35 



STRUCTURE OF THE ORGANS OF ABSORPTION. 



In addition, the medulla oblongata, the spinal cord or the dorsal nerves must 

 have been divided for about a day previously. This apparently depends upon 

 the fact that, in the preparation of an uninjured animal (frog), the fresh division 

 of nerves that becomes necessary acts as an irritant, as a result of which the 

 cells settle down to rest, like irritated amoeba? or like the corneal cells after irrita- 

 tion of their nerves. This fact points to an influence of the nerves upon absorp- 

 tion. 



When the epithelial cells are filled with fat -granules, the processes 

 are withdrawn into the interior of the cell. The border then appears 

 unstriated, and a transparent zone lies between it and the cell-proto- 

 plasm. The goblet-cells appear to be engaged principally in the secre- 

 tion of mucus; although small fat-granules are also occasionally seen 

 within them. 



Pathological: In cases of cholera, as well as after poisoning with arsenic and 



muscarin, enormous desquamation of 

 intestinal epithelium takes place. 



According to the views of 

 Eimer, Heidenhain, v. Than- 

 hoffer and others, the con- 

 stricted root-ends of the epithe- 

 lial cells communicate with 

 anastomosing connective-tissue 

 corpuscles of the villous tissue. 

 Into these the fat-granules are 

 believed to migrate from the 

 interior of the epithelial cells. 

 The soft connective-tissue cells, 

 finally, are thought to com- 

 municate with the central 

 lymph- vessel ; and in this man- 

 ner a communication is estab- 

 lished between the epithelium 

 and the latter. Thus, the fat- 

 granules would migrate through 

 the body of the connective- 

 tissue cells, as through lymph- 

 canaliculi, to the central lymph- 

 vessel. The author is able to 

 agree with this conception with a 

 modification, which approaches 



the views of His, Briicke and v. Basch. As a result of his investiga- 

 tions he believes that the epithelial cell narrows toward its lower 

 extremity, like a funnel; the cell-membrane entering, in various direc- 

 tions, directly into communication with the supporting cells of the 

 adenoid tissue of the villus, as well as with the subepithelial branching 

 layer of the villus, which, accordingly, must be perforated in many 

 places. The supporting cells of the villous tissue surround a spongy 

 system of cavities within which lie protoplasmic, nucleated stroma-cells 

 (Fig. 127, A) of varying appearance. The latter at times contain fat- 

 granules in suspension. According to v. Davidoff , these cells are formed 

 by constriction from the lower extremities of the epithelial cells, which, 

 in time, develop a nucleus within themselves. 



These cells, like ameboid cells without capsules, communicate with one 



A. 



FIG. 128. Blood-vessels of an Intestinal Villus: Cn, 

 capillaries; A, artery; Cl, cylindrical epithelium; O, 

 surface of the epithelium; V, vein. 



