Correspondence is by far the largest in the collection. There are sequences of correspondence, sometimes extending over several decades, with plant biochemists and protein chemists in Britain and overseas, especially the USA and Scandinavia. There are particularly noteworthy sequences of correspondence with W T Astbury, K Bailey, R K Cannan, H J Channon, C S Hanes, K U Linderstrom-Lang, K P G Link, T B Osborne, S H Piper, R R Porter, F Sanger, R L M Synge, H B Vickery and A I Virtanen.