Drain clams, reserving liquid. Add milk to liquid to equal 2/3 cup. Mix flour, cornmeal, baking powder, and salt. Combine the milk mixture, clams, and egg. Stir into the dry ingredients just until moistened.
Carefully drop by tablespoon into deep, hot fat (365 degrees F). Fry 5 or 6 fritters at a time about 2 minutes or until golden brown. Serve immediately with cocktail sauce, if desired. Makes 6 to 8 appetizer servings.