208 



EPITHELIAL CAKCINOHATA. 



to take part in the process by a more or less exuberant prolifera- 

 tion of papillae. The free surface however is to be regarded 

 generally as a locus ininovis resistentice ; accordingly the tumour 

 as a whole projects above it, first as a flat and uniform, later as 

 a fungoid elevation. To enable us justly to appreciate its com- 

 plicated structure, and more particularly to discriminate between 

 the papillary outgrowths and the inter-follicular septa, which are 

 likewise coated with columnar epithelium, we must make use 

 of specimens teased out with needles, or sections of a certain 

 thickness ; since, in very fine sections, there is no break in the 

 continuity of the outline which passes from elevation to depres- 

 sion and vice versa, without indicating the concavity or the 

 convexity of the epithelial ridges (fig. 67). 



Fig. 6; 



Yertical section tkrougli a columnar epithehoma of the 

 stomach. 3^^. 



§ 172. I am aware that nearly all the mucous membranes, 

 especially those of the larynx, uterus, bladder and others, have 

 each their peculiar form of epithelioma, which differs from the 

 chief types, from the squamous and columnar epitheliomata, in the 

 same degree as the transitional forms of epithelium with which 

 these parts are clothed, differ from the simple squamous epithe- 

 lium of the skin, or the simple columnar epithelium of the 

 stomach and bowel. For a detailed account of these finer 

 variations I refer the reader to the special division of this work. 



