Abstract
In order to investigate “pre-silicotic stage” 29 persons engaging in dust labour and 10 healthy persons were examined. And the results are as the following.
1) The roentgenological findings of the pre-silicotic stage are abnormalities in the pulmonary field and blunting of the hilar regions. And these are more frequently observed among the dust labourers than the healthy persons.
2) The grade of subjuntive and clinical symptoms is proportional to the grade of the past silicotic disease of the patient.
3) The pulmonary function test revealed that ventilatory disturbance and emphysema among the advanced stage.
