72 CLINICAL MICROSCOPY AND DIAGNOSIS. 



2. The anatomical sediments consist of cellular ele- 

 ments derived from the urinary passages or from the 

 blood. They consist of various forms of epithelium, 

 tube casts, pus cells and blood. In all normal urines a 

 few epithelial cells, (usually derived from the bladder) 

 are found. As a rule, too, a few leucocytes (polymor- 

 phonuclear) can be seen. Apart from these constitu- 

 ents, the presence of other elements means some lesion 

 of the urinary tract. 



(a) Epithelium may be derived from, 



Kidney ; 



Renal pelvis and ureter; 

 Bladder and urethra; 

 (Vulva and vagina.) 



There are no positive differential features between 

 the epithelium from these parts, but as a rule the cells 

 are fairly characteristic. A diagnosis cannot be based 

 on the presence of epithelium alone, such features as 

 albuminuria or pyuria having always to be considered. 



(6) Tube casts are characteristic of lesions of the 

 renal parenchyma. We find various forms of these casts 

 depending on the intensity and nature of the lesion. 



Tube casts may be epithelial, granular, fatty, hyaline, 

 waxy, uratic, or consist of blood cells. 



(c) Blood may be derived from any part of the urin- 

 ary tract. Note mu§t be taken of the presence of clots, 

 the nature of the admixture with urine and the presence 

 of ureteral or true blood casts, in determining the 

 source of the haemorrhage. 



