Any indication of urinary trouble, and especially with dropsy, weakness, flabbiness and anæmia and a subnormal temperature, should lead to examination of the urine, as a crucial test. A high density is good ground for suspicion. But this is not constant. In advanced cases (chronic interstitial nephritis, small white kidney, atrophic nephritis) it may be 1015 to 1025, in exceptional advanced cases with polyuria, it may be 1010, 1005, or even 1001. With such a condition, however, there is great anæmia, pallor of the mucosæ, and prostration. Tested with nitric acid and heat, the urine throws down an abundant precipitate of albumen. Under the microscope it shows a profusion of granular, degenerating epithelial cells, and casts of the uriniferous tubes. _Progress._ The course of the disease is usually slow, extending over several months, but with a tendency to constant advance. The thirst increases and the urine increases in amount, clearness and levity. There may supervene extreme sluggishness, dropsies, anæmia, and weakness, irritability of the heart, and palpitations on slight exertion. So long as the heart’s action is strong, elimination may be maintained and life prolonged for months (in cow, Dickinson), or years (Friedberger and Fröhner). When the heart’s action becomes weak, elimination is rendered imperfect and the animal shows catarrh of the lungs or bowels (common in dogs), local inflammation of the lungs, pleura or pericardium, or œdemas, or hæmorrhages. The toxic effect on the nerve centres is shown by stupor or lethargy, or vertigo. When an abscess forms it is associated with a temporary rise of temperature (Trasbot). The patient may die in convulsions, in a state of coma, or by gradually advancing debility and failure of the heart. _Lesions._ In cases of comparatively =short standing= the kidney is usually of full size, or somewhat enlarged, with firmly adherent capsule and rough or even nodular surface. The surface of the cortex may be red or grayish or parti-colored, pink and gray. The cortical portion is firm and it may even be attenuated somewhat, while the medullary portion, naturally lighter, has often grayish streaks converging toward the hilus. When the gray streaks are scraped with the knife a serous fluid, mixed with fatty granules or globules, is obtained. The glomeruli may be still about the normal size with some increase of the epithelial tuft cells. The tubules contain casts (colloid, hyaline, granular), and their epithelium normally columnar, are flattened down to cubes and are swollen, granular or fatty.