118 ELEMENTARY PHYSIOLOGY less. 



to be a transpai-ent, faintly yellow fluid. When 

 examined under the niicri)sci>i)e it is seen to contain 

 a luunber ' of corpuscles, the lymph-corpuscles or 

 leucocytes, very similar to the colourless corpuscles of 

 l)lood, though perhaps on the whole rather smaller, and 

 like the latter showing amoeboid movements, especially 

 if kept warm. These leucocytes may represent some of 

 the white blood-corpuscles which migrated from the 

 vessels, but by far the larger number are formed in the 

 lymphatic glands (see p. 91). 



When examined chemically lymph is found to contain 

 the same salts as are present in plasma and in about the 

 same amount ; the total solids are, however, considerably 

 less than in plasma," and this is due to a deficiency of 

 proteins. But the proteins present in lymph are the 

 same in kind as the three already described as found in 

 plasma, viz., fibrinogen, paraglobulin and serum albumin. 

 Hence lymph clots when left to itself and yields fibrin 

 identical with that obtained from blood, only in smaller 

 quantities so that the clot is less firm than from blood. 

 Some gas may also be extracted from it, but in the absence 

 of red corpuscles the amount of oxygen it yields is scarcely 

 ap{)reciable ; the bulk of the gas is carbonic acid and a 

 very small amount of nitrogen. 



Average lymph is therefore very similar to plasma 

 somewhat diluted with water ; but it is important to 

 notice from what has been said above that the dilution 

 does not afi'ect the salts and the proteins to the same 

 extent. Neither is the dilution the same in lymph col- 

 lected from different regions of the body. Thus lymph 

 from the arm or leg contains less, and lymph from the 

 liver more solid matter than is present in average mixed 

 lymph from the thoracic duct. The significance of 



1 Equal on the average to the number of white corpuscles present in 

 blood, so that in a drop of lymph very few would be seen and often none 

 at all. 



2 Only a1x)ut 5 per cent, of its weight as compared with 8 to 10 per 

 cent, in plasma. 



