119 



bladder, and to determine the first flow of the urine, \ve cease that effort, 

 and the bladder alone, still supported by the weight of the surrounding 

 viscera, which compress it as it empties itself, completes the evacua- 

 tion. We repeat the first effort, only in case we wish to accelerate the 

 flow of the urine. In the evacuation of the faeces, on the contrary, the 

 muscular coat of the rectum requires the incessant co-operation of the 

 respiratory powers, as these solid substances are evacuated with more 

 effort than the urine. To prove, beyond a doubt, that the urine is evacu- 

 ated, chiefly by the action of the bladder, OTIC need but observe the violent, 

 but useless straining of patients affected with retention of urine, from pa- 

 ralysis of the bladder*. 



The urine is projected along the urethra with the greater force, as it 

 passes from a spacious cavity, into a straight canal, and it is expelled with 

 a force proportioned to that of the muscular coat of the bladder: we know, 

 that in old men, this is so weak, that the jet of urine is not projected more 

 than a few inches beyond the urethra. The urethra is not to be consider- 

 ed as inert in the evacuation of the urine, it closes upon it and acceler- 

 ates its flow, aided in that action, by the bulbo-cavernous muscles to 

 which several anatomists have given a name taken from their functions, 

 (acceleratores urinas.) 



The action of these muscles expels the last drops of urine which remain 

 within the urethra, when the bladder is completely emptied. The con- 

 tractile and tonic action of the urethra is so distinctly marked, that its 

 spasmodic contraction may be enumerated, among the causes which fre- 

 quently occasion a difficulty in introducing the catheter. If we attempt 

 to inject fluids along the urethra the moment we remove the pipe of the 

 syringe which closes its external orifice, that instant, theparietes of the 

 canal contract on the fluid, and expel it with a rapid jet. 



The bladder and the canal of the urethra are lined internally with a 

 membrane, whose mucous follicles secrete a viscid humour calculated to 

 protect the parietes of these organs, against the action of the urine, and to 

 facilitate the evacuation of that fluid. This membrane, whose surface is 

 more extensive than the cavities which it lines, forms a great number of 

 folds, which disappear when the bladder is distended with urine. This 

 mucus is secreted, in an unusual quantity, in catarahal affections of the 

 bladder, and becomes, likewise, more ropy and more albuminous. The 

 mucous secretion of the glands of the urethrais altered in its quality, and 

 becomes more abundant, from the action of the venereal poison, and gives 

 rise to the discharge of gonorrhaea; the orifices of these lacunae may 

 stop the end of a catheter, so as to add to the difficulty of introducing 

 that instrumentf. 



* It is scarcely credible that^some physiologists should have considered this organ as 

 inert and absolutely passive, in the evacuation of urine, which, in their opinion, is per- 

 formed by the immediate pressure of the abdominal muscles and diaphragm on that 

 cavity. Amid this variety of opinions, if you wish to come at the truth, you must take 

 a medium. Iliacos intra muros peccatur, et extrfi Author's Note. 



f When this operation is performed in a case of simple paralysis of the bladder, it is 

 better to employ a very large catheter, which may stretch the parietes of the urethra, 

 and prevent their forming into wrinkles, and whose rounded beak may not get engaged 

 in the lacunae of that canal. 



When in a case of retention of urine, the bladder rises above the pubis, its bas fond 

 is .earned upwards, and there is a period of excessive distension, at which, like the ute- 

 rus in an advanced state of pregnancy, it seems to make an effort to rise above the brim 



