168 JOHN SUNDWALL 



these goblet cells reach the lumen and from the ends secretion 

 masses can be seen projecting into the lumen. Others again 

 do not reach the surface but are entirely surrounded by the 

 general epithelium. As a rule a flattened nucleus is seen in the 

 base of these cells and a definite network is seen in the cytoplasm. 

 (fig. 8). 



The epithelial cells show great irregularity as to form and size. 

 They occur in several layers. In the crypts usually two layers 

 are seen while in the folds three or even six layers of cells are seen 

 arranged irregularly. Those bordering on the surface (super- 

 ficial cells) are usually elongated and the base is drawn out into a 

 wedge shaped process which projects downward between the 





I-' 



^^ <^^^^t^^ 



Fig. 8 Epithelium of iiiaiii duct. Zeiss, oc. 4, obj. 2 nun. oil. .4, epithelium; 

 B, goblet cells. 



deeper layers of cells. In the crypts these wedge-like pro- 

 jections may reach the basement membrane. The deeper layers 

 of cells are smaller as a rule than the superficial cells and are 

 irregularly cuboidal or polygonal in shape. The deepest layer 

 of cells borders on a basement membrane which is readily seen 

 in sections stained by Mallory's method. The epithelial cells 

 in general stain deeply and homogeneously in the usual stains. 

 Reference is made to mitochondria later on. No secretorj^ 

 granules can be made out in any of these cells. The nuclei are 

 prominent, oval or spheroidal, and show irregular clumps of 

 chromatin. As a rule no definite nucleolus is seen. 



The basement membrane is directly surrounded by a circular 

 coat of connective tissue which averages from 100 to 150^ in 



