with fatty matter, and that the other tissues are correspondingly degenerated. Sometimes the bone is thinned, or even altogether absorbed. At the seat of constriction a line of hypertrophy of the epithelial layers, and of atrophy of the papillary layer of the skin, together with a band of fibrous tissue more or less intimately connected with the derma, surrounds, in whole or in part, the narrow pedicle.
Nothing is known as to the true nature and cause of this disease, to which the European and white-skinned races are not, but to which the African races, particularly the negroes of the West Coast, are especially liable. Some have suggested that it is a trophic lesion depending upon some nervous affection. The occurrence of severe loin pains, which Dupouy says he remarked at the commencement in some of his cases, as well as the tendency of the affection to run in families, as noted by Da Silva Lima, affords a certain amount of support to this view. Others suggest that it is a manifestation of leprosy; others, that it is a form of sclerodermia; others again, and on equally inadequate grounds, that it is produced artificially by intentional ligation or by the wearing of toe rings. My own impression is that it is provoked, at all events in the first instance, by wounds so easily inflicted on bare feet in walking through grass or jungle. The fold o skin in which the lesion of ainhum commences is very liable, especially in the splay ed-out toes of the negro, to be wounded in this way. If we examine the under-surface of the joint flexures of the toes in many individuals of this race, even of those not affected with ainhum, we often find the skin, particularly at the proximal joint of the little toe, thick, rough, scaling, and sometimes even ulcerated. One can understand that continual irritation of this sort, produced and kept up by wounds from sharp grasses or jiggers (Wellman), would in time give rise, especially in the dark-skinned" races so prone to cheloid, to fibrotic changes in the derma, which might very well end in a sort of linear cicatricial contraction, and ultimately in slow atrophying strangulation of the affected member. The disease is said, however,
