ELEMENTAEY PHYSIOLOGICAL CHEMISTRY 



271 





-5 



- -* 

 3 



The reagent, if pure, keeps indefinitely. If impure, however, it turns 

 red on keeping. It has the great advantage over nitric acid in being 

 non-corrosive, and therefore easily carried about (Mac William). 



There are numerous other tests, but their application is superfluous if 

 the above be properly applied. 



Proteoses are detected by the precipitates produced by nitric and 

 salicyl-sulphonic acids clearing up on heating the 

 urine, and returning when it is cooled. The so-called 

 "albumose" in Bence Jones' albumosuria is coagu- 

 lated by moderate heat, but redissolves on boiling 

 the urine. Albumose can best be separated from, 

 albumin by adding salicyl-sulphonic acid, boiling and 

 filtering. The coagulated proteid remains on the 

 filter paper, and the proteose is gradually precipitated 

 in the filtrate as the latter cools. 



Quantitative Estimation of Albumin. For clinical 

 purposes this is done by means of Esbach's albumino- 

 meter (Fig. 163). The determination is made by 

 measuring the depth of the coagulum produced by 

 adding Esbach's reagent to the urine (a mixture of 

 10 grms. picric acid and 20 grms. citric acid in 1000 

 c.c. distilled water). 



EXPERIMENT IV. Place clear urine, filtered if 

 necessary, in an Esbach's tube up to the mark U. 

 If the reaction be alkaline, render slightly acid by the 

 addition of acetic acid, and if the specific gravity be above 1008 

 dilute it with water till this density or something below it is obtained. 1 

 Now add the reagent up to the mark R. Close the tube with 

 a. tightly-fitting cork and invert several times, so as to mix the fluids 

 thoroughly. Allow to stand in an upright position for twenty-four 

 hours, and then read off the graduation corresponding to the top of the 

 precipitate. This gives the number of grammes of dried albumin per 

 litre of urine used. If the urine has been diluted the necessary calcula- 

 tion must be made in order to obtain the percentage in the original 

 urine. 



II. Sugars in the Urine. In the disease known as diabetes mellitus, 

 the most important symptom consists in the detection of dextrose (or 

 glucose) in the urine, or, in other words, of the presence of glycosuria. 

 This condition can also be produced experimentally: (1) By puncture of 

 the floor of the fourth ventricle. The cause of the, glycosuria in this 



FIG. 163. Esbach's 

 albuminometer. 



1 These corrections should be made before the urine is measured into the 

 Esbach's tube. 



