In untreated pernicious anaemia, the binding of folic acid activity (FAA) to protein zone II of the serum (transferrin) had increased distinctly and to zone I (γ-globulin) slightly. A decrease, on the other hand, was noted in zones IV-V (α2-macroglobulin and albumin). During specific treatment, the changes return to normal, with FAA diminishing in zone II and increasing in zones IV-V. There were still some changes present after 7 weeks of treatment, when the anaemia had already been cured. In a pernicious anaemia patient with neuropathy the chromatogram was not much different from normal, and a slight increase in FAA was noted during treatment in protein zones, I, II and IV.