Document byLD0k44dwVxo1V3EV12z4Ke0

-4- In the inert reaction, the dust neither caused an increase in the site of the nodules nor disappeared from the tissues; instead there was more or less a change in its dis tribution, Soapstone, carborundum (Silicon Carbide), jeweler's rouge (Ferric Oxide), anthracite coal, bittmincus coal and certain filter clays have inert reactions, Calcite, limestone, precipitated caloium carbonate, gypsum, and Portland Cement exhibit ed an absorption reaction. Quarts, chat, certain filter clays and flint produced a proliferative reaction, vThe physiological response to the injected dusts were found sufficiently well marked in 90 days to determine the type of reaction, particularly vdiere the reaction was one of absorption or proliferation. Since the reaction elicited by dust was oonstant and uniform in all of the animals injeoted with the dust, it is believed that this response of peritoneal tissue to various dusts can be used as a test to de termine the possible harmfulness of industrial dusts. The fibrosis-produoing properties of a Georgia filter clay (30-60 mesh grade) a sample of American contact clay and a German contact clay were tested by the Intraperitoneal Method, under the direction of Dr. R. R. Sayers, Medical Officer in Charge, U,S. Public Health Service. The Georgia filter clay showed an inert reaction with a slight tendency towards a proliferation in the 90-day test,. The American con tact clay showed an inert reaction with evidence of same slight absorption or dis appearance of same part of dust in the lBO-day tests. The German contact clay caused the formation of light yellowish-brown nodules and as the interval between the in jection and the examination increased the nodules became somewhat flattened, but the amount of dust and the approximate size of the nodule remained -the same throughout the entire period (90-days) of the test. This can be considered an inert reaotionj but as the dust does not disappear from the peritoneum it should be considered as po tentially harmful though not as dangerous as pure 6ilica. In commenting on the results of the tests with the Georgia filter clay and the American contact clay. Doctor Sayers advised that the results of the test indicated that the filter clay 1s more harmful than the American contact clay because the dust remains inert in the tissues as this was the largest portion of the dust and the in ert appearance of the lesions was the most prominent. The modification of the reac tion in the filter clay can be attributed to the presence of 5-10 per cent, quartz (Petrographic), Gypsum in the American contact clay may account for the slight ab sorptive reaction. Doctor Sayers advises that an inert dust, if breathed in suffi cient concentration, may be harmful. These tests were made in acoordanoe with the procedure described in Reprint #1608, Publio Health Reports, Vol, 49, No. 3, January. 19, 1934, pps. 80-89. The inhalation of dust gives rise to "Pneumoooniosis" a term derived from the Greek pneumon. lungs and konls. dust, and used to designate a pathologioal oondition of the lungs caused by the inhalation of any dust. It includes SILICOSIS, a ohronio disease of the lungs caused by the inhalation of minute particles of free silica (Si02) dust which produces a permanent incapacitating alteration of the lung tissue; ANTHRACOSIS, the black lung of the miner due to ooal dust; ANTHRACO-SILICOSIS, the newest of our mineral dust affeotions end introduced by the United States Publio Health Service as a result of their studies in the Anthraoite Distriot of Pennsyl vania. This affection is the result* of breathing anthraoite coal dust that oantains silica. The oommon name for the affection is "Miners' Asthma"; CHALICOSIS, the gray-black lung of the stone-outter due to stone dust; ASBESTOSIS; in asbestos workers due to asbestos dust; SIDEROSIS, due to breathing dusts of iron ore (The lungs are yellow or red from metallio oxides generally of iron.); BYSSINOSIS, due to cotton particles and vegetable fibre dust, and PNEGMONODLTRAMICROSCOPICSILICOVOLCA1J0K0NI0SIS, a special form of silioo6is caused by ultra-microsoopic particles of siliceous volcanic dust. Silicosis, Asbesto6is, and Silico-Anthraoosis are the only three forms of pneumoconiosis which require practical attention. EMOOim