So many instances of Darier's disease have been recorded in the past thirty years that the mere recital of the symptomatology and description of the histopathologic changes in new cases ceases to be of more than passing interest. All the literature relative to the disease throws not one ray of light on the obscure problem of its etiology; the entire question of causation is as much of an enigma today as it was between 1889 and 1891, when J. C. White, Morrow, Darrier and Thibault published reports of their cases. Referring to its etiology, Jadassohn said that in his opinion the disease belongs in the group of congenital anomalies of cornification, and that it may occur in combination with various anomalies in the same individual, or may occur in the same family. In 1916, Boeck, in demonstrating some patients before the dermatologic congress in Christiania, stated that these individuals are