Put into a large saucepot or kettle with a cover the soup bone, cold water, and 1 Tablespoon salt. Cover and bring to boiling, reduce heat and simmer 1 1/2 hours. During cooking, occasionally remove foam that forms on top.
Meanwhile, prepare the potatoes, green beans, carrots, onions, celery and parsley.
After 1 1/2 hours, add vegetables to soup with 2 Tablespoons sugar, 2 teaspoons salt and monosodium glutamate and simmer 30 minutes, or until vegetables are tender.
Just before vegetables are tender, force through a sieve or food mill the can of tomatoes and set aside.
Heat in a saucepan 2 Tablespoons shortening and blend in 1/4 cup all purpose flour and cook over low heat, stirring constantly add the 1/4 cup chopped onion. Cook until mixture bubbles and is lightly browned. Remove from heat and add gradually, stirring constantly, 1 cup of the soup stock. Cook 1 to 2 minutes, or until smooth. Blend into soup with the sieved tomatoes. Bring to boiling, reduce heat and simmer 5 to 10 minutes, or until soup is slightly thickened. Remove soup bone. Serve steaming hot. Serves 8 to 10.