Pig Haggis

Food in England by Dorothy Hartley, p. 110

1 pig's stomach
? Salt
5 cups cooked potato
1/2 cup butter
1/2 tsp dry ground sage of 1 Tbsp fresh, minced
1 large onion, diced
1-2 celery sticks
3/4 tsp salt
1/2 tsp pepper
1/2 cup fresh parsley, minced
Bacon fat
Apple sauce

1. The day before, turn the stomach inside-out and scrub clean. Soak in heavily salted water.
2. Next day, cook the potatoes and mash or rice them. Put them in a large bowl.
3. Melt the butter in a skillet, and poach the celery and onion at medium-low temperatures until the celery is tender, then add everything in the pan to the potatoes, along with the sage, salt, pepper and parsley. Blend well. 
4. Stuff the haggis and roast in the oven for 2-3 hours at ???F (try 350 degrees, check after 1 hour), basting with bacon fat.
5. Serve with apple sauce and gravy.