separate the fatty matter. The filtered liquid mixed with acetate of lead, yields a precipitate, which is to be washed and decomposed by hydrosulphuric acid. The light yellow solution of tanno-caffeic acid thus obtained is deprived, by boiling, of an excess of hydrosulphuric acid. This solution, distilled with peroxide of manganese and sulphuric acid, yields the beautiful substance known as kinone; it is easily discernible by its volatility and peculiarly acrid odour, which greatly resembles that of chlorine. The solution of kinone gives, with ammonia, a sepia-black colour, and becomes reddish-brown with hydrosulphuric acid. It is decolorized by sulphurous acid. The beautiful green hydrokinone is obtained by exactly neutralizing the solution of the yellow kinone with sulphurous acid, great care being taken not to introduce the latter in excess.

The tests for kinone can be applied in a few minutes, and they are sufficient to indicate the presence of 10 or 12 per cent. of coffee in a mixture.1

6. The inorganic salts are easily obtained by incinerating a known quantity of coffee, and submitting the ashes to chemical analysis.

Adulterations of coffee.-Coffee is usually and most extensively adulterated, especially when the berries are roasted and pounded to be sold in the form of ground coffee. The adulteration is principally Chicory, the roasted root of the chicory plant (Cichorium intytus), or wild endive. The importance and extent of this adulteration is such as to require the introduction of a special account of chicory and of the adulteration to which it is itself liable.

1 Messrs. Graham, Stenhouse, and Campbell's Chemical Report on the Mode of Detecting Vegetable Substances mixed with Coffee for the purpose of Adulteration (Quarterly Journal of the Chemica Society,' April, 1856).

Chicory and its adulterations.-This plant belongs to the natural family of the dandelion, and is indigenous, or in other words grows in various parts of this country: it may be observed on the roadside, or in the hedges, and recognised by the compound character of its flowers and their beautiful pale blue appearance. It blossoms in the months of August and September, and any one wishing to obtain a sight of this notorious vegetable, may gratify his or her curiosity by a walk along the banks of the Thames from Kew in the direction of Richmond. It has, moreover, been artificially raised in large quantities in this country. In Germany, and some parts of the Netherlands and France, Chicory is extensively cultivated for the sake of its root, which is occasionally used as a substitute for coffee.

When prepared on a large scale, the roots are partially dried, washed, cut, again dried, roasted by a process similar to that employed in the case of coffee, and finally reduced, between grooved rollers, to a powder. The powder very much resembles dark ground coffee, and has a strong smell of liquorice. The per centage composition of Chicory root in its various conditions is represented by the following analysis.

The composition of the roasted root is as follows:

From a glance at the composition of coffee (see page 102) the reader will observe that there is no analogy between it and chicory, so that the latter cannot be made a substitute for the former. Coffee contains two principles, at least, which are possessed of undoubted value and activity: essential oil and caffein, acting as powerful stimulants on the body, whilst no such substances are found in chicory; add to this, that while the infusion made from coffee is light, transparent, and aromatic, that from the other is thick, viscid, heavy, and almost inodorous. (Hassall, p. 113.) Chicory is also highly objectionable from its medicinal properties.

Structure of chicory root.-Three structures may be distinguished; i. e., 1, cells; 2, dotted vessels; and 3,

vessels of the latex, or milky vessels. In the roasted and charred chicory root the microscopical appearance somewhat • resembles that which is detected in the raw or unroasted article.1

1. Cells, constituting the chief part of the root, generally of a rounded form, but sometimes narrow and elongated.

2. Dotted vessels, particularly abundant in the central and harder parts of the root; they are cylindrical unbranched tubes, tapering to a point at either extremity, and marked on the surface with short fibres.

3. Vessels of the latex, containing a milky juice, they form branched and frequently anastomosing tubes with smooth membranous parietes.

Adulterations of chicory.-Improbable as the fact may appear to the reader, chicory is nevertheless adulterated. The substances employed for this purpose are carrot, parsnip, mangold wurtzel, beans, coffina, roasted corn, biscuit powder, burnt sugar, red earth, ground acorns, oak-bark tan, tan known as croats, mahogany and other sawdust, baked horses' and bullocks' livers, Hamburg powder, and Venetian red.

1. Carrot. This vegetable does not contain any vessels of latex. The adulteration is difficult to detect.

2. Parsnip is also similar in structure to chicory root, but there are no lactiferous vessels, and it contains small starch globules.

3. Mangold wurtzel consists of cells three or four times larger than those of the previously described substances.

4. Beans. The size and form of starch globules suffice to detect this adulteration. (See p. 15.)

A section of roasted chicory root, when viewed under the microscope, is found to consist mainly of broken up cells, and large yellow scales.

5. Coffina, a Turkish plant, having the appearance of coffee in colour, and a bitter taste; it appears (from Dr. Hassall's woodcut) to consist of large egg-shaped dotted cells, of superposed elongated vessels, and of smaller angular cells, closely packed together.

6. Roasted corn.—The most frequent adulteration; the microscope will detect at once this fraud. (See p. 15.)

7. Biscuit powder.-The Commission of the Lancet' has been informed that there exists in London a factory for the express purpose of preparing, on a large scale, from an inferior description of flour, a biscuit to be burnt, ground, and exclusively employed in the adulteration of chicory and coffee.

8. Burnt sugar is usually met with in black lumps about the size of a bean, they exhibit a shining fracture, and have a bitter and well-known peculiar taste.

9. Oak-bark tan is seen, with the microscope, to consist of three structures: 1, radiated cells; 2, woody fibres; 3, cells of a rounded form. Oak bark charred and ground very fine is stated to be employed in the adulteration of coffee and chicory.

10. Tan, known as croats, consisting of fragments of cellular tissue and bundles of dotted fibres.

11. Mahogany and other sawdust.-The fragments of this substance possess a reddish colour, and their woody fibres have a peculiar structure; other kinds of woody fibre besides mahogany sawdust are sometimes employed in the adulteration of chicory.

12. Baked horses' and bullocks' liver.-After baking, they are ground into a powder and sold to low-price coffeeshop dealers, at from fourpence to sixpence per pound. The best way to detect this adulteration is to set aside an infusion of the suspected chicory or coffee, and if any