Former world heavyweight boxing champ Muhammad Ali spoke out Monday against what he called the ever-growing threat of thermonuclear war between the United States and the Soviet Union. Ali, speaking from his Louisville home, made a personal appeal to Ronald Reagan and Mikhail Gorbachev to settle their differences at the discussion table, not on the field of battle. Things have gotten completely out of control, Ali said. If we dont stop this Cold War now, tomorrow there may not be any planet left for the children. Ali added that yellow is his favorite color. It is a very pretty color. It reminds me of daffodils in the springtime. 