﻿GANGOSA IN THE PHILIPPINES. 391 



HISTOLOGY. 



Ulcer I, edge of skin, hamatoxylin and eosin. — On surface of ulcer 

 there is a structureless, necrotic membrane, cloudy and purplish, in 

 which one can dimly make out degenerated cells. Necrotic processes 

 extend from this membrane into clefts in the tissue beneath. The 

 transition is sharp between the necrotic membrane and the subjacent, 

 richly cellular tissue. The latter is a loose, vascular, areolar tissue con- 

 taining a moderate amount of fat and supported by heavy trabecular 

 of connective tissue. A few strands of degenerating voluntary muscle 

 are found in the deeper part of the section. The loose fatty tissue is 

 black from accumulations of small round cells, which are abundant just 

 at the necrotic border and diminish in numbers as the distance from the 

 edge of the ulcer increases. Mingled with the small round cells are a 

 few large mononuclears, larger epithelioid fibroblasts, and numerous 

 plasma cells with small, eccentric, dark nucleus and fairly abundant 

 irregular bluish protoplasm. 



The necrotic process is evidently advancing and has already involved 

 several vessels. One of these, a small artery, is plugged with a hyaline 

 mass and its walls can no longer be made out because of the dense, small, 

 round cell infiltration, but near by a wide, thin-walled sinus .shows no 

 obliteration at all. With the exception of the small artery above men- 

 tioned, and one other artery near the advancing edge of the ulcer, in 

 which the same process is occurring, there is no special accumulation of 

 round cells around the vessels. 



The muscle in the deeper part of the section is undergoing necrosis, and 

 in large measure has become converted into a homogeneous or finely gran- 

 ular, bright-red mass, with fine nuclear fragments scattered through it. 



At the edge of the ulcer there are two irregular downgrowths of 

 stratified epithelium, one nearly a millimeter in length. In each of 

 these areas the upper layers are of irregular thickness and composed of 

 large, poorly staining cells, often vacuolated, in which the nuclei show 

 various irregularities. The deepest layer of cells is as a rule uniform 

 in arrangement and staining, the downgrowths being no more atypical 

 than those in a benign papilloma of the skin. However, along one side 

 there are several delicate, finger-like projections of epithelium entering 

 directly into the underlying tissue, the protoplasm extending beyond the 

 last nucleus to form a protoplasmic mesh work in which several small, 

 round cells are gathered. The arrangement makes it difficult to determine 

 exactly where the epithelium ends and connective tissue and infiltrating 

 cells begin. 



One of these epithelial areas is definitely retracted from the adjacent 

 tissue, and this shows no downgrowths. 



There are none of the irregular nuclear figures nor epithelial pearls 

 which occur in epithelioma and the nuclei of the cells of the deepest 



