Licence: Public Domain Mark
Credit: An introduction to pathology and morbid anatomy / by T. Henry Green. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![The discoloration caused by the long-continued use of the salts of silver must also be distinguished from true pigmentation : the colour here is due to the deposition of the silver in the tissues. The black colour of gangrenous parts, and that sometimes produced by the effusion of large quantities of blood into the tissues, must again not be confounded with pigmentation. The discoloration in these cases is the result of the action of the sulphuretted hydrogen upon the colouring matter of the blood. The greenish-black discoloration so often seen on the surface of the liver, kidneys, and other abdominal organs after death, is in the same manner due to the intestinal gases. Lastly, the mimite particles of inhaled carbon which are always met with in the lungs, must be distinguished from true pigment. PIGMENTATION OF THE LUNGS. In no organs is pigment met with so frequently and in such large quantities as in the lungs, and here much dis- cussion has arisen as to its nature and origin. The lungs normally contain more or less black pigment, the amount of which gradually increases with advancing age—the lungs of infants and young children being almost free from it, whereas those of adults invariably contain it in considerable quantities. This normal pigmentation of the lungs is principally due to the presence of carbon, and not to that of true hsematoidin-pigment. The carbon—which is derived from the incomplete combustion of wood, coal, and other sub- stances, and is always present in varying quantities in the atmosphere—is inhaled, and the minute particles pass into the finest bronchial tubes. Having entered the bronchi, many of them are taken up by the mucus- corpuscles, where they may be seen as small black gra- nules within the cells. These may readily be observed in the cells of the greyish-black s]Dutum which is so fre- quently expectorated in the early morning. Much of the carbon thus inhaled is eliminated by expectoration; many](https://iiif.wellcomecollection.org/image/b21915830_0124.jp2/full/800%2C/0/default.jpg)
