464 THE URINE. 



then combined with bases. This quantity is, however, 

 , liable to considerable vari- 



ation. Any undue exercise of 

 the mind, and all circum- 

 stances producing nervous 

 exhaustion, increase it. The 

 earthy phosphates are more 

 abundant after meals, whe- 

 ther on animal or vegetable 

 food, and are diminished after 

 long fasting. The alkaline 

 phosphates are increased after 

 animal food, diminished after 

 vegetable food. Exercise increases the alkaline, but not 

 the earthy phosphates (Bence Jones). Phosphorus uncom- 

 bined with oxygen appears, like sulphur, to be excreted in 

 the urine (Eonalds). When the urine undergoes alkaline 

 fermentation, phosphates are deposited in the form of an 

 urinary sediment consisting chiefly of phosphate of ammonia 

 and magnesia (triple phosphate) (fig. 123). This compound 

 does not, as such, exist in healthy urine. The ammonia is 

 chiefly or wholly derived from the decomposition of urea 



(P-455)- 



The chlorine of the urine occurs chiefly in combination 

 with sodium, but slightly also with ammonium, and, 

 perhaps, potassium. As the chlorides exist largely in 

 food, and in most of the animal fluids, their occurrence in 

 the urine is easily understood. 



Oystin (fig. 124) is an occasional constituent of urine. It 

 resembles taurin in containing a large quantity of sulphur 

 more than 25 per cent. It does not exist in healthy urine. 



Another common morbid constituent of the urine is 



* Fig. 123. Urinary sediment of triple phosphates (large prismatic 

 crystals) and urate of ammonia, from urine which had undergone alkalin e 

 fermentation. 



