Add soda to sour milk and stir well. Add sweet milk. In a separate bowl sift together flour and salt. Thoroughly beat together milk and flour mixtures.
Add melted butter and beat once more. Fry on a well-greased griddle at medium heat. Pour out batter for 6 inch cakes. Flip when top is covered in popping bubbles, about 3 to 5 minutes. Cakes should be light and golden. Serve immediately with butter and maple syrup or I also mix up soft butter and strawberry or blackberry jam and spread that on my hot griddle cakes. Yum!