The best and most modern methods of the examination of urine as required in medical practice / by W. Henry Kesteven.

  • Kesteven, W. Henry (William Henry)
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The best and most modern methods of the examination of urine as required in medical practice / by W. Henry Kesteven. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    6/20 (page 6)
    oxide in nitric acid. Evaporate this solution to the con- sistence of a syrup, and dilute it to one litre with distilled water (each cubic centimetre of solution thus made is equivalent to o.oi grammes of urea). Saturated solutions of barium hydrate and barium nitrate. Bicarbonate of soda papers. Some crystals of silver nitrate. A Mohr’s burette holding 50 cubic centimetres. Two or three precipitating glasses. Small evaporating dish. Funnel. Filter papers. A 10 cc. measure. The modus opera7idi is as follows : To 20 cc. of the urine add 10 cc. of saturated solution of barium nitrate, and 10 cc. of saturated solution of barium hydrate. These pre- cipitate the sulphates and phosphates. The whole should then be filtered. The chlorides must then be precipitated by adding to the filtered liquid a small crystal of silver nitrate. 20 cc. of the fluid thus treated (= xo cc. of urine) should be then placed in the evaporating dish or shallow vessel, and the solution of mercuric nitrate which has been previously placed in the burette allowed to drop, one cubic centimetre at a time, into it from the burette. After the addition of each cubic centimetre a drop of the fluid under examination should be placed upon paper soaked with solution of sodium bicarbonate. Immediately one of these drops show a yellow tint on the paper, the operation should be stopped, and the amount of the solution of mercuric nitrate used should be read off. The yellow colour on the paper shows that all the urea in the 10 cc. of urine con- tained in the shallow vessel has been precipitated, and that there is now no more to prevent the mercuric nitrate producing its characteristic effect upon the soda paper—/.<?., from combining with the soda, and so forming the yellow colour seen. To calculate the amount of urea per 1000 contained in the specimen under examination, it is only necessary to muliiply the number of cubic centimetres of solution of mercuric nitrate used by 100. For each cubic centimetre of the solution of mercuric nitrate is equivalent to 0.01 grammes of urea. If 25 cc. of mercuric nitrate solution have been used, the calculation is as follows : 25 cc. mercuric nitrate solution='25 grammes in 10 cc. of urine .25 x 100 = 25 grammes contained in 1000 cc. So that simply reading off the number of cubic centimetres shown by the burette to have been used, will give the