through it. After drying, it forms a glistening membrane, like its prototype, the mucus on the track of snails. Its diagnosis is always ensured by the number of epithelial cells imbedded in its substance. But should there be any doubt whether there be any mucus in a microscopic specimen or not, the addition of a little dilute tincture of iodine will, by its precipitating and colouring effect upon the mucus, readily decide the question. The admixture of spermatic filaments, oxalate of lime and triple phosphate crystals, phosphate of lime, urate of ammonia, and tubular casts, may be ascertained by the microscope and the respective tests.

Physiological quantity of Mucus.

This depends mainly upon the nature of the urine passing through the bladder. Concentrated urine causes the exudation of more mucus from the bladder; dilute urine, when not altered otherwise, has no such effect. The largest quantity of mucus seems to be secreted during the night, perhaps owing to the concentrated nature of the night urine, or to the irritating influence of its longer retention.

The normal amount of mucus cannot be expressed in figures. It is best to accustom the eye to an estimate by frequent inspection in transmitted light of urine in glass vessels. Any excess at all important will then easily be perceived by the increased bulk of the cloud.

Excess of Mucus.

This may be caused by pathological conditions of the urine, particularly alkalinity from decomposed urea. A large quantity of free acid may have a similar effect. Thus, the strongly acid urine, which is voided by a person on the morning after the night on which larger doses of benzoic acid were taken, exhibits a mucous cloud double the size of that voided under ordinary circumstances.

The Pathological indications

of an excess of mucus must depend upon the causes which produce it. As such, we may mention all conditions which are characterised by irritation of the urinary organs. Pathological conditions of the urine, the presence of foreign bodies and concretions in the bladder, idiopathic diseases of the bladder and its appendages-all these, and some others, may

be indicated in part by an increased amount of mucus in the urine.

When the characteristic symptoms of other defined diseases are absent, and the secretion of an excess of mucus from the bladder is the only characteristic symptom, then it is termed blennorrhoea of the bladder, or cystorrhoea. The pathological conditions of the mucous membrane giving rise to this excessive secretion are probably not always alike; but they are mostly those of catarrh or chronic inflammation, and of venous engorgement, from enlarged vesical veins.

CHAPTER XXIV.

FAT AND OIL.

APART from any accidental admixture of these substances, which we caution the reader to guard against most scrupulously, they may occur in the urine as the products of diseased action in the body or urinary organs in three different forms.

a. As large and small oil-drops, floating on the surface of the urine. Such oil-drops, called oil because they remain fluid at the ordinary temperature of the air, and are salts of oleic acid, I found on the urine, taken from the bladder after death, of a woman who died of chronic purulent nephritis, with fatty degeneration of the left kidney. The oil-drops make a greasy spot appear on paper, and are easily soluble in ether.

b. As granular fat, most probably solid, or if not surrounded by an albuminous sphere, like the fat in an emulsion (Ascherson's cells), identical with the granular fat enclosed in pus-cells, or epithelial cells of the urinary tubuli, being a product of their degeneration, called fatty from the presence of the fat. These cells and the granular fat are frequently imbedded in fibrinous casts.

c. As fat in very minute particles, appearing as mere points under the highest powers of the microscope, but rising to the surface of the urine, and collecting as a cream, as in some forms of chylous urine.

Chemical characters.

These are very little known, but seem to be identical for the different descriptions enumerated. What we call fat and oil are most probably mixtures of different proportions of oleate and margarate of glycerine, or of the organic base,

which by taking up water forms glycerine, when the acid is separated from the fat by alkalies. The fat, which is fluid at the ordinary temperature of the air, is in all probability the oleate.

Fat and oil are soluble in ether, and are deposited unchanged when the ether is evaporated; but when they are surrounded by cell-membranes, or albuminous husks, ether may fail to take up the whole of the fat. It then becomes necessary, not only to shake the urine with some ether, but to evaporate it to dryness, to boil the residue with some alcohol and acetic acid, to evaporate again, and then to extract the residue with ether (Kletzinsky). Even this extract may be impure from some hippuric acid, which is to be removed by alcohol or water.

Kletzinsky found in the urine of persons labouring under Bright's disease the following quantities of fat in 1000 parts of urine: 024, 0-28, 035, 037, 0:48, 1.27 parts. Beale2 found 14 in 1000 of fat in urine on one occasion.

Pathological indications.

Fat in coagulating or albuminous urine, when causing a milky appearance, is a feature of chylous urine. When occurring in drops, granules, and cells, it is an indication of fatty degeneration of the kidneys, particularly when the cells or granules occur in fibrinous casts of the tubuli.

Heller's Archiv,' 1852, p. 287.

24 Microscopical Journal,' January, 1853, pp. 1, 2.

CHAPTER XXV.

CANCER-CELLS AND TUBERCULAR MATTER.

THE mucous membrane of the urinary bladder is a favorite seat of a certain variety of medullary, and perhaps, in some instances, of epithelial cancer, called villous cancer by Rokitansky and subsequent anatomists, from its peculiar mode of growth in fine villous processes, which make it resemble the surface of a chorion. On the exterior of these villi, the elements of a medullary or melanotic cancer-juice adhere to it, consisting of nucleated cells of various shapes, which form a soft, or a more consistent deposit, and are often present in such quantity, that they make up the greater part of the morbid mass in the bladder, into which then the vegetations seem to grow.1

The cancerous matter, according to Vogel, appears in the urine in small lumps of cells. The latter may be large, enclosing secondary ones; or they may have thick walls, and become elongated into spindle-like bodies. The urine at the same time mostly contains blood and coagula. From these and the collateral symptoms, the diagnosis of this disease offers no difficulties.

When, however, the appearance of cancerous matter is due to cancer of the kidneys, it is frequently difficult to form a diagnosis.

Of tubercle, and consequent phthisis, of the kidneys, I saw a remarkable instance some years ago, when paying an occasional visit to the Brompton Hospital. It was there secondary to tuberculosis of the lungs, as it almost always is. In these cases, the deposit consists of tubercular matter, irregular pus-cells, fragments of cells and their nuclei, granular indefinable matter, and, more rarely, pieces of crystals of cholesterine.

1 Paget' Surgical Pathology,' vol. ii, p. 513.