6 THE HUMAN BODY. 



been called the whey. It is a little less dense than the clot, 

 and contains among other principles a great deal of albumen. 

 The serum is the plasma without the fibrine. 



The chyle is a white opaque fluid closely resembling milk, 

 which is separated from the food during the process of diges- 

 tion, and is drawn by the chyliferous vessels from the surface 

 of the smaller intestine, and serves to form the blood. As 

 it advances toward the point where it mingles with the blood, 

 it resembles this fluid more and more in its composition; it 

 takes a roseate tint, and, if left to itself, it separates into 

 fibrinous clot and albuminous serum. 



The lymph is a clear, transparent fluid, slightly tinted with 

 green or yellow. Drawn from the organs by the lymph- 

 atic vessels, and especially from the skin and the surface 

 of the mucous and serous membranes, the lymph is poured 

 into the mass of blood by two principal canals. Like 

 the chyle it contains white globules and minute specks of 

 fat. When extracted from the lymphatic vessels, it also 

 separates into fibrinous clot and serum, containing a little 

 albumen. 



We see therefore that chyle and lymph are imperfect blood. 

 The chyle leaves the digestive apparatus in a crude state, and 

 goes to the blood-making laboratories for its perfection. The 

 lymph comes from the extreme limits of the organs to these 

 same laboratories, and, uniting with the chyle, is poured into 

 the blood the constituent fluid par excellence. 



The secreted fluids or secretions are produced by special 

 apparatus from the materials furnished by the constituent 

 fluids. They differ from these last in being only a medium 

 for the elements which they hold in suspension, these elements 

 not being essential to them, as the globules are to the blood, 

 for example. They all contain one or several organic fluid 

 substances, to the nature of which the secreted fluid owes its 

 essential properties. These humours are very numerous, and 

 play a very distinct part in the human economy. They are 

 normal or morbid, as they owe their origin to the regular 

 function of the organs or are modified by the action of disease. 

 We shall mention only milk, which resembles the blood by 

 composed largely of serum, and which cannot be 



