URINE. 35 l 



Indigo. Indigo crystals are frequently found in urine which has 

 undergone alkaline fermentation. They result from the breaking 

 down of indoxyl-sulphates or indoxyl-glycuronates. Ordinarily 

 indigo deposits as dark blue stellate needles or occurs as amorphous 

 particles or broken fragments. These crystalline or amorphous 

 forms may occur in the sediment or may form a blue film on the sur- 

 face of the urine. Indigo crystals generally occur in urine which 

 is alkaline in reaction, but they have been detected in acid urine. 



Xanthine. Xanthine is a constituent of normal urine but is 

 found in the sediment in crystalline form very infrequently, and then 

 only in pathological urine. When present in the sediment xanthine 

 generally occurs in the form of whetstone-shaped crystals some- 

 what similar in form to the whetstone variety of uric acid crystal. 

 They may be differentiated from uric acid by the great ease with 

 which they may be brought into solution in dilute ammonia and on 

 applying heat. Xanthine may also form urinary calculi. The 

 clinical significance of xanthine in urinary sediment is not well 

 understood. 



Melanin. Melanin is an extremely rare constituent of urinary 

 sediments. Ordinarily in melanuria the melanin remains in solu- 

 tion; if it separates it is generally held in suspension as fine amor- 

 phous granules. 



(b) Organized Sediments. 



Epithelial cells. 

 Pus cells. 



Hyaline. 



Granular. 



Epithelial. 



Blood. 

 Fatty. 

 Waxy. 



Casts. 



Cylindroids. 



Erythrocytes. 



Spermatozoa. 



Urethral filaments. 



Tissue debris. 



Animal parasites. 



Micro-organisms. 



Fibrin. 



Foreign substances due to contamination. 



