decomposition, and the presence of individuals also tends to vitiate the air with dust, germs, and organic matter from the skin, mouth, lungs, and soiled clothing. Unless proper provision is made for the dispersion of foul air and the introduction of pure air there is much reason for assuming that these impurities play a more or less important rôle in what has been designated as "crowd poisoning," characterized in the acute form by symptoms of oppression, headache, dizziness, and faintness, while the chronic effects of deficient oxygenation and purification of the blood are plainly evinced by the pallor, loss of appetite, anæmia, and gradual loss of physical and mental vigor. All of these effects are intensified when human beings are obliged to occupy rooms with an air supply insufficient for the proper oxygenation of the blood, and as a result of this habitual exposure to vitiated air, we note an undue prevalence of consumption in crowded workshops, dwellings, prisons, public institutions, and formerly also in military barracks and battle ships. Even live stock shows the baneful effects of insufficient air space, for tuberculosis among the range cattle of the far west, which are practically without shelter, is comparatively rare, while it affects from 15 to 25 per cent of dairy herds, which are housed, but without sufficient regard to light and air. Improved ventilation and increased air space has everywhere lessened the death rate, and it is chiefly by just such measures that the rate from consumption has been reduced from 11.9 to 1.2 per 1,000 in the British armies. As a matter of fact, an abundance of pure air has been found the most important factor in the treatment of tuberculosis, because it promotes oxygenation of the blood, stimulates the appetite and nutrition, and thereby increases the general resisting power of the system. OCCUPATIONS INVOLVING EXPOSURE TO IRRITATING DUST. It has long been known that the inhalation of dust predisposes to diseases of the respiratory passages, which may result in consumption. The particles of mineral dust produce an irritation of the mucous membranes of the nose, throat, respiratory organs, and eyes, and the hard, sharp, and angular particles of iron and stone dust may cause actual abrasions. According to Arnold (a) the dust which is inhaled lodges on the mucous membranes of the air passages and vesicles of the lungs, there to be coughed up, although some of the finest particles are taken up by the epithelial cells and white corpuscles and carried to the nearest lymphatic glands. The coarser particles, such as iron, stone, or coal dust, usually lodge upon the surface to be coughed up with the secretions. If not expectorated they will cause harm by clogging up the air vesicles and interfere with respiration. In the a Untersuchungen über Staubinhalation, etc., Leipzig, 1885. meantime not infrequently an irritation is set up, causing catarrhal conditions of the mucous membranes, or a more serious chronic inflammation of the respiratory organs, so common among persons engaged in dusty occupations. The chronic inflammatory conditions thus produced favor infection with the tubercle bacillus. At all events Hirt's statistics show that men employed in occupations that produce much dust suffer more frequently from pneumonia and consumption than those not exposed to dust and that there is practically no difference in frequency of diseases of the digestive system. The relative frequency of these diseases per 1,000 workmen is as follows: (a) CASES OF CONSUMPTION, PNEUMONIA, AND DIGESTIVE DISORDERS PER 1,000 WORKERS IN CERTAIN OCCUPATIONS. ୮ Perlen in his "Inaugural Dissertation," Munich, 1887, (") discussed the records of the Munich Polyclinic, where 65,766 persons were treated between 1865 and 1885, including 4,177 tubercular patients. Of these, 1,425 patients had been engaged in occupations where they were exposed to dust, viz: 30 per cent were by reason of occupation exposed to metallic dust. According to the reports of the census of 1900 the consumption death rate of marble and stone cutters in the United States is nearly six times that of bankers, brokers, and officials of companies, and the rate in fifty-one other employments ranges between these extremes. The amount of dust is perhaps less important than the character of the particles which compose it. The susceptibility to consumption. among metal workers and stonecutters can be explained only by the fact that the hard, sharp, and irregular particles of this kind of dust are more apt to produce injury of the mucous membranes of the respiratory tract. But it is not fair to assume that the less irritating dust is free from danger, for as pointed out by E. Roth (c) even the inhalation a Cited by Harrington, Practical Hygiene, 1901, p. 664. b Cited by Uffelmann, Handbuch d. Hygiene, 1890, p. 587. of plaster of Paris or flour dust can not be regarded with indifference, especially when such inhalation is preventable. Ahrens (a) found the amount of dust for each cubic meter of air in certain industrial establishments as follows: According to Schuler and Burkhardt, cited by Roth, (") the morbidity among 1,000 workmen engaged in dusty occupations is as follows: Bookbinders.... Cement works.. 