Place tripe in a large saucepan and add enough cold water to cover it by at least 2 inches.
Bring to a boil over high heat, then reduce the heat to low and simmer partially covered for 1 1/2 hours. Drain the tripe in a sieve and set aside.
Meanwhile, combine the beans and 3 qts. of water in a heavy saucepan and bring to a boil over high heat.
Boil briskly for 2 minutes, remove the pan from the heat, and let the beans soak for 1 hour. Pour off the soaking water and set the beans aside.
In a heavy 6-8 quart casserole, heat the oil over moderate heat until a light haze forms above it. Add the onions, carrots, celery, leeks, and cabbage.
Stir well, cover the casserole, and simmer over low heat for 15 minutes, or until the vegetables are soft but not brown.
Add the tripe, beans, tomatoes, garlic, oregano, salt, pepper, and chicken stock and, stirring frequently, bring to a boil over high heat. Reduce the heat to low and simmer partially covered for 1 hour.
Then stir in the spinach, potatoes and tomato paste, and continue to simmer for about 20 minutes longer, or until the beans and potatoes are tender but not falling apart.
Taste for seasoning and serve at once from a heated tureen or soup plates.