. 

 There are certain non-vascular tissues, such as the cornea, 

 where the lymph circulation is the only means by which 

 the part is supplied with nourishment. Speaking gener- 

 ally, however, the lymphatic system may be described as 

 the drainage system of the body, in contradistinction to 

 the blood or irrigating system. 



Lymph is a slightly yellow-coloured fluid, alkaline in 

 reaction, with a specific gravity of 1012 to 1022, and 

 possessing the power of spontaneous clotting. The clot 

 it yields is not so firm as that of blood, and takes longer 

 to form; moreover, the bulk of fibrin is much smaller. 

 Lymph may be regarded as blood minus the red corpuscles : 

 it contains, therefore, the proteids of that fluid, cells resem- 

 bling the white cells of the blood, extractives, salts, and 

 gases. The fluid in which these are contained may be 

 spoken of as lymph-serum. The gases consist principally 

 of CO., (which is greater than in arterial, but less than in 

 venous, blood), a small quantity of nitrogen, but no oxygen. 



The Lymph Cells possess amoeboid movements, and are 

 identical with white blood cells. They are more numerous 

 in those vessels which have passed through lymphatic 

 glands, as it is these latter which principally add the cor- 

 puscles to the lymph. The cells consist of proteids, lecithin, 

 cholesterin, and fat, and their nuclei contain nuclein. Owing 

 to their power of movement, they are able to pass through 

 the bloodvessels into the tissues and vice versa. The pro- 

 portion of lymph corpuscles to fluid is about the same as 

 the proportion of white corpuscles to blood. 



In the lymph plasma is found the fibrin factors, hence 

 the power the fluid possesses of spontaneous cloning. 



Amongst the extractives some observers have found 

 urea, which is said to be always present in the cow; 

 more urea exists in lymph than in blood (Halliburton). 

 The salts arc distributed much as those in blood, viz., 

 potash and phosphoric acid in the corpuscles, and soda 

 in the serum. 



The lymph corpuscles originate in the lymphatic -lands. 



