Place the pig╒s head in 4 quarts water, with the bacon, and the ham hock. Bring to a boil and skim. After 1 hour and 30 minutes simmering, add the tied leeks, the carrots, the turnips, the onions, garlic, bouquet garni and pepper. Simmer for another 45 minutes, then add the cabbage and the sausage. Cook for another 30 minutes. Taste for seasoning. In the meantime, cook the lentils with the celery over very low heat, so they don╒t break. Add a small amount salt and pepper. Boil or steam the potatoes separately. To serve, place the sliced meat on a heated platter, with the vegetables and the lentils around them. Serve the degreased stock at the same time in cups. You can degrease the stock fast by pouring it through a tea towel folded in four, placed in a strainer.