198 URINARY SEDIMENTS. 



Of the unorganized sediments some are soluble in acid 

 and some in alkaline fluids. Their presence depends, 

 therefore, upon the reaction of the urine. They fall 

 naturally into two classes in accordance with their solu- 

 bility, and may be farther subdivided according to their 

 microscopic appearance. The table on the opposite page 

 gives the most common varieties. 



Before examining the sediment, test with litmus-paper 

 the reaction of the urine in which it is found. Then place 

 a drop of urine containing the sediment on a glass slide, 

 cover with a cover-glass, and examine microscopically 

 with a 1 / 2 - or 2 /3-rnch objective. The microscopic ex- 

 amination should be made before the liquid evaporates and 

 leaves on the slide the soluble compounds. A higher power 

 may be used afterward if necessary, but generally the low 

 power is preferable. Chemical reagents may be applied 

 on the slide after removing the excess of urine by a piece 

 of porous paper. Place one drop of the reagent on the 

 slide by the side of the cover-glass. It will flow under 

 the cover-glass, and its action can be observed with the 

 microscope as it comes in contact with the different sedi- 

 ments. Care should be taken not to allow the reagents 

 to touch the microscope-stage. If a low power is used 

 without a cover-glass these tests may be made in a flat 

 watch-crystal. Where large quantities of a reagent are em- 

 ployed, as in testing pus with an alkali, the ordinary chem- 

 ical vessels are to be used. 



Urine containing pus is turbid when freshly passed, 

 and gives the albumin reactions. When much pus is pres- 

 ent it soon falls to the bottom as a thick sediment. Small 

 quantities may remain suspended for a long time. In urine 

 of an acid reaction the pus-corpuscles can be seen. They 

 are circular and colorless, about twice the diameter of the 



