STONE IN THE BLADDER 369 



neck of the bladder is carefully dilated and the lithotomy forceps intro- 

 duced with one hand, while the other, in the rectum, directs the calculus 

 between the blades. Seizure having been effected, and the manipulative 

 precautions already prescribed duly observed, its removal is proceeded 

 with in the manner directed. 



Where it is found to be of large size, and the extraction of it by this 

 method impracticable, the animal must be cast and placed under the 

 influence of chloroform. By this means the sphincter vesica will be 

 relaxed and its dilation more effectually accomplished. 



Should the stone be too large to be removed entire, it may be crushed 

 and extracted piecemeal in accordance with the rules already laid down. 



A thick, pasty, yellow deposit of calcic carbonate is occasionally found 

 in the bladder of the male and female as the result of atony or paralysis 

 of its walls. In both instances it may be readily removed by means of 

 the scoop, aided by forcible injections of tepid water driven through the 

 dilated urethra. 



After the whole has been evacuated, an attempt should be made to 

 restore tone to the vesical walls by repeated injection of cold water, 

 supplemented by the administration of nerve tonics and good living. 



General Considerations on the Structure and Formation of 



Calculi. Vesical calculi are usually ovoid in form, with their surfaces 

 sometimes slightly and unequally flat- 

 tened. If they have been enclosed, 

 or partly enclosed, in a pouch or off- 

 shoot from the bladder, they may be 

 round, oblong, irregular, or dumb-bell 

 shaped. The majority are of a dark- 

 brown hue; some are palish -gray, 

 others yellowish - brown, and a few 

 whitish-gray. All, with rare excep- 



J Fig. 162. Vesical Calculus 



tions, present a rough asperous surface 



(fig. 162), usually more marked on one side than the other. The side 

 on which the stone rests while in the bladder is smoother, denser, and 

 less rounded than the other surface. In some the asperities are coarse 

 and rounded, and impart to the stone a distinct mulberry character, but 

 in the majority they are finer, closer set, and less prominent. In density 

 calculi vary very considerably in different specimens, and also in different 

 parts of the same specimen, but it is rare to find them of that flinty 

 hardness which characterizes some examples of vesicular calculus in man, 

 In many instances they present an open spongy texture and are. dis- 

 tinguished by marked brittleness and want of cohesion. As a rule the 



