Abstract

Howell-Jolly bodies in erythroid precursors can be found in the marrow in a variety of diseases. More than 1% in the later erythroblasts is rarely found except in vitamin B₁₂ or folic acid deficiency states.

Giant metamyelocytes are probably always the result of vitamin B₁₂ or folic acid deficiency. A distinction is drawn between the deficiency of, and therapeutic need for, vitamin B₁₂ and folic acid.