494 A MANUAL OF PHYSIOLOGY 



of A for the urine is i'62o. Since for most purposes it is sufficient 

 to fix the second decimal point, much smaller and less expensive 

 thermometers than the ordinary Beckmann may be employed. 



In the same way the freezing-point of blood-serum (or blood), bile, 

 and other physiological liquids can be determined. 



Systematic Examination of Urine. In examining urine, it is con- 

 venient to adopt a regular plan, so as to avoid the risk of overlooking 

 anything of importance. The following simple scheme may serve as 

 an example ; but no routine should be slavishly followed, the object 

 being to get at the important facts with the" minimum of labour. 

 More extensive information must be sought in the treatises on 

 examination of the urine for clinical purposes. 



1. Anything peculiar in colour or smell ? If the colour suggests 

 blood, examine with spectroscope, haemin test, guaiacum test (pp. 65, 

 68, 71) ; if it suggests bile, test for bile-pigments by Gmelin's test 

 (p. 431), and for bile-salts by Pettenkofer's test (p. 430) and by Hay's 

 test (pp. 430, 491). 



2. Reaction. 



3. Sediment or not ? Sediment may be procured by letting the 

 urine stand in a conical glass, or in a few minutes by the centrifuge. 

 If the appearance of the sediment suggests anything more than a 

 little mucus, examine with the microscope. The sediment may 

 contain organized or unorganized deposits. 



Organized Sediments. (a) Red blood-corpuscles (considerably 

 altered if they have come from the upper part of the urinary tract) . 



(b) Leucocytes. A few are present in health. A large number 

 indicates pus. When pus is present the sediment may be white to 

 the naked eye. 



(c) Epithelium from the bladder, ureters, pelvis of the kidney or 

 the renal tubules. A few squamous epithelial cells from the urethra 

 are always present in normal urine. 



(d) Tube casts. 



(e) Spermatozoa (occasional). 

 (/) Bacteria. 



(g) Parasites (rare). 



(h) Portions of tumours (rare). 



Unorganized Sediments. 



IN ACID URINE. 



Uric Acid. Crystals coloured 

 brownish - yellow with urinary 

 pigment. Various shapes, espe- 



IN ALKALINE URINE. 



Triple Phosphate. - - Clear, 

 colourless, coffin-lid or knife-rest 

 crystals. Also deposited in the 



cially oval 'whetstones,' rhom- I form of feathery stars (Fig. 162). 



bic tables, and elongated crys- ! Calcium Hydrogen Phosphate 



tals, often in bundles (Fig. 1 60). j ('stellar' phosphate), CaHPO 4 . 



~U rates. Usually amorphous, \ Crystals often wedge-shaped 



in the form of fine granules, j and arranged in rosettes. May 

 often tinged with urinary pig- 



ment, sometimes brick-red. 

 Soluble on heating. On addition 

 of acids (including acetic acid) 

 they dissolve and uric acid 

 crystals appear in their place. 

 Acid urate of sodium and of 



also occur in a dumb-bell form. 

 (A phosphate of calcium is also 

 occasionally seen in weakly acid 

 urine.) (Fig. 164, p. 439.) 



Calcium Phosphate, Ca 3 (PO 4 ) 2 . 

 Amorphous. 



Magnesium Phosphate. Long 



