Mercurialism following the application of an ointment containing a small amount of ammoniated mercury seems to be very rare. A review of the abstract department of the Journal of Cutaneous Diseases, now the Archives of Dermatology and Syphilology, from 1911 to date, failed to bring a single case to light. The author, with a large dispensary dermatologic practice extending over a period of ten years, has never encountered a case, in spite of the fact that ammoniated mercury ointment is the "pièce de résistance" of our dispensary formularies, and in use all of the time; in fact, its only worthy rival is the calamine and zinc lotion so well known by those of us who worship at the dermatologic shrine. This case, therefore, seems to be of sufficient interest to warrant a brief report. REPORT OF CASE History.— W. H. S., a man aged 45, a native of New York