Document G5K05mNQ0ew11X01ypm1owMQn

r.v. C3** .211 seems to be easing off in South Wales; it appears to be still rising in the rest of the country. . Well, now, in South-Wales itself, there are also quite important changes in the certification pre7alence as ve look across the country. Over in the anthracite area here, this is a map in which little dots imply coal mines employing more than a hundred men, and these are contour drawings on mines with the same prevalence of certified disease over this period 'hO to 'h5 The blacker they are, the worse they are. !Hie black here is over seventy per thousand per annum, and mostly the anthracite, with a tongue out here in the bituminous area, and the surrounding bituminous arean were very much lower prevalence. Well, now, the Medical Research Couhcil did a big investigation of this problem in 1938 and with Doctor Hart and Doctor Haslett and a lot of other people, and they con firmed, from survey work, this distribution of the disease in South Wales, the higher the rank of coal, the more the disease. They failed to show any direct relationship to any particular component of the coal such as the free sil ica or the ash. There was a general relationship to the total amount of dust. The disease, they pointed out, was quite distinct from classical silicosis and from their work this rank of coal'hypothesis, that high rank coals, anthrae it SEVENTH SARANAC -0246