MANUAL FOR STABLE SERGEANTS. 131 



rendered less harmful by spreading it out and exposing it to the sun 

 and air. Feed grass whenever obtainable. Give iodine crystals 

 in 1-dram doses three times a day in capsule or ball, and reduce the 

 dose as the thirst is lessened and the amount of urine diminished. 



Diseases of the Bladder. 



426. Retention of the urine. — Inability to urinate. 



Causes. — Hard, continuous work without an opportunity to urinate; 

 exposure to cold rains; standing in drafts of cold air when hot and 

 tired; the presence of stones or tumors in the bladder or urethra, and 

 poisonous plants in the hay. It also frequently occurs in a tem- 

 porary form as a complication of colic . Some horses refuse to urinate 

 outside of their own stable, or where the floor or earth is hard causing 

 the urine to splash against their legs. A collection of dirt about the 

 end of the penis may also cause it. 



Symptoms. — Frequent and painful attempts to urinate, the urine 

 often being passed drop by drop only. By passing the hand into 

 the rectum the enlarged bladder may be felt. 



Treatment. — Standing the animal on the grass or in a well-bedded 

 stall often results in successful attempts to urinate. This fail- 

 ing, pass the hand into the rectum and apply firm but gentle 

 pressure to the base of the bladder. If neither of these methods is 

 successful, the catheter must be used or the bladder may burst. 

 Warm rectal injections and 3-dram doses cannabis indica often gives 

 relief. 'WTien retention is due to a collection of dirt in the end of the 

 penis, a thorough washing of the part may be all that is required. 



Diseases of the Sheath and Penis. 



427. Screw worms (maggots) in the sheath and penis. — 



Screw worms are the immature forms of several species of flies. Dur- 

 ing hot weather and in tropical climates these flies frequently deposit 

 their eggs just inside the mouth of the sheath, usually in its upper 

 portion, or on the end of the penis. In a few hours the eggs hatch 

 and large numbers of maggots appear which immediately lacerate 

 the skin and burrow into the tissues where they produce destruction 

 and injury, even to perforations of the abdominal wall. 



Symptoms. — A thin bloody serum dripping from the mouth_ of 

 the sheath, the latter being often more or less swollen. Just inside 

 of the sheath, beneath the abdominal wall, may be found a small, 



