In the era before the advent of routine microscopy and immunopathology, mechanical symptoms were described in an attempt to facilitate clinical diagnosis of blistering dermatoses. A plethora of eponyms and signs were described, but no proper original quotations exist. All the eponyms haunt the student and specialist. In the case of an ominous and, therefore, very important clinical phenomenon termed the Nikolskiy sign, this creates confusion about the specific meaning of the term, obscuring diagnosis and delaying initiation of an adequate treatment of pemphigus. We try to set this record straight and go to the sources. Russian, German, French, and English, at the least, are required to properly interpret the relevant descriptions. We provide an accurate interpretation of the major mechanical symptoms pathognomonic for acantholysis, dermoepidermal separation, and peeling of the entire epidermis. Correct performance of the tests and proper interpretation of the results can serve as an invaluable diagnostic tool to assist in the preliminary bedside diagnosis of serious and potentially lethal bullous dermatoses. (J Am Acad Dermatol 2003;48:86-92.)