405. Renal hydragogues.

406. Renal depurants.

407.

408.

illustrated in acetate of potass.

their influence in disease.

409. Persistence of miasmatic poisons.

410. Therapeutical value of acetate of potass.

411. Treatment of ague.

412. Idem.

413. Treatment of acute rheumatism.

414. Use of nitrate of potass.

415. Renal depurants as substitutes for mercurials.

416. Therapeutical value of vegetable acids.

URINARY DEPOSITS,

THEIR

DIAGNOSIS, PATHOLOGY, &c.

CHAPTER I.

PRELIMINARY DETAILS CONNECTED WITH THE CHEMISTRY OF

THE URINE.

Demonstration of the chief Constituents of the Urine, 1-13-Mucus, 3—Uric Acid, 4-Urea, 5-Creatine, Creatinine, 6-Coloring Matter, 7-Hippuric Acid, 8Sulphuric Acid, 9-Chlorine, 10-Phosphate of Magnesia, 11-Lime, 12— Crystalline Salts, 13-Quantitative general Analysis, 13-15-Apparatus required, 16-Estimation of Solids, 17-of Urea, 18—of Uric Acid, 19—of Inorganic Salts, 20—Clinical Examination of Urine, 22—Non-sedimentary Urine, 23— Sedimentary Urine, 24-General Rules for discriminating Deposits, 25-Tabular Analysis, 26-Microscopes, 27-Pillischers' Lenticular Microscope, 28.

1. As it is probable that many practitioners into whose hands this volume may fall, have not had many opportunities of becoming familiar with the chemistry of urine, nor more than acquainted by name with its chief constituents, I have thought the following introductory remarks might not be unacceptable. It is indeed quite essential that every one, who purposes making himself acquainted with the important bearings of urinary pathology on the practice of his profession, should be at least acquainted with the characteristics of the most important constituents of the secretion. I would therefore advise the student to carefully repeat the processes described in the following paragraphs (2-13) before proceeding further, with the assurance that his subsequent researches will be thereby much. facilitated, and the whole subject rendered much more intelligible.

A. Demonstration of the chief Constituents of the Urine.

2. In suggesting the following directions for enabling the reader to become personally acquainted with the most important ingredients of the healthy urine, I am anxious to be regarded as addressing those who are complete novices in chemical manipulations. Directions of this kind are of course quite useless to the adept. By the processes described in the following pages, any one can satisfy himself of the existence of the most important elements of the urine with a very small expenditure of time and trouble, and with no greater amount of chemical knowledge than necessarily falls to the lot of every practitioner of medicine.

The urine chosen for examination should be some passed into a glass vessel immediately on rising from bed.

3. Examine the urine by holding it between the eye and the light; a delicate cloud of mucus (331) will be observed floating in it. On passing the urine through a paper filter, the mucus will be left upon it in a thin varnish-like layer.

4. Gently warm about an ounce of the urine, concentrating it, unless it be already of moderately high specific gravity, to half its bulk; pour it into a conical wine-glass, in which a few drops of hydrochloric acid have been previously placed, and set it aside. In a few hours a thin crystalline pellicle, varying in hue from a reddish brown, to almost perfect black, will be observed on the surface; this, on agitation, breaks up and falls in minute crystals to the bottom of the vessel. A drop of the fluid containing these crystals should be Fig. 1.

Fig. 2.

placed on a slip of glass and examined by the microscope. The fascicular and laminar crystals of uric acid will be readily recognized (Fig. 1). The crystals thus obtained, being impure, must be washed

URIC ACID-UREA-CREATINE.

35

with water, dissolved in a few drops of hot potash, filtered, cooled, and treated with hydrochloric acid to excess, and the crystalline deposit then examined.

5. Place about a teaspoonful of urine in a watch-glass, and evaporate it to about one-third its bulk by the heat of a lamp. When cold, add an equal bulk of colorless nitric acid; in a few seconds crystals of nitrate of urea will fill the vessel. If they be collected on blotting-paper and dried by pressure, they will present a fine satin-like lustre, resembling, under a lens, laminæ of mother-of-pearl (Fig. 2). Even this little trouble may be saved by placing a drop of urine on a plate of glass, and adding to it an equal quantity of nitric acid. In a space of time, varying from a few minutes to half an hour, a solid white mass of satin-like lustre will be left, chiefly composed of nitrate of urea.

6. Evaporate an ounce of urine to a syrupy consistence, and allow it to cool. Carefully decant, after a few hours' repose, the dense supernatant fluid from the deposited salts. Warm it in a watchglass, and dissolve in it a piece of fused chloride of zinc, the size of a small pea, and set the whole aside for twenty-four hours. On then examining it, a deposition of minute granular crystals will be observed. They consist of a triple compound of zinc and chlorine, with creatine and creatinine. Under the microscope their appearance is quite characteristic (Fig. 3), consisting of radiating crystals like minute zeolites, and exhibiting beautiful colored rings by polarized light. Their crystalline form becomes more obvious by dissolving them in a drop of water on a slip of glass over a spirit-lamp, and Fig. 3. Fig. 4.

allowing the solution to evaporate spontaneously. These crystals were formerly mistaken for those of lactate of zinc, from which they differ most completely. This salt crystallizes in rhombic prisms (Fig. 4), and does not present the radiating structure. Liebig proposes

the following method of obtaining creatine from fresh urine: Treat the urine with lime-water and chloride of calcium, to precipitate the phosphates, filter the liquor, and separate the crystalline inorganic salts by evaporation. Treat the decanted liquor with chloride of zinc, and allow it to stand for a few days; a mass of crystals will then be obtained, consisting of creatine and the triple compound alluded to above. Dissolve the crystals in boiling water, and treat them with hydrated oxide of lead, until there be an alkaline reaction. Remove the oxide of zinc and chloride of lead by filtration, free the fluid from the lead and coloring matter by means of animal charcoal, and evaporate to dryness. Treat the residue, which consists of creatine and creatinine, with boiling alcohol, which takes up the creatinine and leaves the creatine. The crystals, which are very distinct, are represented below from a specimen prepared by Dr. A. Clark. Being thick, they cannot be perfectly shown without altering the focus during the examination (Fig. 5).

The creatinine may be obtained from the alcoholic solution mentioned above, and the crystals assume the following form; they are

taken from a plate in Dr. Hassall's paper in the twenty-third number of the "British and Foreign Medico-Chirurgical Review" (Fig. 6).

7. Fill a test-tube one-third full of urine, boil it over a lamp, and add immediately one-fourth its bulk of hydrochloric acid. The production of a fine pink or purple color will at once demonstrate the existence of the peculiar carbonized coloring matter of the urine (100).