This section is from the book "The Epicurean", by Charles Ranhofer. Also available from Amazon: The Epicurean, a Complete Treatise of Analytical and Practical Studies on the Culinary Art.
Soak in cold water for five or six hours, six pounds of fresh pork skin; put it into a saucepan with cold water to double its height, and blanch it in this water until it boils, then drain and refresh it: scrape off the pieces one by one, wash them well, and return them to the saucepan with more clean, cold water and boil the liquid while skimming it; set it on one side of the range or on the gas Stove, and add half a bottleful of white wine, then continue boiling for seven hours, skimming it frequently. Pass the liquid through a sieve into a basin, let it get cold and firm on ice, then remove all the fat from the top and wash the surface off with very hot water; melt it once more to mix it in with the necessary broth and clarify it with meat and eggs or white of eggs, proceeding the same as for aspic-jelly (No. 103).