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VETERINARY PHYSIOLOGY 



In the lymphatics, coming from the alimentary canal, 

 after a meal containing fat, the lymph has a milky appear- 

 ance and is called chyle. This 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 

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

 toneum, pericardium — and these effusions behave differently 

 as regards coagulation. The following table helps to explain 

 this (S.A. is Serum Albumin, S.G. Serum Globulin) : — 



2. Formation of Lymph. — The amount of lymph formed is 

 measured by opening the thoracic duct in the neck and 

 collecting the lymph which flows from it. 



Lymph is derived partly from the blood and partly from 

 the tissues. Two processes may be involved — (1) Filtration, 

 the forcing of fluid and of substances dissolved in it through 

 the pores of a membrane under pressure. (2) Osmosis, the 

 passage of water through semi-permeable membranes — 

 membranes allowing the passage of water, but not of 

 substances in solution — to a point of higher molecular con- 

 centration. Diffusion, or the passage of dissolved substances 

 through a membrane from a point of high to a point of low 

 concentration, can play only a small part. 



If the formation of lymph cannot be explained in terms 

 of these purely physical processes, then some unknown 

 action of the cells of the capillaries must be invoked to 



