Irritant vegetables that are resinous or diuretic, and irritant diuretic insects are incriminated (cantharides, caterpillars in grass, or on plants, etc., lice on cabbages particularly,—Cruzel, Neubert). Irritant drugs that are eliminated by the kidneys have been equally charged (tar, carbolic acid, iodoform, chlorate of potash, nitrate of potash, phosphorus, arsenic, lead, mercury). Compulsory suppression of micturition is undoubtedly injurious in house dogs shut up, mares kept long in harness, or horse on railway car, above all if this follows a diuretic or drinking abundantly. In such cases it is altogether probable that bacteria already exist in the blood or kidneys and take occasion to attack the tissues weakened by the overdistension or other inimical cause. This is all the more probable seeing that the kidneys are a favorite channel for the elimination of bacteria present in the system. It should be noted that nephritis is liable to supervene on extensive skin burns, chronic dermatitis and other skin diseases. Some cases are traceable to embolism, the clots coming from the lungs, heart or arteries, in others the irritation is due to calculi in the renal pelvis or tubules, and their attendant bacteria. These are especially common in cattle that are winter fed on dry food. Again, the infection may have travelled forward through the ureters from a pre-existing infective cystitis. _Symptoms._ There may be obscure or intense colic; trembling or rigor may occur, yet is often omitted or unobserved; the loins are arched; the hind feet are advanced under the belly, or there is frequent shifting of the weight from one foot to the other; the walk shows stiffness of the back and hind limbs which appear to straddle or drag behind; urination is frequent in small amount, or there are frequent ineffectual attempts to urinate; the patient is indisposed to lie down, and if he does so it is carefully, with difficulty and groaning; the testicles are drawn up and dropped alternately, the penis is often protruded from and retracted within its sheath, the loins are sensitive to pinching, percussion, or electric current; when mounted the animal drops under the weight; he carries the head low and refuses to go fast. In bad cases there is constipation, grinding of teeth, anorexia, and in dogs, vomiting. Temperature may be normal or there may be considerable fever. Dogs may lie curled up, with occasional tremors. Dropsical effusions are frequent in the form of anasarca under the chest or abdomen, or beneath the lower jaw, or as stocking of the limbs, or the effusion may occur into an internal serous cavity. Convulsions may occur from brain poisoning by urea or other retained urinary product. In the slighter forms the severe symptoms may be absent, and the _condition of the urine_ must be investigated as affording _the most constant and characteristic_ phenomena.