4. Suppurative Pyelo-Nephritis with Cystitis.--LESIONS.--Usually both kidneys are affected. They are increased in size, and both the kidneys and their pelvis are congested. The mucous membrane of the pelvis is thickened and coated with pus or patches of fibrin. Scattered through the kidneys are abscesses and purulent foci of different sizes. The smallest foci are not visible to the naked eye, but with the microscope we find collections of pus-globules between the tubes, with swelling and degeneration of the epithelium within the tubes. The larger purulent foci look like white streaks or wedges running parallel to the tubes and surrounded by zones of congestion. The larger abscesses replace considerable portions of the kidney. The ureters in some cases are inflamed, their walls thickened, their inner surface coated with pus or fibrin. The bladder presents regularly the lesions of acute or chronic cystitis. ETIOLOGY.--For the production of this form of nephritis inflammation of the bladder seems to be necessary. How the inflammatory process is transmitted from the bladder to the kidneys is still uncertain, but it seems probable that it is effected by bacteria. The cases of cystitis in which a suppurative nephritis is likely to be developed are those due to strictures of the urethra, stone in the bladder, operations on the urethra, bladder, and uterus, paraplegia, gonorrhoea, and enlarged prostate. SYMPTOMS.--When the nephritis occurs with cystitis due to stone in the bladder, strictures, or operations on the genito-urinary tract, the {101} symptoms are much the same. The patient has first the symptoms belonging to the cystitis, then he is attacked with rigors, followed by a febrile movement. The rigors are often repeated; the febrile movement is very irregular and often accompanied by profuse sweating. There is a rapid change in the general condition of the patient. He becomes much prostrated and emaciated from day to day. The face is drawn and anxious, the tongue dry and brown, the pulse rapid and feeble, and delirium is developed, and the patient finally dies in a condition resembling that of typhoid fever or of pyæmia. The urine is diminished in amount; it may be suppressed. It contains blood, pus, and mucus. The pus and mucus belong to the cystitis; the blood seems to be derived both from the kidneys and the bladder.