URINARY DEPOSITS. 



121 



(a). Donne's test. Filter off the fluid, and add to the 

 deposit a small piece of caustic potash, or a few drops of 

 strong solution of caustic potash ; the deposit becomes ropy 

 and gelatinous, and cannot be dropped from one vessel into 

 another due to the formation of alkali-albumin the deposit 

 is pus. The same reagent with mucus causes the deposit to 

 become more fluid and limpid, to clear up, and look like 

 unboiled white of egg. 



(b.) With the microscope numerous pus corpuscles are 

 seen, which when acted on by acetic acid show a bi- or tri- 

 partite nucleus. This test is not absolutely conclusive. 



(c.) Urine containing pus gives the reactions for albumin, 

 while, if mucus alone be present, it gives only those for 

 nmcin. 



UNORGANISED DEPOSITS. 

 A. IN ACID URINE. B. IN ALKALINE URINE. 



1. Amorphous. 



(a.) Urates. Soluble when 

 heated, redeposited in the cold; 

 when hydrochloric acid is added 

 microscopic crystals of uric acid 

 are formed = urates. 



(6.) Tribasic Phosphate of 

 Lime. Not dissolved by heat, 

 but disappears without efferves- 

 cence on adding acetic acid. It 

 is probably tribasic phosphate 

 of lime (Ca 3 2P0 4 ). 



(c.) Oil Globules. Very 

 small highly refractive globules, 

 soluble in ether (very rare). 



2. Crystalline. 



(a.) Uric Acid. Recognised 

 by the shape and colour of the 

 crystals and their solubility in 

 KHO. 



(6.) Oxalateof Lime. Octa- 

 hedral crystals, insoluble in 

 acetic acid (Fig. 31, b, c). 



1. Amorphous. 



(a.) Tribasic Phosphate of 

 Lime dissolves in acids without 

 effervescence. 



(b.) Carbonate of Lime. 

 (See (c.) below.) 



2. Crystalline. 



(a.) Triple Phosphate. 



Shape of the crystals (knife-rest 

 or coffin-lid), soluble in acids. 



(b.) Acid Ammonium 

 U rate. Small dark balls, often 

 covered with spines, and also 

 amorphous granules (Fig. 32). 



