440 



OP ABSORPTION AND SANGUIFICATION. 



blood through them is essential to the introduction of chyle into the absorbents. 1 

 Hence, some have supposed that the contents of the lacteals are first imbibed 



Fig. 132. 



A section of the Ileum, inverted so as to show the ap- 

 pearance and arrangement of the villi on an extended 

 surface, as well as the follicles of Lieberkuhn ; the whole 

 seen under the microscope. A close examination of this 

 cut will show a great number of black points in the spaces 

 between the projections of villi : these are the follicles 

 of LieberkUhn. 



Vessels of an Intestinal Villus of 

 a Hare, from a dry preparation by 

 Dollinger : a, a, veins filled with 

 white injection: Z>, b, arteries in- 

 jected red. 



by the bloodvessels, and are afterwards eliminated from them by a kind of 

 glandular action on the part of the absorbents; but of this there is no adequate 

 evidence ; and it seems more probable that the constant supply of blood is re- 

 quired for that peculiar cell-action, to which the selection of the materials of the 

 chyle is due. The curious fact has recently been substantiated by Prof. Kolliker, a 

 that the villi contain numerous muscular fibre-cells ( 305), and that they pre- 

 sent themselves in very different degrees of contraction and extension. This 

 observation confirms the statement formerly made by M. Lacauchie 3 as to the 

 existence of contractile tissue in the villi, which statement was based on the 

 contraction which he had observed them to undergo after their removal from 

 the body ; and also the yet more remarkable assertion of MM. Gruby and Dela- 

 fond, that rhythmical movements of contraction and extension in different direc- 

 tions take place in the villi whilst absorption is going on, 4 which have an im- 

 portant influence on the propulsion of the fluids contained within their vessels. 



1 See especially the experiments of Mr. Fenwick in the "Lancet," Jan. and Feb., 1845. 



2 " Mikroskopische Anatomic," band ii. $ 168. 



3 "Etudes Hydrotomiques et Micrographiques," Paris, 1844, p. 50. 



4 "Comptes Rendus," 1842, p. 1199; and 1843, p. 1195. 



