In a large stock pot combine celery, onion, potatoes, bouillon cubes, pepper, celery salt and parsley. Add enough water so that vegetables are fully submerged, cover and cook until vegetables are tender. Remove from the heat and set aside. In a small skillet melt butter. Once melted add flour and mix until a paste like consistency is formed. Add milk all at once and stir over low heat until it thickens. Add milk and flour mixture to the vegetables and stir gently. Add half and half and keep warm until serving. If desired serve with Cheese Biscuits II.