The effect of the administration of HN2 on the utilization of plasma iron

T in therapeutic doses to human subjects produces changes in the peripheral blood indicative of an injurious effect on the hematopoietic system. There is usually a marked reduction in the number of white blood corpuscles, appearing most often 2 or 3 weeks after the injection.1~2~49 6 -9 ~1 1 As far as the erythrocytes in the peripheral blood are concerned, the decline in number occurs during the first 2 weeks but does not exceed 300,000 or 400,000 per cu. mm. of blood after the administration of a total dose of 0.3 mg. per kg. of body weight of HN2.11 A return to normal values is observed usually after 4 to 5 weeks." These observations do not give precise indications on the extent of the effect of HN2 on the erythropoietic system, because it is well known that the bone marrow can increase its activity several times to compensate for a temporary interruption of activity. This interruption if not too long will not necessarily be reflected in alterations of the peripheral red cell counts, provided the life span of the erythrocytes is not shortened.