Increase of fibrous tissue.

Fibrous processes separating tubes.

fibrous tissue in the organ. This has accumulated around the malpighian bodies and the blood vessels, so that when either are crossed by the section a thick fibrous ring is seen surrounding them.

The most conspicuous alterations are immediately under the capsule, which itself is thickened and adherent. At the points of superficial depression streamlets of fibrous tissue pass into the organ imbedding the malpighian bodies, which retain their size, and the tubes which become compressed, to mere microscopic threads. As the fibroid material extends inwards it becomes diffused, and spreads over and between

Section of an advanced granular kidney from a gouty subject, showing the destruction of tubes consequent upon the contraction of the fibrous tissue, and the consequent aggregation of the malpighian bodies. a b, capsular surface, c c, malpighian bodies. A few tubes are seen at the deeper part of the

section.

all the tubes in its vicinity. The fibrous growth may be seen opposite each depression, as in plate 5, of visible breadth; or its existence may be chiefly indicated by the contraction it has caused, so that an angular space under the capsule is seen filled by the shrivelled remains of tubes. The malpighian bodies in such cases are aggregated, owing to the contraction of the parts between them, while they themselves resist the compressing agency. (See woodcut.)

The new fibrous growth which is the essence of the disease

is sometimes seen in isolated patches of some extent, in the deeper parts of the cortex, but this is comparatively uncommon. Some portions of the cortical tubes have been reduced to mere threads, through which no passage remains, while in other places they are irregularly dilated. They are Consenot uniformly affected. It is a character of the disease that quent changes in the effusion which leads to increase of fibrous tissue takes tubes; place, not evenly throughout, but at points a little removed from each other. The tubes in the track of the effusion may be involved while others escape. Thus it is common, particularly in the earlier stages of the disorder, to find many tubes per- some fectly natural. Those that are altered are in one of two connatural; ditions, both of which are generally found in the same kidney. Some are irregularly packed with their epithelial growth. others This condition is not uniformly spread through the organ. packed with epiThe accumulation of epithelium is much less decided, as well thelium, as less general, than with tubal nephritis. In many cases some of the ducts are distended with dark granular matter, probably the result of the breaking up of the epithelial cells, subsequent to their detachment from the wall of the tube. This detachment and accumulation of the cells may perhaps be explained by supposing them to have become undermined by the fibrinous exudation which is poured out by the tubular membrane.

matter.

Beside the tubes thus affected are others in a different or fibrincondition which is a constant accompaniment of the disease. ous Many of the tubes are occupied by a transparent fibrinous material, which has taken the place of the epithelial lining. This material is sometimes quite uniform, transparent, and glassy; it is sometimes studded with oil globules, the result of a degenerative change in itself. Sometimes this matter, probably by being forced along the windings of the tube, becomes broken up into very fine fragments, and may eventually pass out with the urine as dark, coarse, granular casts. Such casts display at first no stricture; they look opaque and granular, but if touched with acetic acid they lose their obscurity and show the broken pieces of fibrine of which they chiefly consist.

Epithe

lium

What has been said with regard to the convoluted tubes will apply almost word for word to the tubes which form the cones. The contents of the latter channels exactly correspond with the casts found in the urine. They are usually filled with transparent fibrinous matter, sometimes with dark granular plugs, while sometimes they contain more or fewer entire cells of cortical epithelium.

While dwelling upon the morbid anatomy of granular degeneration of the kidney, it may be well to add a few words upon the condition of the epithelium. It is the more necessary to do so, as Dr. George Johnson, in his valuable work, has expressed an opinion that the change is primarily due to a crumbling or disintegration of the epithelial cells. I have examined these cells in a great number of granular kidneys, and have carefully drawn their outlines and dimensions as seen through a 3-inch object-glass. The conclusion I long ago formed, one which has been justified by careful and continued observation, is this. In the vast majority of cases, in all cases excepting those in which the contraction of the organ has become extreme, the epithelium is exactly such as is found in healthy kidneys. When changed, it is by an alteration in its regularity of form, becoming somewhat torted by angular, as if cramped in growing space. In one or two cases, it was found that some cells had become shrivelled, much as the cells are found to be reduced in advanced cirrhosis of the liver. These changes, slight as they are, are never found excepting in very advanced cases. The cells may of course, from various causes, contain oil, but they do not do so more often than do the cells of kidneys, which appear to be natural, or which are affected by other morbid changes.

generally

natural; in advanced

cases dis

pressure.

Cysts.

In the more advanced stages of the disease the granular kidney almost always contains cysts, sometimes of considerable size, sometimes microscopic. Cysts are found also in connection with the amyloid' disease, as will be hereafter seen, but they never occur in consequence of tubal nephritis.

Cysts are found both in the cortex and in the cones. Although frequently conspicuous objects to the naked eye,