DISEASES AFFECTING THE SKIN 349 
sometimes became scabbed over. Under local antiseptic treatment the lesions 
healed within three weeks. The histology showed proliferation, oedema of the 
mucous layer, with infiltration, and mononuclear infiltration of the dermis. 
Vesiculation soon appeared deep in the mucous layer and local cellular necrosis 
occurred rapidly. At this stage the papillae were very congested, the greater 
number of the invading cells being polymorphonuclears with few groups of 
eosinophils, irregularly distributed. Usually the infiltration descended only as 
far as the papillary layer, never reaching the subcutaneous tissues. The con- 
dition suggested a microbie origin, but attempts at culture and animal inocula- 

No. 272. — Photomicrograph of edge of abscess showing character of inflammatory exudate 
and numerous cocc!, many in chains, Case 184, Zeiss obj. 2mm., oc. 6 
tions appeared inconclusive, although the latter were possibly suggestive of a 
streptococcal infection. 
Vitiligo or leucoderma was also found to be common in Liberia. It is not only 
more frequent in the dark-skinned races generally than in the Caucasian race, 
but is particularly frequent in the negro. Apart from the idiopathic form ap- 
parently due to heredity and consanguinity of parentage, other forms with 
depigmented areas, relative or complete, also were found to be common. These 
were especially observed in skin lesions of leprosy or of syphilis and in the scars 
of treponemiasis. Dr. Shattuck also has observed that ringworm or even the 
mild tinea vesicolor infections may cause a diminution of pigment in the affected 
areas. 
Gupta ! points out that leucoderma in some of the natives of India may ap- 
1 Gupta: Far Eastern Asso. Trop. Med., Brit. India (1927), I, 129. 
