Letter from Howard Walter Florey to E Lester Smith, Glaxo Laboratories, Greenford Thanks Smith for testing remainder of the radioactive B12 - says G M Watson has gone to Australia - unlikely that work will be continued - effect was only shown with extract of the rat's stomach - no satisfactory results were obtained with a guaranteed source of intrinsic factor - operation on rats was not easy - will send copy of paper on the work. 22 October 1954