87 



point wliere the incision is to be made beneatli the anus. The skin is 

 then rendered tense by the thumb and fingers of the left hand i)ress- 

 ing on the two sides of the sound, while the right hand, armed with a 

 scalpel, cuts downward on to the catheter. This vertical incision into 

 tlie canal should escape w^ounding any important blood-vessel. It is 

 in making the obliquely lateral incision in the subsequent dilatation 

 of the urethra and neck of the bladder that sucli danger is to be 

 apprehended. 



If the stone is too large to be extracted through the urethra it may 

 be broken down with the lithotrite and extracted x^iecemeal with the 

 forceps. The lithotrite is an instrument composed of a straight stem 

 bent for an inch or more to one side at its free end so as to form an 

 obtuse angle, and having on the same side a sliding bar moving in a 

 groove in the stem and oijerated by a scrcAV so that the stone may be 

 seized between the two blades at its free extremity and crushed again 

 and again into pieces small enough to extract. Extra care is required 

 to avoid injury to the urethra in the extraction of the angular frag- 

 ments, and the gravel or jjowder that can not be removed in this way 

 must be washed out as advised below. 



When a j)ultaceous magma of carbonate of lime accumulates in the 

 bladder it must be washed out by injecting water tlirough a catheter 

 by means of a force T)ump or a funnel, shaking it uf) with the hand 

 introduced through the rectum and allowing the mudd}^ liquid to flow 

 out through the tube. This is to be rex^eated until the bladder is 

 empty and the water comes away clear. A catheter with a double 

 tube is sometimes used, the injection passing in through the one tube 

 and escaiDing through the other. But the advantage is more apparent 

 than real, as the retention of the water until the magma has been 

 shaken up and mixed with it hastens greatly its complete evacuation. 

 To prevent the formation of a new deposit any fault in feeding {dvj 

 grain and hay with privation of water, excess of beans, peas, wheat 

 bran, etc.) and disorders of stomach, liver, and lungs must be cor- 

 rected. Give abundance of soft drinking water, encouraging the 

 aninml to drink by a handful of salt dailj^; let the food be laxative, 

 consisting largelj^ of roots, apples, pumiDkins, ensilage, and give daily 

 in the drinking water a dram of carbonate of potash or soda. Pow- 

 dered gentian root (3 drams daily) will also serve to restore the tone 

 of the stomach and sj^stem at large. 



Urethral calculus. — Stone in the urethra. — This is less frequent than 

 in cattle and sheep, owing to the larger size of the urethra in the horse 

 and the absence of the S -shaped curve and vermiform appendix. Tlie 

 calculi arrested in the urethra are never formed there, but consist of 

 cystic calculi Avhich have been small enough to pass through the neck 

 of the bladder, but too large to pass through the whole length of tlie 

 urethra and escape. Such calculi therefore are primarilj'- formed eitlier 

 in the bladder or kidney, and have the chemical composition of the 



