First work out the contrast. Before reading further, think what happens when one keeps the opposite of happy, whatever be the actual stage between the extreme homicidal or suicidal violence or suicidal melancholia on the one hand, and, on the other hand, ordinary fear, worry, resentment, depression, grumpiness, and so on. Those who wish to study the effects of these states of mind more fully, can consult Elmer Gates' "The Mind and the Brain," or William S. Sadler's "Physiology of Faith and Fear," both quoted in my book. Professor Elmer Gates, of the Smithsonian Institute, Washington, says:— "My experiments show that irascible, malevolent, and depressing emotions generate in the system injurious compounds, some of which are extremely poisonous; also that agreeable, happy emotions generate chemical compounds of nutritious value, which stimulate the cells to manufacture energy.... "If an evil emotion is dominant, then during that period the respiration contains volatile poisons, which are expelled through the breath and are characteristic of these emotions. "Wearisome, unpleasant memories weaken health, and do not generate thought energy. Cure is accomplished in expelling these by another crop of wholly pleasant memories, which put the necessary structures of the mind in systematic order and teach the patient how to use the mental faculties."
