The relation between lung dust and lung pathology in pneumoconiosis.

Methods of isolation and analysis of dust from pneumoconiotic lungs are reviewed, and the results of lung dust analyses for different forms of pneumoconiosis are presented. A tentative classification separates beryllium, aluminium, abrasive fume, and asbestos, which cause interstitial or disseminated fibrosis from quartz, coal, haematite, talc, kaolin, and other dusts, which cause a nodular or focal fibrosis which may change to forms with massive lesions. The data suggest that in the first, but not in the second, group the dusts are relatively soluble; only in the second group do amounts of dust and severity of fibrosis go in parallel for a given form of pneumoconiosis. In classical silicosis the quartz percentage is higher and the amount of total dust much lower than in coal-miners' pneumoconiosis. Mixed forms of both groups occur, for instance, in diatomite workers. The need for more research, especially in the first group, is pointed out.