Moreover, it is extraordinarily contagious. Every one knows how a hearty laugh spreads, and how quick the response to a smile. Indeed, emotion has probably for one of its main functions the producing of an effect on some one else, and all the world uses emotion for this purpose. Anger is used to produce fear, sorrow to evoke sympathy, fear is to bring about relenting, a smile and laughter, friendliness, except where one smiles or laughs _at_ some one, and then its design is to bring sorrow, anger, or pain. The leader maintains a hopeful, joyous demeanor so that his followers may also be joyous or hopeful and thus be energized to their best. Morale is the state of emotion of a group; it is raised when joyous, energizing emotions are set working in the group and is lowered when pessimistic deënergizing emotions become dominant. A city or a nation becomes energized with good news and success and deënergized when the battle seems lost. The spread of emotion from person to person by sympathetic feeling or the reverse (as when we get depressed because our enemy is happy) is a social fact of incalculable importance. The problem of the nervous housewife is a problem of society because she gives her mood over to her family or else intensely dissatisfies its members so that the home ties are greatly weakened. This spread of emotion was happily portrayed by a motion picture I recently saw. Old Grouchy Moneybags, wealthy beyond measure and afflicted with gout, is seated at his breakfast table. In the next room, seen with the all-seeing eye of the movie, the butler makes love to the very willing maid. In the kitchen the fat cook is feeding the ever hungry butcher's boy with gingerbread and cake, and on the back steps the household cat is purring gently in contentment. Happiness is the predominant note. Then Old Moneybags savagely rings the bell. Enters the butler, obsequious and solicitous. "The coffee is bad, the toast is vile, everything is wrong. You are a _deleted deleted deleted deleted_ rascal." Exit the butler, outwardly humble, inwardly a raging flood of anger, and he meets the maid, who archly invites his attentions. She gets them, only they are in the form of an angry shove and an oath. White with indignation, she stamps her foot and runs into the kitchen, bursting into tears. The cook, solicitous, receives a slap in the face, and as the maid bounces out, the cook, seeking a victim, grabs away the gingerbread from the butcher's boy. And that still hungry juvenile slams the door as he leaves and kicks the slumbering cat off the back doorstep.