Pare and boil half a pound of white potatoes; drain; dust lightly with salt; shake them until dry and press them through a colander. Add one pint of scalded milk, two tablespoonfuls of butter, a tablespoonful of sugar, two eggs well beaten, and one compressed yeast cake dissolved in a quarter of a cupful of warm water. Add a quart of white flour, and beat continuously for five minutes; then add flour slowly until you have a soft dough; knead for ten minutes until it is light and elastic. Put it in a bowl that has been slightly buttered; cover and stand in a warm place, 75° Fahrenheit, until it has doubled its bulk, or about three hours and a half. Divide it in two loaves, mould each lightly, put in greased square pans; cover and stand in the same place for one hour and a quarter, and bake in a moderate oven for three-quarters of an hour.