330 REPORT OF THE HARVARD AFRICAN EXPEDITION 
(‘‘aene bacilli’). In other sections, masses of a gram-positive coccus were found 
in the plugs. Hyperkeratosis and parakeratosis of the stratum corneum was 
common in the region of the hair follicles. As regards the corium, the infiltra- 
tion was strikingly nodal in type. Subsequent fusion of these nodes or tubercle- 
like lesions resulted in the formation of irregular areas. The infiltration was 
most marked around the hair follicles and corresponding sebaceous glands. In 
some of the cases examined, the sweat glands were markedly involved. He 
thought the involvement of sweat-units probably explained why the pilocarpine 
test failed to evoke a reaction in some of these cases. With reference to the 
nature of the inflammatory reactions, he points out that a striking feature is 
the presence in considerable numbers of well-defined giant cells which persist in 
the more chronic areas but are not sonumerous. The fundamental lesion appeared 
to be a tubercle-like collection of cells. These component cells were spindle- 
shaped, with elongated or vesicular, faintly-staining nuclei, and were probably 
derived from endothelium. The whole bore a close resemblance to a somewhat 
oedematous tubercle. Later, lymphocytes, polymorphonuclears and mast cells 
were involved in the reaction. Plasma cells were scanty. In the older lesions 
the round cells predominated, the infiltration becoming denser and more com- 
pact in character. Considerable congestion of the capillaries was present, 
both the capillary and lymph spaces being rendered more distinct by their 
hypertrophied lining endothelium. The infiltration extended right up to the 
epidermis, the narrow separating layer of corium, so typical in leprosy, not being 
present. Examination for acid-fast bacilli and for spirochaetes was negative. 
Smith regards the cases as being non-leprotic on account of the clinical his- 
tory (prolonged duration with but scant progress of the lesions); absence of 
acid-fast bacilli; absence of anidrosis in many of the cases; and the histological 
appearances. He thinks it of more importance to draw attention to the non- 
leprotic nature of the lesions than definitely to label the condition, and says that 
possibly it is a form of acne or of lichen, or that seborrhoea in one of its many 
guises may be a factor, and syphilis and yaws possible predisposing causes. 
Therapeutic measures appear to have little or no effect. 
Smith’s observations are of very great importance and further studies of this 
nature should be made. While there is apparently, from his investigation, no 
question that the histological picture is partly produced by the infection he de- 
scribes, in view of the difficulty we have often had of finding leprosy bacilli in the 
skin in the neurotrophic forms of the disease,! in other countries as well as in 
Africa, we believe that leprosy cannot be excluded by the negative bacteriologi- 
cal examination in such cases. The question arises whether leprosy in more or 
less quiescent form may not also be present in at least some of the cases which 
Smith refers to. He gives very excellent photographs. Our recollection is that 
in two of these the lesions illustrated very closely resemble the maculae of leprosy. 
Also, his description of the histological picture is in part very similar to the 
condition sometimes observed in the older skin lesions in maculo-anaesthetic 
leprosy. 
1 Strong: Diagnosis of Leprosy, ‘‘Bedside Diagnosis,’ ed. by George Blumer (1928), I, 176-180. 
