THE URINARY ORGAN-. 339 



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

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



Fig. 221. 



,- ^^^ ez ^^- 



'-'-' '-' 





Various preparations from the bladder. 



1. Silver preparation of the mucous membrane; seen fnnu tlie surface. After List (enlarged 

 400 ti 



a Cell* of the surface. 

 d Goblet-celk. 

 i' Young cells. 



II. Vertical section of the mucous membrane ; after List (enlarged 600 time). 

 a Cells of upper layer. 

 6 Cells of middle layer. 

 e Cells of lower lay^r. 



III. Large mnlticellular ganglion ; after Wolff. 



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



times). 



a Upper layer. 



6 Middle layer, 



r Lower layer. 



// Goblet-cells. 



V. Small ganglion of bladder ; after Wolff. 



a Non-medullated nerve-fibre leading to ganglion. 

 6 Process of a ganglion cell. 



arranged in three layers : the cells of the uppermost (II and 

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

 organ ; seen from their free surfaces (I) they have polygonal 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, fj) 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, /_) 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. 



7. 2 