224 98 Cotton spinners. According to Sommerfeld, cited by Roth, () the mortality in Berlin of persons engaged in nondusty occupations is 2.39 per 1,000; of persons engaged in dusty occupations is 5.42 per 1,000; the mortality of the total population of Berlin at the same ages is 4.93 per 1,000. Of 1,000 deaths in Berlin the number of deaths from consumption in occupations without development of dust was 381; in occupations with development of dust it was 480; in the total population of the city at the same ages 332.3 deaths of every 1,000 were due to consumption. METALLIC AND MINERAL DUST. It will be readily understood that in the cutlery and tool industry, especially in the grinding and polishing departments, more or less dust is evolved not only from the metallic surfaces, but also from the numerous grindstones and emery and corundum wheels. This dust production is not wholly avoidable, even when the wet process is employed. It is known that the inhalation of this dust tends to produce diseases of the lungs, such as bronchitis, peribronchitis, and fibroid pneumonia, but tuberculosis, also spoken of by the workmen as "grinders' asthma" and "grinders' rot," leads the list. Moritz and Röpke (c) have shown that 72.5 per cent of the deaths among the metal grinders of Solingen are due to consumption, as compared with 35.5 per cent among the general population. a Kompendium der Gewerbekrankheiten, Berlin, 1904, p. 106. b Ibid., p. 107. c Ibid., p. 26. The death returns for 12 years of the city of Northampton, Mass., one of the centers of the cutlery and tool industry, show that among "grinders," "polishers," and "cutlers" diseases of the lungs were responsible for 72.73 per cent of the mortality, inclusive of 54.5 per cent of deaths from tuberculosis. (a) Hirt gives the percentage of consumption in the total number of sick among different classes of workers in metal as follows: Needle polishers, 69.6 per cent; file cutters, who are also exposed to inhalation of lead, 62.2 per cent; grinders, 40 per cent; nail cutters, 12 per cent. Greenhow() over 50 years ago called attention to the excessive mortality among the needle polishers of Sheffield. Beyer() found that of 196 needle polishers at Remscheid only 24 were over 40 years of age. The reason why this occupation is especially dangerous is because the "wet process" can not be employed for small objects, which moreover have to be brought more closely to the eyes, and thus the chances for the inhalation of this metallic dust are increased. The danger in all such establishments can be reduced to a minimum by the employment of respirators and forced ventilation to carry the dust away from the operator. The Massachusetts report, cited above, states that even when employers have provided hoods, connected with a system of exhaust fans or blowers, "a very large proportion of grinders recklessly remove the hoods, and thus expose themselves unnecessarily to this especially dangerous form of dust. They assert that they prefer freedom of movement, with dust, to the protection offered by hoods." Stonecutting is regarded as a dangerous occupation, and consumption is quite common among men engaged in the industry. Those who have observed the various operations realize that in spite of wet processes and employment in the open air the workmen, especially those who operate the pneumatic tools, are exposed to a great amount of this irritating form of dust. A collective investigation published in 1901, and cited by Roth (c) shows that of every 100 deaths among stonecutters, polishers, and quarrymen 86 were due to diseases of the lungs, inclusive of 55 deaths from consumption. Of 2,013 stonecutters examined by Sommerfeld, 19.7 per cent were afflicted with consumption, 17.98 per cent with other diseases of the lungs, and nearly all had a chronic catarrh of the throat or larynx. a Report of the State Board of Health of Massachusetts upon the Sanitary Condition of Factories, Workshops, etc., 1907, p. 87. Cited by Sanders, Handbuch der öffentl. Gesundheitspflege, 1885, p. 106. According to the report of the Board of Health of Massachusetts, previously cited, (") of 343 deaths which occurred in the city of Quincy, Mass., among stonecutters during a period of about 16 years; 41.4 per cent were due to pulmonary consumption, 12 per cent to other diseases of the lungs, 12.8 per cent to diseases of the heart, 7 per cent to violence, and 26.8 per cent to all other causes. Millstone and slate cutting are also regarded as dangerous occupations. Persons engaged in glass cutting and polishing are not only exposed to the inhalation of a sharp and irritating dust, but also to lead poisoning from the use of putty powder, which contains 70 per cent of lead oxide. In glass establishments in Massachusetts, where all the cutting and polishing is done by the wet method, no dust is perceptible and the employees as a class appear to enjoy good health.() Gem finishers also have a high consumption and sick rate. Workers in mica dust and bronzing powders used in the manufacture of wall papers, fancy souvenir cards, moldings, frames, etc., are predisposed to diseases of the respiratory passages, and the bronze powder in addition is liable to produce headache, loss of appetite, nausea, vomiting, and diarrhea. It is said of the bronzing department of some of the lithographing establishments in Massachusetts that in spite of the exhaust ventilation the air is heavy with bronze dust most of the time. "The boys who run the five bronzing machines wear handkerchiefs over the nose and mouth. They look pale and unhealthy, and all show the characteristic green perspiration due to contact with bronze. The great majority of the employees appear to be healthy."(c) In the manufacture of machinery and metal supplies some of the operations involve exposure to dust, fumes, vapors, or extreme heat. In some of the processes emery wheels and revolving wire brushes are used, and unless the wheels are equipped with exhaust ventilating appliances, enormous quantities of fine steel and emery dust are given off. In a Massachusetts investigation covering 24 establishments the air of some of the rooms was found exceedingly dusty, and about one-tenth of the occupants looked pale and sickly and complained of the irritation of the air passages by the dust. The number of employees in these establishments ranges between 12,500 and 15,000. Some of the establishments were models in character as regards light, ventilation, and general sanitation. "The tumblers and emery wheels are provided with hoods and blowers which are effective, and there is practically no dust. The rooms in which castings are dipped are properly a Report of the State Board of Health of Massachusetts upon the Sanitary Condition of Factories, Workshops, etc., 1907, p. 79. b Ibid., p. 80. c Ibid., p. 102. |