In things pertaining to enthusiasm, no man is sane who does not know how to be insane on proper occasions.
Source: In The Ultimate Success Quotations Library, 1997.
-- Henry Ward Beecher, (Jun 24 1813-1887), US clergyman, abolitionist; He was famed as an orator of anti-slavery and woman suffrage; wrote Seven Lectures to Young Men, 1844.