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DISEASES OF THE KIDNEYS.

4ะ GENERAL REMARKS:

It has become an established custom in all accounts of urinary pathology and therapeutics to prefix to the special part, which treats of the various renal and urinary diseases, their diagnosis, prognosis and therapeutics, a general part treating of the nature and importance of certain prominent symptoms in the quality and quantity of urine and in the reacting effects of urinary and renal disturbances on the organism in general. To these symptoms belong the presence of albumin, blood or hæmoglobin and renal casts in the urine, as also of dropsy and uræmia.

I. ALBUMINURIA.

Without taking into consideration the so-called false albuminuria, i.e., that condition in which the urine contains albumin only in consequence of a mixture of blood, pus, sperma, etc., we will now only discuss the genuine albuminuria.

According to the old clinical view the expression albuminuria is identical with the presence of coagulable albumin in the urine, be it produced by serum-albumin (sereoalbuminuria, serinuria), be it by serum-globulin (globulinuria, paraglobulinuria), or by both substances combined, whereby the presence of fibrinogen is irrelevant. As recent researches prove, this latter case seems the rule, as indeed it might a priori have been explained from the great facility of diffusion and filtration of the serum-globulin. F. Hofmann even suggests for the albuminous urine the idea of an albumin quotient varying from 1 to 10, a quotient the value of which is found by dividing the quantity of the globulin by that of the albumin. In some cases even the globulin forms the total of the albumin found in the urine. Now-a-days in testing for albumin we completely ignore the presence of globulin, as no importance for diagnosis and prognosis can be attached to it, and our methods for ascertaining its presence and quantity being so uncertain (Hammarsten, Kamenski, Ott, Viglezio).

For testing whether urine contains albumin various procedures are ployed :

1. One warms a quantity of filtered urine in a test tube, adding 30 per cent. nitric acid. According to the quantity of albumin

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contained we obtain a mere haze, a dense white cloud or thick coagulated masses. This test is not always reliable, especially not for the beginner, as in certain cases (rare ones it is true) the coagulation may be mistaken for such produced by resinous substances, i.e., resinous acids resulting from the decomposition of aromatic salts (Löbisch and Rokitansky). Furthermore the dark colour of the urine often prevents our detecting slight hazes. In such cases Roberts advises to add a concentrated solution of sulphate of magnesia, which prevents the too strong decomposition of coloured matter. Nitric acid is also used as alburnin test without heating the urine. About thirty drops of strong nitric acid are placed in the bottom of a test tube and then an equal quantity of urine is floated gently over the surface of this acid. At the line of junction a zone of coagulated albumin is developed. A fallacy may arise by the appearance of a zone of hydrated uric acid in highly acid urines or amorphous urates in neutral urines being developed at the line of junction. In these latter cases, however, the lower line of junction is indistinct and the upper one hardly developed. The fact of urates producing the typical zone can be avoided by diluting the urine with an equal quantity of water. *

2. Filtered urine is heated to boiling point, and to every 10 c.c. about five drops of diluted acetic acid are generally added. It is necessary to neutralise alkaline urine before filtration. This modification proves to be a very sensitive test and in no way discolours the urine. A still more sensitive test can be obtained if we add an equal volume of a concentrated solution of Glauber's salts (Panum) or one third part of a concentrated solution of chloride of sodium (Heynsius). Acetic acid must then be freely added and the whole heated. By this excellent method we avoid the danger that a surplus of acetic acid redissolves the albumin. Precipitation of mucin hardly ever occurs.

3. Albumin is precipitated by adding acetic acid and potassium ferrocyanide to the urine. Numerous comparative tests have proved that the following proportions are the best: To

of urine and eighteen drops of acetic acid add one to two drops of a ten per cent solution of potassium ferrocyanide. This test, so sensitive for diluted urine, has proved inefficacious in a certain number of concentrated urines. A minute generally elapses before coagulation takes place.

Rapid processes. The necessity of simplifying the tests of urine has led to the use of picric acid (Bouchard, Galippe, Johnson, Esbach, Ralfe), trichloric acetic acid (Raabe) and metaphosphoric acid (Hindenlang, Wikstrand). Pavy, who does not con

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* This fallacious zone also disappears when heat is applied. On addition of nitric acid to highly concentrated urines, crystals of urea nitrate may be formed; heat likewise dissolves them. Provided these precautions are taken I find this method to be one of the most reliable for practical use.-W. H. G. * Alkali and acid albumin peptones, alkaloids and urates are precipitated. Discrimination between these is however easy by application of the heat tests; if the precipitate consists of either peptones, alkaloids or urates it redissolves : when heated, on the other hand a fresh sample coagulating by heat shows it to be serum-albumin and not alkali or acid albumin.-W. H. Ĝ.

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sider the ebullition and slow solution of the last-named acids as sufficiently reliable, has had globules and tablets made of citric acid and natrium ferrocyanide, which he pulverises and adds to the urine. Tanret recommends a mixture of corrosive mercury, potassium iodide and acetic acid. Among the various prepared test papers Wilson and Geissler's are the most popular. They are an invention which has done much to facilitate the testing of urine at the bedside. Two papers are necessary for this procedure; one is impregnated with potassio-mercuric-iodide, the other with citric acid. Almost all these methods are simple and sensitive in general, but, as Penzoldt first proved, not reliable, as they sometimes lead one astray by producing coagulation in cases when the urine is not albuminous * (according to Johnson this coagulation is produced by mucin). Fleischer is much in favour of using corrosive mercury and succinic acid.

When the urine can be analysed in a laboratory, hospital, or in the physician's consulting-room, the old tried tests are to be preferred. A different thing when the analysis has to take place without filter or lamp at the bedside of a patient, for instance, in the country, or when we have to execute a greater number of tests for purely diagnostic purposes. In such cases the much occupied physician must content himself with rapid methods as a preliminary. We should not hesitate a moment in recommending for such cases, prepared papers, if (quite apart from their quality of precipitating alkaloids) the fact of placing and extracting the papers twice in the urine did not in so far cause a disturbance, inasmuch as the soft paper leaves numerous fibres, and the extracting of these shreds soaked in the liquid is most objectionable. To avoid this we have together with Stütz prepared small gelatine capsules filled with a mixture of hydrargyrinatriumchloride, chloride of sodium and citric acid. By simply cutting off the ends of the capsule, placing it into a test tube containing about 5 ccm. of urine, we have a neat and clean method. These capsules share with Geissler's reagent the peculiarity of precipitating uric acid in very concentrated urine, which sometimes causes a slight non-albuminous haze. These cases, however, are of no intrinsic value to the practitioner. We do not for a moment pretend that our capsules (obtainable from Stütz's pharmacy in Jena) are suitable for such tests where very small quantities of albumir have to be taken into consideration. Even a physician unpro vided with the necessary utensils will be able to make a prelim inary test with Heynsius' method, for one finds in the poorest cottage a spoon, a light, table-salt and vinegar.

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