"... I think ... of a young cat I once introduced to the joys of catnip. He took only the preoccupied, casual, dutiful sniff which was the routine response to any new object presented to his attention before he started to walk away. Then he did what is called in the slang of the theater "a double take." He stopped dead in his tracks; he turned incredulously back and inhaled a good noseful. Incredulity was swallowed up in delight. Can such things be? Indubitably they can. He flung himself down and he wallowed."