EPITHELIAL CARCINOMATA. 207 



epitlielium of the ciypts and that of the papillae in so uniform a 

 manner, exhibits so constant a ratio between the elevations 

 and depressions of the dermo-epithelial bomidary-line, that it is 

 absolutely impracticable to draw a hard and fast line between 

 the two. This explains how it is that the very same morbid 

 growth may, with equal fairness, be regarded as a destructive 

 papilloma {Fdrster)^ or a proliferating adenoma (Klebs). 



To these two observers we owe what knowledge we possess 

 concerning the finer details of the development of columnar 

 epithelioma. The alteration invariably begins with a deepening 

 of the glandular tubuli and an increase in the number of their 

 terminal divisions. Here, however, it is important to note that 

 this phenomenon from the very first, I feel almost inclined to 

 add, designedly, presents the character of an extension of super- 

 ficial area ; for we never find solid cellular protrusions like those 

 in squamous epithelioma, but always protrusions of the existing 

 cavity of the gland, which are lined with a single layer of 

 columnar cells. The growth next proceeds to cause a positive. 

 extension of surface ; i.e. to produce pajoillary excrescences from- 

 the walls of the cavities. In this connexion, some statements 

 made by Klehs are of great interest ; he says that acuminated 

 and club-shaped outgrowths, consisting at first entirely of epithe- 

 lial cells, rise from the fundus of the glandular tubuli (fig 6G). 

 At a later period w^e find branching papilla^, which grow in all 

 directions, and especially inwards, contributing thereby to the 

 destruction of the affected parts. 



Fig. 66. 



From an adenoma of the digestive tract. Copied from Klehs. 

 (Handbuch der Patholog. Anatomie, fig. 4.) 



The free surface of the mucous membrane has already begun 



