MICROSCOPICAL DIAGNOSIS. 55 



has a pale straw color and a high specific gravity. The speci- 

 fic gravity is almost always above 1030 and it may be as high 

 as 1060. Sometimes, however, the specific gravity is below 

 normal ; hence this is no sure guide as to the amount of 

 sugar present. Deposits are rarely observed in diabetic urine. 

 To test for sugar, it should be first ascertained if there is 

 any albumen in the urine. If heat and acid show that no al- 

 bumen is present then apply Trommer's test at once. If albu- 

 men be present then add a few drops of acetic acid to the 

 specimen and boil. Filter, and neutralize the filtrate with car- 

 bonate of sodium and apply the test of Trommer. If the urine 

 has an alkaline reaction then boil it in a test-tube with a 

 small quantity of sodic hydrate or potassic hydrate. Filter and 

 apply Trommer's test to the filtrate. 



Two solutions are necessary to carry out the test of Trom- 

 mer ; a solution of sulphate of copper, ten grains to the ounce, 

 and a solution of caustic potash, of twenty-five per cent, 

 strength. 



A drachm of the urine is placed in a test-tube and three 

 or four drops of the copper solution added; then nearly half 

 as much of the potash solution as there is of urine is added; 

 enough of the potash solution should be added to completely 

 dissolve the precipitate at first formed. The clear blue solu- 

 tion is now heated to the boiling point. If the precipitate be 

 either blue or black it denotes an absence of sugar ; if the 

 precipitate be yellow or brown or brownish-red then sugar is 

 present. 



There are various modifications of Trommer's test. One of 

 the best modifications is that of Fehling. Fehling's solution is 

 made as follows : "69 grains of sulphate of copper are dis- 

 solved in 345 grains of distilled water, to this solution a con- 

 centrated solution of 268 grains of tartrate of potash, and 

 then a solution composed of 80 grains of carbonate of soda 

 in an ounce of distilled water are added ; water is added in 

 sufficient quantity to make 1,000 grains." To use this solution 

 it is only necessary to add about an equal bulk of it to the 

 suspected urine in a test-tube and boil the mixture. If sugar 

 be present a similar precipitate will occur to that from Trom- 

 mer's test. 



