VESICAL CALCULUS. 



623 



the practice should be condemned as favouring fistula formation and 

 infection of the bladder. The tube must be cleansed and placed 

 for a short time before insertion in the lotion to be injected. 



Under anaesthesia the membranous urethra and neck of the 

 bladder are capable of considerable dilatation, and sufficient space 

 for the extraction of a large calculus can be made without 

 danger by gradually opening the lithotomy forceps whilst still 

 in the bladder ; if not, the probe-pointed knife may be passed 

 along the director towards the bladder and 

 the mucous membrane of the superior wall, 

 just behind the neck, incised on each side. If 

 only a small calculus, or gravel, has to be 

 removed, an attempt should be made to 

 extract the stone without resorting to dilata- 

 tion. In removing large stones, the neck of 

 the bladder must sometimes be enlarged to 

 such an extent as to admit the entire hand. 

 After incision of the constrictor urethra? 

 Moller once removed a cystic calculus weighing 

 over 20 ounces. 



The danger of operation increases with the 

 size of the calculus, though stones of con- 

 siderable magnitude may be safely removed, 

 as shown by Moller extracting two calculi 

 from the bladder of a nine-year-old gelding, 

 one weighing 2| ounces and the other 20£ 

 ounces. The operation wound took three 

 weeks to heal. In a second horse from which 

 he took a stone weighing 20 ounces gangrenous 

 cystitis with septic paraproctitis and peritonitis 

 resulted, from which the animal died on the 

 fifth day after operation. 



Large calculi may be crushed, though the instruments intended 

 for this purpose are not constructed for calculi of the above size. 

 Calculi indeed often yield to powerful pressure from the forceps and 

 fall to pieces ; Bouley's forceps (Fig. 431) may be employed as 

 a lithotrite. They have the advantage that they can be fixed after 

 grasping the stone, thus rendering easier the extraction of large 

 concretions. Bouley's instrument is useful, though in most cases 

 the older calculus forceps are sufficient (Fig. 430). After crushing 

 the stone, the pieces are removed with forceps and lithotomy spoon, 

 or washed out by injecting warm boracic solution. 



Fig. 431. — Bouley's cal- 

 culus forceps. 



