The examination of pickles naturally includes a determination of the character of the vinegar used in their preparation. This is made by the methods just described. The practice of imparting a bright green colour to pickles which have become bleached by long preservation in brine or by other means, is doubtless still prevalent, and calls for a brief notice. The greening of pickles is effected either by the direct addition of cupric sulphate to the water in which they are heated, or by introducing some form of metallic copper into the bath. Alum is stated to be also occasionally employed for the same purpose. The presence of copper is readily detected by incinerating a rather considerable quantity of the pickles, treating the ash with a little nitric acid and adding an excess of ammonium hydroxide to the solution, when, in presence of the metal, a blue coloration will be produced. The quantitative estimation of copper is made by boiling the residue, obtained by the evaporation of the vinegar or the incineration of the pickles, with dilute nitric acid, adding a small quantity of sulphuric acid and expelling the excess of nitric acid by evaporating nearly to dryness. The solution is next diluted with water, filtered, and the filtrate placed in a platinum capsule. The copper is then deposited by electrolysis. In the Report of the Brooklyn Board of Health for the year 1885, a case is recorded where a child ate a portion of a pickle coloured with cupric sulphate (containing an estimated quantity of 2½ grains of the salt), with fatal results.