Mirth, and even cheerfulness, when employed as remedies in low spirits, are like hot water to a frozen limb.
Source: In Quotations to Cheer You Up When the World is Getting You Down, by Allen Klein, 1991.
-- Benjamin Rush, (Jan 4 1746-1813), US physician, congressman; He was the most famous doctor of his time; signer of the Declaration of Independence, 1776; Surgeon General of the Continental Army, 1777-1778.