ABSORBENTS. 115 



contents of the vessels, otherwise termed chyle, undergo certain changes 

 in composition. 



The Lymphatic vessels are larger than the lacteals. Numerous lym- 

 phatic glands are distributed over the body. All lymphatic vessels at 

 various points of their course run through these glands. Like the lac- 

 teals they all run into the thoracic duct, and their contents are ultimately 

 discharged into one of the large blood-vessels near the heart. 



The structure and uses of the lymphatic glands are similar to those of 

 the lacteal glands. 



220. Functions of the Absorbents generally. 



The function of absorption is necessary both for the purposes of nutri- 

 tion, and also for carrying off the used up or no longer required or super- 

 fluous material of the system. It is by means of absorption that the 

 body is constantly undergoing change, both receiving new material from 

 the food, and eliminating waste products. 



It has been generally supposed that the lacteals receive the new 

 material, whilst the lymphatics carry off the waste and effete products. 

 In this latter function the lymphatics are undoubtedly assisted by the 

 veins, which possess considerable powers of absorption. It is now, how- 

 ever, generally believed that the process of absorption of waste material 

 is wholly performed by the veins ; and that the lymphatics as well as the 

 lacteals are engaged in absorbing and elaborating organi sable principles, 

 which are capable of being still further employed in the animal economy. 



221. Functions of the Lacteals. 



The Lacteals absorb from the food the parts useful for nutrition. They 

 contain a white milky albuminous fluid called chyle, abounding in innu- 

 merable particles of oily or fatty matter. In passing through the various 

 lacteal glands, and especially in those situated in the mesentery, the chyle 

 undergoes considerable changes. The quantity of molecular and oily 

 particles diminish ; and cells, to which the name of chyle corpuscles is 

 given, are developed in it, and it also acquires the power of coagulating. 

 The chyle, as mentioned above, after passing through the thoracic duct 

 is ultimately discharged into one of the large blood-vessels near the heart. 



222. Functions of the Lymphatics. 



The Lymphatic vessels absorb from the blood those elements which 

 are capable of being again employed in the animal economy. They con- 

 tain a limpid colourless fluid. As in the case of the lacteals, the fluid, 

 which they absorb, undergoes considerable changes in its composition in 

 passing through the lymphatic glands. After passing through the glands 

 the fluid is carried by the vessels to the thoracic duct, and ultimately 

 discharged into one of the large blood-vessels near the heart. At the 

 period of entering the thoracic duct the lymphatic fluid and chyle appear 

 to be identical except in colour. Chemical analysis fails to detect any 

 difference in their properties or composition. 



