The Urinel j 219 



require a tedious isolation which can only be carried out in 

 a laboratory. 



For all the above observations filtered urine should be 

 used. 



To obtain deposits for microscopical examination, the 

 unfiltered urine is placed in a glass and allowed to stand 

 for some hours ; the deposit may be taken up with a 

 pipette and placed on a slide. 



In this way red blood corpuscles, pus, casts, epithelium, 

 etc., may be readily determined. The inorganic deposits 

 of healthy urine are carbonate of lime in beautiful large 

 wheel-shaped, dumb-bell, or rosette crystals (Fig. 18), and 

 oxalate of lime (Fig. 17), in unmistakable octohedra or 

 square envelope-shaped crystals, insoluble in acetic acid, 

 carbonate of lime being soluble. Occasionally considerable 

 quantities of oxalate crystals are formed ; they are nearly 

 always very small in size, though sometimes large. If the 

 urine be very alkaline from standing, quantities of the large 

 tombstone or coffin lid crystals of ammonio- magnesium 

 phosphate are found; they can be readily seen by the 

 naked eye as glistening glass-like masses (Fig. 19). 



Such are the common crystals found in normal urine. 



