1. A clinical remission in one case of pernicious anemia in relapse treated with 50 µg. of vitamin B12 from liver is reported; the patient was followed for 114 days after two doses of 25 µg. were given on successive days and a peak of 3,900,000 erythrocytes occurred on the eighty-sixth day.
2. Preliminary observations are reported in 2 patients with pernicious anemia in relapse treated with a vitamin B12 derived from Streptomyces griseus; the first patient who had no neurologic complaints received 32 µg. while the second was given two doses of 32 µg. each because of severe, subacute, combined degeneration. A good hematologic response and a satisfactory clinical remission occurred in both cases. There was definite improvement neurologically in the second case.
3. The administration of 32 µg. of vitamin B12 derived from Streptomyces griseus to each of 5 cases of pernicious anemia in remission resulted in minor subjective and objective improvement.