1. Clinical Research Unit, Royal Prince Alfred Hospital, and the Department of Medicine and Electron Microscope Unit, The University of Sydney, N. S. W., Australia.
2. University of Sydney; Director, Clinical Research Unit, Royal Prince Alfred Hospital, Camperdown, Sydney, Australia.
3. Clinical Research Unit, Royal Prince Alfred Hospital, Camperdown, Sydney, Australia.
4. Department of Medicine, University of Sydney, New South Wales, Australia.
5. Electron Microscope Unit, University of Sydney, New South Wales, Australia.