Dangerous trades : the historical, social, and legal aspects of industrial occupations as affecting health, by a number of experts / edited by Thomas Oliver.

  • Oliver, Thomas, Sir, 1853-1942.
Date:
1902
Catalogue details

Licence: In copyright

Credit: Dangerous trades : the historical, social, and legal aspects of industrial occupations as affecting health, by a number of experts / edited by Thomas Oliver. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

    305/976 (page 271)
    LUNG DISEASES DUE TO DUST Lung Diseases due to Dust. In pneumoconiosis the lung is altered in structure as the result of irritation caused by inhaled dust. A healthy lung is composed of loose spongy tissue, through which run in all directions the bronchial tubes and their fine ramifications (see Fig. 38). The essential part of the lung is made up of alveoli or air-cells, like the meshes of a net. Just as an ordinary net is made of strands of cord, so are the walls of the pulmonary alveoli formed of delicate lines of connective and elastic tissue, in which run capillary blood-vessels. The partitions thus formed are coated on both sides by a layer of flattened epithelial cells. It is this loose and almost uncovered condition of the pulmonary capil- laries that allows of the rapid interchange of gases between the blood circulating in the alveolar walls and the air in the lung during respiration. Nature has placed certain obstacles in the way of particles of dust gaining easy access to the lungs, to wit, the narrow openings of the nostrils, the mucus secreted by the lining membrane of the nose, and of the trachea and bronchi ; the narrow chink between the larynx and trachea known as the vocal chords, the ciliated epithelium already described, and a mechanical difficulty generally; so that while even with forced inspiration it is not easy for dust to be carried into the lungs, yet the fact remains that where an individual is working in the dusty atmosphere of a factory for several hours a day, week after week, particles of dust ultimately find their way into the finer bronchi, and subsequently into the pulmonary tissue itself. It is the repeated working in a dusty atmosphere that causes the trouble. A good deal depends, too, upon the character of the dust. Certain fine dusts, such, for example, as flour, may for a time be arrested in the mucus secreted by the respiratory passages, and be expectorated ; while others, such as white lead, become dissolved in the alkaline mucus, are absorbed into the system, and thus induce constitutional poisoning. Fine fluffy material, like that given off from cotton and flax, can reach the lung, while sharp- pointed particles of metallic dust wound the epithelial lining of the smaller bronchi and penetrate into their walls, or they destroy the protecting layer of epithelium, and reach the alveoli either directly or indirectly through the lymphatics. These particles set up irritation in the lung, followed by a very marked increase of its fibro-connective tissue, which encroaches upon the spongy structure of the lung and destroys its aerating function. In the