Healthy urine is perfectly clear when it is first passed, although it may present, on standing for some time, a slightly clouded appearance. In various diseases, however, which are greater or lesser departures from health, the urine contains, after standing, a sediment which varies in color and character according to various circumstances which we will not now explain. On examination by means of various chemical tests and the microscope, this sediment is found to be composed, in the majority of cases, of one or more of the following substances: Uric acid, urates, phosphates, oxalate of lime, blood, mucus, pus, or matter, epithelium, and casts.

Each one of these we will notice briefly.

Pus in the Urine

Fig. 328. The occurrence of pus in the urine is indicated by a deposit which closely resembles that of phosphates, but which does not dissolve when heated with acids, as does the lat ter deposit. It sometimes has a ropy or stringy appearance. It is due to decomposition in the bladder. It indicates the presence of inflammation or ulceration in the kidneys, bladder, or urinary passages. It is a very serious symptom, to which intelligent medical attention should be called at once.

Fig. 328. Pus Cells.

Fig. 328. Pus Cells.

Bloody Urine or Hematurea

Blood in the urine, or hematurea, is indicated by a deep brown, reddish, smoky, or even black appearance. It may be produced by hemorrhage from the kidneys, bladder, or urinary passages. It often occurs in Bright's disease and catarrh of the bladder.

Casts and Epithelium

Figs. 329 to 331. When present in great abundance, casts and epithelial cells form a white, flocculent deposit after the urine has been allowed to stand for some time. They cannot be distinguished, however, without the use of the microscope.

Epithelium in great abundance indicates catarrh of the bladder. Casts of the small tubes of the kidneys indicate Bright's disease.

Fig. 329. Epithelial Casts.

Fig. 329. Epithelial Casts.

Fig. 330. Granular Casts.

Fig. 330. Granular Casts.

Fig. 331. Hyaline Casts.

Fig. 331. Hyaline Casts.

Chylous Urine

A milky appearance of the urine sometimes occurs in consequence of the very abundant deposits of pas or phosphates It is also caused, in some cases, by the presence in the urine of chyle, which is supposed to be occasioned by the filaria, a parasitic worm which infests the blood-vessels and lymphatics, causing rupture of the latter into the urinary passages, an affection which is almost wholly confined to tropical countries.