638 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



That this difference is dependent only on differences in diet is proved 

 by the fact that during fasting the urine of the herbivora agrees in all 

 its characteristics with the urine of the carnivora. Under such circum- 

 stances the herbivora are not consuming vegetable matters, but living at 

 the expense of their own tissues, are then practically carnivorous, and 

 their urine becomes acid, clear, and rich in urea and phosphatic salts. 



The Urine of the Horse is cloudy and has an alkaline reaction. Its 

 specific gravity varies from 1016 to 1060, 1050 being about the average. 

 It contains a large percentage of mucin, and is therefore viscid and may 

 be drawn into threads. It becomes brown on exposure to the air, deposits 

 CaC0 2 , and a pellicle forms on it, showing iridescent colors. 



The characteristics of normal horses' urine depend largely on the 

 mode of feeding. When fed exclusively on hay and straw the urine is 

 always alkaline, while when oats constitute the principal food it is 

 secreted in small quantity, is turbid, and of acid reaction, and more 

 viscid than alkaline. The influence of the diet on the amount of solids 

 in the urine is shown in the following table : 



A high percentage of calcium salts is characteristic of horses' urine. 

 Of the amount contained in the food, from one-third to one-half passes 

 into the urine, while in the ruminant, especially in the sheep, not more 

 than 5 per cent, passes. In the case of potassium the conditions are 

 just reversed. In the sheep 95 per cent, of the potassium in the food 

 passes into the urine, while in the horse at most 66 per cent, appears. 

 The following table gives the percentage of inorganic constituents in 

 one hundred parts of the ash of horses' urine : 



Potassium, . , . . . .36.85 per cent. 



Sodium, 3.71 



Calcium, 21.92 



Magnesium, . 4.41 



Phosphoric acid, . . . . . .... 



Sulphuric acid, . . . . . .17.16 



Chlorine 15.36 



Silicic acid, 0.32 



