129 



LESSON XII 

 PATHOLOGICAL UBINE 



1. TJrine A is pathological urine containing albumin. It gives the usual 

 proteid tests. The two following are most frequently used in practice. 



(a) Boil the top of a long colmnn of urine in a test-tube. If the urine is 

 acid, the albumin is coagulated. If the quantity of albimiin is small, the 

 cloudiness produced is readily seen, as the unboiled urine below it is clear. 

 This is insoluble in a few drops of acetic acid, and so may be distinguished 

 from phosphates. If the urine is alkaline, it should be first rendered acid with 

 a Uttle dilute acetic acid. 



(6) Heller's Nitric-Acid Test. — Pour some of the urine gently on to the 

 surface of some nitric acid in a test-tube, A ring of white precipitate occmrs 

 at the junction of the two Uquids. This test is used for small quantities of 

 albumin. 



If the urine is cloudy, it should be filtered before applying these tests. 



2. Estimation of Albumin by Esbach's Albominometer. — Esbach's reagent 

 for precipitating the albumin is made by dissolving 10 grammes of picric acid 

 and 20 grammes of citric acid in 800 or 900 c.c. of boiling water, and then 

 adding sufficient water to make up to a litre (1,000 c.c). 





Fig. 53. — Albaminometer of Esbacfa. 



Pour the urine into the tube up to the mark U ; then the reagent up to 

 the mark K. Close the tube with a cork, and to ensure complete mixture 

 tilt it to and fro a dozen times without shaking. Allow the corked tube to 

 stand upright twenty -four hours ; then read off on the scale the height of the 

 coagulum. The figures indicate grammes of dried albumin in a Utre of mine. 

 The percentage is obtained by di^-iding by 10. Thus, if the coagulum stands 

 at 3, the amount of albumin is 3 grammes per litre, or 0-3 gr. in 100 c.c. K 

 the sediment falls between any two figures, the distance ^, i, or f from the 

 upper or lower figure can be read off with sufficient accuracy. Thus the 

 surface of the sediment being midway between 3 and 4 would be read as 3-5. 

 "When the albumin is so abundant that the sediment is above 4, a more 

 accurate result is obtained by first diluting the urine with one or two volumes 

 of water, and then multiplying the resulting figvure by 2 or 3, as the case may 

 be. If the amount of albumin is less than O'Oo per cent., it cannot be accu- 

 rately estimated by this method. 



3. TIrine B is diabetic urine. It has a high specific gravity. The presence 

 of sugar is shown by the reduction (yellow precipitate of cuprous oxide) that 

 occurs on boiling with Fehling's solution. FehUng's solution is an alkaline 

 solution of copper sulphate to which EocheUe salt has been added. The 

 Eoehelle salt (double tartrate of potash and soda) holds the cupric hydrate in 



