Thoroughly wash the stomach bag in cold water. Turn it inside out and scald it, then scrape the surface with a knife. Soak it in cold salted water overnight. Next day remove the bag from the water and leave it on one side while preparing the filling. Wash the pluck. Put it into a pan, with the windpipe hanging over the side into a bowl, to let out any impurities. Cover the pluck with cold water, add 1 teaspoon of salt and bring the water to a boil. Skim the surface, then simmer for 1 1/2 to 2 hours. Meanwhile parboil the onions, drain, reserving the ligquid, and chop them roughly. Also tpast the pinhead oatmeal until golden brown. Drain the pluck when ready and cut away the windpipe and any excess gristle. Mince half the liver with all the heart and lights, then stir in the shredded suet, the toasted oatmeal and the onions. Season well with salt and pepper. Moisten with as much of the onion or pluck water as necessary to make the mixture soft. With the rough surface of the bag outside fill it just over half full, the oatmeal will swell during cooking, and sew the ends together with the trussing needle and fine string. Prick the bag in places with the needlw. Place the haggis on and enamel plate and put it into a pan of boiling water. Cover the pan and cook for about 3 hours, adding more boiling water when necessary to keep the haggis covered. Serve with the traditional accompaniment of Tatties-an'Neeps. (Mashed potatoes and mashed turnips.)