Use 3 pigs feet or about 2 lbs. Scrape, wash and clean thoroughly. Place in stew pan with 1 chopped onion, ½ c. chopped celery and cover with cold water. Let it come to a boil, then reduce heat and simmer until meat is tender and comes easily from the bone. Pick meat from the bones, strain liquid, which should measure a scant 3 cups. (If less add water) Put meat and liquid into a bowl. Add 3 T. strong cider vinegar, ¾ t. salt, black pepper and several thin slices of lemon. Chill overnight; remove surplus fat from the top. Turn out on a platter and serve with lemon slices and parsley.