from a copper still. They make a sort of tincture of the Cayenne pepper; and then filter and pour it upon a quantity of salt in a copper still—it there takes up a little copper; and then this salt is dried and mixed with vermilion and rose-pink. The proportion of vermilion added is about six drachms to three pounds of salt.

6

The Detection of the Adulterations of Cayenne. The adulterations of Cayenne with rice flour, turmeric, and mustard husk, are determined by means of the microscope; the structure of these articles has already been described and their microscopical characters represented.

For the detection of the other adulterations of Cayenne, recourse must be had to chemistry. The fact of the presence of red earths may indeed be ascertained by means of the microscope, by viewing under that instrument a portion of the Cayenne, when the red earthy particles may be plainly discerned. To determine their composition, however, chemistry must be appealed to.

The method for detecting the presence of the red ferruginous earths, and for their quantitative determination, will be found described at pp. 111 and 190, and that for salt under the head of Water,' pp. 83 and 86. We have, then, now to describe more particularly the processes to be followed for the detection of lead and mercury.

On the detection of lead.—The presence of lead in Cavenne may be determined by simply shaking up half a drachm or so of the Cayenne in water, and adding a few drops of sulphide of ammonium ; if lead be present, the liquid will become more or less dark or black, according to the quantity of the metal.

But it should be remembered that iron gives a greenish-black precipitate with the above-named reagent; and therefore it is not safe to trust to the appearance presented on the addition of solution of sulphide of ammonium to water containing Cayenne.

It is proper, therefore, in all cases to proceed as follows:-Incinerate 10 grammes of Cayenne previously dried on a water-bath in a porcelain basin; treat the ash with about 5 cc. of strong nitric acid; heat nearly to dryness, so that part of the acid may become dissipated ; dilute with distilled water, filter, and pass sulphuretted hydrogen through the solution. The precipitate is collected on a filter, washed with water containing some sulphuretted hydrogen in solution, and then boiled with a little strong nitric acid. Io the liquid a few drops of sulphuric acid are added, and it is then evaporated to dryness on the water-bath. The residue is exhausted with water, and the precipitate, consisting of sulphate, of lead is collected on a filter, washed with a very dilute solution of sulphuric acid, incinerated in a porcelain crucible and weighed.

The solution of the ash of Cayenne in nitric acid may be tested qualitatively for lead by rendering it alkaline by means of ammonia,

adding then acetic acid in excess and testing with a drop of a solution of neutral chromate of potash. A bright yellow precipitate of chromate of lead will be thrown down if lead be present.

On the detection of bisulphuret of mercury.—As mercury sublimes

CAYENNE, adulterated with, a a, red lead; b b, ground rice ; and cc, turmeric.

dd, husk and seed of cayenne much infested with the thallus and sporules of
a fungus, to the attacks of which damaged cayenne is very subject.

a

at a red heat, we cannot proceed in the analysis by incineration; the solvent must be added to the Cayenne direct-this being aqua regia, a mixture of nitric and hydrochloric acids, in the proportions of one part of the former to two of the latter acid.

About 5 cc. of the acid should be added to 3 grammes of Cayenne and boiled with it for an hour or so; a small quantity of distilled water is then to be added; the mixture filtered and the filtrate evaporated nearly to dryness; a little water must then again be added, and the solution tested.

The tests employed are liquor potassæ and iodide of potassium. The former gives a yellow precipitate, and the latter either a yellow or more commonly a beautiful scarlet-coloured precipitate of biniodide of mercury. The solution of iodide of potassium should be added in very minute quantity, as the iodide or biniodide is readily and almost instantly dissolved in an excess of this reagent; and it should be known that very often, when the colour of the precipitate is yellow rather than red, after standing an hour or two it will frequently change to the characteristic scarlet hue.

To determine the quantity of the mercury in Cayenne, the solution in nitric acid is precipitated by means of sulphuretted hydrogen ; the precipitate is exhausted with a solution of sulphite of soda, to remove any free sulphur which may have been thrown down, collected on a weighed filter, dried and weighed.

CHAPTER XXXIII.

SPICES AND THEIR ADULTERATIONS.

DEFINITION OF ADULTERATION.

Any added vegetable or mineral substance not acknowledged in the names under which they are sold, including the admixture of cassia with cinnamon or its substitution for the latter spice.

We now come to the consideration of the important subject of Spices and their Adulterations.

The spices, of the adulteration of which we are about to treat, are Ginger, Cinnamon, Cassia, Nutmegs, Mace, Cloves, and Allspice or Pimento.

When it is remembered that many spices are sold in the state of powder, most of them bearing a high price, and that they are nearly all subject to a duty, which in some cases is considerable, it might be supposed that they would be particularly subject to adulteration.

Notwithstanding these facts, little attention has been bestowed upon this subject by writers on the sophistication of food, or eren by the Excise authorities, whose duty it is to protect the revenue from all frauds resulting from the adulteration of duty-paying articles.

GINGER AND ITS ADULTERATIONS.

The ginger plant, Zinziber officinale, belongs to the very useful natural order, Zinziberacee, from which turmeric, East Indià arrowroot, and some other productions, are obtained.

Ginger grows and is cultivated in the tropical regions of Asia, America, and Sierra Leone.

The stem reaches generally three or four feet in height, and is renewed yearly ; while the root, which is the part known as ginger, botanically termed a rhizome, is biennial.

The roots, or rhizomes, are dug up when about a year old ; in Jamaica this occurs in January or February, and after the stems are withered. They are well washed, freed from dirt, and in some cases, especially with the better kinds, the epidermis or outer coat is stripped off; and hence the division of ginger into white (scraped or uncoated), and into black (unscraped or coated).

In estimating the quality of ginger, a variety of particulars have

to be taken into consideration—as whether the rhizomes are coated or uncoated, their form, colour, and consistence.

The rhizomes of ginger of good quality have no epidermis, are plump, of a whitish or faint straw-colour, soft and mealy in texture, with a short fracture, exhibiting a reddish, resinous zone round the circumference;

the taste should be hot, biting, but aromatic. The rhizomes of ginger of inferior quality are frequently coated with the epidermis, are less full and plump, often contracted and shrivelled; of darker colour, being of a brownish-yellow; of harder texture, termed finty; and more tibrous ; while the taste is inferior, and less aromatic.

Composition of Ginger. Ginger was analysed by Bucholz in 1817, and by Morin in 1823.

The volatile oil is pale yellow, very fluid, lighter than water ; odour resembling that of ginger, taste at first mild, afterwards hot and acrid.

Soft resin, obtained by digesting the alcoholic extract of ginger, first in water, then in ether; it possesses an aromatic odour, and a burning aromatic taste. It is readily soluble in alcohol, ether, and turpentine.

Structure of Ginger. Examined with the microscope, the rhizome of ginger is found to present a well-marked and characteristic structure.

The outer coat or epidermis consists of several layers of large, angular, transparent cells of a brownish colour, adhering firmly together, forming a distinct membrane, and, when macerated in water, becoming soft and somewhat gelatinous (fig. 169).

Lying upon the under surface of this membrane, and scattered