Stst^l^l 



BY B^L^UDEE BRUNTON/ 665 



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color. These appearances prove that a slight excess of sugar 

 solution has been added. The number of cubic centimetres of 



diluted urine added is again read off. If the arithmetic mean 

 of the first and second results be now taken, a number will be 

 obtained which represents, very accurately, the volume of the 



dilute urine, in cubic centimetres, which was capable of re- J 



ducing the whole of the copper in ten cubic centimetres of 

 the standard solution employed. Now, as this volume of 

 copper solution is reducible by exactly 0.05 gramme of dia- 

 betic sugar, this quantity must have been present in the 

 volume of diluted urine made use of. An example will render 

 the calculations required intelligible : The urine of a diabetic 

 patient was found* to have a specific gravity of 1035. 100 

 cubic centimetres were placed in a litre flask, and distilled 

 water added until the fluid exactly measured 1000 c. c. Ten 

 cubic centimetres of standard copper solution required 30.49 

 c. c. of the diluted urine in order to be completely reduced, or 

 30.49 c. c. of the'diluted urine contained 0.05 gramme of sugar. 

 As the urine had been diluted to ten times its original bulk, 

 the same volume of the undiluted urine would contain ten 

 times as much sugar, i. <?., 0.5 gramme of sugar. From these 

 data we can easily ascertain how much sugar was passed in 

 the twenty-four hours. 



Thus, if the quantity of urine passed in twenty-four hours, 

 in the case under consideration, amounted to 3000 cubic 

 centimetres, the amount of sugar passed during the same 

 period would be at once found by the following proportion : 



30.49 : 0.5 : : 3000 : X 



=49.19 grammes. 



The student, in carrying out the process just described, must 

 be careful to dilute the urine to a sufficient extent. In cases 

 where the percentage of sugar is very large, it is, for instance, 

 convenient to dilute the urine twenty times instead of ten. 



** 201. Detection of Albumin in Urine. Except in 

 very exceptional cases, which need not be alluded to here, the 

 only albuminous body proper which appears in urine possesses 

 the reaction of serum albumin. Accordingly, when albumi- 

 nous urine is boiled,' tt~w-" found to be coagulable, i. e., the 

 albumin separates in the insoluble form, and the coagulated ^Ct 

 albumin is insoluble in nitric acid. Nitric acid, when added 

 alone to urine containing albumin, likewise precipitates that 

 substance, and the precipitate is not dispelled by heat. It 

 must be stated, however, that in certain cases, when nitric acid 

 produces a mere haze, this may disappear on boiling, although 

 it be really due to a trace of albumin. Albuminous urine 

 possesses the property of rotating the plane of polarization to 

 the left. 



