=Urethral Cysts.=--Small cysts are occasionally found in the course of the urethra. They may occur at any point from the internal to the external meatus. They are caused by obstruction and distention of the urethral glands. They produce no symptoms unless large enough to cause obstruction to the flow of urine. They may be seen by the endoscope or may be palpated through the vaginal wall. The _treatment_ consists of incision and removal of part of the cyst-wall. =Polypus.=--Mucous polyp of the urethra is of very rare occurrence. The tumor generally has a delicate pedicle, and may protrude from the meatus. It is painless, and causes discomfort only by obstructing the flow of urine. The _treatment_ consists of removal by torsion, ligature, or excision. =Sarcoma= and =cancer= of the urethra have rarely been observed. The phenomena are those similar to cancer in other parts of the body. The _treatment_ consists in thorough removal. DISEASES OF THE BLADDER. The urinary bladder has three coats--an outer incomplete peritoneal investment, a middle muscular coat, and an inner lining of mucous membrane. The empty bladder is always collapsed, its walls being in apposition. A median sagittal section of the bladder and urethra shows a Y-shaped fissure lying between the symphysis pubis and the uterus, the uterus lying anteverted upon the upper surface of the bladder. For convenience of description the bladder is divided into three parts--the corpus, or body, the fundus, or base; and the cervix, or neck. The body of the bladder is all that portion that lies above the plane of the vesical orifices of the ureters and the center of the symphysis pubis. The part lying below this plane is the base. The vesical triangle, or the trigone, is that triangular area in the base of the bladder, the angles of which are marked by the vesical orifices of the ureters and the internal meatus of the urethra. The neck of the bladder is the funnel-shaped portion where the bladder merges into the urethra. The mucous membrane of the bladder is covered partly with squamous, partly with cylindrical epithelium. The mucous membrane is loosely attached to the muscular coat throughout the body of the bladder, so that when the organ is contracted the membrane is thrown into uneven folds. The mucous membrane is much more closely attached to the underlying structures in the region of the vesical triangle, and it here preserves a smooth surface when the bladder is collapsed. The vesical triangle is more richly supplied with nerves than are the other portions of the bladder, and is consequently the most sensitive portion. The vesical orifice of the ureter appears as a dimple, a small truncated cone, or a pin-hole or slit on the mucous membrane. A transverse band or fold of mucous membrane, known as the intra-ureteral ligament, extends between the orifices of the ureters.