degeneration of the kidneys is not yet certain, but it is probable.

10. Fat. Most commonly when fat is present, it is free and suspended in the urine. Much more rarely, as mentioned in the previous section, the fat is in combination, and is indetectible except on chemical analysis.

When passed in large quantities, the fat is evident to the unaided eye, and gives the urine a turbid emulsion-like appearance. In small quantities, it forms part of a sediment, and is detected only by the microscope.

When the fat is in large quantities, it may be derived from fatty food. (Rayer1 and Bernard' in dogs).

Mettenheimer3 has seen it after the use of cod-liver oil in one case, and of emulsio cannabina in another; the cause of the passage of the fat in such cases is quite unknown. It may be inferred, however, from the observations of Lanz, that the occurrence is more common than is usually supposed.

In other cases, however, the passage of the fat is not so obviously connected with food, and in addition to fat there is albumen, and in some cases fibrine also, in the urine. From the very fine division of the fatty particles, and probably from the presence of molecular coagulated albumen, the urine has a milky appearance, and has received the names of the chylo-serous, chylous, or milky urine. When there is fibrine, a white coagulum of varying size forms, and is sometimes extremely firm. Occasionally a few blood particles are present, and give a red tinge to the coagulum.

The causes of the milky or so-called chylous urine are at present unknown; it is not necessarily connected with food; it is sometimes evidently augmented by exercise. Gallic acid may check it temporarily, as if the vessels of the kidney were relaxed; it may continue for many years without much, if any, detriment to the health.

In a third class of cases the fat is in small quantity, and only detectible microscopically; it may then be derived from the food, or be an evidence of fatty degeneration of the kidney. In this last case, it is both free and in the interior of renal epithelium.

Gmelin noted the occurrence of cholesterin in the urine; and lately Beale has extracted cholesterin in some amount from the

1 Op. cit., p. 171.

2 Leçons, tome ii, p. 86.

3 Ausscheidung von Fett durch den Urin von Dr. C. Mettenheimer (Archiv des Vereins für wissen. Heilkunde, Band i, p. 374).

4 Bence Jones, Medico-Chirurg. Transact., 1850-1853.

5 Archives of Medicine, 1851, vol. i, p. 8.

sediments forming in the urine passed by persons with fatty degeneration of the kidneys.

11. Uro-stealith.-Some calculi, composed of a peculiar fatty substance, were examined some years ago by Heller;1 and lately Dr. William Moore, of Dublin, has met with another case of this curious affection.2 To Moore's paper in the 'Dublin Journal' I beg to refer for full details.

12. Spermatozoa occur in variable numbers, according to circumstances. They are at once recognised by their form.

13. Sarcina have been found by Mackay, so long ago as 1848 (quoted by Begbie), by Heller,3 Welcker, Beale, Begbie, Johnson, and others. Hepwood ('Microscopical Journal,' No. 16) found sarcina in the pelvis of the kidney. Rossmann 5 thinks that the sarcina of the urine is a different variety from the sarcina of the stomach, and names it S. Welckeri. Welcker, in his last paper, describes the sarcina minutely, and it would appear that the cells of the urinary sarcina are decidedly very much smaller than in the case of the stomach or lung sarcina; the largest masses are not composed of more than sixty-four cells. In Begbie's case, the sarcina were present for two months.

14. Hydatids (Echinococci) forming in the kidney, or in surrounding parts and opening into the kidney, are described by several authors. Generally some hooklets of the Echinococcus may be seen, but occasionally only portions of the cyst are noted.7 15. Hair is sometimes found in the urine or in calculi. It has three origins:8

1st. It is formed in the urinary passages. This is rare; is seen in both sexes; its causes are unknown.

2d. It is formed in cysts which have opened into the bladder. These cases occur only in women.

3d. It has entered from without, being either introduced intentionally or through vagino-vesical fistulæ. The intentional introduction is the most common cause.

1 Heller's Archiv für path. Chem., 1844 and 1845.

2 Dublin Med. Journal, 1854, vol. xvii, p. 474.

3 Archiv für path. Chem., 1852-4.

4 Edin. Med. Journ., April, 1857.

5 Virchow's Archiv, Band xiv, p. 393.

6 Henle's Zeitsch., 1859, Band v, p. 199.

7 Guitrac, Observ. d'hydatids rendus par les voies urinaires. Journal de Méd. de Bordeaux, 1852, Oct.

Kuchenmeister, Deutsche Klinik, 1852, No. 25.

See Med. Times and Gazette, February, 1855.

