LYMPHATIC SYSTEM. 189 



Besides arteries and veins, it is probable that the villi have 

 nerves distributed to them. 



They likewise have lacteals, which, according to Lieberkiihn, 

 open on the extremities of the villi, sometimes by one and 

 sometimes by more orifices (see Note LXXXIII). 



Each villus, the same author thinks, has an ampullula, into 

 which these orifices lead, and from the other side of the ampul- 

 lula the lacteal passes through the coats of jthe intestines. This 

 is the only circumstance concerning these parts in which I 

 should differ from this very accurate observer, whose experi- 

 ments in support of his opinion about this ampullula seem to be 

 liable to fallacy. Of this I was first persuaded from observa- 

 tions made on fish, birds, and amphibious animals, in all of 

 which I can demonstrate that the villi have a network of 

 lacteals as well as a network of arteries and veins. 1 



That the villi in some fish have a network of lacteals, I 

 have distinctly seen in the turbot, where I have injected the 

 lacteals with .mercury, which readily runs from those vessels 

 into the villi, and makes them turgid and erected. In the 

 same way, I have likewise seen a network of lacteals on the 

 villi of a turtle, where these villi are of a different shape, and 

 in some parts of the gut are cellular, or honeycombed, some- 

 thing like the lower part of the human stomach, only the par- 

 titions of the cells are here much larger. 



In birds the experiment is more difficult, because their lac- 

 teals are full of valves, and their villi are small compared to 

 those of the turbot ; nevertheless, I have succeeded in getting 



1 An account of some preparations exhibiting these facts was printed in the Phil. 

 Trans, vol. lix. (LXXXVI.) 



(LXXXVI.) At the College of Surgeons, in Lincoln's inn-Fields, 

 there is a small box, marked on the lid, " Mr. Hewson's Microscopical 

 Preparations of the Intestinal Villi," but in which there is now only 

 one portion of small intestine left. 



The circumstantial observations in the text on the intestinal villi of 

 the turbot and turtle seem to have been completely overlooked. Pro- 

 fessor Miiller, a after stating that something similar to villi may be seen 

 in a few fishes, remarks that Retzius has described in a serpent " pro- 

 cesses of the mucous membrane of the intestine, which resemble villi, 

 and can scarcely be anything else, although Rudolphi has said that 

 fishes and reptiles have no true villi." 



Physiology, tr. by Baly, vol. i, p. 267, 1st edition. 



