1. The night before, place uncooked rice in a Dutch oven, just covered with water, and soak overnight. Set bread slices out on a cooling rack to dry.
2. On the day of, heat oven to 350 degrees . Drain rice in a colander. Cut bread slices into cubes.
3. In a large skillet, brown sausage over medium-high heat and break into small pieces. Transfer to a large bowl; add onion, celery, mushroom pieces and water chestnuts. Add soup and wild rice; mix gently. Add bread cubes and mix gently.
4. Pour mixture into a 4-quart covered casserole (or cover dish with foil) and bake at 350 degrees for 11/2 hours.