BY DR. LAUDER BRUNTON. 553 



which cannot be recommended, even on the score of rapidity, 

 as preferable to the one first described. 



** 199. Detection of Sugar in Urine. It is still a mat- 

 ter of doubt whether the urine in health contains sugar; the 

 processes which have'been suggested, for the separation of this 

 substance, by those who maintain its constant occurrence in 

 healthy urine, are, however, complicated ; and, as they have led 

 to veiy various results in the hands of different observers, 

 their consideration would be out of place in this book. (See 

 Pfliiger's Archiv.'fiir Physiol. V. pp. 359 and 375.) 



When present in abnormal quantities in urine, as in diabetes, 

 glucose ma}' be very readily detected. The following experi- 

 ments will be sufficient to make the student acquainted with 

 the more common reactions. 



Experiment 1. Take 5 cubic centimetres of diabetic urine, or 

 of a solution of grape-sugar, and add to it two or three drops 

 of a solution of copper sulphate, so that a very slight green 

 tinge is perceptible; flien add to the fluid a solution of caustic 

 soda, or potash, until the precipitate of hydrate copper oxide, 

 at first formed, is rediss,olved. 



The fluid, which has assumed a blue tint, is now boiled, when 

 an abundant precipitate of cuprous oxide falls ; before this has 

 separated, the fluid in which the precipitation is effected be- 

 comes opaque, and presents a reddish-yellow color. This is 

 known as Trommer's test (xee 77 and 12). 



2. To five cubic centimetres, of urine add nearly an equal 

 volume of a solution of caustic soda, or potash, and boil. The 

 fluid will assume at first a light-yellow, then an amber, and 

 lastly a dark-brown coloration. This is known as More's test. 



3. Some diabetic urine is mixed with a little brewer's yeast. 

 and the mixture is poured into a test-tube half full of mercury ; 

 the orifice of the tube is closed with the thumb, and the tul)e 

 is inverted into a capsule containing mercury. 



After a period of twenty-four hours, at ordinary tempera- 

 tures, the test-tube will be found to contain large quantities of 

 carbonic acid gas, which can be readily absorbed by passing 

 up into the tube a fragment of caustic potash. 



In addition to these tests, the student may with advantage 

 determine, by means of a polariscope, that diabetic urine pos- 

 sesses the property of rotating the plane of polarized light to 

 the right, 



** 200. Determination r.f the Quantity of Sugar in 

 Urine. This may be best effected by one of the two follow- 

 ing methods : firstly, by determining to what extent a known 

 depth of the saccharine fluid rotates the plane of polarized 

 light to the right; or, secondly, by determining the quantity 

 of urine which has to be boiled with a standard solution of 



