A Spectrophotometric Test in Attempts to Differentiate Pemphigus Serum from That of Other Bullous Diseases**From the Dermatological Department of the Rothschild-Hadassah University Hospital, Jerusalem, Professor A. Dostrovsky, Director, and from the Department of Dermatology and Syphilology of the New York University Post-Graduate Medical School (Dr. Marion B. Sulzberger, Chairman).