108 THE URINARY ORGANS. 
Chronic diffuse nephritis with exudation. 
Chronic diffuse nephritis without exudation. 
What changes occur in acute congestive nephritis ? 
There is an increased amount of blood in the organ producing a 
hyperemia. The condition is transient and there are no microscopical 
changes. 
Give the changes occurring in acute degenerative nephritis. 
This condition, sometimes known as parenchymatous inflammation, 
or as cloudy swelling, occurs principally in the cells lining the convol- 
uted portions of the uriniferous tubules, and in the cells lining the 
capsule of Bowman. The changes that occur in the renal epithelium 
are, viz.: a swelling of the cell-body and an infiltration with albuminoid 
granules and fat. The cells break down, degenerate and crumble or 
desquamate. A growth of new cells takes the place of the cells 
destroyed. Casts are sometimes formed in the straight tubules, and 
there may be a congestion of the bloodvessels, with an exudation of 
serum. 
What changes occur in acute exudative nephritis ? 
They are the same as are seen in any exudative inflammation, viz.: 
Congestion, emigration of white-blood cells, exudation of blood plasma 
and red-blood cells. There are changes also in the tubules, stroma and 
Malpighian capsules of the kidney. Inthe tubules the lining cells may 
be flattened or swollen and detached. The tubules themselves may be 
dilated and may contain cylinders or irregular masses of hyaline mate- 
rial, identical in composition with the casts found in urine. There 
may also be red and white-blood cells free in the tubules. The exuded 
white-blood cells are collected in larger or smaller foci in the cortical 
portions of the kidney. Inthe Malpighian capsules the changes are very 
marked ; the cells lining the capsule may be swollen; the cavity of the 
capsule may contain coagulated material, also both red and white-blood 
cells. On the capillary tufts there isa marked increase in the number 
of cells, which, in severe cases, even fill up the space between the tuft and 
inner wall of the capsule. In many cases the arterial walls are swollen. 
What are the changes in acute diffuse nephritis ? 
They are the same as have been described in acute exudative 
nephritis, but with two additions, viz: There is a growth of connective 
tissue in the stroma and a proliferation of cells within the capsule of 
Bowman. The growth of connective tissue occurs in strips or wedges, 
each wedge having one or more arteries with thickened walls. The 
