MEDICINES ACTING ON THE BLADDER 127 



cavities as in hydro thorax or ascites. When dropsy is con- 

 nected with cardiac disorder, digitalis, and other drugs which 

 act on the vascular system, are indicated, their efficacy being 

 rendered more certain by combination with some saline 

 diuretic, such as nitre. Copaiba is added to the prescription 

 when the liver is affected. In dropsy connected with chronic 

 kidney disease, nitrous ether and oil of juniper are preferred ; 

 but they should be used with extreme caution. 



Calomel augments secretion of urea, and hence promotes 

 secretion of urine. In excessive or too frequently repeated 

 doses diuretics are apt unduly to stimulate the kidneys and 

 urinary organs, and provoke strangury, inflammation and 

 hsematuria. In cystitis, urethral disease, or obstruction, to 

 prevent alkaline decomposition of the urine, antiseptics, 

 such as benzoic and salicylic acids, or urotropine are 

 prescribed. 



MEDICINES ACTING ON THE BLADDER 



LITHONTRIPTICS URINARY SEDATIVES, TONICS, AND 

 ASTRINGENTS 



The movements of the urinary bladder are mainly reflex 

 and regulated by a centre in the lumbar portion of the spinal 

 cord, but in all the higher animals there is also a certain 

 amount of voluntary control. Most drugs influencing the 

 bladder appear to come into actual contact with it, and 

 produce their effects reflexly. Thus irritant agents, such as 

 cantharides, which are excreted in the urine, irritate the 

 bladder and cause frequent micturition. Some horses will 

 not urinate while in harness ; others will not while the rider 

 is in the saddle. As with other animals, the desire to urinate 

 is suggested, and the act facilitated, by seeing or hearing 

 other animals staling, or even by the sound of flowing water. 

 If, as is often the case, the horse is in the habit of being 

 whistled to when urinating, the act will be encouraged by 

 whistling to him. Control of the sphincter of the bladder is 

 frequently lost after injuries to the posterior part of the 

 spinal cord or in paralysis of the hind parts of the body. 

 Partial loss of control may be caused by nervous debility, 

 and will disappear with improved general condition. 



