4io 



TESTS FOR ALBUMIN IN URINE. 



is to add a pellet to the suspected urine. Oliver's papers. Dr Oliver uses papers, one saturated 

 with citric acid and another with ferrocyanide of potassium. The two papers are added to the 

 clear filtered urine. Other precipitants of albumin, such as small pieces of paper impregnated 

 with potassio-mercuric iodide, are used by Oliver. ] 



(4) Boiling Acid Urine. If the urine be alkaline, although albumin may be present, it is 

 not precipitated by heat alone. We require to add acetic acid until a slightly acid reaction is 

 obtained. Boiling may give a precipitate of earthy phosphates in an alkaline urine, owing 

 perhaps to the CO s being driven off. This precipitate might be mistaken for albumin, but 

 on adding acetic or nitric acid, the earthy precipitate is dissolved, while the precipitate of 

 albumin is not dissolved. In testing for albumin, always use clear urine. If it is turbid, 

 filter it. 



[(5) Metaphosphoric acid is dissolved in water just before it is to be used and added to clear 

 urine (HindetUang). Graham pointed out that metaphosphoric acid precipitated albumin. A 

 20 per cent, solution of the ordinary glacial phosphoric acid is a good test for albumin, but it 

 also precipitates peptones. It, however, changes into ordinary phosphoric acid by keeping, 

 and then it no longer precipitates albumin.] 



[(6) Sodic Sulphate and Acetic Acid. Acidulate 10 c.c. of urine with acetic acid, and add of 

 its volume of a concentrated solution of sulphate of soda or magnesia. On heating, if albumin 

 be present, a distinct cloudiness is obtained.] 



[(7) In picric acid, according to Dr Johnson, we have a more delicate test for minute traces 

 of albumin than either heat or nitric acid, or than both these tests combined. It is used either 

 in the form of crystals or powder, or as a saturated aqueous solution. Take a four-inch column 

 of urine in a test-tube, hold the tube in a slanting direction, and pour an inch of 

 the picric acid solution on the surface of the urine, where in consequence of its low 

 specific gravity (1005) it mixes only with the upper layer of the urine. It coagu- 

 lates any albumin present. The precipitate occurs at once, and is increased by 

 heat, while the urate of soda, which is sometimes precipitated, is soluble on 

 heating. ] 



[Dr Roberts regards any test for albumin which requires strong acidulation with 

 an organic acid, citric, acetic, or lactic, as unsatisfactory, since it precipitates 

 mucin. For this reason he rejects the tungstate, mercuric iodide, and potassic 

 ferrocyanide tests. Dr Roberts regards the heat test, with the addition of a small 

 definite quantity of acetic acid, as the best test for the detection of small quan- 

 tities of albumin.] 



1. Quantitative Estimation of albumin. 100 c.c. of urine are boiled in a capsule, 

 some acetic acid being ultimately added, whereby the albumin is precipitated in 

 flakes. The precipitate is collected on a weighed, dried (110), ash-free filter, and 

 repeatedly washed with hot water, then with alcohol, and dried in an air-bath at 

 110. The weight of the filter is deducted, and finally the dried filter with the 

 albumin is burned in a weighed platinum capsule, and the weight of the ash also 

 deducted. [This method is not available for the busy practitioner on account of 

 the time it takes. Practically, it is sufficient to compare from day to day the 

 proportion that the precipitated albumin bears to the bulk of the urine tested. A 

 graduated tube may be used, so that after the precipitate has subsided, the physi- 

 cian may see what proportion of the whole the precipitate occupies.] 



Esbach's Albumimeter (fig. 263). A glass cylinder is filled with the urine up 

 to the mark U, and to R with the precipitant (20 citric acid, 10 picric acid, 970 

 water). The vessel is corked and then shaken. After twenty-four hours the coagu* 

 lated albumin subsides, when the graduation on the tube indicates the number of 

 grms. of albumin per 1000 c.c. of urine. Very albuminous urine must be pre- 

 viously diluted. 



2. Globulin occurs only in albuminous urine, and is frequently present. Its 

 presence is ascertained by adding powdered magnesium sulphate in excess to the 

 urine; when it is present it is precipitated ( 32). The more globulin there is in 

 the presence of albumin, the more difficult it is to precipitate it. [Sometimes, 

 when, an albuminous urine is dropped into a large cylinder of water, each drop as 

 it sinks is followed by a milky train, and when a sufficient number of drops has 



been added, the water becomes opalescent, the opalescence disappearing on adding an acid. The 

 globulin is kept in solution by common salt and other neutral salts, but when these are largely 

 diluted, the globulin is precipitated (Roberts).] 



3. Peptone occurs in some specimens of albuminous urine, but also in non-albuminous urine. 

 Maixner found it constantly in the urine in all cases where suppuration is present, and even in 

 phthisis, constituting pyogenic peptonuria. Peptone occurs in pus, and the peptonuria in these 

 cases is a sign of the breaking up of the pus-cells {Hofmeister). Also when many leucocytes 

 are broken up in the blood (homatogenic). It occurs in cases where there is great disintegration 

 of albuminous tissues, e.g., in cancer. It is frequently found after child-birth. Ammonium 

 sulphate precipitates all proteids except peptones (p. 249). 



Fig. 263. 

 Esbach's 

 albumi- 

 meter. 



