“…Six mature males had 9,000,000 and 3 mature females 8,800,000 cells. Sure, Kik and Walker (1929) have made a relatively large number of cell counts and hemoglobin (Newcomer method) measurements on growing rats reared on various diets. Age and diet were shown to exert such marked effects that it is perhaps questionable whether the observed slight and temporary sex difference (lower values in female, from 75 days to 90 or 120 days) is at all significant.…”