A low protein intake will cause limited hemoglobin production in standard anemic dogs. It appears that the dog on a limited protein intake is unable to produce the usual amount of globin and therefore of hemoglobin even in the presence of a large excess of iron.
Iron given by mouth or by vein shows the same result—the dog made anemic by blood withdrawal cannot produce the expected new hemoglobin related to the iron intake when the protein intake is held at low levels. These dogs can be kept in perfect health and weight equilibrium during these long periods of limited diet intake and anemia.
Under the stress of protein limitation the proteins of salmon muscle, banana and carrot are well utilized and it requires only 7 to 8 gm. of these food proteins to produce 1 gm. of new hemoglobin.
These experiments show clearly that the iron content of liver is not wholly responsible for its potency in anemia due to hemorrhage.