Inhale gradually for ten seconds, then exhale in the same way and time.
Look steadily at some point or object for a minute without winking the eye, keeping your attention fixed on the object.
Look at a picture critically, then close your eyes and mentally reconstruct it.
Close your eyes and construct the face of a friend, feature by feature.
Fix your attention on a hand or foot, hold on it the idea of heat and continue until the hand or foot feels warm. Then try cold; then try pain.
Will that the person in front of you shall turn around or put his hand on his head or neck.
Hold your hand on some one in pain and say, "I will the pain to depart." Repeat till the pain goes.
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Note.—For a scientific understanding of positive and negative concentration, see "Practical Psychology and Sex Life," by the author.