Another function of the inner ear: facilitation of the emetic response to poisons.

If a foot were surgically removed and it was observed that walking was then impaired, it could be concluded that the foot is part of the normal mechanism for walking and that one of the physiological functions of the foot is to facilitate walking. In seven dogs, the vestibular apparatus of the inner ear was surgically removed and it was observed that the emetic response to certain poisons was impaired. It was concluded that the inner ear is part of the normal mechanism for vomiting in response to poisons, and that one of the physiological functions of the inner ear is to facilitate the emetic response to poisons. It seems likely that the mechanism, whereby the vestibular apparatus facilitates the emetic response to poisons, is the basis of motion sickness. In essence, motion sickness can be considered the result of activation, by motion, of a mechanism that normally functions to facilitate vomiting in response to poisons.