Bladder, in anatomy, a thin membranous, expanded receptacle of some juice or humour secreted in the animal body. This term principally applies to the vessels in which the urine and bile are respectively collected; and hence the two chief reservoirs of this nature are the urinary lladder, and that containing the bile. In this place we shall treat only of the former, which is situated within the cavity of the pelvis: its form is oval, and being a continuation of the abdo-pjen, it is almost uniformly su rounded with bones, though below, and at each side, encompassed by muscles. It is remarkable, that this vessel is considerably larger in the female than in the male sex.

Nature has wisely contrived that the human bladder should possess a high degree of expansion, for containing the watery parts secreted from the chyle, as they would otherwise mix with the blood of animals, and render that fluid too thin for the performance of its functions. Though a large proportion of such aqueous humours, from three to four pounds every day, are insensibly evacuated by the skin, yet a still greater quantity must be secreted by the kidneys, and thence conducted to the bladder, lest they should accumulate between the interstices of the cellular membrane, which covers all the muscles, and occasion dropsical swellings. On the other hand, the diseases incident to the bladder are various, but principally arise from debility, spasms, and calculous concretions; for an account of which, we refer to the articles Gravel, Stone, and Urine. At present, we shrill confine ourselves to the inflammatory state of that vessel, which requires immediate relief. This dangerous malady is occasioned by stimulating medicines; gravel or stones lodged in the orifice of the bladder; violent exercise after a long retention of urine, and especially in hot weather; lying in soft, effeminating feather-beds, etc. The symptoms are manifest from an acute burning pain, and tension of the part; frequent inclination to go to stool, and a constant desire to make water, while the patient is in a state of fever. As, under such circumstances no time should, be lost in applying for proper advice, it would be needless to enlarge on the treatment of the disease; but we shall observe that, beside bleeding and purgatives both by the mouth and injections, it will be necessary to drink plentifully of emollient decoctions, or other beverage of a cooling and diuretic nature. Previous to the arrival of a medical man, leeches may be applied to the part affected, the lower belly should be diligently fomented with warm water, and the patient be placed in a tepid bath, not exceeding 980. - If, however, the pain suddenly abates, and is succeeded by cold sweats, hiccough, fetid urine, or a total suppression of it, there is reason to apprehend a mortification, and fatal issue of the disease.