7. Extremes of Humidity.—Sedentary work should not be done in a humid atmosphere. If the air be excessively dry, provision should be made for its humidification.
8. Dust affects the lungs, the skin, the eyes and the external auditory canal. Protection from it may be secured by the use of goggles, respirators, wet processes, exhaust ventilation and the avoidance of dry sweeping. Of the different dusts en countered in industries, soil dust is the least harmful, then in order of increasing danger come flour and starch, soapstone and talc, wood dust, bran dust, coal dust, clay dust, shell dust, ore dust, mineral dust and stone dust. These dusts may be either poisonous or irritating. The latter have an important rela tionship to industrial tuberculosis. The problem of dust will be considered later in more detail.
9. Poisons are encountered in industry as either fumes, gases, solutions, pastes or solids. The list includes lead, benzine, benzol, turpentine, brass or zinc fumes, acids, alkalies, wood alcohol, anilin oil, carbon bisulphid, antimony, illuminating and fuel gas, hydrogen sulphide, arsenic, phosphorous, mercury and cyanide. Industrial poisonings usually occur because the amount of risk is not appreciated either by the employees or the employer. In combating their danger it is frequently necessary to overcome the following handicaps: (r) an employer's policy of keeping the employees in ignorance of the poisons used; (2) misbranding of poisonous substances; (3) lack of instruc tions or, (4) disregard of instructions; (5) absence of mechanical health appliances, such as adequate ventilation; (6) permitting employees to eat while at work or in the work rooms; (7) lack of personal cleanliness among employees; (8) lack of sufficient washing facilities; (9) absence of gloves and respirators; and (ro) no change of clothing on leaving work. Each poison presents a different problem. These also will later receive more detailed consideration.
io. Infections.—Infections may be contracted either from other workmen by the agencies of contact, or from the mate rial handled. Wounds received while at work and improperly cared for may become seriously infected. Contact transmission
is favored by overcrowding, by the use of common towels and drinking cups, absence of cuspidors and consequent spitting on the floors, by sweeping during working hours, and by mouth ing objects handled by another. Agriculturists may become infected from sick livestock, while workers in hair and wool may become infected with anthrax from this material. A cer tain degree of protection is afforded by first aid training, but still better in a manufacturing plant is a surgical emergency room with a trained nurse in charge, and a supervising surgeon.
ii. Unguarded or Defective is one of the most potent sources of danger. The following moving parts of machinery should be protected by suitable guards so that hair, clothing, or the fingers may not be caught or the person crushed or mangled, viz.: gears, rolls (Fig. go), belting, rope or chain drives, all horizontal belts or shafting less than seven feet from the floor, beltshifts or loose pulleys, clutches, shaft guards and set screws. Fly wheels and emery wheels should also be guarded, and the latter should be suitably connected to an exhaust vent. Additional points for safety in factories are the following: (r) Glass panels on swinging doors in passage ways, (2) ladders should have sharp points on their feet, (3) elevated platforms around machinery should be railed (Fig. ioo), (4) saws of different types and planes should have suitable guards. Convenient provision should be made for the rapid shutting off of power in the event someone is caught. Similarly power of any sort should not be turned on, or machinery set in motion, unless it is known that no one is in a position to be injured.
12. Transportation suffer from these more than passengers, while trespassers suffer the most. Acci dents upon the railroad are mainly due to the following: Care lessness, lack of discipline, overwork, and the lack of safety devices. Passengers mainly suffer from derailment and collis ions while employees suffer from accidents arising in coupling and uncoupling cars, and by falling from cars or engines.