460 



PHYSIOLOGY. 



allowed to proceed for twenty-four hours before any readings are 

 taken. 



Proteoses are detected by the precipitates produced by nitric and 

 salicyl-sulphonic acids clearing up on heating the urine and return- 

 ing on cooling. 



SUGAR. While it is known that normal urine may contain 

 traces of sugar,, attention is required with the sugar that occurs in 

 excess, especially from the disease known as diabetes mellitus. 



In the first place, diabetic urine is abnormal in amount, even 

 reaching 10 liters a day. It has a high specific gravity, and is of a 



Fig. 176. Crystals of Phenylglucosazone. (PuRDY, after v. JAKSCH.) 



pale and greenish yellow, so that sugar may be suspected at once; 

 when the increased density is due to urea the urine is intensely red- 

 dish. However, it must be remembered that the nitrogenous excreta 

 are also increased. 



The sugar present is in the form of dextrose, or grape-sugar. It 

 is increased with a carbohydrate diet and diminished with one that 

 is nitrogenous. Upon standing, there are developed in diabetic 

 urine torulce. 



Fehling's Test. Eesults are obtained by the use of Fehling's 

 solution. This is an alkaline solution of -copper sulphate to which 



