The author inquired into 7300 cases, out of the twenty thousands who were examined about silicosis by the Minis try of Labour in 1952 till 1954, and classified their X ray findings into the nodular conglomerate and complicated shadows. 1. The auther classified the nodula shadows into regularly and irregularly circular forms. Among the workers engaged in the industries exposed to heavy dust, the author found the more irregulary circular forms in the bigger nodular shadows. 2. Among the workers engaged in the industries exposed to heavy dust, the nodular shadows grow, generally speaking, bigger in proportion to the number of the shadows, but among those engaged in the industries exposed to light dust the shodows over 4mm are scarcely seen. 3. The nodular shadows are apt seen in the interior (the 5th) or inner (the 4th) part of the lungs in attached figures no. 1. But the distribntion becomes wider over the lung in proportion to the thickness of the dust and this phenomenon is apt to be seen in those who have bigger nodular shadows. 4. The auther classified the conglomerate shadows into five types, These types are seen more frequently when the nodular shadows are bigger 5. In the left and the right lungs, the distribution of the conglomerate shadows are not always the same, nor are the numbers of the shadows. 6. The swelling of the pulmonary hilum, the pulmonary emphysema and the callosum of pleura are seen in many workers engaged in the industries exposed to heavy dust, and they become distinguished when the patients suffer from heavy pneumoconiosis.
