Sprinkle half of vanilla wafer crumbs evenly into the bottom of a buttered 9-inch square pan; and set aside.
Beat milk in a medium mixing bowl at high speed of an electric mixer until stiff peaks form. Gradually add sugar, beating well after each addition. Fold in lemon juice.
Pour lemon mixture into prepared pan; sprinkle with remaining crumbs, and freeze overnight.
Cut into squares, and serve on chilled dessert dishes.