The concentration of haemoglobin in the blood of young adult men and women: the effect of administering small doses of iron for prolonged periods.

We now realize that individual values, obtained while observing apparently healthy animals, may deviate appreciably from the mean of such values and still, so far as we can tell, be compatible with health. Values that deviate considerably from the mean may nevertheless be ‘normal’. Values for the concentration of haemoglobin in the blood belong to this category and pose rather special problems of their own. Here we are dealing with two variables, the mass of the haemoglobin and the volume of the plasma, and these may vary independently. The reading obtained in conventional haemoglobinometry is a function of both. Whitby (195 I) discusses this problem fully. The accepted ‘normal’ value for the concentration of haemoglobin in human blood has increased progressively with the passage of years. Whereas 13.8 g/Ioo ml. blood was ‘ IOO % ’ for Haldane’s original twelve healthy men, something approaching 16 g/Ioo ml. blood is now thought to be the desirable concentration in men. But the concentration in the blood of apparently healthy adult women, even when all factors other than sex are comparable, has obstinately lagged behind, so that something of the order of 14 g haemoglobin/Ioo ml. blood is accepted as normal for them (Osgood, 1926; Price-Jones, 1931; Osgood, Haskins & Trotman, 1931-2; Jenkins & Don, 1933; Wintrobe, 1933 ; Sunderman & Boerner, 1949; Whitby, 1951 ; Berry, Cowin & Magee,