436 DISEASE IN WILD MAMMALS AND BIRDS 
whether it is directly employed in the production of hemo- 
globins has not been proved. Undoubtedly most of the 
extra iron given with the food passes through the ali- 
mentary tract mthout being absorbed or metabolized. 
The greater the amount of iron in the food, the greater the 
influence of the inorganic iron. Anemia occurred in all 
the animals we examined at least four times as frequently 
in omnivorous as in all the other dietary groups, a fact 
probably explained by the low content of iron and calcium 
in this diet. Both Von Wendt(13) and Sherman (14) 
demonstrated that larger amounts of iron were required 
to maintain the iron equilibrium when the amount of cal- 
cium was low. 
Herter has showTi that many anemias are associated 
with intestinal putrefaction. The carnivores, however on 
a diet that putrefies very easily and on one in which the 
iron content is apparently of distinctly lower nutritive 
value than that of the iron found in milk, eggs and vege- 
tables, presented an anemic incidence of only 0.32 per 
cent. This is probably due to the excellent hygienic care 
of the meat foods and to the morphology of the carniv- 
orous intestinal tract, which is short, straight and 
fashioned for quick elimination. The cases of anemia 
steadily increase among the animals as the conformation 
of the tract approaches the omnivorous type with the 
longer and \vider hind-gut. 
Herbivora, obtaining their iron from vegetable 
sources, are much less liable to blood disorders. The 
iron needs of the female are greater than those of the 
male because of the drains of pregnancy and lactation. 
Young animals demand more iron than adults. All 
exclusively breast-feeding animals have a considerable 
storage of iron in the body at birth, while those that eat 
food immediately have no such supply. Bunge's(15) 
(13) Skandinavisches Archiv. f. Physiologic, Vol. 17, p. 211, 1905. 
(14) Bull, 185. Experiment Station, U. S. Dept. Agriculture, 1907. 
(15) Physiological and Pathological Chemistry, Blakiston, 1902. 
