Although that form of tuberculosis of the skin first described by Riehl and Paltauf, under the name of tuberculosis cutis verrucosa can no longer be regarded as a rare affection, and usually presents such well-marked and special features that its diagnosis is ordinarily made without any difficulty, I have thought that it might be of interest to report the three cases the subject of this paper, since each of them presents features, clinical and histologic, which are uncommon. The first case reported, presented in its early stages a form of cutaneous tuberculosis to which attention has not yet, so far as I am aware, been called.
Case 1.
—R. L., about 40 years of age, was referred to me for advice concerning an affection of the thumb which had existed for three years, in spite of much and varied treatment. The disease consisted of an irregularly outlined, noticeably elevated, bluish-red