200 A Manual of Veterinary Physiology. 



all we wish to know, the examination of a single portion of 

 urine may suffice. 



The Odour of urine is said to be due to certain aromatic 

 substances of the phenol group. Perfectly fresh urine has 

 a most distinct though faint smell of ammonia. 



The normal fluid is always turbid, some specimens more 

 so than others : very rarely is it clear, and then only for a 

 short time. The turbidity is due to the amount of sus- 

 pended carbonate of lime and magnesia which exists in it ; 

 as the urine cools, particularly if it undergoes ammoniacal 

 fermentation, the amount of turbidity becomes intense. 



The consistence of the fluid depends upon sex, and per- 

 haps on the season. It is certain that some mares excrete 

 quite a glairy tenacious fluid, which can be drawn out in 

 strings, due to the amount of mucin it contains : it is very 

 common to find it as thick as linseed-oil, and very rare to 

 find it fluid and watery. 



Of the total water consumed, about one-fifth passes away 

 in the urine, though Munk* considers that one-third passes 

 away by the kidneys and two-thirds by the lungs. An 

 interesting point is the ultimate disposal of the water con- 

 sumed by various animals ; it has been found that carni- 

 vora excrete by the kidneys the greater part of the water 

 they drink, whilst herbivora excrete the greatest part by the 

 lungs. 



Here is Munk's table : 



Man : 60 per cent, of water escapes by the kidneys, and 40 per cent. 



by the lungs and skin. 

 Carnivora : 70 per cent, of water escapes by the kidneys, and 30 per 



cent, by the lungs and skin. 

 Herbivora : 30 per cent, of water escapes by the kidneys, ami 70 per 



cent, by tin; lungs and skin. 



The Colour of the urine is yellowish-red, rapidly turning 

 to brown, the dark tint commencing en the surface of the 

 fluid and gradually travelling into its depth. The cause of 

 the colour will be dealt with shortly. 



* Quoted by M'Kendrick. 



