The Vitamin B 12 Concentrations of Serum and Urine of Normals and of Patients with Megaloblastic Anaemias and Other Diseases

Until recently deficiency of vitamin B12 in man could only be recognized by finding the characteristic clinical and haematological signs of the deficiency and by demonstrating that these signs were cured or relieved by treatment with the vitamin. Changes in the vitamin B12 content of the tissues could only be inferred from the responses of patients to treatment.