24 ALKALINITY OF UKINE. 



cient quantity of the acid have been added, remain fixed and 

 in a suitable form to be used as a manure. What occurs in 

 the stable, and the test glass of the chemist, sometimes 

 occurs in the bladder of animals. If mucus or pus be 

 secreted by the coats of that organ, or if the animal be pre- 

 vented from voiding its urine for a long time, the urea is 

 decomposed, and ammonia is evolved. The ammonia com- 

 bines with the phosphate of magnesia which exists in the urine 

 of carnivorous animals, and forms an insoluble compound, 

 which is called triple phosphate, or phosphate of ammonia, 

 magnesia, and water ; thus it is that urine, which has become 

 alkaline from the decomposition of urea, is always thick from 

 the deposit of triple phosphate which it contains (such urine 

 is, in fact, called phbsphatic). 



The urea and the deposit of phosphates give rise to an 

 irritable condition of the bladder; the animal makes frequent 

 attempts to empty its bladder, but does so ineffectually. The 

 urine which remains in the bladder acts as a ferment to that 

 which is poured into it from the ureters, and thus the condi- 

 tion becomes permanent ; the bladder begins to secrete pus ; 

 its muscular coat becomes thickened ; ulceration of the 

 mucous membrane may set in, and the animal, gradually 

 exhausted by the continued pain and irritation, dies. 



How can this alkaline condition of the urine be, then, 

 recognised and distinguished from the alkaline state which 

 is brought on by an alkaline diet and by alkaline remedies, 

 and which is quite compatible with health? In the first 

 place, urine which is ammoniacal emits the odour of ammonia, 

 and always contains a sediment of phosphates. In the 

 second place, if a piece of litmus paper which has been red- 

 dened by a weak acid, be placed in the urine containing 

 ammonia, the blue colour will be restored, but the red will 

 reappear if the paper be cautiously heated, showing that the 



