| Water | 837·58 | |
| Solid constituents | 162·42 | |
| Urea | 8·27 | |
| Uric acid | Not isolated. | |
| Sugar | 134·32 | |
| Extractive matters, and soluble salts | 20·34 | |
| Earthy phosphates | 0·38 |
“Diabetic urine usually possesses a peculiar smell, which has been compared with that of violets, apples, new hay, whey, horses’ urine, musk, and sour milk. Such comparisons serve only to show how difficult it is to give by description a correct idea of a particular odour. The colour of diabetic urine is generally pale. Sometimes, but not usually until after two or three days, the surface becomes coloured with a whitish film, owing to the development of the sugar fungus, and the penicillium glaucum, and gradually the urine becomes opalescent in consequence of these fungi multiplying in great numbers in every part of the fluid. See Urinary deposits (FUNGI).
“Diabetic urine has a sweet taste, and often numbers of flies are attracted to it, which fact sometimes leads the patient to suspect that the urine is not healthy.”[251]
[251] ‘Kidney Diseases, Urinary Deposits,’ &c., Dr Lionel Beale.
White merino, that has been wet with a solution of bichloride of tin, is also said to form a ready test for sugar in urine.
Albumen in urine may be detected by the nitric acid, or by the heat test. The nitric acid test is performed as follows.—Fill a test tube to about an inch with the urine, then incline the tube and pour in strong nitric acid down the side of the tube, so that the acid sinks to the bottom and displaces the urine, which by reason of its smaller specific gravity rests above it. Let the acid be added till it forms a stratum about a quarter of an inch thick at the bottom.
If the urine contain albumen three layers will be perceptible—one, perfectly colourless, of nitric acid at the bottom; immediately above this an opalescent zone of the coagulated albumen; and, on the top, the unaltered urine.
In his work, ‘Kidney Diseases and Urinary Deposits,’ Dr Lionel Beale directs attention to the very important fact that “two or three
drops of nitric acid to about a drachm of albuminous urine in a test tube will produce a precipitate of albumen which will be dissolved on agitation, while, on the other hand, about half as much strong nitric acid as there is of urine will redissolve the precipitate of albumen, unless the quantity present be excessive. Albumen precipitated by nitric acid is soluble in weak nitric acid, and in a considerable excess of urine, and it is also soluble in strong nitric acid. It is therefore necessary in employing the nitric acid test to add from ten to fifteen drops of the strong acid to about a drachm of the urine suspected to contain albumen.”
Dr Roberts gives the following directions for applying the heat test:—If the urine have its usual acid reaction it becomes turbid on boiling when it contains albumen, and this turbidity persists after the addition of an acid. There are two points to be remembered on using heat alone as a test for albumen. First, that albumen is not coagulated by heat when the urine is alkaline; in such cases, therefore, it is necessary before boiling to restore the acidity by a few drops of acetic acid (carefully avoiding excess). Secondly, when the urine is neutral or very feebly acid, it may become turbid on heating, from precipitation of the earthy phosphates, but turbidity from this cause is easily distinguished from albumen by a drop of nitric or acetic acid, which instantly causes the phosphates to disappear. It may sometimes happen that the patient whose urine is to be submitted to examination for albumen may be taking large doses of nitric or hydrochloric acid. Under these circumstances Dr Bence Jones recommends the addition of ammonia to the urine, nearly to the point of neutralisation.