CH. XXXIX.] ALBUMIN AND SUGAR IN URINE 601 



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 little 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 occurs at the 

 junction of the two liquids. This test is used for small quantities of albumin. 



(c) Estimation of Albumin by E shack's Albuminometer. 

 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 suffi- 

 cient water to make up to a litre (1000 c.c.). 



The albuminometer is a test-tube graduated as shown in 

 fig. 387. 



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

 reagent up to the mark R. 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 litre of urine. The percentage is obtained by dividing 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. 



A condition called " peptonuria," or peptone in 

 the urine, is observed in certain pathological states, 

 especially in diseases where there is a formation of 

 pus, and particularly if the pus is decomposed owing 

 to the action of bacterial growths such as staphy- 

 lococcus: one of the products of disintegration of 



j , , . * , , FIG. 387. Esbach's 



pus cells appears to be peptone ; and this leaves the Albuminometer. 

 body by the urine. The term "peptone," however, 

 is in the strict sense of the word incorrect ; the protein present is 

 deutero-proteose. In certain diseases of bone a curious protein 

 passes into the urine. It is called Bence- Jones protein, after its 

 discoverer ; it somewhat resembles hetero-proteose in its properties. 



Sugar. Normal urine contains no sugar, or so little that for 

 clinical purposes it may be considered absent. The conditions in 

 which glycosuria occurs are described on p. 538. 



The sugar present is dextrose. Lactose may occur in the urine 

 of nursing mothers. Lsevulose, pentoses, and other sugars are found 

 but rarely. Diabetic urine also contains hydroxybutyric acid, and 

 may contain and yield on distillation acetone, and aceto-acetic acid. 

 The methods usually adopted for detecting and estimating the sugar 

 are as follows: 



(a) The urine has generally 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. Fehling's solution is 

 an alkaline solution of copper sulphate to which Rochelle salt has been added. The 

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

 solution. Fehling's solution should always be freshly prepared, as, on standing, an 

 isomeride is formed from the tartaric acid, which reduces the cupric to cuprous 

 oxide. Fehling's solution should, therefore, always be tested by boiling before it is 

 used. If it remains clear on boiling, it is in good condition. 



