DERANGEMENT OF URINARY RETENTION AND MICTURITION. 523 



be relaxed into inactivity. It has not yet been possible to stimulate 

 this center experimentally. 



With respect to the mutual relations between the activity of the mus- 

 culature of the bladder expulsion of urine and of the sphincter of the 

 urethra retention of urine the action of the sphincter muscle pre- 

 ponderates, as a rule, when the distent ion of the bladder is not excessive. 

 In other words, as soon as urine is forced into the urethra by contraction 

 of the musculature of the bladder, reflex closure of the urethra takes 

 place. The action of the sphincter muscle, however, predominates 

 only to a certain degree; and neither the reflex nor the voluntary con- 

 traction of the sphincter is capable of resisting strong pressure by the 

 urine. In the act of micturition, as it takes place when the bladder is 

 moderately distended, the sphincter of the urethra must always be vol- 

 untarily inhibited in its contraction during the contraction of the walls 

 of the bladder. 



The foregoing description of the innervational conditions of the bladder is 

 based upon the published experiments of Budge, all of which were performed in 

 collaboration with Landois. Division of the sacral nerves, in the dog, causes 

 degeneration of the nerves of the bladder and of the rectum, but not of the internal 

 genitalia some fibers of the urethral and vulvar nerves undergo degeneration. 

 Bilateral division renders micturition an'd defecation impossible, while unilateral 

 division renders these difficult. In addition, there is complete anesthesia at the 

 anus, of the vagina, and on the posterior aspect of the thigns, together with weak- 

 ness at the ankle-joint. 



Normally, the bladder is completely evacuated. The residual urine that col- 

 lects abnormally in greater or lesser amount is a source of danger, on account of 

 the tendency to decomposition. The urine undergoes alterations during its 

 sojourn in the bladder. According to Kaupp, retention is attended with an 

 increase in the amount of sodium chlorid, and a diminution in the amount of 

 urea and of water. The reduction in the latter is much more marked in con- 

 junction with simultaneous sweating. The question whether the mucous mem- 

 brane of the bladder absorbs soluble matters has been answered in the affirmative 

 by Cl. Bernard, for the dog. Under such circumstances, water is again excreted 

 into the bladder. Maas and Pinner noted absorption also on the part of the 

 urethral mucous membrane, Lewin and Goldschmidt also on the part of the 

 ureter, and the pelvis of the kidney, as well as the prostatic vesicle (strychnin). 



As the ureters empty rather toward the base of the bladder, the urine most 

 recently secreted is always the lowermost. Under varying conditions of secretion 

 the urine may therefore (in a resting posture) form layers in the bladder, so that 

 when evacuated the different layers may be clearly distinguishable. In quiet 

 dorsal decubitus, the pressure in the bladder is from 13 to 15 cu. cm. of a column 

 of water. The pressure is naturally increased by increase of the intra-abdominal 

 pressure, especially in consequence of coughing and expulsive efforts. The erect 

 posture has a similar effect, in consequence of the pressure of the viscera from 

 above. In the evacuation of the urine, the amount expelled is at first small; this 

 increases later in the same interval of time, and toward the end of the act it again 

 diminishes. In men, the last portions are expelled from the urethra through 

 voluntary contraction of the bulbo-cavernous muscle. Adult dogs constantly 

 accelerate the stream of urine rhythmically through the action of this muscle. 



MORBID DERANGEMENT OF URINARY RETENTION AND OF 



MICTURITION. 



Derangement in the mechanism of retention and evacuation of urine may be 

 referred by the physician to its cause from a consideration of the physiological 

 conditions described. Retention of urine ischuria results (i) from occlusion of 

 the urethra by foreign bodies, concretions, strictures, prostatic enlargement; (2) 

 from paralysis or exhaustion of the musculature of the bladder, the latter also 

 following parturition in consequence of the pressure of the child's parts against 

 the bladder; (3) primarily, after division of the spinal cord. Under such circum- 



