With the exception of the above-mentioned congenital small-ness of the bladder, and the congenital dilatations of the organ from contraction or atresia of the urethra, the anomalies to be classed under this head are all acquired; they are the conditions of permanent and excessive dilatation and contraction.

Dilatation of the bladder is seen under various forms. It may be uniform and general, and in solitary cases attains such an extent, that the bladder is represented by a fluctuating paralyzed sac, with relatively thickened parietes, filling the entire pelvis and hypogastric region. It is caused by accumulation of urine, consequent upon insensibility and paralysis of the bladder, but more particularly by mechanical obstacles in the neck of the bladder and in the urethra; in the last case especially, that extreme degree is developed which is always accompanied by hypertrophy of the parietes.

Dilatation of the ureters is a consequence of this affection; it proves fatal by inflammation resulting from the influence of the stagnating and decomposed urine upon the mucous membrane, by the consequent suppuration and gangrene, and especially by peritonitis.

Dilatation occasionally affects in a greater or less degree certain portions, or predominates in certain directions; thus we find lateral expansions at the fundus vesicae, and saccular indentations produced by the pressure of calculi at or posterior to the triangle of Lieutaud.

An important variety of partial vesical dilatation is presented to us in the hernial dilatation, or acquired diverticulum of the bladder. It is always developed in a bladder the muscular coat of which is hypertro-phied, and this hypertrophy, being accompanied by increased irritability of the bladder, affords an evident and intelligible explanation for the predisposition. The vesical mucous membrane insinuates itself between the fissures left by the rounded or hypertrophied fleshy columns, is gradually forced through them, and forms saccular appendages to the bladder, which increase by degrees, and attain a size varying from that of a walnut or hen's egg to that of a fist or a human head. Their cavity at first communicates with the bladder by means of an elongated rhomboidal opening, and the more they increase, the more the latter, being enlarged at the same time, is converted into a round sphincter.

These diverticula occur principally at the lateral portions and near the vertex of the bladder; they are also found at the posterior surface, and may frequently be seen at all these points at once. The diverticulum is very rarely developed in the triangle near the perineum. Its parietes are formed of the mucous membrane of the bladder, which, under certain self-evident circumstances, is invested by the peritoneum. Sometimes a few muscular fibres traverse the diverticulum, which circumstance may cause it to be viewed as congenital.

If there happens to be concurrent calculous disease of the bladder, the diverticula acquire additional importance, as the calculi may pass into them, or be formed within their cavity, and either be firmly grasped or float unattached. The mucous membrane of small diverticula is frequently the seat of chronic inflammation, causing a muco-purulent secretion, and followed by ulcerative perforation and the formation of sinuses between the vesical coats; these sinuses traverse the trabecular structure of the muscular coat in the most various directions.

Permanent contraction of the bladder occurs in various degrees as a consequence of enduring irritation, e. g. by a calculus; or of increased irritability of the mucous membrane from inflammation. The longer these influences last, the more the parietes increase in thickness and hardness, so that they not unfrequently present the appearance of a ball contracted to the size of a duck's or hen's egg.

The contraction is at times partial, and may then give rise to a permanent coarctation of the bladder at one or even at several points. The bilocular vesicae, noticed by ancient anatomists, probably took their origin in a morbid contraction of this nature.

As regards the diameter of the vesical parietes, we pass over numerous morbid conditions which give rise to thickening, and which will be investigated subsequently, and have now to examine the states of hypertrophy and atrophy.

Both are most apparent in the muscular coat; hypertrophy of the mucous membrane is chiefly seen in connection with chronic congestion and catarrh of the bladder, and we shall examine into it more fully in speaking of these affections.

Hypertrophy of the muscular coat takes place in consequence of catarrhal affections of the vesical mucous membrane; of repeated and enduring irritation, especially from urinary concretions; of excessive efforts made to overcome obstacles to the discharge of the urine. The latter may affect either the neck of the bladder or the urethra, and be caused by the pressure exerted upon these parts by enlarged or dislocated organs in the vicinity; as by prolapsus, tumors, and degenerations of the uterus, uterine, vaginal, and rectal cancer, by the enlarged prostate, strictures of the urethra, etc. The muscular fasciculi are found thickened, so as to form rounded trabecule, which project from the inner surface of the bladder in the shape of a trabecular network, comparable to the inner surface of the right ventricle of the heart (vessie a colonne), the mucous membrane insinuates itself within its meshes, unless, the bladder 'be permanently contracted, and finally forces its way through them in the shape of diverticula.

The bladder is at the same time either dilated, or if the irritability of the mucous membrane is increased, it is contracted. In the latter case especially, the entrance of the urine from the ureters is variously impeded, and thus a dilatation of the urinary passages ensues.

We must, however, be cautious not to mistake a bladder with thick walls, which is perfectly contracted after it has been completely emptied, for a case of hypertrophy.

Atrophy of the vesical parietes occurs rarely. The mucous membrane may be reduced to a very delicate, shining membrane, resembling the arachnoid, and the muscular coat disappears, with the exception of a few almost imperceptible pale traces; the contractile power of the bladder ceases, its parietes are in a state of permanent relaxation, soft, thin, transparent, pale, anaemic, and friable. We have twice observed atrophy of the vesical parietes of this description as a substantive disease.

The shape of the bladder is liable to numerous deviations, All the congenital malformations that are connected with the above-mentioned anomalies of development belong to this head, and as acquired malformations, we may mention those accompanying dilatation, especially when effected in one direction, and causing diverticula, those resulting from irregular and constant contraction, and those assuming the cylindrical, cuneiform, or cordate form, in consequence of hypertrophic conditions.

3. Anomalies Of Position

These involve the dislocation of the bladder from its normal position, and in various directions, by enlarged neighboring viscera, and voluminous morbid growths in the pelvic cavity, by contraction and malformation (especially that resulting from mollities ossium) of the pelvis; the dragging down of the bladder by dislocated viscera in its vicinity, especially by the prolapsed uterus, and by large morbid growths in the perineum, the position occupied by the bladder in large inguinal, perineal, and vaginal herniae; the intussusception of the bladder in the urethra, and its prolapsus through the latter in females; the eversion of the bladder in consequence of a rupture affecting both it and the vagina.

4. Solutions Of Continuity

We class under this head -

1. Injuries of the bladder by means of cutting instruments, including the surgical wounds caused by cystotomy and puncture of the bladder; the contusions produced by the head of the child during parturition, by obstetric instruments, by splinters of bone arising from pelvic fractures, or by concussion received by a fall or a blow; rupture of the bladder accompanied by more or less diffused infiltration of the vesical membranes and the surrounding cellular tissue, and hemorrhage.

2. The very rare spontaneous ruptures of the bladder resulting from excessive repletion and distension of the latter.

In both cases the termination may vary; in favorable circumstances a cure may result; extravasation of urine into the peritoneal cavity and peritonitis, or urinous infiltration of the cellular tissue, with diffuse inflammation, suppuration, gangrene, and under these circumstances commonly a fatal issue, may take place; or if the secondary processes are circumscribed, abnormal openings may be established, and vesical fistulae form.

3. The ulcerative solutions of continuity occurring from within as well as from without, together with the consequent and frequent constricted or patulous communications between the bladder and neighboring cavities and channels, the intestinal tube, and particularly the rectum, the uterine and vaginal cavities, abscesses, etc.