Corn bread can be made with sour milk in this way: Sift the cornmeal with the flour, salt, shortening, and then add the sour milk and egg. Lastly, add the soda. It is well to add the soda last, where a light mixture is desired, as it begins to give off carbon dioxide, the gas that makes the dough rise, as soon as it is moist and comes in contact with the acid of the sour milk.
The Suffrage Cook Book (1915).