"It is held that the health of the body may be affected, beneficially or injuriously, by certain states of the mind, as of hope or despondency. Or, more in detail, medical men have observed that certain mental states affect certain functions in certain definite ways. As, for instance, sudden anxiety, as of the non-arrival of a friend when expected, may cause an increase of the peristaltic action, while prolonged anxiety is apt to cause the contrary effect. Joy over good news or at the return of long-absent friends diminishes gastric secretion and causes loss of appetite. The feeble hold on life of the suicidal, and the surprising recoveries from serious diseases and after apparently fatal injuries, in persons whose mental characteristics are hopefulness and determination, are often-recurring facts, familiar to all..."