In a mixing bowl, combine the veal, ham, pork, and chicken livers. Add three of the bay leaves, the salt, thyme, oregano, cayenne, black pepper, celery, onions, garlic, brandy, and port. Toss well and cover. Refrigerate for 24 hours.
Remove from the refrigerator and drain the mixture, discarding the liquid. Remove the bay leaves. Using a standing mixer with a meat grinder fitted with a 1/2-inch die, grind the meat once. Transfer the mixture to a large bowl. Add the egg whites, pistachios, and parsley. Mix well.
Line the bottom and sides of two earthenware terrines with the bacon. Leaving enough of the bacon overlapping all sides of the pan so that the bacon will completely cover the top of the pati mixture when folded over. Divide the mixture equally between the two pans, pressing down with your fingers. Fold the overlapping bacon slices over the mixture to encase it. Top each pate with 4 bay leaves.
Set the pans in a roasting pan large enough to accommodate both and place in the oven. Pour boiling water into the roasting pan to come three quarters of the way up the sides of the pan. Bake for 1 1/2 hours or until the internal temperature reaches 170 degrees F. Remove from the oven and carefully drain off any excess fat, by pouring or by using a bulb baster. Cover the pans with aluminum foil, then place a 2 to 3 pound weight on top of each pati. Return to the oven and bake for 1 hour.
Remove from the oven and with the weight still on refrigerate for at least 8 hours before serving. Remove the bay leaves. Cut into 1/2-inch slices and serve.