THE URINE 



1. Uric Acid. These appear as a " cayenne -pepper " deposit at 

 the bottom of the specimen, the crystals being pigmented with uro- 

 erythrin. In shape, the crystals resemble whetstones, dumb-bells, 

 orange pips, etc., and are often grouped together in rosettes (Fig. 223) 



2. Amorphous Urales occur as a brickdust or pinkish deposit. 

 They consist of masses of amorphous granules tinted with urinary 

 pigment. They easily pass into solution when the urine is warmed 

 or rendered alkaline. 



3. Sodium Urate. This occurs but seldom in adults; frequently, 

 however, in the urine of the newly-born. In appearance, the crystals 

 resemble the thorn-apple, little spheres with numerous spines radiating 

 from them (Fig. 222). 



4. Calcium Oxalate occurs as characteristic colourless, shining, 

 " envelope " crystals (Fig. 224). In reality, they are small octahedra. 

 In some cases, calcium oxalate occurs also in dumb-bells forms. 

 They are insoluble in acetic acid and ammonia, but soluble in hydro 

 chloric acid. 



FIG. 228. TRIPLE PHOSPHATE 

 CRYSTALS. 



FIG. 229. STELLAR PHOSPHATE 

 CRYSTALS. (Savill.) 



Rarely, deposits may occur in acid urine of (a) acid calcium 

 phosphate (CaHP0 4 ) rosettes of prisms or dumb-bells; (b) hippuric 

 acid, especially after the administration of benzoic acid colour- 

 less four-sided prisms, insoluble in hydrochloric acid, soluble in am- 

 monia; (c) cystin colourless hexagonal crystals, often thrown out 

 of solution by the addition of acetic acid, soluble in ammonia ; (d) cones 

 of leucin and white sheaves of tyrosin. 



In alkaline urine, the chief salts to be deposited are the phosphates. 

 They are all soluble in acetic acid, and the amount of deposit is in- 

 creased by boiling. There occur 



1. (a) Most commonly the Phosphate of Calcium, ''Earthy'' 

 Phosphate, Ca 3 (PO 4 ) 2 , generally as white amorphous granules, more 

 rarely as colourless prismatic crystals radiating in clusters. 



(6) Ammonium Magnesium Phosphate, MgNH 4 PO 4 , or Triple 

 Phosphate, especially in 'urine which has undergone ammoniacal fer- 

 mentation. In appearance, they resemble coffin-lids or feathery 

 stars " feathery phosphates " (Fig. 223). 



2. Ammonium Urate, especially in cases of inflammation of the 

 bladder " cystitis." Small spherical crystals resembling sodium 



