ANCHOVY SAUCE — FOR FISH

Cut the flesh of three anchovies into small shreds, and steep them in vinegar for half an hour or more. Then mince them fine, and throw them into a saucepan with a little butter rolled in flour. Add pepper and mustard to your taste. Pour in sufficient vinegar to cover it, and let it boil gently for a quarter of an hour. Strain it, and squeeze in a little lemon-juice before you serve it up.