THE T'RIXARY ORGANS. 



339 



(3) The mucous coat is formed of epithelium resting- on a layer of 

 loose, areolar tissue. Tlie epithelium (Fig-. 221 I, II, and IV) is 



Fig. 221. 



Various preparations from the bladder. 

 1. Silver preparation of the mucous membrane ; seen from tlje surface. After List (enlarged 

 400 times). 



a Cells of the stirface. 

 d Goblet-ceUs. 

 <• Young ceUs. 



11. Vertical section of the mucous membrane ; after List (enlarged 600 times). 

 a Cells of upper layer. 

 h Cells of middle layer. 

 y c Cells of lower layer. 



III. Large multicellular ganglion ; after Wolff. 



IV. Vertical section from a silver preparation of the mucous membrane ; after List (enlarged 600 



times). 



a Upper layer. 



6 Middle layer. 



c Lower layer. 



d Goblet-cells. 

 V. Small ganglion of bladder ; after Wolff. 



a Non-meduUated nerve-fibre leading to ganglion. 



b Process of a ganglion cell. 



arrang-ed in three layers : the cells of the uppermost (II and 

 IV^ a) always present a flat or convex border to the cavity of the 

 organ ; seen from their free surfaces (I) they have polyg'onal out- 

 lines intermixed with round apertures belonging- to goblet-cells, the 

 remaining surfaces of these cells are serrated. The cells of the 

 middle layer (II and IV, ù) are polygonal in outline, they are not 

 so tall as the cells of the layer above ; all their borders are serrated. 

 The cells of the deepest layer (II and IV, c) are more or less pointed 

 above where they project between the cells of the second layer ; their 

 lowest surfaces are flattened towards the subepithelial tissue, and 

 all their surfaces are serrated. 



z 2 



