1 . The patient described in this report had macrocytic anemia, megaloblastic maturation arrest in the bone marrow, glossitis, hyper-reflexia and diminished vibration perception in the feet. None of these abnormalities was improved by liver extract or vitamin B12 but all responded rapidly to folic acid except the neurologic signs.

2. This patient appears to have had a megaloblastic anemia which has been described in European clinics under the names "achrestic anemia" and "refractory megaloblastic anemia." It appears to be similar to "Wills" factor deficiency anemia" and some cases of pernicious anemia of pregnancy.

3. This patient did not appear to have a primary deficiency of folic acid since the excretion of this substance in the urine was within normal limits. A deficiency of an unknown factor probably equivalent to "the Wills’ factor" is suggested.

4. It seems likely that folic acid induced a remission in this case by a "mass action" effect. The possible relationship of folic acid, vitamin B12, the unknown factor and liver extract to nucleo-protein synthesis is discussed.

ACKNOWLEDGMENT We wish to thank Doctor Charles Foertmeyer for referring this patient to us for the clinical study used in this report.