CHAPTER XXIL 



ABSORPTION. 



1. (ABSORPTION is another function of the animal body, 

 immediately connected with nutrition.^ By it is meant that 

 process by which food and drinks, designed for the nourish- 

 ment and growth of the body, are taken up and carried into 

 the blood ; and also those particles and materials that have 

 been already deposited, and have become either useless or 

 injurious, are conveyed into the general mass of the circula- 

 ting fluids, and thus removed from the system. The first is 

 effected by the lacteal vessels ; the second by the lymphatics. 



2. The absorbent system, so called, consists of the lym- 

 phatic vessels, the lymphatic glands, and the thoracic duct) 



[ The lymphatic vessels arise, not only from all the mucous 

 surfaces, but also from the whole surface of the body} the 

 intimate tissue of every structure ; and from all cavities, 

 such as the chest, abdomen, the joints, the pericardium, and 

 even the ventricles of the brain. jThey are exceedingly 

 small at their origin, but by uniting, form larger and larger 

 trunks as they proceed, which is generally in the course of 

 the veins, till they finally discharge their contents, either in- 

 to the thoracic duct, or some of the large veins near the 

 heart. Throughout their whole extent, they are provided 

 with numerous valves, which, when they are distended with 

 lymph, causes them to resemble a string of beads.^) 



3. Every part of the body is supposed to be furnished 

 with absorbent vessels, with the exception of the nails, the 

 hair, the cuticle, and the enamel of the teeth. And even in 

 these, it is not impossible that they may exist ; only they 

 are too small to be detected. 



4. (The lymphatics of the small intestines, called lacteals,/ 

 are the agents of digestive absorption. $They arise from the 



