Rub exceedingly fine the butter in the flour. Mix the yest in half a pint of warm milk; set a light sponge in the flour till it rises for an hour; beat up the eggs in the sugar, and intermix it with the sponge, adding to it a little less than half a pint of warm milk with the salt. Mix all up to a light dough, and keep it warm, to rise again for another hour. Then break it in pieces, and roll them to the thickness of your finger of the proper length; lay them on tin plates, and set them in a warm stove for an hour more. Then touch them over with a little milk, and bake them in a slow oven with care. To take off the bitterness from the yest, mix one pint of it in two gallons of water, and let it stand for twenty-four hours; then throw off the water, and the yest is fit for use; if not, repeat it.