This is great food. The clear stock is by itself a tremendous soup, and the meat, so tender it falls apart, is a natural response to the gravest of cravings.
Sear the ox tail in a large pot over high heat until its nicely browned on all sides. Add the rest of the meat, and continue searing until browned. (You may need to remove the ox tail while searing the diced meat, as the meat will give away a lot of moisture, boiling rather than searing it. Return the ox tail when the meat is thoroughly seared.) Cover with water and bring to a boil. Reduce the heat to medium. Add bay leaves and black pepper, and let simmer for 3 hours or more.
Remove the ox tail. Increase the heat to medium high, and bring to the boil. In a small bowl, separate the white from the yolk of one egg. Using a fork, whisk the white lightly. Gently pour the egg white onto the surface of the stock. As the egg white stiffens, it will attract most of the impurities of the stock, and can be easily removed with a skimmer.
Add cabbage and rutabaga, and let simmer for 12-15 minutes until the vegetables are tender. Serve.