Cook and stir bacon or salt pork and the onion in a 2 quart saucepan until the bacon is crisp and onion is softened. Drain clams and reserved liquor. Add enough water, if necessary, to clam liquor to measure 1 cup. Stir clams, clam liquor, potato, salt and pepper into bacon and onion mixture. Heat to boiling. Reduce heat, cover and simmer about 15 minutes, our until potatoes are tender. Stir in milk and heat, stirring occasionally, until hot. Do not boil.