Causes: acrid diuretics, loss of kidney, catheterization, dermatitis, burns, traumas, overexertion. Lesions: enlarged, blood-gorged kidney, red or black, petechiated. Symptoms: stiff, arched, tender loins, tardy, dragging of hind limbs, urine passed often, clear to bloody, albuminous, anorexia, nausea, vomiting, diarrhœa, dullness, stupor. Treatment: stop cause, give emetic, laxative, in surgical cases antiseptic, for cantharides, camphor, bromides, vegetable food. Warm clothing or building. _Causes._ This comes most commonly from the ingestion of acrid or diuretic agents, saltpeter, turpentine oil, cantharides and, according to Cadeac, various essential oils including oil of mustard. It takes place in the remaining kidney after the one has been extirpated, or had its functions abolished by disease or urethral obstruction. Again, surgical operations on the urinary organs, even the simple passing of a catheter, will cause sympathetic renal congestion. Extensive acute dermatitis, and burns of the skin may have a similar sequence. Falls, kicks, blows, or crushing beneath a wheel or otherwise are additional causes. Finally violent overexertion as in coursing, causes congestion with albuminuria, and blood globules and even casts in the urine. This is common to the human athlete, who undergoes a violent and continued overexertion, race and draught horses, and dogs. _Lesions._ When congestion is produced experimentally by cantharides the kidneys are found to be enlarged and the cortex gorged with blood so that it has a deep red or blackish port wine hue, with here and there spots of ecchymosis. The veins, capillaries and glomeruli are especially congested, and the epithelial cells of the convoluted tubes have become laterally distended, so that they approximate to a globular form. A loose coagulum containing blood globules may be found in the capsule of the glomerulus and in the convoluted tubes. _Symptoms._ These are arching and stiffness of the loins, a tardy, dragging movement of the hind limbs and tenderness of the loins. The urine may be scanty or in excess, and tends to be passed frequently, in small quantities and with evidence of pain. It may be clear, pinkish or bloody, and shows albumen and frequently casts, and blood globules or small clots. There is some impairment of appetite, and, in severe cases, nausea and vomiting, with, it may be, diarrhœa, nervous depression, dullness and stupor. When due to poison or other transient cause the symptoms improve when this factor has been stopped.