Scald the milk and add the cornmeal, half of the sugar, and the salt. This is, in fact, a starter and should be left, covered with a cloth, in a warm place to ferment, which depends on the presence of yeast in the air, and also the climate. When the starter begins to bubble (which may take 2 or 3 days), stir in the remaining sugar, the water and 2 cups of the flour. Mix, and leave to continue fermentation (at least 10 hours), until you have a light sponge, well aerated with bubbles. Add the rest of the flour to make a smooth dough, and knead for about 5 minutes. Shape or place in loaf pans, brush with melted butter, cover and leave to rise till doubled in bulk. Bake at 375 degrees for 15 minutes, then reduce the heat to 350 degrees and bake a further 30 minutes.