We like to deceive ourselves, and, above all, not to see our faults. That is the most prevalent of all weaknesses. We look upon ourselves not only as cleverer but also as better than all others. We forget our faults so easily and divide them by a hundred, whereas our virtues are ever present to our mind and multiplied by a thousand. To himself everybody is not only the first but also the wisest and the best of mortals. That is why we complain about the ingratitude of our fellow-men, because we have forgotten all the occasions on which we proved ungrateful,--in exactly the same manner in which we manage wholly to forget everything calculated to awaken painful emotions in ourselves. The complaint about man’s ingratitude is as old as the history of man himself. The Bible, ancient legends, the folk-songs, and the proverbs of all nations, ancient and modern, bewail man’s ingratitude. It is “the touch of nature that makes the whole world kin.” A trait that is so widely distributed, investing the egoist with the glory of supreme worldly wisdom and branding the altruist as half a fool, must be founded deep in the souls of men. It must be an integral part of the circumstances conditioning the life of the individual. It must send its roots down into the unconscious where the brutal instincts of primal man consort with humanity’s ripened instincts. But if ingratitude is a genuinely (psychologically) established fact then we must be able to determine the dark forces that have it in them to suppress the elementary feeling of gratitude. For even to the most casual observation it is apparent that the first emotion with which we react to a kindness is a warm feeling of recognition, gratitude. So thoroughly are we permeated by it that it seems impossible ever to withhold this gratitude from our benefactor, let alone repay him with ingratitude. The first reaction with which the human soul requites a kind deed is a firm purpose “ever” to be grateful therefor. But purpose, “the slave to memory,” is only the puffed sail that drives the boat until the force of the storm and the weakness of the rudder compel a different course. So, too, the intent to prove grateful is driven about fitfully by the winds of life. Of course, not at once. It requires the lapse of a certain latency period ere gratitude is converted to ingratitude. In the beginning the feeling of gratitude reigns supreme. Slowly it grows fainter and fainter, is inaudible for a time, then on suitable occasions is heard again but ever more faintly. After a while, quite unawares, ingratitude has taken its place. All those pleasurable emotions that have accompanied gratitude have been transformed into their opposites: love into hatred, attraction into aversion, interest into indifference, praise into censure, and friendship into hostility. How does this come about? Where lie the sources of these hidden streams that drive the wheels of our emotions?