THE ADVL TERA TION OF FOOD. 3 75 



which it is made; but in addition to these, other substances are used in its 

 .preparation. Alum is eaiployed to prevent the action of the diastaste upon 

 •the starch, and to prevent the bread from becoming sour and mouldy ; and 

 .although this salt tends to accomplish these results and imparts a fine white 

 a,ppearance to the bread, its use is not justifiable. When taken into the 

 ■stomach it is liable to occasion acidity and dyspepsia ; furthermore, it pre- 

 vents a solution of a large proportion of the gluten of the bread, thereby 

 ■causing a decrease of its nutritious value. A far more reprehensible adul- 

 -teration consists in the addition of sulphate of copper, which has the same 

 effect on the color of the bread and on the diastase. Although this salt is 

 but seldom employed, and then in very small amounts, its use is to be con- 

 demned in the strongest terms, as it acts as a virulent poison, and its effects 

 are cumulative. A simple and delicate test for detecting the presence of 

 ■copper is to moisten the suspected bread with a few drops of solution of fer- 

 ■rocyanide of potassium, which will cause a pinkish color to become apparent 

 if the metal be present. 



Pickles and preserves are often artificially colored. The deejD green color 

 frequentlj" noticeable in the tormer is almost invariably due to the presence 

 of a sort of copper (the sulphate or acetate), which is either directly added 

 to them or is produced in using coi5j)er vessels in their preparation, both 

 methods being recommended in several cooking books. This adulteration 

 can be detected by allowing a piece of clean and polished iron to remain 

 immersed in the pickling vinegar for a few hours ; in presence of copper a 

 thin coating of this metal will be deposited upon the iron. 



The condiments used at the table are also frequently far from pure. Ad- 

 ditional acidity is often imparted to vinegar by the addition of sulphuric 

 acid, the use of which was formerly considered necessarj^ in order to pre- 

 vent its decomposition, and was allowed by law in Great Britain ; but 

 although the fallacj^ of this belief has been demonstrated, the practice is 

 still resorted to. A few weeks ago five carloads of vinegar received in 

 Washington from Chicago were found to contain over fifty-four grains of 

 sulphuric acid per gallon, in the form of suphate of lime, in addition to five 

 grains per gallon of the free acid. On adding a little nitrate of baryta to 

 vinegar containing sulphuric acid, a heavy white precipitate will be imme- 

 diately formed. 



The sophistications practiced upon tea are large in number and often 

 harmful in character. The greater part of the adulteration occurs in China, 

 but the English and Americans appear to have become skillful imitators of 

 the Chinese in at least some branches of this nefarious industry. Mineral and 

 organic substances are used to increase the weight and bulk of the tea; fic- 

 titious strength is imparted to it by the addition of certain vegetable sub- 

 ■stances and pigments are employed in order to produce a desirable color. 

 The operation which is most generally carried on, at least in this countr}^, 

 is the artificial "facing" or coloring of teas. This practice is almost entirely 

 ■confined to green teas, of which, it is said on high authority, but few 



