Wash the vegetables thoroughly, cutting them fine and boiling until tender in three pints of water. When very soft, mash them and press through a sieve. The Carrots must be mashed very fine. Then return to the fire, and, adding about two quarts of boiling water, cover and simmer gently for a while, adding one teaspoonful of corn starch that has been blended well with a little milk. Add the boiling milk, cook for about two minutes more, and serve with Croutons.