Soften yeast in warm water. Cream the shortening and sugar. Beat in the eggs and salt. Stir in one or two cups of flour and beat vigorously. Add the milk and softened yeast. Mix well and add the remaining flour. Beat again. Cover and let rise in a warm place until doubled. Stir down and spoon batter into a tube pan. Cover and let rise again. Bake at 325 for ten minutes, then increase heat to 375 and bake another 20 minutes. Cool thoroughly before slicing.