This phenomena that has been experienced by subjects treated by Mesmerism and observed by the operators. Usually the subjects were in a cataleptic state, resembling a close to death condition, displaying no signs of intelligence, when a audible question was directed toward the ear the subject makes no response, but when the question is directed toward the pit of the stomach, or at times toward the fingertips or toes the response answer is produced by the subjects
Dr. Petetin, of Lyons, France, recorded several such cases. He, in 1808, published his Electricite Animale. Other Mesmerists published works concerning the phenomena too. The stomach, independent of sense organs, performed not only hearing, but also seeing, tasting, and smelling.
Petetin attached the phenomena to "animal electricity," and stated that objects placed on the subject's stomach were not seen when wrapped in wax or silk, that is, non-conductors.
The most efficient way to communicate with the patient in the cataleptic state was for the operator to place his hand on the subject's stomach and direct his question to the fingertips of the subject's free hand.
This trance state phenomenon, as well as others, may now be considered as being caused be suggestion, and hyperaesthesia.