URINE 



467 



tinues the cell outline ceases to be visible, the nuclei fade, and finally 

 only a mass of debris containing isolated nuclei and an occasional 

 cell remains. 



It is frequently rather difficult to make a differentiation between pus 

 corpuscles and certain types of epithelial cells which are similar in form. 

 Such confusion may be avoided by the addition of iodine solution (I in 

 KI), a reagent which stains the pus corpuscles a deep mahogany-brown 

 and transmits to the epithelial cells a light yellow tint. The test pro- 

 posed by Vitali often gives very satisfactory results. This simply 

 consists in acidifying the urine (if alkaline) with acetic acid, then filter- 

 ing, and treating the -sediment on the filter paper with freshly prepared 

 tincture of guaiac. The presence of pus in the sediment is indicated 



FIG. 141. Pus CORPUSCLES. (After Ullzmann.) 



i, Normal; 2, showing amoeboid movements; 3, nuclei rendered distinct by acetic acid; 4, 

 as observed in chronic pyelitis; 5, swollen by ammonium carbonate. 



if a blue color is observed. Large numbers of pus corpuscles are present 

 in the urinary sediment in gonorrhoea, leucorrhcea, chronic pyelitis, 

 and in abscess of the kidney. In addition to the usual constituents 

 found in leucocytes Mandel and Levene 1 claim that pus cells contain 

 glucothionic acid. See Pus tests, page 431. 



Casts. These are cylindrical formations, which originate in the 

 uriniferous tubules and are forced out by the pressure of the urine. 

 They vary greatly in size, but in nearly every instance they possess 

 parallel sides and rounded ends. The finding of casts in the urine is 

 very important because of the fact that they generally indicate some 

 kidney disorder; if albumin accompanies the casts the indication is 



1 Mandel and Levene: Biochemische Zeitschrift, 4, 78, 1907. 



