THE URINE. 789 



without any of the named features. This form of diabetes has 

 110 clinical significance. Not any of the tests for sugar taken 

 alone are entirely reliable, and for a thorough determination of 

 its presence several methods must be resorted to. 



Tests for Sugar, (a) Moore's Test. Pour into a test-tube two volumes of 

 urine and one volume of hydrate of potassa, and heat to boiling. Phosphates, 

 if precipitated in a larger quantity, must be filtered off. When the fluid 

 becomes hot, according to the amount of sugar present, a lemon-yellow, a 

 yellowish-brown, or a blackish-brown color appears. By addition of a few 

 drops of nitric acid the liquid loses its dark color and gives out an odor like 

 molasses. The addition of KOH to cold urine may produce a dark color, which 

 is due to the presence of coloring matters of the biie. 



(b) Bottger's Test. Pour into a test-tube two volumes of urine and one 

 volume of KOH ; add subnitrate of bismuth in a quantity held by the point 

 of a pen-knife and heat for a short time. If sugar is present, it reduces the 

 bismuth salts to the black suboxide of bismuth. Small quantities of sugar 

 will render the bismuth salts slightly gray. Albumen must be eliminated by 

 boiling and filtration, if present in larger quantities. 



(c) Trommer's Test. Pour two volumes of urine into a test-tube, and add 

 one volume of KOH or NaOH (solution 1:3); add, drop by drop, a solution 

 of sulphate of copper (solution 1 : 10), and shake until the mixture shows a 

 blue color. Heat the mixture, without boiling : if sugar is present, the 

 copper-salt is reduced in such a way that at first yellow cuprous hydroxide, 

 and afterward a red sediment of cuprous oxide is formed. Albumen, if 

 present in large quantities, must be removed first by coagulation and after- 

 ward by filtration. The yellow color of the mixture alone indicates either a 

 small quantity of sugar or an excess of urates. Mucus in large quantities 

 also reduces the sulphate of copper in the same manner as sugar. If no 

 sugar is present, the mixture assumes a dirty grayish-green, and no red pre- 

 cipitate appears at the bottom. 



(d) An approximate estimation of the amount of sugar present, which is 

 not admissible by simply considering the specific gravity, may be made by 

 the method of Vogel of boiling two volumes of urine with one volume of 

 KOH. A one per cent, solution of sugar assumes a canary-yellow ; a two 

 per cent, solution a dark amber ; a five per cent, solution a brown-red color, 

 the liquid remaining transparent ; while a ten per cent, solution is rendered 

 dark brown and opaque. 



(e) Roberts' Fermentation Test. Into each of two bottles one of four 

 ounces, the other of twelve ounces capacity four ounces of the urine are 

 poured. A piece of fresh yeast, the size of a walnut, is added to the urine 

 in the larger bottle, which is closed with a cork nicked for the escape of gas 

 evolved by fermentation. The smaller bottle is tightly corked, and the two 

 bottles are placed side by side in a uniform temperature of 68 to 75 F. 

 At the end of twenty-four hours the subsidence and clearing off of the scum 

 from the urine in the larger bottle will announce the completion of the fer- 

 mentation. The specific gravity of each specimen is carefully taken by an 

 accurate uriiiometer, when any difference of specific gravity will indicate 

 sugar, and the number of degrees of difference the number of grains per fluid 

 ounce. For example, if the specific gravity of the unfermented urine is 



