﻿- YAWS: A HISTOLOGIC STUDY. 473 



The absence of any degenerative changes in the plasmoma, either as giant cell 

 formation or as fusion, makes the structure simpler than that of a syphilide of 

 which the yaws nodule is otherwise suggestive." It is especially like a condy- 

 loma, from which it is distinguished by the greater dryness of the cutis in yaws 

 and by the more marked keratinization. This explains the firmness and resistance 

 of the nodule. Its cranberry form results from the overgrown papillary bodies 

 which are covered by such a thin layer of prickle cells — that is, it is the result 

 of the great vascular dilatation in. the papilla 3 . 



He thinks Charlouis was mistaken in interpreting his infiltrating cells as 

 leucocytes, and suggests that they must have been plasma cells, while the 

 leucocytes entered as a result of secondary infections. He thinks that "there 

 is no question that the cause of framboesia should be sought only in the first 

 stages of the exanthem and should be looked for in the cutis." He observed the 

 "abscess-like areas" in the keratinizing epithelium, but attributed them to 

 secondary pyogenic infections. As another point against Charlouis' interpreta- 

 tion of the leucocytes he mentions that he could not find them around the 

 dilated capillaries or veins. 



Comparing these accounts, is seems clear that the histologic picture 

 of the yaws papule at an early stage is somewhat different from that of 

 the older nodules. The description given in this article and those given 

 by Charlouis, Glogner, and to a less extent by Plehn, evidently refer to 

 the younger nodules, while TJnna's description is true only of the older 

 ones. 



The characteristic features of the early stage are (1) the epithelial 

 degeneration, with (2) epithelial downgrowths into the cutis in the 

 form of irregular columns; it seems clear that this appearance is due 

 to the actual downgrowth of epithelium and not entirely to the upgrowth 

 from the cutis, (3) capillary dilatation with engorgement, marked 

 (edema and cellular infiltration limited quite sharply to the cutis and 

 most marked at the under border' of epithelium. The cells occurring 

 are chiefly polymorphonuclears, large and small mononuclears, and 

 plasma cells and cesinophiles. It is clear that the infiltrating cells are 

 derived, at least in great measure, from the vessels. In addition Plehn 

 found mast cells and G-logner giant cells. This last finding has been 

 verified by no other writer. The changes in the fixed tissue cells of the 

 cutis are relatively slight. 



In the older nodule the chief difference concerns the infiltrating cells. 

 The epithelial changes are the same, the oedema has largely disappeared, 

 and the plasma cells are present in such enormous numbers as to domi- 

 nate the picture. Here again, the changes in the fixed tissue cells of 

 the cutis are of minor extent. 



Remembering the remarkable regenerative power of epithelium, and 

 noting how slight are the degenerative and regenerative changes in the 

 cutis, we can understand how it comes about that Avhen recovery occurs 

 there is so little scar formation at the seat of a yaws ulcer. 



A comparison of the descriptions of the different writers mentioned 

 above, with Unna's description of the syphilitic condyloma does not 



