BAIBD &WLOCK. (LONDON) LTD. 



5808-5809 



5808* 



with one 



11 

 11 



15 

 15 



Polariscope, half-shadow, Mitscherlich, with divided circle reading to o.i c 



each patent tubes 100 and 200 millimetres long, and gas lamp 

 5809 T Polariscope, as above, with two tubes 94.7 and 189.4 millimetres long 



This is a cheap form of polariscope which has been specially designed for the estimation of sugar and albumen in urine. 



Behind the analyser is a small telescope, and behind the polariser a semicircular plate of quartz. The telescope is focusse 

 on to this plate, and the field of vision appears as a circle divided into two halves as shown in the figure above. A pointer i 

 attached to the analyser, which moves to the right or left on a metal disc divided into angular degrees. A vernier upon whic 

 ten divisions correspond to nine divisions of the disc enables the observer to read tenths of an angular degree 

 estimate twentieths. 



In the annexed figure the zero point of the vernier is not quite at 3 on the scale of the disc, and the eighth division of 1 

 vernier is the only one which coincides with a division of the scale consequently the reading is 2.8. 



The instrument is constructed for homogeneous light. A sodium lamp must therefore be used as the source of illumination 

 The zero point, as in other half-shadow instruments, is found when both halves of the field are of the same tint. 



The tube filled with the liquid to be examined is placed in the instrument, and after having focussed the plate by means i 

 the telescope, the pointer is turned to the right or left according to whether the solution is dextro or laevo rotatory, until both 

 halves of the disc are again equally tinted. 



If the instrument is to be used for general work, a tube of the length of 200 millimetres is supplied, and another of too milli- 

 metres for dark coloured solutions, but when used exclusively for urine it is more convenient to have one of 189.4 millimetres, 

 and another of half that length. These tubes give at once the percentage by volume of sugar and albumen, each degree being 

 equal to i gramme in 100 cubic centimetres. Albumen polarises to the left to the same extent as glucose does to the right. 



The estimation of sugar and albumen in urine is effected in the following manner : -The urine, if necessary, is filtered. Should 

 it be too dark coloured to be read in the long tube, the short one is tried, and if still too dark, some extracted animal charcoal 

 is added, and the whole well shaken. In the event of this not effecting decolorisation, 100 cubic centimetres of the urine is intro- 

 duced into a flask graduated to contain 100 and no cubic centimetres, basic acetate of lead is added to the no cubic centimetre 

 mark, the mixture is then shaken and filtered, and the reading multiplied by o.i i to correct for dilution. The temperature should 

 be 15 to 20 C. If the urine is free from albumen the reading corresponds to the percentage of sugar. Should it contain albumen, 

 a few drops of acetic acid are added to 100 cubic centimetres boiled, cooled, filtered, and made up again to volume at 15 to 20 C. 



EXAMPLES. 



1. A clear urine free of albumen read 3.1 in the 189.4 millimetre tube. Sugar = 3.i per cent. 



2. A clear urine free of albumen read 1.6 in the 94.7 millimetre tube. Sugar = 1.6x2 = 3.2 per cent. 



3. Urine brown, no albumen, taken 100 cubic centimetres+io cubic centimetres lead solution, tube 189.4 millimetres. 

 Reading 2. 8, sugar 2.8x0.11 = 3.08 percent. 



4. Urine brown, no albumen, taken 100 cubic centimetres+io cubic centimetres lead solution, tube 94.7 millimetres. 

 Reading 1.4, sugar 1.4x2 xo.n = 3.o8 per cent. 



5. Urine slightly coloured with albumen tube 189.4 millimetres. 



(a) Direct reading 0.6 



(b) After removal of albumen reading o. 

 Therefore sugar o per cent., albumen 0.6 per cent. 



6. Urine clear, slightly coloured, containing albumen tube 189.4 millimetres 



(a) Direct reading 2.6. 



(b) After removal of albumen 3.1. 

 Therefore sugar 3.1 per cent. 

 Albumen 3.12.6 = 0.5 per cent. 



CROSS STREET HATTON GARDEN, E- C 



1056 



