442 PRACTICAL PHYSIOLOGY 



tion of benzole acid. It crystallises in four-sided prisms. It is quite 

 common in the urine of herbivora. 



In Alkaline Urine the following may occur : 



1. Phosphates. Of these there are two kinds, viz. phosphate of 

 calcium and ammonium-magnesium phosphate. 



(a) Phosphate of Calcium. The sediment is chalky and never 

 pigmented ; it clears up on adding a few drops of nitric acid ; it is 

 increased by boiling. Microscopically it is usually amorphous, but 

 may exist as long prismatic crystals arranged in star-shaped clusters, 

 hence called Stellar Phosphates (Fig. 253). The crystalline form may also 

 occur in faintly acid urines. 



(b) Ammonium-magnesium Phosphate, Triple Phosphate. When 

 urine gets stale and ammonia develops in it, a white sediment and 

 a white surface film form. Under the microscope these are seen to be 

 made up of large clear crystals like "knife rests" or, if excess of 

 ammonia be present, they may look like "feathery stars" This latter 

 type can be easily obtained by adding ammonia to normal urine 

 (Fig. 254). 



2. Urate of Ammonia. This looks like the urate of soda crystals, 

 but is associated with crystals of phosphates, and occurs in an alkaline 

 urine. 



3. Carbonates. In the urine of vegetarians these are not uncommon. 

 The urine effervesces on adding acetic acid. Microscopically the sedi- 

 ment is usually amorphous, but may exist as biscuit-shaped crystals or 

 as dumb-bells (Fig. 251). 



CHAPTER XX. 

 PATHOLOGICAL URINE. 



I. Proteins in the Urine Albuminuria. Traces of mucin or nucleo- 

 protein may be added to the urine in its passage along the urinary 

 tract, but otherwise healthy urine does not contain any protein. When 

 the kidneys or urinary passages are diseased, however, a certain amount 

 of the plasma proteins leak into the urine, where they can be recog- 

 nised by certain tests, the condition being called Albuminuria. 



Also when proteins other than serum albumin and globulin gain 

 access to the blood, they are at once excreted in the urine. It is on 

 this account that albuminuria results after the consumption of a large 

 number of raw eggs (egg flip), because the intestinal epithelium allows 

 a certain amount of the unchanged albumin to pass into the blood, 



