The Retention of High and Low Rank Coals in Rats' Lungs

The prevalence of coal workers pneumoconiosis appears to be higher in high rank than in low rank coal mines. Two experiments were carried out to test whether rats inhaling dust of high and low rank coal at equal concentrations, take up and retain the high rank coal more than the low rank coal. The results did not show any sign of such an effect and it is concluded that a similar effect in man is unlikely. Certain differences in the results of the two experiments are described and discussed.