1. Fluorescent Protein Tracing;Nairn, R.C.,1962
2. Ghose, T., Porteous, I. B., and Urquhart, J. A. (1962). J. clin. Path., 15, 594.
3. Taylor, K. B., Roitt, I. M., Doniach, D., Couchman, K. G., and Shapland, C. (1962). Brit. med. J., 2, 1347.
4. Recently I described a 'microspot' test for antigenantibody interaction in thin agar films (Feinberg, 1961) and its adaptation to and enhanced sensitivity on cellulose acetate membranes (Feinberg, 1962). The antibody for these tests had been induced in rabbits by immunization with hetero-antigens
5. Auto-immune thyroiditis was chosen for this preliminary investigation because of the well-authenticated occurrence of precipitating antibody in patients suffering from this condition. Sera of two patients with autoimmune thyroiditis and a solution of 40 mg./ml. human thyroglobulin were kindly provided by Dr. I. M. Roitt of the Courtauld Institute of Biochemistry. A preliminary 'microspot' test was carried out on both sera and they were found to contain approximately similar amounts of precipitating antibody to the thyroglobulin. One of these Received for publication,1962