Numerous studies made on the blood of new-born infants have fairly well established the fact that the number of their erythrocytes per cubic millimeter is much higher than it is in the adult. Furthermore, a review of the results of hemoglobin determinations in new-born infants shows a much higher hemoglobin content than is found in adult life. The high hemoglobin content rapidly falls.
Williamson, in a spectrophotometric analysis of 919 cases, shows in his tables that the hemoglobin of the new-born infant averages 23.2 gm. hemoglobin per hundred c.c. of blood. The hemoglobin falls rapidly and by the end of the second month the reading is 18.3 gm. At the end of the fifth month it is 13.7 gm., and then remains practically constant during the next few months, falling to 12.5 gm. at the end of the first year. From this point up to the sixth year there is