ABSORBENTS OF THE TRUNK. 591 



the office of the latter to convert the crude aliment into 

 chyme and chyle, it is the business of a portion of the for- 

 mer to take up this chyle, thus prepared for the nutrition 

 of the body, and introduce it into the circulation, whence 

 it is conducted, along with the blood, to the lungs, where 

 it receives its final and finishing stroke as blood, to be now 

 taken up, by the organs of circulation, and distributed 

 throughout the system for the support of every part. 



The organs of absorption comprise three sets of struc- 

 tures the lactealSj lymphatics, and lymphatic or absorbent 

 glands. 



Under the head of glandular tissue, some general re- 

 marks are made upon the absorbent system. The lacteals 

 (Fig. 182) and lymphatics are regarded as parts essentially 

 of the same system of vessels, though having different 

 names. The structure of both is the same, consisting each 

 of two coats an external, which is regarded as fibrous by 

 some, and muscular by others ; and an internal, which is 

 very delicate and transparent, resembling that of the veins. 

 A middle coat is also spoken of, which is thin, as in the 

 veins, but destitute of the elastic lamina. Like the veins, 

 the internal coat of the absorbents presents numerous folds 

 constituting valves. These valves are of semilunar shape, 

 and arranged in pairs, giving the vessels containing them 

 a braided or knotted appearance, (Fig. 18.) These valves 

 prevent the retrograding of the chyle and lymph. The 

 absorbents, like the veins, are divided into the superficial 

 and deep, and have their fluids running the same direction. 



The trunks of the absorbents terminate in the venous 

 system; hence these two are only regarded by some 

 as continuations of one and the same system. This 

 difference however is observed, that all the absorbents, 

 whether superficial or deep, converge and pass through a 

 set of bodies called lymphatic or absorbent glands, while 

 veins do not. The absorbents, on entering these glands, are 

 termed vasa inferentia, and on passing out vasa efferentia. 

 These glands, as elsewhere stated, are very numerous, pre- 

 senting a reddish, or gray color, varying in size from a cur- 



