ELEMENTARY CHEMICAL PHYSIOLOGY 269 



scopically the sediment is usually amorphous, but may exist as 

 biscuit-shaped crystals or as dumb-bells (Fig. 189). 



CHAPTER XVII 

 PATHOLOGICAL URINE 



Proteins in the Urine Albuminuria. Traces of mucin or 

 nucleo -protein may be added to the urine in its passage along the 

 urinary tract, but otherwise healthy urine does not contain any 

 protein. When the kidneys or urinary passages are diseased, 

 however, a certain amount of the plasma proteins leaks into the 

 urine, where they can be recognised by certain tests, the condition 

 being called Albuminuria. 



Also when proteins other than serum albumin and globulin gain 

 access to the blood, they are at once excreted in the urine. It is on 

 this account that albuminuria results after the consumption of a 

 large number of raw eggs (egg flip) because the intestinal epithelium 

 allows a certain amount of the unchanged protein to pass into the 

 blood, where it is foreign (in being egg- and not serum-albumin), 

 and is consequently excreted by the kidneys. In certain diseases 

 of bone, a substance somewhat similar in its reactions to a 

 proteose is added to the blood and is excreted by the urine 

 (Bence Jones' proteosuria). 



Although globulin may occur along with albumin in the urine, or 

 even in some cases independent of it, it is of no practical importance 

 to distinguish between them, so that the tests about to be described 

 include both bodies. 



The tests employed depend on certain of the reactions described 

 under proteins. It is obvious that the colour reactions will not be 

 applicable to the urine ; those employed depend on the production 

 of coagula. The most important of these are : 



EXPERIMENT I. Heat Coagulation. Place some clear urine in a 

 test tube, and boil. A white turbidity or coagulum indicates the 

 presence of either albumin or phosphates (earthy phosphates are 

 precipitated by boiling). To the boiling solution, whether it show a 

 turbidity or not, add 3-4 drops of concentrated nitric acid. If due 

 to phosphates, the turbidity will disappear, but will remain if due 

 to protein. In nitric acid any acid- or alkali- albumin which the 

 urine may contain is insoluble. Where there is doubt as to the 

 occurrence of a haze, the test tube should be about three-quarters 

 filled, and only the upper layer should be boiled, the test tube 

 being meanwhile held low down. By holding it against a dark 

 background the slightest haze becomes very evident by this method, 

 on account of contrast with the unboiled layer beneath. 



EXPERIMENT II. Heller's Test. Place some clear urine in a test 

 tube. Hold the test tube in a slanting position, and allow con- 

 centrated pure nitric acid to run very slowly down the side, so that it 



