Dust from metals and minerals may produce mechanical injury to the membrane of the respiratory tract because of the sharp edges. Inhalation of dust might also bring about catarrhal conditions and coughs. There may be deposits of dust in the bronchi and even in the parenchyma of the lungs from long exposure to and inhalation of dust. This may result in consolidation and other conditions which may be purely adaptative on the part of Innate Intelligence to compensate for the presence of the foreign substances. In F. Hoffman’s Bulletin of the Bureau of Labor, Vol. LXXIX, he gives the following classification of dusty trades according to the character of the dust produced: “=Group I=—Exposure to Metallic Dust: Grinders, polishers, tool and instrument makers, jewelers, gold leaf and brass workers, printers, engravers and pressmen. “=Group II=—Exposure to Mineral Dust: Stone, marble and cement workers, glass blowers, glass cutters, diamond cutters, potters, plasterers, paperhangers, moulders, core makers and lithographers. “=Group III=—Exposure to Vegetable-fiber Dust: Cotton ginning, textile, linen, hemp, cordage and paper manufacturers, weavers, spinners, hosiery knitters, lace makers, jute and wood workers. “=Group IV=—Exposure to Animal and Mixed Dust: Furriers, taxidermists, hatters, silk, wool, and worsted workers, carpet, rug, rag, and shoddy workers, hair mattress workers and upholsterers.” The mortality rate from pulmonary tuberculosis and other respiratory incoördinations is very high in the dusty trades. INDUSTRIAL POISONS In the case of poisonous gases and fumes the necessity becomes even greater for proper prophylactic measures. The methods used in dusty trades may be here employed, but with greater care. All poisonous materials should be eliminated as far as possible and less objectionable material substituted. This may be done in a great many instances without decreasing the value of the article manufactured. An illustration of this is in the substitution of red phosphorus for the use of the more poisonous yellow phosphorus in the manufacture of matches. This eliminates danger from phosphorus poisoning. Price states: “The chief industrial poisons are lead, arsenic and mercury, although phosphorus, copper, zinc, brass, and chromium poisoning are frequently met with in various industries.” Lead Poisoning The symptoms produced by lead poisoning are: lead colic in acute cases, loss of appetite, cramps, pain in the joints. There will be bluish lines found along the edge of the gums; wrist drop and loss of motor function in the hands and feet; arteriosclerosis, indigestion, restlessness during sleep, anemia, lead palsy, loss of strength and weight and constipation. The patient experiences a disagreeable sweetish taste, and there will be a grayish pallor and pinched expression of the face. In severe cases there may be blindness, great fatigue, apoplexy, insanity and death.