98 
weeks or months the ulcerations gradually heal; but others quickly form 
in the adjacent areas of the skin. In one of the cases the lesion persisted 
for a year and a half, in another for nine months, and in the third (see 
fig. 20) for nearly three years. Nodules which have not yet broken down, 
shallow ulcerations, and scars of old lesions may be distinguished in the 
photograph. In addition to the ulcerations, there are usually to be seen 
nodular thickenings of the skin and subcutaneous tissue, which have not 
yet broken down. The skin over the unbroken nodules is reddened. 
Occasionally these nodules become covered with scales for some time 
before opening ; when they ulcerate, there is only a very small amount of 
pus present. Potassium iodide and mercury seem to exert no effect on 
the course of the disease. 
Cultures from the ulcerations of two of the cases developed pure 
growths of Staphylococcus aureus, while those from the third showed 
colonies both of this organism and of those of Staphylococcus albus. In 
one of the cases cultures were taken from an unbroken nodule and these 
remained sterile. Therefore, the infection does not appear to be of 
bacterial origin; though it must be emphasized that I was not able to 
inoculate any cultures in the vesicular stage. The nature of the lesions 
suggests in some respects that they are blastomycetic in their causation. 
However, none of these organisms could be discovered in sections. 
In one of the cases the histological examination of a section from one 
of the nodules, which had not perforated the skin, shows in the subcuta- 
neous tissue a cellular infiltration about a vein. The process consists of 
a true endo-, meso-, and peri- phlebitis. The proliferation may be seen 
beneath the endothelial layer of cells lining the vessel and extend- 
ing outward into the surrounding subcutaneous tissue; it consists chiefly 
of endothelial cells, small round cells poor in protoplasm, and a very few 
plasma cells. Practically no polymorphonuclear leucocytes are visible 
and eosinophiles also are not observed outside the vessel; there is in ad- 
dition early but extensive proliferation of the fixed connective-tissue 
cells. 
As may be seen from fig. 21, the infiltration is eccentric and does not 
include the whole circumference of the vessel wall. A short distance 
from the vein the tissue appears normal. Several other foci of infiltra- 
tion of a similar character are found in the subcutaneous tissue and one 
in the papillary layer, but none of these are about blood vessels. In sec- 
tions stained by Weigert’s method, no fibrin is demonstrable in these 
areas. There is no infiltration around the hair follicles or sweat glands 
and no marked cedema of the tissue. The papillary layer is in general 
unaffected. Indeed, the section, apart from the areas of infiltration 
already mentioned, appears normal. 
In a section of tissue taken from near the edge of one of the ulcera- 
tions a small area of degeneration chiefly composed of degenerating cells 
of the mucus layer may be seen in the Malpighian layer. In many cases 
