Haematite Pneumoconiosis in Cumberland Miners

Iron oxide occurs as a dust in many industries apart from iron-ore mining.It is found in silver polishing, electric welding, and boiler scaling, as well as in the more obvious metal grinding, fettling, and blast furnace working where it may be mixed with varying amounts of silica.Some still consider iron oxide a harmless dust (Baldi, 1952) while others think that, like coal, it can produce changes in the lung substance even in the absence of silica.Kettle (1932) observed that if he covered quartz with iron oxide little or no fibrosis occurred and animals inoculated with ferric oxide developed no fibrosis.In 1933 I found that if ferric oxide alone was injected into guinea-pigs and rabbits localized dust aggregates appeared but no progressive fibrosis, When the experiment was repeated with itoir-oe contiining' 10% silica, even with the addition of dead tubercle bacilli, progressive massive fibrosis could not be produced, and as time