The Nitric Magnesian Test

It is prepared by mixing one part of pure nitric acid with five parts of a saturated solution of the sulphate of magnesia, and filtering. It is used the same as the former test, and is recommended as a very delicate one, It is one-third more delicate than the pure nitric acid test, showing one part in 150 000, where the latter shows one in 100.000. It also condenses the layer of albumen, so that an estimate of the percentage of albumen present, can be more readily made.

When the urine contains sngar as well as albumen, it must first be boiled to precipitate the albumen, then filtered to separate it, after which the test for sugar may be made. • It is well to remember that sugar or albumen, when discovered in the urine, is not necessarily indicative of fatal disease, such as diabetes or Bright's disease.

Sugar

The detection of sugar in the urine does not always indicate the existence of diabetes or kidney disease.* It is often found after an excess of saccharine or starchy food has been taken, or after the use of chloroform, ether, turpentine, etc. In many diseases there are small quantities of sugar detected in the urine, - in whooping-cough, asthma, epilepsy, softening of the brain, abscesses and tumors of the cerebellum, nervous affections; also in mental grief and shocks, after blows on the epigastrium, in dyspepsia, liver disease, temporary cold, uterine disorders, and in certain hereditary conditions.

*Prof. J. W. draper.

Diabetes is differentiated by a general decline of health, a dry and harsh skin, great thirst, voracious appetite, accompanied by the voiding of large quantities of urine loaded with sugar.

Qualitativei Tests. - Specific Gravity

This usually exceeds 1.030, and if, in addition, a large quantity of urine is voided daily, diabetes may be suspected.

Trommer's Test

In all tests, filter and remove the albumen, which negatives the test. Take a test tube and put in it a drachm or two of urine; add liquor potassa in excess, then slowly add a few drops of a solution of the sulphate of copper, which forms a bluish-white precipitate, the shaking of which produces a characteristic blue fluid. When this precipitate ceases to dissolve, neither reagent can be in excess, and heat may be applied. Next, boil, and when sugar is present a red or orange deposit of the suboxide of copper will be precipitated. Where the solution is added first in excess, some of the blue hydrated oxide of copper may remain unchanged; and if too much liquor potassa be used, it may blacken the sugar.

Caution

"Saccharose," or cane sugar, as when ordinary sugar or molasses is put in the urine, gives a black precipitate with Trommer's test.

A Better Test

The presence of animal sugar forms the red precipitate, but many other organic substances have the same effect. Tartaric acid is one of the substances possessing this property, and yet does not reduce the copper by boiling; it is therefore used in the following test: