IN 1796 Erasmus Darwin,1 grandfather of the naturalist, proposed an inquiry into the effects which "whirling a person" at the end of a revolving beam might have on certain symptoms of disease, particularly headache. The preliminary results of such an analysis, begun a century and a half later, and using a modern man-carrying centrifuge, have been presented briefly elsewhere, and are described in detail in the present report.2
The observations here presented chiefly concern the effects of centrifugal forces on certain experimentally induced and clinical headaches. Incidental to the main investigation, studies were made on headache induced by centrifugal forces, illustrating in an unusual way the importance of vascular mechanisms in headache. Also incidental, but essential to the interpretation of the studies on headache, was an investigation of the effects of centrifugal forces on pain perception per se.
The behavior of the human subject exposed to accelerations and