Soften yeast in lukewarm water. Combine milk and remaining water and scald. Add shortening, salt, and sugar. Cool to lukewarm; add yeast and 2 cups flour. Stir to blend well, then knead in remaining flour until firm and elastic. Let rise until double. Punch down and roll out 1/4 inch thick on board sprinkled with cornmeal. Cut into rounds. Cover and let rise until double again. When light, bake slowly on an ungreased, heavy griddle or frying pan. Have griddle hot first, then reduce heat so that muffins will brown slowly. Bake 7-8 minues on each side. To serve, split, toast, and butter.