114 CHAPTER 12. 



CHAPTER 12. 



THE ABSORBENTS. 



218. Of the Absorbent system. 219. Structure. 220. Functions of the 

 Absorbents generally. 221. Functions of the lacteals. 222. Functions of 

 the lymphatics. 223. Diseases of the lacteals. 224. Diseases of the lym- 

 phatics. 225. Stimulants to the superficial absorbent system. 226. Weed. 



218. The Absorbent system. 



Besides the arteries and veins there is yet another or third system of 

 vessels in the body, called the Absorbents. 



Although they play a very important part in the animal economy, yet 

 they are comparatively speaking little thought of or observed, probably 

 because as a rule they perform their functions so regularly and well, that 

 no disturbance sufficient to call attention to them takes place. When, 

 however, disease does occur in the absorbents, the effect on the constitu- 

 tion as well as on the vessels more immediately affected is not only very 

 marked, but very rapid. 



For the purpose of description the absorbents may be separated into 

 two divisions, namely, the Lacteals and the Lymphatics. Each class is 

 further subdivided into vessels and glands. The lacteals are distributed 

 in infinite numbers over the whole of the mucous membrane of the intes- 

 tines. The lymphatics are found in almost all the structures of the body. 

 The lacteals are merely the lymphatics of the digestive organs. 



219. Structure. 



In structure the Absorbents are very like the veins, a description of 

 which was given in Chapter 10. Their walls have some power of con- 

 tractility. They are furnished with valves, and in the smaller veins in 

 particular the valves are very numerous. Some peculiarities connected 

 with these valves will be noticed hereafter. The absorbents accompany 

 the veins and arteries, but are more numerous in some than in other 

 parts. They anastomose freely everywhere. Though with difficulty 

 distinguished in the dead animal, they are very readily seen in injected 

 preparations. 



The Lacteals are very minute vessels, having their origin in the innu- 

 merable villi of the intestinal mucous membrane. Each villus gives rise 

 to a lacteal. They afterwards unite and form larger vessels, which pass 

 into and through the mesenteric glands, and thence on to the thoracic 

 duct, and ultimately they discharge their contents into one of the large 

 blood-vessels near the heart. 



The lacteal glands are situated in the mesentery. Each gland is com- 

 posed of a plexus of lacteal vessels. The vessels passing out of a gland 

 are less numerous and larger than those entering it. In the glands the 



