The fact that there is a reciprocal relation between mental states and bodily conditions, acting both for good
and ill, is nothing new in human experience. Even among the most crude and unobserving, traditions and
incidents have given witness to this knowledge. For centuries stories of the hair turning white during the night
on account of fright or sorrow, the cause and cure of diseases through emotional disturbances, and death,
usually directly by apoplexy, caused by anger, grief, or joy, have been current and generally accepted.