A Thesis presented for the degree of Doctor of Philosophy in the University of the Witwatersrand. Johannesburg, January, 1967. / Although reports of the medicinal use of iron date back to ancient times it was not until the present century that the many functions of iron in the body were studied. Once started, the investigation received impetus from the seriousness of iron deficiency anaemia, a major cause of ill health throughout the world. The introduction of radio-isotope tracer techniques in 1939 greatly facilitated investigation of absorption, excretion and the metabolic pathways of iron. The tremendous amount of work already carried out has led to a fairly comprehensive knowledge of the various aspects of iron metabolism. Nevertheless, there remain wide gaps in the overall picture. In / IT2018