346 HEALTH AND DISEASE 



Oxalate of Lime, although frequently occurring in the urine of 

 healthy horses, is now and again found to exist in large quantities, 

 associated with a disease of an obscure character, to which, for want of 

 a better name, " oxaluria" has been applied. In a case recorded by the 

 late Professor Morton the urine was found to contain this salt in con- 

 siderable amount (fig. 144). 



When first examined, Professor Morton says the pulse was found to 

 be thirty-two in a minute, tone feeble, a peculiarly anxious countenance 

 was observed, and a looking from time to time to the loins, with an ex- 

 pression indicative of pain. The appetite was impaired and capricious, 

 although there was but little loss of flesh. On walking the animal out 

 of the stable, considerable languor and listlessness were evinced, and the 

 .slightest exertion produced great fatigue. On his being returned to the 

 stable he immediately placed him.self in the position to urinate, and, after 

 making several ineffectual attempts, a few ounces of urine were voided, 

 having a very peculiar smell, and being somewhat viscid. In this case 

 the urine had a light amber colour, and was clear. It gave an acid 

 reaction to test-paper, and its specific gravity was r00045. It did not 

 contain albumen, but when examined microscopically was found to contain 

 a large amount of oxalate of lime, in the form of bright octahedral crystals. 



The presence of oxalic acid in the urine is believed to arise out of 

 some defect in the digestion and assimilation of the food. 



DIABETES, POLYURIA, OR PROFUSE STALING 



Definition. — A morbid activity of the kidneys, resulting in an ex- 

 cessive secretion of urine. 



Diabetes assumes two forms, distinguished as diabetes mellitUS and 

 diabetes insipidus. The former is characterized by the pre.sence of sugar 

 in the urine, and an increase in the specific gravity. In the latter there 

 is an absence of sugar, and the specific gravity is usually below the normal 

 standard. Diabetes mellitus is rarely seen in the horse. 



Causes. — Profuse staling, or polyuria, is sometimes associated with 

 indigestion and suppressed skin function. Hay that has been badly 

 harvested, and by excessive fermentation become heated and " mowburnt", 

 is one of the most frequent causes of the disorder, while in other cases 

 the drinking water may be at fault. Foreign oats and hay are more 

 frequently found to affect the urinary organs of horses in these islands 

 than those grown at home. Debility and exposure to great vicissitudes 

 of climate are also considered as a probable cause. The disorder is usually 

 found to exist without any organic disease of the kidneys themselves. 



