In the third stage, the kidney is small. The surface is rough, granular, and pale. The tubular structures are swollen. The tufts and vessels are waxy. A few tubes are distended, most are collapsed, and are represented only by fibrous tissues.
3. The Cirrhotic, or Contracting Form.—This consists of an hyper trophy of the connective tissue of the organ, and a consequent atro phy of all the other structures.
There is at first little diminution in the size of the organ, but the capsule is thickened and adherent, and the surface is rough and gran ular. The color is pale and reddish. The arteries are prominent, their walls thickened, and their cavities often dilated. On the surface, and in the substance, cysts are often seen. Some are produced by dilatation of the Malpighian capsules, some by dilatation of the tubes, some by a morbid growth of epithelial elements. The tubes are com pressed and atrophied by the new fibrous tissue. They contain little opaque material, but often hyaline matter. Sometimes urate of soda is found in the stroma and tubes of the pyramids. The disease is a non-inflammatory increase of connective tissue.
Both the waxy and contracting forms may be secondarily affected with the inflammatory disease.
4. Simple Fatty Degeneration.—The kidneys are of about the nor mal size. The surface is smooth, the capsule not adherent. Their texture is soft, the cortex is pale and mottled, with sebaceous-looking deposits. The epithelium of the tubes is fatty.
Dickinson describes tubal nephritis, granular degeneration, and depurative infiltration : 1. Acute Tubal Nephritis.—This, the nephritis of scarlet fever and of exposure to cold, is described in very much the same terms as the acute desquamative nephritis of Johnson.
2. Chronic Tubal Nephritis.—The kidney is large, the cortex of an opaque white or buff-color, the pyramids pink. The surface is smooth, the capsule not adherent. The convoluted tubes are dis tended with granular and fatty epithelium and with fibrinous exuda tion. The straight tubes are packed with the products of epithelial growth, while others contain transparent fibrin. The tubes are not
changed, save as regards their contents. The Malpighian bodies are normal or somewhat dilated. There is no increase of intertubular tissue. These kidneys remain large and smooth to the last, unless complicated with the depurative change.
Sometimes the cortex is sprinkled with white, sharply defined specks, like bits of bran. This change is characteristic of a great amount of fatty change in the accumulated epithelium.
3. Granular Degeneration.—The kidneys may be of normal or even increased size, but are usually small. The capsule is adherent. The surface is irregular and covered with little rounded nodules. The cortex is thin. Cysts are often found in the cortex and cones. There is an increase of fibrous tissue around the Malpighian bodies and ves sels, and beneath the capsule and deeper in the cortex. The cortical tubes are atrophied or dilated, but many tubes may remain un changed. The tubes may be filled with epithelium, or with trans parent, fibrinous material. In the majority of cases the epithelium such as is found in normal kidneys. When changed, it is by an alteration in its regularity of form, becoming somewhat angu lar, as if cramped in growing space. The circulation through the blood-vessels is much obstructed. The formation of cysts is clue to dilatation of the tubes or of the Malpighian capsules.
4. Depurative Infittration.—The kidney is at first of normal size, pale, and its surface smooth. The only change is in the Malpighian tufts, which react with iodine. As the disease goes on, the kidney becomes larger and its capsule adherent. The cortex is of a pale, opaque fawn color, or has a pinkish or gray translucency. After ward the kidney atrophies and its surface becomes noclulated. There may be small cysts. In cases of long standing, almost the entire organ gives the characteristic reaction with iodine. The.first change is the infiltration of the Malpighian bodies and vessels. Afterward new fibrous tissue is formed between the tubes, the epithelium degen erates, the tubes are dilated and contain fibrinous casts.