ABSORPTION. 301 



The tonsils, in part, and Beyer's glands of -the intestine, are really 

 lymphatic glands, and doubtless discharge similar functions. 



THE LYMPH AND CHYLE. 



The lymph, contained in the lymphatic vessels, is, under ordinary cir- 

 cumstances, a clear, transparent, and yellowish fluid. It is devoid of 

 smell, is slightly alkali ae, and has a saline taste. As seen with the 

 microscope in the small transparent vessels of the tail of the tadpole, it 

 usually contains no corpuscles or particles of any kind; and it is only in 

 the larger trunks in which any corpuscles are to be found. These corpus- 

 cles are similar to colorless blood-corpuscles. The fluid in which the cor- 

 puscles float is albuminous, and contains no fatty particles or molecular base; 

 but is liable to variations according to the general state of the blood, and 

 to that of the organ from which the lymph is derived. As it advances- 

 toward the thoracic duct, and after passing through the lymphatic glands, 

 it becomes spontaneously coagulable and the number of corpuscles is much, 

 increased. The fluid contained in the lacteals is clear and transparent 

 during fasting, and differs in no respect from ordinary lymph; but, during 

 digestion, it becomes milky, and is termed chyle. 



Chyle is an opaque, whitish, milky fluid, neutral or slightly alkaline 

 in reaction. Its whiteness and opacity are due to the presence of innu- 

 merable particles of oily or fatty matter, of exceedingly minute though 

 nearly uniform size, measuring on the average about yg-J-g-g- of an inch. 

 These constitute what is termed the molecular base of chyle. Their 

 number, and consequently the opacity of the chyle, are dependent upon 

 the quantity of fatty matter contained in the food. The fatty nature of 

 the molecules is made manifest by their solubility in ether, and, when 

 the ether evaporates, by their being deposited in various-sized drops of 

 oil. Each molecule probably consists of oil coated over with albumen, in 

 the manner in which oil always becomes covered when set free in minute 

 drops in an albuminous solution. This is proved when water or dilute 

 acetic acid is added to chyle, many of the molecules are lost sight of, and 

 oil-drops appear in their place, as the investments of the molecules have 

 been dissolved, and their oily contents have run together. 



Except these molecules, the chyle taken from the villi or from lacteals 

 near them, contains no other solid or organized bodies. The fluid in 

 which the molecules float is albuminous, and does not spontaneously 

 coagulate. But as the chyle passes on toward the thoracic duct, and 

 especially, while it traverses one or more of the mesenteric glands, it is 

 elaborated. The quantity of molecules and oily particles gradually dimin- 

 ishes; cells, to which the name of chyle-corpuscles is given, are devel- 

 oped in it; and it acquires the property of coagulating spontaneously. 

 The higher in the thoracic duct the chyle advances, the more is it, in all 



