URINE. The properties of urine vary considerably, according to the constitu tion and health of the body, and the pe riod when it is voided after taking food. The urine of a healthy person is of a light orange colour, and unifitrmly transparent. It has a slightly aromatic odour, in some degree resembling that of violets. It has a slightly acrid, saline, bitter taste. The specific gravity varies from 1.005 to 1.033. The aromatic odour, which leaves it as it cools, is succeeded by what is called the urinous smell, which latter is converted to another, and, finally, to an alkaline odour. Urine converts the tincture of turnsole into a green colour, from which it is concluded that it contains an acid. No less than thirty different substances have been detected in urine by chemical analysis; viz. a great variety of salts, acids, ammonia, &c.
Urine is much disposed to spontaneous decomposition. The time when this pro cess commences, and the rapidity of the changes which take place, depend on the quantity of the gelatine and albumen.
When the proportion of these substances is considerable, the decomposition is very rapid. This is owing to the great number of substances, and the united force of their attractions overcoming the existing affinities of the different compounds of which fresh urine consists, and especially to the facility with which urea is decom posed. This substance is converted dur ing putrefaction into ammonia, carbonic acid, and acetic acid. Hence the smell of ammonia is always recognized while urine is undergoing these changes. Part of the gelatine is deposited in a flaky form, mixed with mucilage. Ammonia combines with phosphoric acid, and the phosphate of lime is precipitated. It com bines also with phosphate of magnesia, and forms a triple salt. The other acids, the uric, benzoic, the acetic, and carbon ic acids, are all saturated with ammonia.
See PHYSIOLOGY.