258 THE AMERICAN MONTHLY [Sept. 



wool, cotton, silk, wood, etc., are likely to gain entrance, 

 so it is of the utmost importance that the observer be 

 familiar with the appearance of all such common objects 

 before deciding upon the character of the urinary de- 

 posit. 



With a pipette, which has been carefully cleansed and 

 sterilized, a small drop of the deposit is placed on the 

 center of the slide and covered with a thin glass. If too 

 much fluid has been dropped to hold the cover-glass in 

 place, the slide should be put aside for a little while or 

 until sufficient evaporation has taken place to permit it 

 to be turned on its edge without slipping the cover. 

 Care should be taken that no pressure is made upon the 

 cover, lest the object to be studied be unduly compressed. 

 It is really necessary sometimes, especially when the de- 

 posit contains renal casts of large size, to give support 

 to the cover-glass to prevent compression. This may be 

 easily accomplished by placing on either side of the drop 

 a bit of a fine hair, say a half inch in length, which will 

 answer instead of a shallow cell, if not better. If the 

 sediment is stained before the drop is placed on the slide 

 it will greatly facilitate the examination. To do this 

 take a pipetteful of the sediment and transfer it to a 

 small vial, add a drop or two of the aqueous solution of 

 saf ranin and shake for a few moments. This stains all 

 organized matter. 



Epithelial Cells. — Although much has been said 

 about the different kinds of urinary epithelium, there is 

 not difference enough to say of a certainty that this flat- 

 tened, tesselated form comes from the renal pelvis (fig. 

 1 a, healthy, b, fatty), or that, that flattened or pyriform 

 cell is from the bladder (Fig. 2), for unfortunately in 

 practical work there is no such sharj* distinction ; but it 

 is true that the superficial layers of the mucous mem- 

 brane furnish epithelial cells of polygonal or elliptical 

 shape with a single large nucleus and granular proto- 