Rayer, Recherches sur la Trichiasis des voies urinaires, Gazette Méd., 1851,

No. 31, p. 484.

16. Entozoa. Lawrence and Farre1 have described two kinds of worms passed from the bladder, and Farre has termed one Diplosoma crenata; the other is unnamed. For a full description, I beg to refer to Dr. Farre's paper.

II. Second class of Sediments, forming in the Urine
after secretion.

1. Sediments containing uric acid and bases.-The most common sediments in the urine are those which are known as the "yellow, lateritious, brickdust, fever" sediments, and which are composed of uric acid in various combinations with soda, potash, lime, and, rather less commonly, ammonia; they are usually coloured with normal or abnormal urine-pigment. Phosphate and oxalate of lime are also often present.

The exact composition of the sediments of uric acid and bases has been a subject of much dispute. It was at one time thought that ammonia was the only base-an opinion which was probably founded, not on direct analysis, but on the fact of urate of ammonia existing in large amount in calculi. The presence, or not, of free uric acid has been also a subject of much controversy.2

The analyses of Heintz3 implied that soda, and not ammonia, is a usual base. In four analyses the per-centage proportions

The following analyses were published by Scherer in 1849,4 and show that the composition varies more than would be inferred from Heintz's table.

1 Beale's Archiv of Med., vol. i, p. 290.

2 Heintz has strongly denied the occurrence of free uric acid in the lateritious sediment, and asserts that it is simply acid urate of certain bases.

3 Heller's Archiv, 1845, p. 246.

4 Canstatt's Jahresberichte for 1848. Scherer's Report on Pathological Chemistry, p. 57.

In four cases of lateritious sediment, the per-centage compo

sition was as follows:

A glance at this table will show that the uric acid is in great

Uric acid to the amount of 25.99 grains in every 100 of the sediment must have been therefore uncombined. A still greater quantity would be uncombined in analyses 1 and 4.

Another fact evident from the tables is the constancy of the per-centage amount of uric acid; and in spite of the great variation of the bases, this would lead us to believe that the uric acid is in some constant form of combination.

The following analyses of four specimens were made by Hassall:1

1 British and Foreign Medico-Chir. Review, 1853, July, p. 132.

Whatever be the composition of the deposit, it dissolves with great readiness when the urine is heated to 130°; nor has any instance ever been known when this did not occur, except in the case of the dense globular urate of ammonia, which requires more water and longer boiling. Acids decompose it, and liberate uric acid.

Under the microscope three forms are seen, viz., irregularly formed or amorphous particles, round globules,1 of various size, and fine acicular and prismatic crystals. The crystals are sometimes single or grouped; occasionally the acicular crystals project from the surface of a dark globule of urate of soda, or ammonia, or an accidental impurity. The round globules have sometimes hooked or curved projections, which may themselves be studded with minute crystals. Sometimes two globules adhere together, or fuse into each other so as to form true dumb-bells.

The special composition of these forms is not known. It is generally assumed that the amorphous powder is urate of lime, potash, or soda; that the globules and crystals are urate of ammonia and of soda; and that the globules with projections are urate of soda. No separation has yet been made of these several forms of deposit; but this opinion is founded on the fact that these several compounds, when pure, crystallize out of their solutions in these forms. According to Heintz, when the urate of lime exists alone, it forms globules; and so do the urates of ammonia and soda, when they precipitate out of a solution of chloride of sodium. When the three urates are together, however, the precipitate is amorphous. The extractive matters of the urine also have an influence on the form, and prevent the formation of crystals.

Sometimes the round globular form is given by the deposit of the urate upon some foreign substance; even, according to Inman, on the spores of fungi. An acid added to the deposit decomposes it, and uric acid crystallizes out.

The causes of the deposit of urates are very various, and in many cases two or more are acting simultaneously.

It is quite certain that the deposit of urates is not necessarily connected with any absolute excess of uric acid, and to speak

1 Boedeker has procured artificial sediments of urate of soda, which exactly resemble in optical characters oil-globules. Henle's Zeitsch., 1859, Band vii, p. 127.

2 For drawings of the prismatic crystals of urate of soda, see Lehmann's Handbuch der Phys. Chem., 2d edit., 1859, p. 80. Lehmann states that they appear in the urine passing from the acid to the alkaline fermentation. During the fermentation, some of the extractive-like" matters which hinder the crystallization of the urate are destroyed.

3 Quevenne, in Henle's Handb. der rat. pathol., Band ii, p. 313.

4 Med. Times and Gazette, Dec., 1851.