Acute Silicosis

A QUARTER of the earth's crust is composed of silicon, so it is not surprising that the inhalation of dust has been recognised for centuries as a cause of shortness of breath in miners and stone operatives. In 1649 Dimerbrook (Collins, 1915) described chest rigidity associated with dyspncea in the granite workers of the Carpathians, who were themselves painfully aware of the occupational hazards encountered, since they referred to their implements as 'widow-makers,' because many of the local women had married several times due to the extremely high incidence of lethal respiratory disease in their male partners. Even to this day the above term is used by European immigrants in the iron mines of Michigan, in the same sense as in the seventeenth century, although the risks are happily minimised by modern protective procedures. The real nature of silicosis was first recognised by two English physicians (Peacock, 1861; Greenhow, 1895), when they demonstrated the presence of a hard gritty material, which they called 'sand,' obtained at autopsy from the lungs of a mason and knife-grinder respectively. The ceaseless and ever-expanding exploitation of mineral resources has, from time immemorial, provided ample opportunity to study the deleterious effects of siliceous dusts on the health of workers exposed to them, and evolve the necessary modern protective measures which have made acute silicosis a rare disease. It is chastening then in this day and age to have the doubtful privilege of observing the effects of an atmosphere freely charged with freshly fractured flint particles, on the unprotected respiratory system, where environmental control did not exist, because the noxious nature of the dust was not appreciated. The misadventure occurs where limestone of high calcium content is extensively quarried and processed either for itself (calcium carbonate), its bye-products, or for admixture with local aluminous clays in the manufacture of cement. When crude chalk is crushed flints contained therein are enucleated and separated as they are of little commercial value. Small independent enterprises, however, may acquire these rocks, and crush them into a small aggregate about the size of lentil seeds; this is bagged and sold as 'Poultry Grit.' It was following such an occupation that the cases to be described contracted acute silicosis, and it seems ironical that Visconti gave this disease its present name ninety-three years ago, when he described pulmonary disability in a flint worker.