ics, especially such as are
irritating (cantharides, turpentine, copaiba, resin, etc.), by the
presence of a stone or gravel in the bladder, the irritation of a
catheter or other foreign body introduced from without, the septic
ferment (bacterium) introduced on a filthy catheter, the overdistention
of the bladder by retained urine, the extrication of ammonia from
retained decomposing urine, resulting in destruction of the epithelial
cells and irritation of the raw surface, and a too concentrated and
irritating urine. The application of Spanish flies or turpentine over a
too extensive surface, sudden exposure of a perspiring and tired horse
to cold or wet, and the presence of acrid plants in the fodder may cause
cystitis, as they may nephritis. Finally, inflammation may extend from a
diseased vagina or urethra to the bladder.

_Symptoms._--The symptoms are slight or severe colicky pains; the animal
moves his hind feet uneasily or even kicks at the abdomen, looks around
at his flank, and may even lie down and rise frequently. More
characteristic are frequently repeated efforts to urinate, resulting in
the discharge of a little clear, or red, or more commonly flocculent
urine, always in jets, and accompanied with signs of pain, which persist
after the discharge, as shown in continued straining, groaning, and
perhaps in movements of the feet and tail. The penis hangs from the
sheath, or in the mare the vulva is frequently opened and closed, as
after urination. The animal winces when the abdomen is pressed in the
region of the sheath or udder, and the bladder is found to be sensitive
and tender when pressed with the oiled hand introduced through the
rectum or vagina. In the mare the thickening of the walls of the bladder
may be felt by introducing one finger through the urethra. The
discharged urine, which may be turbid or even oily, contains an excess
of mucus, with flat shreds of membrane, with scaly epithelial cells, and
pus corpuscles, each showing two or more nuclei when treated with acetic
acid, but there are no microscopic tubular casts, as in nephritis. If
due to stone in the bladder, that will be found on examination through
rectum or vagina.

_Treatment_ implies, first, the removal of the cause, whether poisons in
feed or as medicine, the removal of Spanish flies or other blistering
agents from the skin, or the extraction of stone or gravel. If the urine
has been retained and decomposed it must be completely evacu