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DISEASES OF THE URINARY APPARATUS. 



litus). The demonstration of sugar in the urine may be made in 

 different ways : 



1. By four reduction tests, a. Trommer's test : by means of 

 carbonate of soda and a solution of sulphate of copper (Fehling's 

 liquor) ; by heating, a red coloration is produced, due to the forma- 

 tion of peroxide of copper, h. Bottger's method : the urine, con- 

 taining soda, must be boiled (carbonate of soda or Seignette salts 

 are advised by Almén), on adding a pinch of subnitrate of bismuth 

 a black coloration is obtained, due to the reduced metallic bismuth, 

 c. Salkowski's method : heat the urine with an ammoniacal solu- 

 tion of chloride of silver ; we obtain a black precipitate of reduced 

 silver, d. Indigo test : heat the urine with soda and indigo-blue 

 carmine, a yellow coloration is produced as a consequence of the 

 reduction of blue or yellow indigo. 



As reagents for grape sugar, we must also mention : 



1. Picric acid, sulphodiazobenzolic acid (Penzoldt), sugar of lead 

 (Rubner), acetate of lead, phenylhydrazin and acetate of soda (of 

 Jaksch). 



2. The fermentation test : urine which contains grape sugar gives 

 carbonic acid and alcohol when yeast is added to it ; the respective 

 quantity of these two products permits us to easily obtain the quan- 

 tity of sugar. 



3. The optical method, or polarization : grape sugar produces a 

 •deviation to the right of the polarization ray. 



4. Moor's test : the urine becomes brown when it is boiled with 

 carbonate of potash (caramel formation at the expense of grape 

 sugar). 



V. Indican. Indican (indoxylo-sulphate of potash) comes from 

 indol, which is formed in the small intestine by pancreatic diges- 

 tion ; in minute proportion it forms a normal principle of the urine. 

 The excretion of indican by the urines is increased in all affections 

 which are accompanied by paresis of the intestine, abnormal fer- 

 mentations, and in the conditions of consumption and inanition. 

 The normal quantity of indican in the horse's urine is 0.15 gramme 

 per litre ; in the urine of the dog fed on meat there is found about 

 0.01 gramme ; in a dog the small intestine of which was ligated, 

 Jaffé has found 0.043 gramme of indican per litre of urine. 



The presence of indican is revealed by Jaffé's method (for the 

 horse's urine the operation is easy) ; we add to the urine an equal 

 volume of commercial hydrochloric acid and containing a few drops 



