ABSORBENT VESSELS. 



69 



plexus, however, and mixed up with larger veins which 

 anastomose with the superficial venous plexus, the arteries ramify- 

 to a great degree of minuteness. 



Of the Absorbent Vessels. 



— The lacteals of the small intestines arise partly from the 

 villi, and partly from the surface of the intervillous mucous 

 membrane. Nearly all the best microscopical observers now 

 agree, that there are no orifices of the lacteals visible on the 

 villi of the intestines. The villi which are short processes, a 

 quarter of a line, or at most a line and two-thirds in length, 

 project above the surface of the mucous membrane and give to 

 it, when magnified, the appearance of a thick fleece. They 

 have various forms, cylindrical, pyramidal or lamellated. In 

 most of our domestic animals, they are generally flattened, broad 

 at the base, which runs off into a fold of the mucous membrane, 

 so that many of the villi appear only as a modification of the 

 rugae or folds of the membrane. The villi are formed exteriorly 

 by a coating of mucous membrane, filled within by a net-work 

 of minute blood-vessels, which can only be well demonstrated 

 by injection, and in which the lacteals take their origin by 

 branches anastomosing in the form of net-work. Fig. 138, is a 

 Fig. 138.* magnified representation of a villus, seen by 

 Krause, of Hanover, in the jejunum of a 

 young man, who had eaten a short time pre- 

 vious to his execution the lacteals being 

 found after death filled with chyle. The 

 mucous membrane between the villi, when 

 examined with a single microscope, presents 

 an extraordinary number of small orifices, 

 which are the openings of Lieberkuhn's fol- 

 hcles. See figs. 140 and 143. 



— Neither Fohman, in his most perfect mercurial injection of 

 the lacteals of the intestine in fishes, nor Schwann, in the injection 

 of the lacteals in the intestinal villi of man, ever found any 

 mercury to escape into the cavity of the intestine. Hence it 

 may be inferred, either that there are no open orifices by 



