APPENDIX TO URINE 567 



(9) Tyrosine. 



Tyrosine may be present as fine "needles in star-shaped bundles (p. 268). 

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

 acid and give Millon's reaction. 



(10) Cystine. 



Cystine deposits are very rare and consist of colourless regular hexagonal 

 plates (p. 143) which are soluble in ammonia, but insoluble in acetic acid. 



B. IN ALKALINE URINE. 

 Amorphous. 



(1) Earthy Phosphates. 



Earthy phosphates appear as fine granules and are easily soluble in 

 dilute acetic acid. 



(2) Calcium Carbonate. 



Deposits of calcium carbonate consist of fine granules or dumb-bell 

 shaped spheroidal masses sometimes having a concentric striation. They are 

 easily soluble in acetic acid with evolution of carbon dioxide and efifervesc- 

 ence. 



(3) Acid Ammonium Urate. 



Spherules with small crystals adhering, "hedgehog spines," are composed 

 of acid ammonium urate (Fig. 82). They are generally pigmented and dis- 

 solve in hydrochloric acid from which uric acid separates. 



Crystalline. 



(4) Ammonium Magnesium Phosphate. 



Ammonium magnesium phosphate crystals are easily obtained from urine 

 undergoing ammoniacal fermentation. They consist of large colouiless 

 prisms of knife-rest or coffin-lid shape. 



(5) Crystalline Calcium Phosphate. CaHPO 4 . 



This deposit occurs rarely and appears as rosettes of prisms or spherules. 



