CIRCULATING SYSTEM. 361 
analysis. ‘The colour of urine is usually a pale yellow, 
and its specific gravity rather higher than water. It has a 
peculiar odour. When first discharged, it is sensibly acid, 
readily reddening vegetable blues, but in a short time it 
suffers decomposition, ammonia is evolved, the excess of 
acid is neutralised, and alkaline properties predominate. 
Such is the case with the urine of man and many qua- 
drupeds, but VauauEtin found that of the hon and 
tiger alkaline, owing to the excess of ammonia*. It 1s not 
determined which of the acids existing in urine, are in an 
uncombined state,—the uric, phosphoric, acetic, lactic, and 
carbonic acids having been successively referred to, as occa- 
sioning the change in vegetable blues +. 
In the urine of different species of quadrupeds, nearly 

* Berzevevs lays it down as a rule, (Annals of Phil. ii. 206,) that all 
the excreted fluids, such as urine, are acid. The alkaline nature of the urine 
of the lion and tiger, however, furnish a striking exception. 
+ The foliowing are the ingredients contained in a 1000 parts of urine : 
Water, oe ‘ : ; ee: KES 933.00 
Urea, . 4 ; 3 : . 30.10 
Sulphat of potash, 4 - : ; ; 3.71 
Sulphat of soda, : : A : : 3.16 
Phosphat of soda, - : : : : 2.94: 
Muriat of soda} > 4 F ; . 4.45 
Phosphat of ammonia, . - 5 , 1.65 
Muriat of ammonia, : 4 - F - 1.50 
Free lactic acid,—lactat of ammonia,— animal matter soluble in 
alcohol, and usually accompanying the lactat,-—animal 
matter insoluble in alcohol,—urea nat separable from the 
preceding, é A : : 17.14 
Earthy phosphate, with a trace of fluat of lime, : 1.00 
Uric acid, F : A : : 1.00 
Mucus of the bladder, d ° : : 0.32 
Silex, - ; A A . : 0.03 
1000.00 
Berzecius,—Annals of Phil 11. p. 422 
