Pickles, vegetables of various sorts, as small cucumbers, onions, string beans, and cabbage, and also some fruits, such as melons, peaches, India mangoes, and soft unripe nuts, preserved in vinegar to be eaten as a condiment. The articles are steeped or parboiled in brine and then transferred to the vinegar, to which some salt is added, and some of a variety of spices are also introduced, as well as mustard, horse radish, etc. East India pickles are flavored with curry powder mixed with mustard and garlic. For some articles the vinegar is used cold, for others hot, and for onions pure distilled vinegar is employed in order that their natural whiteness may be preserved. The use of pickles is so general that they are almost one of the common necessaries of life; and among seafaring men especially their consumption is prodigious. They are often contaminated with a poisonous salt of copper, which is intentionally introduced to give them a pleasant bright green color. To obtain this effect the vinegar is boiled in brass or copper vessels, or copper coins are introduced into the boiling liquid, and sometimes verdigris and blue vitriol or the sulphate of copper.
This salt is produced by boiling vinegar which contains sulphuric acid in copper vessels, and most of the vinegar that is used in the pickle factories is of this character. Dr. Hassall reports that 23 samples of pickles examined by him all contained copper to some extent, and two or three of them in dangerous quantities. Sulphuric acid also was detected in 19 out of 20 samples of vinegar used for pickling. Numerous fatal cases of poisoning are reported as having occurred from the use of such pickles. The presence of copper may be suspected in all pickles of a brighter green color than the vegetables naturally possess; and it is proved when a bright piece of iron immersed for a short time in the liquid becomes coated with copper; or if, when a bit of the pickles is minced fine and put into a vial with liquid ammonia diluted with an equal amount of water, the liquid becomes blue, it is owing to the presence of copper.