Investigates the organic effects of repeated bodily rotation in human subjects. It was observed by many of the earlier investigators that, when the vestibular branch of the eighth nerve was cut, or one or more of the canals injured, the compensatory movements either of the eyes or of the head and the changes in posture were at first intense but gradually disappeared within a few days. It is strange that this fact did not suggest that continued or repeated excitation of the end-organs in the canals would lead to a profound modification in the effects usually produced. As a matter of fact, however, we have failed to find an instance where a consistent effort has been made to repeat ampullar stimulation in the same organism a great number of times. This failure is partially due, no doubt, to the fact that almost all of the earlier work on the subject involved surgical means of excitation, a method which naturally excludes extensive repetition. Therefore, the experiment undertakes to excite the vestibular end-organs in the human subject a large number of times in succession and then seeks to describe the organic effects issuing from this repeated stimulation. The effects of multiple bodily rotations on nystagmus, and visceral and vascular changes are reported. Overall, the findings indicate that nystagmus is only a small part of the total organic effect of rotation and that all of the effects, both local and systemic, tend to decrease in complexity and in intensity and finally to disappear under the influence of prolonged turning. These effects can be profoundly modified in their appearance by certain physical and physiological factors. (PsycINFO Database Record (c) 2006 APA, all rights reserved)