It has been suggested that the nervous system of the ear is capable of identifying the periodicity of a complex sound, as such, isolated from other factors. Because many phenomena in hearing have their counterparts in the vibratory sensations of the skin, the question is analyzed whether the skin also is able to identify and isolate periodicity of the stimulus. Since a phenomenon described by Seebeck 100 years ago seems to provide the best demonstration of periodicity perception in hearing, an analogous phenomenon the skin has been investigated for both mechanical and electrical stimulation. The skin too showed the Seebeck phenomenon. But it became obvious that on the skin it is possible to change the periodicity without altering the “pitch sensation” or to change the pitch sensation without having modified the periodicity. The pitch sensation for complex sounds and complex vibrations is probably not a simple process.