Structure of the integuments surrounding the seed in which A, B, C, D, and E indicate the several layers, and F the oil cells.

A, B, C, D, and E, the several layers enveloping the seed; F, cells from the interior of seed containing much oil.

Capsicum, (Fig. 26.)-Each capsicum pod is divided lengthwise by a thick membrane called the placenta, to both sides of which are attached small flat seeds of a yellow colour. Cayenne pepper (so-called) consists of the ground pods of capsicum, and is itself occasionally adulterated, especially with common salt, red oxide of iron, and-it has been alleged-red lead. Cayenne pepper is subject to the same customs duty as common pepper, and when added to the latter alone, does not constitute an adulteration. On account of its greater pungency, it is sometimes mixed in small quantity with common peppers, to restore the pungency lost by the adulteration of these with ground rice, sago-flour, and other like materials. It may be observed, that « chillies," capsicum, and cayenne powder are botanically

the same.

Three coats form the structure of the capsicum pod, as represented in Fig. 26. The epidermis or first coat, A, is a thick membrane of a yellow colour, and consists

A, B, and C, the respective coats of which it is composed.

of large, angular, thick walled cells, containing granular matter and orange coloured globules of oil. The second coat, B, consists of cells with rounded outlines, containing abundance of orange coloured oil. These cells are traversed by bundles of spiral tubes and a little woody tissue. The inner layer, C, consists of divisions of peculiarly formed tortuous cells of a yellow colour through the boundary lines of which runs a dotted line.

The placenta, A, (Fig. 27) consists of a membrane formed of cells with wavy borders, and which gradually assume a hexagonal form as they recede from the pod.

A, placenta with numerous globules of oil; B, outer coat of seed; C, inner coat of seed; D, cells forming substance of seed.

Figure 28.
Starches.

(Magnified 150 diameters.)

H

A, potato starch; B, orris-root starch; C, sago stareh; D, pea or bean starch; E, wheat starch F, maize starch; G, oat starch: H, rice starch.

Each seed is formed of two distinct coats, B and C, which envelop a mass of cells, D, composing the interior; B represents a fragment of the outer coat, and is formed of thick tortuous cells of a bright yellow colour. The second coat, C, consists of small, angular, thick-walled colourless cells which enclose those, (D) forming the substance of the seed.

In a sample of spurious pepper, particles of linseed, capsicum, and rice, if present, may be picked out with the aid of a pocket lens, in the following manner. Place a little of the suspected pepper in a small, fine sieve and shake it. The finer particles of the pepper will pass through, together with wheat, pea, bean, potato, and sago starches, and the chief portion of mustard, linseed, capsicum, and rice. There will always, however, remain sufficient of the last four for detection. Linseed may be known by its clear, shining coat and brown appearance. Capsicum, by its reddish-brown colour and pungent taste, and rice by its semi-transparency, the angular form of its particles, and the resistance which it offers to the attempt to bruise or flatten it under a knife or other instrument. Officers may, after a little practice, dispense with the sieve, as by simply spreading out the sample, the adulterants just mentioned may be readily detected. The appearance which the granules of potato starch present under the pocket lens has been described in the article on snuff (page 341). A better method, perhaps, is to moisten a portion of the suspected pepper on a slip of glass, bruise it, then scrape off the larger particles, cover the remainder with a thinner slip, and on looking through the combined lenses the same glistening specks will be seen on holding the glass up to the light.

With the aid of a microscope pepper may be examined in the following manner. It is best to look for starches in the first place. For this purpose, take as much of the pepper as will lie on a sixpence, place it on a microscope-slide, add a few drops of water, then bruise the sample well with a knife, and scrape off gently the thicker particles; add a few more drops of water to the residue, spread it evenly, cover with a thin slip of glass, and examine with a quarter-inch objective. All the starches may be thus easily distinguished: potato (A, Fig. 28), by its size and resemblance in the form of some of its granules to an oyster-shell, (the other granules being oval) and also by the concentric rings; sago (C), by the piece seemingly cut from the end of each particle; pea and bean (D), by the longitudinal grove running up the centre; wheat (E), by its circular appearance; oat (G), by its angular shape, and its proneness to form into clusters; and rice (H), by its smallness and angular form. To obtain confirmatory evidence of the presence of any of the different starches, it is necessary to mount pure specimens of starches, and compare them with those observed in the sample.

