=Cancer.= Secondary, is of more frequent occurrence than primary cancer. The scirrhus and colloid varieties are rarely, if ever, found. Encephaloid growths, especially in children, attain in the kidneys an enormous size. Cancer of the liver and right kidney, or of the adjacent parts of the stomach, or descending colon and left kidney, frequently coexist according to the observations of M. Rayer and Dr. Walshe. The period of life between fifty and seventy is most liable to cancer of the kidneys. The natural character of the urine excreted by cancerous kidneys is seldom changed until the encephaloid growth softens and breaks down, when blood, puriform matter and detritus may appear. =Cystic Tumors=, supposed to originate from a dilatation of the Malpighian capsules, are sometimes found. The cysts vary in size from a pin’s head to a small bird’s egg. They may be few or many in number, and are filled either with a clear watery fluid, or with a gelatinous or pigmentary substance. The walls of the cysts are thin and smooth, partly divided into compartments by imperfect septa. They are confined to the cortical portion of the gland, and may be imbedded in that substance, or project from the surface. The kidney may be unchanged in size, or considerably enlarged. The clinical symptoms of these cysts are very obscure, and of the cause of their formation, little is known.[32] Cysts of a congenital origin, are sometimes found in the kidney at birth. They may be of great size, and vast number, and appear to result from a dilatation of the uriniferous tubes, and Malpighian capsules. _Fibroid_ and _Adenoid_ tumors of small size are rarely found in the kidneys; the former within the tubular, the latter within the cortical portions. Parasites. =Entozoa= are occasionally found within the kidneys, among which may be mentioned the _hydatid_, or larval form of the Tænia echinococus. _Cysticercus cellulosæ._ The larval form of the Tænia solium. _Eustrongylus gigas._ A small cylindrical worm, with the body tinged with red. Male—ten to fourteen inches long, three lines wide. Female—three feet long, six lines wide. _Pentastoma denticulatum._ Supposed to be the larval form of a worm found in the nasal cavities of some animals, and consisting of a small sac, with calcified walls. The Ureters. As a congenital defect, we find the ureter terminating in a _cul-de-sac_, either in the vicinity of the kidney, or of the bladder. Sometimes they are double or even triple, but they generally unite before their vesical termination.