[Footnote 45: No more precise directions than this are given by Oliver, either in his papers in the _Lancet_ for 1883 or in his little book just published, _On Bedside Urine-Testing_. The sugar test-papers, as well as the entire series of albumen test-papers, suggested by Oliver, are now made by Parke, Davis & Co. of New York, and by Wilson & Son, Harrogate, London.] Mode of Testing.--One of the test-papers and a sodium carbonate paper[46] are dropped into a half-inch test-tube, and water added until the upper end is just covered; a column of fluid one inch in height and half an inch in diameter will thus be produced, so that the solution of carmine obtained on boiling will always acquire the same concentration. Heat is now applied, the tube being gently shaken, and boiling kept up for a second or two. A beautiful blue solution will result. The test-paper may now be removed or allowed to remain. [Footnote 46: Test-papers of the same size, charged with a saturated solution of sodium carbonate.] Not more than one drop of the suspected urine is let fall into the tube from a pipette held in an upright position. Drops of equal size are thus secured. The contents of the tube are again freely boiled for a few seconds, after which the tube should be raised an inch or more from the flame and held without shaking, while the solution is kept quite hot, but not boiling, for exactly one minute. If glucose be present in abnormal amount, the soft rich blue will be seen first of all to darken into violet; then, according to the quantity of sugar, there will appear in succession, purple, red, reddish-yellow, and finally straw-yellow. When the last-named color has been developed the slightest shaking of the tube will cause red streaks to fall from the surface and mingle with the pale yellowness of the solution, while further agitation will cause the return of purple and violet and the restoration of the original blue. The time required for the commencement of the reaction after the boiling of the test liquid is in inverse proportion to the amount of glucose present. When the latter is large, over 20 grains to the ounce, it will be but a few seconds; but when small, 2 or 3 grains, from thirty to sixty seconds may elapse. If the urine do not contain more than the normal amount of sugar[47]--_i.e._ under half a grain to the ounce--the color of the solution {217} at the end of the heating for one minute will be unchanged. The test is available by artificial light as well as by daylight. [Footnote 47: It will be noted from this that Oliver accepts the view that there is a small amount of sugar in normal urine.]