When moistened with water the particles become soft, while those of coffee remain hard and difficult to bruise.

Chicory. The tissues composing chicory-root are shown in Fig. 14. A represents the pitted tubes, which are present in considerable quantity and are highly characteristic. They resemble

long jointed cylinders, and are distinctly marked with bars or pits. The joints frequently overlap each other, and give to the cylinders an uneven appearance. B represents what are called laticiferous or milk vessels. They are narrow, transparent, branching tubes, filled with latex. In the roasting of the root the latex is dried up, and the interior of the tubes presents the appearance of being filled with granular matter, as shown in the drawing.

c represents the cellular tissue, which consists of round or oval, smooth, and thin-sided cells. Those composing the bark or skin are somewhat angular, as seen at D.

Chicory is free from starch.

The size of the dotted tubes, the peculiar appearance of the

joints, and the presence of the laticiferous vessels, afford a ready means of distinguishing chicory from the other root adulterants. Dandelion root has a structure somewhat similar to that of chicory, but the pitted tubes of the former are narrower and more regular, and the laticiferous vessels more abundant and better defined than the corresponding tissues of the latter.

Mangold Wurzel.-The microscopic appearance of the tissues composing mangold wurzel is shown in Fig. 15. The pitted

tubes represented at A are very abundant and large. Many of them have blunt oblique ends, and on trituration they break up into shorter tubes which terminate obtusely. The cells of the tissue shown at в are larger than those of chicory; they are very transparent and thin-sided, possessing little cohesion, the slightest trituration causing them to separate. The cells composing the outer skin are angular.

The absence of laticiferous tissue and the size of the cells serve to distinguish mangold wurzel from chicory. Like the latter, however, mangold wurzel is free from starch.

Turnips.-The turnip when roasted and ground presents the appearance shown in Fig. 16. It is composed of cellular, pitted, and woody tissues. The first two of these are very similar to the

corresponding structures in mangold wurzel, except that the cells are more irregular in size, and have no tendency to separate, but hold together with considerable tenacity. The woody tissue, which is present in abundance, breaks up on boiling into bundles of short flakes having a striated appearance.

The absence of starch and the presence of the woody tissue make the identification of turnip comparatively easy.

Carrots.-The cells of the cellular tissue of this root are small, transparent, and thin-sided, and those of the skin or bark are angular in shape and very regular. The pitted tubes occur amongst the cells, and, excepting that they are somewhat smaller, resemble those of turnip and chicory.

Carrots contain starch, the granules of which are very small and round, and in some cases muller-shaped, with distinct central hilums.

Parsnips.-The tissues of parsnips so closely resemble in form and size those of carrots, as to render it almost impossible by these characters alone to distinguish between them when roasted and ground. The cells of parsnips, however, contain a much greater proportion of minute starch-grains than those of the carrot, and there is a greater irregularity in the size of the granules.

Carrots and parsnips differ from chicory in not containing laticiferous tissue, and also from chicory and the other root adulterants in containing starch.

II.-SEEDS.

Seeds are usually best detected by the microscope, and, as neither they nor their seed-coats contain pitted tissue, there is little difficulty in distinguishing them, even when roasted and ground, from roots.

When a seed is roasted and ground with its seed-coat, there is usually to be found in the structure of the latter some

characteristic tissue by which the seed can be identified; but where it happens that the seed is skinned before being roasted, it becomes necessary to seek for evidence of its identity, either in the condition of the cells or in the character of the starch, if any be present. It is not, however, always practicable to distinguish very clearly the particular kind of starch present, owing to the broken condition of the granules produced by torrefaction.

E

FIG. 17.-BEAN.
Tissues of Bean, magnified 50 diameters.

When a few grains of a sample containing a leguminous or other starchy seed are placed under the microscope, and a little iodine solution added, the particles of roasted starchy matter will appear of a more or less distinct purple colour.

Beans. The garden bean consists principally of very tough thick-walled cells, seen in mass at E, Fig. 17, filled with large starchgranules. These cells are generally oblong, and when crushed