042 REPORT OF THE HARVARD AFRICAN EXPEDITION 
quently in pairs, and occasionally in clusters of five, were also present. These 
organisms are found both free and within cells. They are particularly abundant 
in the smears that contain numbers of red blood corpuscles and many leucocytes. 
Epithelial cells may contain anywhere from several to many partially agglom- 
erated forms. The organisms vary in size even in the same group, some hay- 
ing a much larger diameter than others. Whether they are spores of a fungus or 
bacteria is not entirely clear. No double contour can be distinguished in them. 
Films stained with Ziehl-Neelsen-Gabbett’s method do not reveal any acid-fast 
bacilli. The sections of the tissues were stained in haematoxylin and eosin, 
methylene blue and eosin, Giemsa’s solution, Gram’s stain, Ziehl-N eelsen- 
Gabbett’s method, and Levaditi’s silver impregnation stain. 
Histological study shows that in most of the sections the surface epithelium 
of the skin is unbroken. However, the epidermis varies considerably in character 
and in thickness. In the sections made from one block of the tissue, in some areas 
the stratum corneum is greatly thickened, and in others very much thinned. 
Likewise, the stratum mucosum in some places is also greatly thickened, and in 
others atrophied or very little of it remains. No. 264 illustrates very well this 
condition. In one portion of the section there are downgrowths of the epithe- 
lium into the corlum, sometimes simulating an appearance that may be seen 
in epidermal carcinoma. However, such hyperplasia is not present in the sec- 
tions from other parts of the tissue removed. The papillae in places are elon- 
gated, and the stratum mucosum so thin that a few papillae reach on the surface 
almost to the stratum granulosum or stratum lucidum. In examining the epider- 
mis (with objective AA, ocular 6), especially in sections stained with Giemsa’s 
solution, deeply-staining blue, wavy, and sometimes irregular lines are visible on 
the surface of the pinkly-stained stratum corneum where it is greatly thinned, 
or invading it in areas where it is hypertrophied. With higher powers of the 
microscope these blue lines are seen to consist particularly of the elements of a 
fungus. This fungus, by invading the stratum corneum in its deeper portions, 
evidently gradually causes its cells to exfoliate and to be split off sometimes 
at a depth as low as its base in the stratum granulosum. In No. 265, near the 
lower edge of the illustration, the line of cleavage of the epithelium that has 
already occurred by the growth of the fungus, may be distinguished, and in the 
upper portion of the picture may be seen the blue line of invasion of the fungus 
growing in and extending almost to the surface of the stratum mucosum. With 
objective 7'y (2 mm. N.A. 140), the cylindrical, elongated, and undulating my- 
celial threads may be distinguished as well as the rounded spores, sometimes 
budding, or lying in clusters or partially agglomerated groups. In No. 266 
large numbers of such forms of the parasite are seen in the stratum corneum, 
some of which have already entered the cells of the stratum mucosum. In these 
areas a few endothelial phagocytes are also present. In No. 267, a drawing 
ade with objective AA, ocular 10x, the stratum mucosum is richly infiltrated 
with polymorphonuclear and endothelial leucocytes, and the papillary layer also 
shows infiltration, though with smaller numbers of these cells. Proliferating 
fibroblasts are also visible. In the endothelial cells about the sweat glands and 
