Soak the sweetbreads in cold water for an hour or more. Change the water several times, so that all the blood will be extracted, and leave the sweetbreads very white. Put them on the fire in cold water, and simmer (not boil) for twenty minutes. Then immerse them again in cold water. This is to parboil and blanch them. Remove all the pipes, strings, and fibers it is possible to do without breaking the sweetbreads to pieces. When half cold tie each one in a piece of cheese-cloth, drawing it tightly into an oval form, and place them under a light weight until cold. They will then be smooth and a uniform shape, and may be larded with fine lardoons if desired. Use a silver knife for cutting sweetbreads.