388 



STRUCTURE OF A VILLUS. 



like a chalice, narrower above and below, and broad in the middle, with a tapering 

 fixed extremity. The outer part of each cell is filled with a clear substance or 

 mucigen, which, on the addition of water, yields mucus. The mucigen lies in the 

 intervals of a fine net-work of fibrils, which pervades the cell protoplasm. The 

 protoplasm, containing a globular or triangular nucleus, is pushed into the lower part 



B 



o .'a 



Fig. 150. 



.Scheme of an intestinal villus A, Transverse section of part of a villus ; a, 

 columnar epithelium with, b, clear disc ; c, goblet-cell ; i, i, adenoid reti- 

 culum ; d, d, spaces within the same and containing leucocytes, e, e ; f, section 

 of the central lacteal ; B, scheme of a cell with processes supposed to be 

 projected from its interior ; C, columnar epithelium after the absorption of 

 fatty granules ; D, the columnar epithelium of a villus seen from above with 

 a goblet-cell in the centre. 



of the cell. These goblet-cells are simply altered columnar epithelial cells, which 

 secrete mucus in their interior. They are more numerous under certain conditions. 

 Not unfrequently in sections of the mucous membrane of the gut, after it is stained 

 with logwood, we may see a deep blue plug of mucus partly exuded from these 

 cells. When looked at from above they give the appearance seen in Fig. 150, D.] 

 The epithelial cells are shed in enormous numbers in cholera, and in poisoning 

 with arsenic and muscarin (Bo'hm). 



[The epithelial cells covering the villus are placed upon a layer of squamous 

 epithelium (basement membrane) the sub-epithelial membrane of Debove. This 

 basement membrane is said to be connected by processes with the so-called 

 branched cells of the adenoid tissue of the villus, while it also sends up processes 

 between the epithelial covering.] 



The villus itself consists of a basis of adenoid tissue, containing in its centre one 



