1. Department of Small Animal Medicine and Surgery (Lipscomb), Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA England and the
2. Departments of Surgical Sciences (Hardie) and Pathobiological Sciences (Dubielzig), School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive, Madison, Wisconsin 53706
3. From the