Place a layer of crumbs in the bottom of a rather deep baking-dish, then a layer of oysters, and sprinkle with salt and white pepper. Repeat the process till the dish is filled. Cover the top with crumbs and a layer of soft bread broken into bits and placed round the edge of a circle of small oyster crackers. Wet the whole with the soup stock and a quarter of a cup of oyster liquor. Cover the top generously with butter cut into fine bits. Pour the sherry over the whole, and bake an hour.