Clean the heart, and cut it lengthways into large pieces. Put them into a pot with a little salt and pepper, and cover them with cold water. Parboil them for a quarter of an hour, carefully skimming off the blood that rises to the top. Then take them out, cut them into mouthfuls, and having strained the liquid, return them to it, adding a head or two of chopped celery, a few sliced onions, a dozen potatoes pared and quartered, and a piece of butter rolled in flour. Season with whole pepper, and a few cloves if you like. Let it stew slowly till all the pieces of heart and the vegetables are quite tender.
You may stew a beef's kidney in the same manner.
The heart and liver of a calf make a good dish cooked as above.