Proper diagnosis of megaloblastic anemia requires differentiation between a deficiency of vitamin B12, a failure to absorb vitamin B12, as in pernicious anemia due to a deficiency of intrinsic factor, a deficiency of folic acid, and a disturbance of folic acid metabolism due to a deficiency of ascorbic acid. The clinical associations and underlying causes, such as achlorhydria, total gastrectomy, blind intestinal loop, fish tapeworm, malabsorption syndrome, or pregnancy, must be sought and need to be taken into account. Fortunately pernicious anemia is mostly a disease of older people, so megaloblastic anemia of pregnancy is almost always due to a disturbance of folic acid metabolism. Young women with pernicious anemia are rare and hardly ever get pregnant or carry the pregnancy beyond the early months. Working at the Queen Elizabeth Hospital in Birmingham, England, R. J. Boscott and W. T. Cooke observed excessive quantities of p-hydroxyphenylacetic acid in the urines of 20 patients with steatorrhea and megaloblastic anemia.