By this time the dermatologic profession has become accustomed to think at once of hypercholesterolemia when xanthoma is mentioned; moreover, thanks to Darier,1 Pollitzer and other disciples of the French school, it has learned to go still further and to look at diabetes, rheumatism and nephrosis as among the morbid states that might underlie the hypercholesterolemia. But here any further current knowledge of the relationship of the xanthomas to the hemic state stops, as far as the specialty in general is concerned. Yet back of the more outstanding facts there is a large store of information, concerning not only xanthoma but also xanthosis in general, which is more or less denied to many dermatologists because it is so widely scattered in the literature. As an intimate knowledge of this is necessary to an understanding of several different yellowish dermatoses already well known to dermatologists, to the interpretation of yellowing