Selected monographs.

Date:: 1888

Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs. Source: Wellcome Collection.

30/440 (page 14)

in the urine. As, however, notwithstanding those drawbacks, the test in question is the only one in common use, it will not be superfluous to give a bi-ief account of far more reliable tests which should be used in doubtful cases, or I would rather say in all cases in future. These are as follows : (i) to acidify the urine with acetic acid, and then add carefully a (concentrated) solution of ferrocyanide of potassium, according to Hofmeister the most delicate of all the tests for albumen,- and which precipitates all the albuminous bodies, but not peptone.-^ 2. The careful addition of nitric acid to the (non-warmed) urine, followed by boiling if any cloudiness results. 3. The addition of a concentrated solution of chloride of sodium, or sulphate of magnesia to urine acidu- lated by acetic or nitric acid. All three tests, or at least the first and one of the others, should invariably be tried. If after applying the second or third, a precipitate which is formed on heating, entirely or partially disappears, the pre- sence of pro-peptone is indicated. Hindenlang (21) has lately recommended metaphosphoric acid as a delicate test for albumen and it also precipitates peptone. As far as my present experience goes, and as regards delicacy and con- venience of testing, I can support his recommendation, but for cases where great exactness is required, I would recommend that recourse should also be had to the other tests, both for the purpose of checking results, and also because when the quantity of albumen is small, the saline constituents of the urine, the presence of other organic sub- stances and other unknown influences are apt to cause slight difierences in its behaviour towards one or other of the reagents. For the discovery of pro-peptone, however, it^s necessary to have recourse to one test which is applicable^to cold urine and to another which requires the addition^of warmth. , -, , ^ j. 1. If as we may assume from Hmdenlang's statement, metaphosphoric acid is adopted for the discovery of very small quantities of peptone in the urine, we shaU have obtained a very convenient method for the detection of 1 Salkowski states that this test fails only when a large amount o£ chloride of sodium is present, hut the urine never contains this constituent in such quantities as to prevent the precipitation of albumen.