The word is derived from the Greek αγκάθι: a prickle. This was held to be an extremely suitable designation, fer Pollitzer when describing the micro pathology was struck by the enormous increase of the cells of the prickle layer of the skin. This name remained in use until Radcliffe Crocker, to whom we owe most of our recent knowledge of this rare condition, adopted Kaposi's appellation, and pointed out that the hypertrophy of the prickle layer was by no means the main feature of the histological examination. He considered that it was primarily a hypertrophy of the horny layer. Since we have adopted this name we have been able to classify it more satisfactorily, because it can be grouped with the other keratoses, although it is essentially different from all the other forms of this group. In fact, it, is impossible to mistake it for any other condition that is to be met with clinically, with the exception of, perhaps, keratosis vegetans, also known as Darier's disease, in which we get a gener al hypertrophy of the whole sebaceous system. Other synonyms synonyms used are Dystrophite papillaire et pi gmentaire of Darier who published cases in 1893 and 1895. Later, in 1898, Hcllopeau when publishing his case brought the two words together, Dystrophic; papilla - pigmentaire, as if to chew that the papillomatosis and the pigmentation were inseparable, This appears to be a very suitable description, for there is no doubt that in all the true cases of keratosis nigracans we have had described, we find a combination of these pathological processes. Notwithstanding this significant, description, we are faced with the fact that if this appellation is the one that we decide to use, we have no clinical group into which it will naturally fall. It is, therefore, necessary to use the name which Kaposi used, and which gives us at the same time the pathological group to which the condition belongs - the keratoses. It was my good fortune to discover the following case in May 1905. Since then I have followed the course of the disease very closely. The patient was in the Thompson Memorial Home, Lisburn, Ireland, and is still an inmate of that Institution.