Abstract
Though various opinions have been published on the above subject, no detailed report has yet been cited in the past. The author made investigations on this subject because the results of this investigation will be reflected upon the significance of the change of the occupation and the judgement of the effect of the treatment.
The results of the present investigation are as follows:
1. The progress of silicosis is found more advanced in a more serious case, and is found more advanced with the time lapse from the abandonment of the occupation.
2. Even after 1 year, progress is recognized in certain number of cases.
3. During the progress of silicosis, fine or medium sized granular shadows in the cases of Grade I, fine, mudium and large sized granular shadows and fused shadows in the cases of Grade II are recognized, while, in the cases of Grade III, fused shadows, massive shadows, bipolar shaped shadows, shadows induced by pulmonary emphysema and changes in the pleura are observed.
4. Among the cases of the same Grade, those developed within a shorter period demonstrated a more rapid progress than those developed after a longer period of time.
