Dissolve yeast cake in 1/2 cup warm water. Add sugar, salt and Snowdrift to milk; warm until Snowdrift melts. Add to this the yeast dissolved in warm water, the well beaten egg and sufficient flour to make drop batter. Cover and set in warm place to rise about 4 hours. Add raisins well floured and flour enough to make stiff dough. Mold into 2 loaves that fit nicely in pans. Set to rise about an hour. Bake in moderate oven.