488 



A MANUAL OF PHYSIOLOGY 



600 parts, or cri6 per cent. If the interval is longer or shorter than 

 three minutes, the urine of the first dilution (i to 10) must be diluted 

 less or more than five times until the interval amounts to about 

 three minutes. The total dilution corresponding to a percentage 

 of 0^0033 of albumin is thus known, and the percentage in the 

 undiluted urine can be easily calculated. 



(c) Esbach's Method. Esbach's reagent is made by dissolving 

 10 grammes of picric acid and 20 grammes of citric acid in boiling 

 water (800 or 900 c.c.), and then making up the volume to a litre. 

 The so-called albuminimeter is simply a strong glass tube graduated 

 and marked in a certain way. Fill the tube up to the mark U with 

 the urine. Then add the reagent up to the mark R. Close the tube 

 with the rubber cork, and invert it a dozen times without shaking. 



Set the tube aside for twenty-four 

 hours, then read off the gradua- 

 tion on the tube which corre- 

 sponds with the top of the pre- 

 cipitate. The figures indicate the 

 number of grammes of dry pro- 

 tein in a litre of the urine. Sup- 

 pose the top of the sediment is at 

 4, this will indicate 4 grammes per 

 litre, or 0^4 per cent. The method 

 is of some clinical importance, 

 owing to its simplicity, although 

 it is, of course, not very accurate. 

 13. Sugar (i) Qualitative Tests 

 (a) Trammer's Test (seep. 10). 

 It is to be remarked that some sub- 

 stances present in small amount in 

 normal urine reduce cupric sul- 

 phate e.g., uric acid (present as 

 urates) and kreatinin but al- 

 though a normal urine may thus 

 decolourize the copper solution, it 

 rarely causes so much reduction 

 that a yellow or red precipitate is 

 formed, as is the case in diabetic 

 urine. Glycuronic acid, which may 

 occur even in normal urine in very 

 slight traces (p. 442), also reduces 

 cupric salts, as does alcapton or 

 homogentisinic acid, a substance 

 found hi rare cases in disease (p. 444). If less than 0*5 per cent, of 

 sugar is present in the urine, no precipitate of cuprous oxide will be 

 formed till the urine is cooled. The test may also be performed with 

 Fehling's solution. 



(b) Phenyl-hydrazine Test. This test depends upon the fact that 

 phenyl - hydrazine forms with sugars such as glucose (dextrose), 

 maltose, isomaltose, etc., but not with cane-sugar, characteristic 

 crystalline substances (phenyl-glucosazone, phenyl-maltosazone, etc.) 

 which can be recognised under the microscope., and are distinguished 

 from each other by melting at different temperatures. Phenyl- 

 glucosazone (CjgH^JS^C^) melts at 205 C. To perform the test for 

 dextrose in the urine, proceed thus : Put 5 c.c. of urine in a test- 

 tube, add i decigramme of hydrochlorate of phenyl-lrydrazine and 



FIG. 181. PHENYL-GLUCOSAZONE AND 



PHENYL-MALTOSAZONE CRYSTALS 



(MACLEOD). 



The phenyl-glucosazone crystals are 

 in the upper part of the figure, the 

 phenyl-maltosazone in the lower. 



