342 A MANUAL OF VETERINARY PHYSIOLOGY 



ordinary circumstances, only pass urine when standing still, 

 though both sexes can defalcate while trotting ; but in a con- 

 dition of oestrum the mare can empty her bladder while cantering. 

 In the ox the urine simply dribbles away, owing to the curves in 

 the urethral canal, and is directed towards the ground by the 

 tuft of hair found on the extremity of the sheath. The ox can 

 pass his urine while walking. The cow arches her back to 

 urinate, but instead of extending her hind-limbs, as does the 

 mare, she brings them under the body, at the same time raising 

 her tail. 



The upright position is essential to micturition ; no horse of 

 either sex can evacuate the bladder while lying down — a point 

 of extreme importance in practice. Further, it will be remem- 

 bered that in an over-distended bladder the fundus hangs into 

 the abdominal cavity, and is thus brought on a lower level than 

 the urethra, both of which contribute to the difficulty of emptying 

 an over-distended organ. As a horse cannot micturate at work, 

 it is obvious that opportunity for this should be regularly afforded, 

 or much suffering results. 



Pathological. 



There is scarcely any organ of the horse's body so free from disease 

 as the kidneys. The material in the pelvis which looks like pus is 

 really the natural mucus of the urine, mixed with insoluble lime 

 salts. We have never found sugar in the horse's urine ; protein is 

 not uncommon, but only as the result of inflammatory affection 

 of the lungs and pleura. 



Vesical calculus would be one of the most common diseases among 

 the herbivora, but for the fact that they excrete the insoluble salts 

 at each evacuation, and calcium carbonate has but little tendency 

 to cohere. 



