﻿YAWS: A HISTOLOGIC STUDY. 



By Harry T. Marshall. 

 (From the Biological Laboratory, Bureau of Science.) 



Doctors Ashburn and Craig kindly turned over to me the tissues from 

 the cases discussed in the preceding paper, for study. The tissues exam- 

 ined consisted (1) of an early yaws papule removed from a patient 

 suffering with leprosy and yaws, and (2) of ulcerating yaws nodules 

 from a monkey inoculated from a patient seen near Manila. 



As the photographs illustrate, the lesions in the two cases are essen- 

 tially, alike and a single description suffices for them. 



Sections through the papule and ulcers were fixed in Zenker's fluid 

 immediately after removal and were treated with the ordinary stains. 

 Hematoxylin and eosin gave the clearest pictures. The sections show 

 (a) regressive, (b) vascular and exudative, and (c) regenerative changes. 

 The regressive ones are confined to the epithelial structures ; the exudative 

 are most marked immediately beneath the epithelium ; the regenerative 

 changes are evidenced as atypical epithelial formations and by the pres- 

 ence of a few epithelioid connective tissue cells. 



(a) The degenerative changes are confined to the epithelial structures, 

 including surface epithelium, epithelial downgrowths, hair follicles, seba- 

 ceous and sweat glands. There is at first an increase in the thickness 

 of the epithelium affecting chiefly the polyhedral cells, with blurring of 

 the outlines between the separate layers and disappearance of the pig- 

 ment layer. The horny layer is thrown off and the epithelium appears 

 as a greatly thickened structure, made up of large, swollen, cloudy, vacil- 

 lated cells, with swollen, pale nuclei, showing irregular dots of chromatin. 

 The columnar cell layer is the only one that is well preserved. Where 

 the disease is more advanced, the surface layers have been thrown off, 

 exjjosing either the columnar layer of cells or the subjacent corium. 

 The ulcer is coated in places with a crust of necrotic material, leucocytes, 

 etc. (See PI. I, fig. 1, a, b, c, e.) Similar changes appear in the 

 epithelial downgrowths, the hair follicles, and to a lesser extent in the 

 sweat glands; the centrally placed epithelial cells being swollen, very 

 cloudy, vacuolated, and often replaced by cavities containing a few leuco- 

 cytes and a small amount of granular debris, while the peripheral one 

 or two rows of cells preserve fairly well their columnar shape, alignment, 



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