The scarcity of information concerning the normal blood picture during adolescence suggested the feasibility of investigating in a large group of healthy high school girls some factors of physiologic significance. Accordingly, determinations of the hemoglobin content, the red cell count, the white cell count, the percentage of reticulocytes and the red cell diameter were made on 258 high school girls ranging in age from 12 to 19 years, 98 per cent of whom were between the ages of 13 and 18 years. This group represented a random sampling of high school girls from several Minnesota communities.1 The subjects were selected with the aid of the school nurse or some other member of the staff who was familiar with their physical status.
Samples of blood were obtained from freely flowing drops secured by puncture of the finger tip. Determinations of the hemoglobin content were made in duplicate or triplicate