It has a dirty yellow color, is cloudy, and is passed in small quantity. The odor is putrid. The specific gravity is diminished, the reaction being usually neutral or alkaline.

The normal constituents, especially urea, are excreted in diminished quantity.

Of the abnormal constituents, albumen is present in greater mass (to 1 per cent.). Blood-coloring matters are usually present. Not seldom carbonate of ammonium and ammonium-sulphide are present in greater quantity.

The sediment is considerable, and consists chiefly of flocculent pus mixed with blood in greater or smaller amount. Microscopically are found, besides numerous bacteria, molecular detritus and kidney epithelium, and not seldom beautifully formed, thick, often-branched cylinders, which are formed of bacteria (pyelo-nephritis parasitica, Klebs). If it is complicated with parenchymatous nephritis, we find also dark, granulated, mostly thick cylinders from the straight tubules.

The course is usually acute, and the process generally ends fatally. In chronic cases the large abscesses discharge into the pelvis of the kidney.

We can only diagnose kidney abscesses by estimating the amount of pus excreted per diem, which we can easily do with graduated cylinders. A suddenly appearing and then disappearing amount of pus in the urine, together with microscopical evidences of brokendown kidney-tissue (glomeruli, tubules, etc.), furnish the best points for the diagnosis.

4. Amyloid Kidney.

Amyloid degeneration of the kidney is generally a local manifestation of a constitutional disease. It occurs therefore frequently in connection with extended osseous suppuration, as well also as with other long continuing and profuse suppurations. With pyonephrosis on one side, not seldom the other kidney becomes amyloid. Scrophulosis, chronic tuberculosis, and obstinate syphilis, and at times also malarial cachexy, favor especially amyloid degeneration of the kidney. In rare cases this affection is due simply to disturbance of nutrition. Frequently it is complicated with parenchymatous nephritis.

The amyloid disease of the kidney is developed quite insidiously and without marked symptoms, though as a rule the amyloid kidney excretes a larger amount of urine in twenty-four hours than the healthy kidney in the same space of time. This excess is never so great, however, as is usually found in general atrophy of the kidney.

The urine shows the following conditions:

It is pale yellow, clear, and has a low specific gravity and acid reaction, and deposits no visible macroscopic sediment.

The normal constituents are generally excreted in diminished amount.

Of the abnormal matters, serum-albumen is present in moderate quantity (from 0.1 to 1-2 per cent.). Besides serum-albumen, we often find globuline in relatively considerable mass (Senator, Edlefsen), which may

be regarded in such cases as characteristic of this dis

ease.

In the sediment, seldom visible macroscopically, are found generally no cell-elements, but sometimes narrow hyaline, or also broader waxy, glistening, fragile, yellowcolored cylinders. (Pl. VII., A, 4.) Occasionally we observe brightly glistening, amyloid, degenerated kidney epithelium, which, in the same manner as the waxy cylinder, is colored reddish brown by a watery solution of iodine, and further upon addition of sulphuric acid a dirty violet color. Blood does not appear in the sediment with pure amyloid kidney.

The prognosis depends upon the constitutional disease. If one has to do with syphilis and malaria, favorable response to treatment may be expected.

In the differential diagnosis of the various forms of albuminuria, the following points are to be observed:

1. If already in the urine a macroscopically visible sediment is present, consisting of a great mass of cellelements (blood-corpuscles, pus-corpuscles, cylinders, etc.), we have to do either with parenchymatous or suppurative insterstitial nephritis.

a. In parenchymatous nephritis we find in the sediment epithelial, fibrinous, and granular cylinders, kidney epithelium, and blood- and lymph-corpuscles.

b. In suppurative interstitial nephritis we find in the sediment blood- and pus-corpuscles, much bacteria, and sometimes also bacterian cylinders, or short and thick darkly nucleated granular cylinders.

2. If the urine is clear or only clouded by urates, and no sediment is discovered which consists of a considerable mass of cell-elements, then we have to do with renal stasis, or with a hyperplastic interstitial nephritis, or with an amyloid kidney.

a. Renal stasis is distinguished from both the other diseases of the kidney by a decrease in the twenty-four hours' amount of urine, by its dark color and high specific gravity, and often by the abundance of urates. The amyloid kidney and the hyperplastic interstitial nephri tis are characterized by an increase of the amount of urine; also in both diseases the urine is bright and clear, of pale yellow color and low specific gravity.

b. Amyloid kidney differs from interstitial nephritis in that the urine contains globuline, and by the presence of waxy cylinders and amyloid degenerated kidney epithelium.

Clinically we very constantly find with amyloid kidney (as with parenchymatous nephritis) dropsy, while with genuine atrophy this occurs seldom, and if at all in the latter stages.

In genuine kidney atrophy is found constantly hypertrophy of the heart and a quickened pulse, while these do not occur in parenchymatous nephritis and with amyloid kidney.

Finally, with amyloid kidney usually there is an enlargement (amyloid degeneration) of the liver and the spleen.

B. Forms of Mixed Albuminuria.

Mixed albuminuria is recognized from the fact that there is more albumen present than corresponds to the amount of pus in the sediment. It includes those diseases of the kidney-pelvis which in advanced stages involve the kidney-structure, and thereby complicate the pyorrhoea with true albuminuria.

The kidney-pelvis is limited toward the kidney by the calices and the papillæ renales. It is therefore easy to understand how with extended inflammation of the kidney-pelvis the neighboring papillary part may become involved. A proof that the papillary part of the kidney has become involved by the pyelitic process, is the presence of kidney-epithelium in the sediment. One also finds in long-continued suppurative processes in the pelvis of the kidney, that the same is enlarged at the expense of the papillary part, the latter being more or less consumed.

1. Pyelitis.

Pyelitis is often a local manifestation of an acute febrile process; it not infrequently accompanies parenchymatous nephritis and (in advanced stages) diabetes mellitus. The use of copaiva balsam, cubebs, and similar powerful medicaments, sometimes has this disease as a consequence. Kidney-stones, parasites, new growths, and tuberculosis of the kidney-pelvis are almost always accompanied by suppurative pyelitis. From contiguity, either this or pyelo-nephritis is developed by the damming back of the urine in prostatic hypertrophy, para