LYMPH AND CHYLE 57 



rather less than one- fourth; and the rest of the body about one-fifth, 

 of the total blood. The kidney and spleen of the rabbit each contain 

 one-eighth of their own weight of blood, the liver between one-third 

 and one-fourth of its weight, the muscles only one-twentieth of their 

 weight. 



SECTION V. LYMPH AND CHYLE. 



Lymph has been denned as blood without its red corpuscles 

 (Johannes Miiller); it resembles, in fact, a dilute blood-plasma, 

 containing leucocytes, some of which (lymphocytes) are common to 

 lymph and blood, others (coarsely granular basophile cells, present 

 only in small numbers) are absent from the blood. Lymph also 

 contains thrombocytes. The reason of this similarity appears when 

 it is recognized that the plasma of tissue-lymph (p. 460) is derived, 

 in large part at any rate, from the plasma of blood by a process of 

 physiological filtration (or secretion) through the walls of the 

 capillaries into the lymph-spaces that everywhere occupy the inter- 

 stices of areolar tissue, while the lymph of the lymphatic vessels is 

 in turn derived from the tissue fluid. But in addition to the con- 

 stituents of the plasma, lymph contains substances produced in the 

 metabolism of the tissues which pass into it directly. As collected 

 from one of the large lymphatic vessels of the limbs, or from the 

 thoracic duct of a fasting animal, lymph is a colourless or some- 

 times yellowish or slightly reddish liquid of alkaline reaction. Its 

 specific gravity is much less than that of the blood (1015 to 1030). 

 It coagulates spontaneously, but the clot is always less firm and less 

 bulky than that of blood. The plasma contains fibrinogen, from 

 which the fibrin of the clot is derived. Serum-albumin and serum- 

 globulin are present in much the same relative proportion as in blood, 

 although in smaller absolute amount. Neutral fats, urea, and sugar 

 are also found in small quantities. The inorganic salts are the same 

 as those of the blood-serum, and exist in about the same amount, 

 sodium preponderating among the bases, as it does in serum. The 

 following table shows the results of analyses of lymph from man and 

 the horse (Munk) : 



* The term ' extractives ' is somewhat loosely applied to organic substances 

 which exist in so small an amount, or have such indefinite chemical characters, 

 that they cannot be separately estimated, and are extracted together from the 

 residue by various solvents. 



