Here too the diseases of the mucous membrane are of main interest, as those of the muscular coat are rare in themselves, and when they occur are generally consecutive or secondary. We shall consider them in their proper places.

1. Hyperaemia Of The Bladder

Besides the congestion existing as a stage preparatory to and associated with inflammation, we find hyperaemia occurring not unfrequently as a result of mechanical impediments to the circulation in the pelvic veins and the vena cava. It is commonly complicated with hyperemia of the neighboring pelvic viscera, of the rectum, the uterus, and the vagina; it gives rise to a more copious secretion of mucus in the bladder, to hypertrophy of the mucous membrane, and is followed by a permanent dilatation of the vessels, and habitual congestion. The condition accompanying stases in the hemorrhoidal vessels of the rectum, in the shape of vesical hemorrhoids, is one of this nature.

Extravasation or apoplexy of the vesical membranes, and hemorrhage into the cavity of the bladder, as a consequence of hyperaemia, is a very rare occurrence. Even in those rare cases it is always limited to a few small spots, and they must be carefully distinguished from the dark-red suffusions of the vesical mucous membrane, into which the hyperaemic condition which is followed by secondary exudative processes and gangrene frequently degenerates.