784 URIXE. 



It is not yellow or brown like ammonium urate, and does not give the 

 murexid test. 



Calcium Phosphate. The CALCIUM TRIPHOSPHATE, Ca3(PO 4 ) 2 , which 

 occurs only in alkaline urines, is always amorphous and occurs partly 

 as a colorless, very fine powder and partly as a membrane consisting of 

 very fine granules. It differs , from the amorphous urates in that it is 

 colorless, dissolves in acetic acid, but remains undissolved on warming 

 the urine. CALCIUM DIPHOSPHATE, CaHPO 4 +2H 2 O, occurs in neutral 

 or only in veiy faintly acid urine. 1 It is found sometimes as a thin 

 fiim covering the urine and sometimes as a sediment. In crystallizing, 

 the crystals may be single, or they may cross one another, or they may 

 be arranged in groups of colorless, wedge-shaped crystals whose wide 

 end is sharply defined. These crystals differ from crystalline alkali 

 urates in that they dissolve without a residue in dilute acids and do not 

 give the rnurexid test. 



Calcium sulphate occurs very rarely as a sediment in strongly acid urine. It 

 appears as long, thin, colorless needles, or generally as plates grouped together. 



Ammonium-magnesium phosphate, TRIPLE PHOSPHATE, may separate 

 from an amphoteric urine in the presence of a sufficient quantity of ammo- 

 nium salts, but it is generally characteristic of a urine which is ammo- 

 niacal through alkaline fermentation. The crystals are so large that they 

 may be seen with the unaided eye as colorless glistening particles in the 

 sediment, on the walls of the vessel, and in the film on the surface of the 

 urine. This salt forms large prismatic crystals of the rhombic system 

 (coffin-shaped) which are easily soluble in acetic acid. Amorphous 

 magnesium triphosphate, Mg 3 (PO4) 2 , occurs with calcium triphosphate 

 in urines rendered alkaline by a fixed alkali. Crystalline magnesium 

 phosphate, Mg 3 (PO4) 2 H-22H 2 O, has been observed in a few cases in 

 human urine (also in horse's urine) as strongly refractive, long rhombic 

 plates. 



Kyestein is the film which appears after a little while on the surface of the urine. 

 This coating, which was formerly considered as characteristic of urine in preg- 

 nancy, contains various elements, such as fungi, vibriones, epithelium-cells, etc. 

 It often contains earthy phosphates and triple-phosphate crystals. 



As more rare sediments we find cystine, tyrosine, hippuric acid, xanthine, h&ma- 

 toidine. In alkaline urine blue crytsals of indigo may also occur, due to a decom- 

 position of indoxyl-glucuronic acid. 



URINARY CALCULI. 



Besides certain pathological constituents of the urine, all those urinary 

 constituents which occur as sediments take part in the formation of 

 urinary calculi. EBSTEiN 2 considers the essential difference between an 



1 C. Th. Morner, Zeitschr. f. physiol. Cliem., 58. 



2 Die Natur und Behandlung der Harnsteine. Wiesbaden, 1884. 



