Towards the completion of the work it was realized that the results obtained by the nesslerization method described in Parts 2-4 of this series of papers tended to differ from those obtained by the micro-Kjeldahl digestion of a larger quantity of serum followed by titration (Young, Bishop, Hickmans and Williams, 1949; Young, Poyner-Wall, Humphreys, Finch and Broadbent, 1950; Poyner-Wall and Fin...