So few are the reliable observations of the hemoglobin content of the blood during infancy and childhood that it would seem unwise to make a more precise statement concerning the average values and the normal limits of variation for the different age groups.... The data concerning red cell counts during infancy and childhood are so meager and so conflicting that no final statements can be made concerning the average values for the age periods nor the normal limits of variation.... The important values are not the averages, but the average limits of variation. It is just these which are particularly uncertain.
This quotation from the report of the White House Conference on Child Health and Nutrition1 indicates clearly the need for the study of normal hematologic standards in children. To help fill this need we have determined the red cell count, hemoglobin content and erythrocyte volume and have calculated