366 



THE URINE. 



with which the phosphoric acid in the blood is combined, by 

 the several new acids which are formed or discharged at the 

 kidneys, namely, the uric, hippuric, and sulphuric acids, all of 

 which he supposes to be neutralized with soda. 



The presence of the acid phosphates accounts, in great 

 measure, or, according to Liebig, entirely, for the acidity of 

 the urine. The phosphates are taken largely in both vege- 

 table and animal food ; some thus taken, are excreted at once ; 

 others, after being transformed and incorporated with the tis- 

 sues. Phosphate of calcium forms the principal earthy con- 

 stituent of bone, and from the decomposition of the osseous 

 tissue the urine derives a large quantity of this salt. The de- 

 composition of other tissues also, but especially of the brain 

 and nerve-substance, furnishes large supplies of phosphorus to 

 the urine, which phosphorus is supposed, like the sulphur, to 

 be united with oxygen, and then combined with bases. This 



quantity is, however, liable to 

 FIG. 130. considerable variation. Any 



undue exercise of the mind, 

 and all circumstances produc- 

 ing nervous exhaustion, in- 

 crease it. The earthy phos- 

 phates are more abundant af- 

 ter meals, whether 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 uncombined with 

 oxygen appears, like sulphur, 

 to be excreted in the urine 

 (Ronalds). When the urine undergoes alkaline fermentation, 

 phosphates are deposited in the form of a urinary sediment 

 consisting chiefly of phosphate of ammonia and magnesia 

 (triple phosphate) (Fig. 130.) This compound does not, as 

 such, exist in healthy urine. The ammonia is chiefly or 

 wholly derived from the decomposition of urea (p. 360). 



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. 



Urinary sediment of triple phosphates 

 (large prismatic crystals) and urate of 

 ammonia, from urine which had under- 

 gone alkaline fermentation. 



