338 HEALTH AND DISEASE 



ing in dry air and in hot weather, the quantity is diminished, whilst it 

 is increased when the animal is at rest and exposed to cold. The quantity 

 discharged per diem varies under these circumstances, and with the size of 

 the animal, from four or five quarts, which is about the average, to twelve 

 or more, or putting it in another form, from about one-quarter to one-half 

 ounce for each one pound of the body weight of the animal. It is more 

 abundant, as might naturally be expected, in grass-fed animals than in 

 those whose food is confined to such dry matter as oats and hay. 



When first emitted the urine of the horse is a clear yellowish fluid, 

 but it soon becomes turbid. It has a peculiar and rather unpleasant 



Fig. 134.— Urine Salts 

 Various forms of calcic carbonates ami ammonium urate- tonial in normal urine of the horse. 



odour, and a specific gravity of about 1*042, but varying from 1*030 to 

 1*055 or more. Its reaction to test-paper is always alkaline in health, 

 the alkalinity being chiefly due to the presence of potassium bicarbonate. 



When the urine of the horse is analysed it is found that in every 1000 

 parts there are about 905-910 of water, 55 of organic substances, and 40 

 of inorganic substances. The organic substances include urea, hipptiric, 

 benzoic, uric, and oxalic acids and their salts, with mucus and epithelial 

 scales from the lining membrane of the bladder and urethra; whilst the 

 inorganic substances are represented by the lactates, carbonates, sulphates, 

 and, in very small quantity, phosphates of the metals sodium, potassium, 

 calcium, and magnesium, with some chloride of sodium and silica. The 

 relative proportions of these vary greatly with the nature of the food, and 

 also according as it has been examined when taken from the animal in the 

 fasting state or during full digestion. 



The urine of the horse contains, in addition, a considerable quantity 



