346 PHYSIOLOGICAL CHEMISTRY 



is convenient to arrange a tile with several drops of ferro- 

 cyanide before beginning the titration. The first appearance 

 of brown is taken as the end point. Calculate the weight of 

 P 2 5 represented by the phosphates in 50 c.c. of urine, and 

 from this the amount in the 24 hour sample. Calculate what 

 weight of phosphorus this represents. 



Pathologic Urine 



Some substances occur in pathological urine which are 

 absent from, or found only in traces in normal urine. Im- 

 portant among these substances are various proteins, carbohy- 

 drates, and the acetone bodies. 



Proteins. The proteins most frequently found are albu- 

 min, globulin, nucleo-protein, hemoglobin, glycoprotein; of 

 the protein derivatives, metaproteins, proteoses, peptones and 

 amino acids. 



As turbidity would interfere with the detection of small 

 amounts of protein, the urine should be clear before testing. 

 If necessary, filter, repeating the filtration and adding a 

 small amount of bismuth subnitrate if the filtrate did not 

 come through clear. If the urine still remains cloudy, add 

 a drop or two of barium chloride and then a drop or two of 

 sodium carbonate solution. Barium carbonate precipitates 

 and carries down with it the suspended material. 



ALBUMINS AND GLOBULINS. 



45. H&at Test. The heat test should be made in acid solu- 

 tion, as only in a weak acid solution will the proteins coagu- 

 late properly on boiling. The urine should be tested with 

 litmus and acidified if necessary with 0.5% acetic acid. Even 

 if the urine is acid, it is well to add a few drops of dilute 

 (0.5%) acetic acid to insure coagulation of proteins possibly 

 present. 



Boil a few cubic centimeters of acidified urine. If no pre- 

 cipitate forms, albumin and globulin are absent. If it becomes 

 cloudy or a precipitate forms, albumin or globulin is present. 