For the detection of the other adulterants, boil a portion of the sample in a small basin, test tube, or other convenient vessel, with some water and a few drops of solution of potash or soda. The liquid portion should then be poured off, and the residue washed once or twice with water, or if a sieve be at hand, thrown on to it and well washed; a small portion is then placed on a slide, a drop or two of water added, a covering glass placed over it, the superfluous liquid and excess of other matters pressed out, and the mounting viewed under a half-inch object-glass. Linseed will be distinguished by its second and third coats (Fig. 23); white mustard by its first and third skins (Fig. 24), and the absence of any colour; black mustard, by its second coat and reddish colour (Fig. 25); capsicum, by the first and third coats of the pod (Fig. 26), and the

first of the seed (Fig. 27), but chiefly by the latter; and woody fibre, by its spindle-shaped tissue and the appearance of bars or medullary rays crossing it (A and B, Fig. 17).

COFFEE.

The botanical family, Cinchonaceae, furnishes many plants possessing high medicinal properties and conducing in other respects to the well-being of man. Not the least useful of these plants is an evergreen shrub called Coffea Arabica, better known as the Coffee tree. It is said to be a native of the mountainous parts of Ethiopia, but is now extensively cultivated in both Asia and America.

The fruit of the coffee tree is a reddish, succulent berry, formed of two cells, lined with a cartilaginous, parchment-like membrane, and each enclosing a seed which is convex on the outer and flat on the inner side, with a furrow running lengthwise up the latter. This seed is the coffee bean (erroneously termed berry)

of commerce.

There are many varieties of raw coffee, but the characteristics of each are due in a great measure to climate and the mode of culture. The manner in which the berries are prepared for commerce by the planter varies in different countries. In Arabia, the fruit, when fully ripe, is shaken from the trees; while in the West Indies it is plucked by hand as soon as it assumes a deep red colour, and is then spread on mats and dried by the heat of the sun. It is next crushed between rollers to break and separate the husk from the seeds or beans, and these on being again dried, are ready for the market.

The essential constituents of raw coffee are caffeic acid, a nitrogenous substance termed caffeine, identical with theine, the alkaloid of tea, and an aromatic oil. The changes which the bean undergoes during the process of roasting are not well understood, but two new bodies seem to be formed, namely, a bitter principle, and an oil called caffeone, to which the peculiar aroma of roasted coffee is supposed to be due. During this process the beans increase about one-fourth in bulk, and lose from 12 to 20 per cent. of their weight.

The coffee berry (Fig. 29) consists of four well defined parts, namely, the husk, the parchment, the skin, and the two seeds or beans. The first of these is made up of hexagonal cells, with a few small spiral vessels. The parchment or lining of the husk consists of only one form of structure, being composed of elongated cells, lying irregularly one upon the other, and marked with transverse bars. These (the husk and parchment) are seldom, if ever, found in commercial coffee, as they are almost wholly separated from the bean by a process of winnowing, before the latter is imported. The third layer or skin is the covering of the seed proper. It is formed of long, spindle-shaped cells, having oblique bars or markings within their outlines. The same skin also contains a few, fine, spiral vessels in that part which extends into the groove or fissure of the bean. Part of this skin separates from the bean in the roasting, and is termed «flights," but a considerable portion is always found in genuine coffee, and often forms a valuable and characteristic feature in microscopical investigations relating to the subject. The fourth and last part of the berry consists of the two seeds or beans, which are made up entirely of thick-walled quadrangular cells.