The greatest danger from lead comes in the form of dust or fumes and therefore the poison enters the body principally through the respiratory tract, but it may enter through the digestive tract and through the skin. Prophylactic measures include devices to protect the workmen by means of respirators, but special effort should be made to keep the air in the breathing zone free from the dust and fumes. Since the poison may be taken in through the skin, special provision should be made to protect the hands and arms in fingering the materials. The workmen should exercise the greatest cleanliness and precaution to prevent ingestion of the lead into the digestive tract. Care should be taken that it is not brought into the mouth by the fingers or by pipe, for example. There is a high mortality from pulmonary tuberculosis among lead workers. Arsenic Poisoning The mouth, lungs and skin are the portals of entry for arsenic into the body. Arsenic poisoning is characterized by catarrhal inflammation of the eyes and respiratory tract, anemia, neuritis, gastritis, and degenerative changes in the liver and kidneys. Many of the symptoms of arsenic poisoning resemble those of lead poisoning such as gastric disturbances, anorexia, anemia and loss of strength. There may be progressive muscular atrophy, eczematous eruptions and ulcers of the lips, nostrils and in the folds of the skin. Arsenic is used in the manufacture of wall paper, artificial flowers, textile fabrics; by taxidermists and as a preservative for hides; it is also used in different preparations to kill insects and parasites. Mercurial Poisoning Mercury enters the body through the digestive and respiratory tracts and through the skin. The symptoms usually manifest in this kind of industrial poisoning are headache, gastric disturbances, stomatitis, metallic taste in the mouth and fetid breath; there is swelling and ulceration of the gums that cause the teeth to become loose, and there may be an excessive flow of saliva with a swelling of the submaxillary glands. In severe cases there may be tremors, paralysis, melancholy and loss of memory. Mercury is used in the manufacture of incandescent lamps where they employ mercury pumps, in the manufacture of barometers and thermometers, in the felt and fur industries, in the manufacture of pharmaceutical preparations and chemical works, and in photography. Methods used to prevent mercurial poisoning are almost identical with those used in lead poisoning. Special devices should be provided to keep the air in the breathing zone free from the fumes. This can best be accomplished by providing a proper system of mechanical ventilation. The workmen should wear rubber gloves to lessen the possibilities of the absorption through the skin. The workmen should also practice cleanliness and exercise care that mercury is not carried into the mouth by the hands which should be thoroughly washed before eating. Phosphorus Poisoning