Wash the beans and soak them over night in luke warm water. Drain and put them in a saucepan with the cold water and allow them to come gradually to a boil; then set them back, and let them simmer gently for about two hours. Melt the butter or lard in a saucepan and fry in it the onion, parsley, thyme and bay leaf until brown. Add these to the Beans and boil about an hour and a half longer. If the Beans are perfectly tender at this point, press the whole through a colander. Return to the fire, and add the seasonings. Let them boil up once and serve with the Croutons. Some think that the flavor is enhanced by beating up an egg in the tureen and pouring the boiling Soup gradually over it, stirring constantly. This Soup should always be served with Croutons.