68 ORGANIC CONSTITUENTS. 



of urine can be readily detected ; and even wlien mixed with 

 2000 parts the indications arc tolerably distinct. 



According to Dr. G. Bird, the presence of albumen causes the 

 acid to yield a tint nearly resembling that produced by sugar. 



c. Moore's test depends on the conversion of diabetic sugar 

 into brown melassic (or perhaps sacchulmic acid) under the in- 

 fluence of a caustic alkali. Place in a test tube about two 

 drachms of the suspected urine, and add nearly half its bulk of 

 liquor potassa. Heat the mixture over the spirit-lamp, and 

 allow it to boil for a minute or two ; the previously pale urine 

 will become of an orange-brown or even bistre tint, according 

 to the proportion of sugar present. This reaction has been long 

 known, but Mr. Moore deserves the credit of bringing it pro- 

 minently forward. 



d. Trommer's test. Add to the suspected urine contained 

 in a large test tube, a few drops of a solution of sulphate of 

 copper ; a very inconsiderable troubling generally results, pro- 

 bably from the deposition of a little phosphate of copper. 

 Sufficient liquor potasses should then be added to render the whole 

 strongly alkaline ; a grayish green precipitate of hydrated oxide 

 of copper falls, wdiich, if siigar be present, wholly or partly re- 

 dissolves in an excess of the solution of potash, forming a blue 

 liquid, not very unlike the blue ammoniuret of copper. On 

 gently heating the mixture nearly to ebullition, the copper falls 

 in the state of suboxide, forming a red and copious precipitate. 

 If sugar is not present, the copper is deposited in the form of 

 black oxide. 



This test is founded on a fact long known, but not pre^dously 

 applied to the detection of sugar, of the power possessed by 

 some organic matters of reducing oxide of copper, as well as 

 some other oxides, to a lower state of oxidation. It certainly 

 is the most delicate of all the chemical tests hitherto proposed 

 for the detection of sugar in the urine, and will readily detect 

 it in diabetic urine, even when very largely diluted. 



It is important in using this test that no more of the solution 

 of sulphate of copper be used than is sufficient to afford a de- 

 cided precipitate on the addition of the liquor jwtassa. If 

 this precaution be not attended to, a part only of the black oxide 

 will be reduced to red suboxide, unless a very large quantity of 

 sugar is present, and thus the indications afforded by this test 

 will be rendered indistinct. 



