URINE. 



353 



Pus Cells. Pus corpuscles or leucocytes are present in extremely 

 small numbers in normal urine. Any considerable increase in the 

 number, however, ordinarily denotes a pathological condition, gen- 

 erally an acute or chronic inflammatory condition of some portion 

 of the urinary tract. The sudden appearance of a large amount of 

 pus in a sediment denotes the opening of an abscess into the urinary 

 tract. Other form elements, such as epithelial cells, casts, etc., 

 ordinarily accompany pus corpuscles in urinary sediment and a 

 careful examination of these associated elements is necessary in 

 order to form a correct diagnosis as to the origin of the pus. Pro- 

 tein is always present in urine which contains pus. 



FIG. 106. 



Pus CORPUSCLES. (After Ultzmann.) 



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

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



The appearance which pus corpuscles exhibit under the micro- 

 scope depends greatly upon the reaction of the urine containing 

 them. In acid urine they generally present the appearance of 

 round, colorless cells composed of refractive, granular protoplasm, 

 and may frequently exhibit amoeboid movements, especially if the 

 slide containing them be warmed slightly. They are nucleated 

 (one or more nuclei), the nuclei being clearly visible only upon 

 treating the cells with water, acetic acid or some other suitable 

 reagent. In urine which has a decided alkaline reaction, on the 

 other hand, the pus corpuscles are often greatly degenerated. They 

 may be seen as swollen, transparent cells, which exhibit no granular 

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