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a section of the mid-rib near the extremity, or at the termination of a vein, there will only be found one bundle, and that in the middle of the section, and somewhat resembling the «horseshoe" in the smaller veins of the tobacco leaf. In chicory leaf, there are usually from three to five bundles in the mid-rib, and one in each vein. In all the veins of the cabbage the bundles are similar to that represented in Fig. 15 (page 337).

It would be well for officers to make themselves acquainted with the outward appearances of tobacco leaves, and those of the chief vegetable adulterants. Rhubarb, dock, and cabbage are sufficiently known to all; coltsfoot, as its name implies, is supposed to resemble in outline the hoof of a horse. It is found plentifully during the summer months in waste places on clay and chalky soils. Burdock is found in most parts of the kingdom by the wayside and in gravel pits. Chicory, in addition to being cultivated, is found growing wild in many parts of the country on chalky and gravelly soils. The leaf is acutely pointed, and somewhat resembles the leaf of the dandelion in form.

PEPPER.

Pepper is the fruit of a plant belonging to the natural order Piperacæ. The plant is cultivated almost exclusively in tropical regions, and particularly in the islands of Sumatra, Borneo, Java, Siam, Malabar, &c. The best pepper comes from Malabar; the least esteemed from Java and Sumatra.

The chief commercial varieties are, black and white pepper, both being procured from the same plant, known botanically as Piper nigrum.

Black Pepper.-(The dried unripe fruit.) To obtain this variety, the berries are gathered before they are ripe, or as soon as any of them are noticed to change in colour from green to red. If allowed to remain longer on the plant they lose some of their pungent quality. They are then exposed to the sun for several days to dry-a process which gives them their shrivelled appearance and lastly separated from the stalks. In this state they form the black pepper corns of

commerce.

White Pepper.-(The dried berry divested of its husk.) This variety may be prepared either from the ripe seeds or from the dried shrivelled berries of the Piper nigrum. In both cases the seeds are soaked in water for some time, which causes them to swell; the husk softens, cracks, and falls off, and the seeds on being dried by exposure to the sun become the white pepper of commerce. Before being sent into consumption they are sometimes bleached with chlorine or chloride of lime, to give them a more sightly appearance.

The pungent, aromatic quality of pepper is due to a volatile oil, an acrid resin, and a crystalline body termed piperine. This pungency appears to pervade the entire plant, but is found in its most concentrated form in the seed.

Another kind of pepper may be mentioned here which belongs to the same family of plants. It is called long pepper, and is procured from Piper longum or Chavica Roxburghii. This, although it has no outward resemblance to the common pepper berry, yet bears to it in respect of microscopical structure and dietetic properties a very close affinity. It is found growing wild in various parts of India, and is cultivated to some extent in Bengal. Very little of it finds its way

to this country as it forms one of the ingredients in the favourite masticatory of the Indian.

Before giving an account of the several adulterants of pepper and the methods employed for their detection, it will be proper to describe in detail the structure of the pepper berry.

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Section of berry showing by the letters A to I, the several layers of which its cortex is composed; J, the interior of berry, filled with cells containing numerous minute starch granules and a few oil globules.

Fig. 20 represents a transverse section of a black pepper berry, and shows the position of the several coats forming the husk or cortex, as indicated by the letters A to I. J is the farinaceous interior of the berry.

Fig. 21 shows the various coats of which the husk of pepper is composed. The first coat, A, consists of a very delicate membrane devoid of colour, and apparently formed of cells of hexagonal shape, in which occur a few stomata. B, is composed of small, irregularly formed, brown coloured cells, containing granular matter. The third coat, C, is composed of sclerogen or radiating cells somewhat oval in form, and bounded by thick walls of a yellowish tinge. In the centre of each cell is a cavity filled with brown colouring matter, and from which lines radiate towards the circumference. Viewed vertically in C, (Fig. 20), these cells appear considerably elongated. D, consists of several layers of

small and large cells of a rounded form, and containing both oil and starch. The fifth coat, E, is a cellular membrane which is traversed by spiral tissue and long narrow cells with beaded walls of a yellowish hue, their cavities being filled with a deep brown colouring matter. Immediately under the membrane just described, is a layer of large round cells, F, containing oil of a bright yellow

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The various skins of which it is composed are denoted by the letters A to I; J, cells filled with minute starch granules.

colour, underlying which is a layer of thick-walled, hexagonal cells, G; the eighth coat, H, consists of peculiarly shaped, reddish-brown coloured cells having crooked or waved outlines, immediately under which and forming the last layer of the cortex is a thin, colourless, transparent membrane, I, composed of cells somewhat resembling in shape those last described. In ground pepper this layer is generally curled up.

The interior of the berry, J, consists of an aggregation of small and large cells containing oil and abundance of starch granules of extreme minuteness, somewhat resembling those of rice, H, Fig. 28, but much smaller.

Fig. 22 is the appearance which genuine black pepper presents when boiled in dilute solution of potash for a few minutes, and viewed with a four-tenths object glass. In this state the various structures composing the berry may be seen to be distorted and confused. In the examination of ground pepper a striking difference will be observed in the size of the cells forming the various structures of the berry, which is due to the fact, that at the base and apex of each berry the cells are much smaller than they are at the other points.

White pepper, being the berry deprived of its four outer coats, can only contain those structures represented in Figs. 20 and 21, and distinguished by the letters E to I and the starch cells J.

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Microscopical appearance of ground Pepper after having been boiled for a few minutes in a dilute solution of potash.

Adulterants.-Black Pepper.-The ordinary adulterants of black pepper as found, from time to time in the Board's Laboratory, are linseed meal, husks of black and white mustard seed, Cayenne pepper, woody fibre, wheat, pea, and bean flour, oatmeal, and the starches of potato and sago.

White Pepper.-In this variety most of the preceding adulterants have been found, with the exception of black and white mustard husks and linseed. In addition, rice-starch, and chalk have been used as adulterants of white pepper.

The husk of linseed, Fig. 23, consists of five distinct coats, four of which are very characteristic. The outer coat, A, is a delicate, colourless membrane, formed of hexagonal cells. The second coat, B, is made up of thick walled circular cells. The third coat, C, is composed of long spindle-shaped cells arranged longitudinally, attached to which and running transversely is an indistinct layer of similar cells. The fourth layer, D, consists of irregularly formed cells, having beaded walls enclosing masses of dark, brown coloured matter, similar in form to the cells, but which are easily displaced.

The interior of linseed is formed of successive layers of cells, F, containing globules of oil.

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A, outer layer of seed; B, second layer; C, third, very characteristic; D, fourth; E, fifth; F, cells composing the interior of the seed containing much oil.

The testa of white mustard seed, (Fig. 24) consists of five layers. The outer layer, A, is formed of colourless, hexagonal cells, having perforated centres which are filled with bodies exhibiting faintly marked concentric lines, and having a slender tube attached to their upper surface. The second coat consists of a double layer of colourless cells, under which is a tissue, C, formed of small angular cells resembling net work. The fourth division of the testa, D, is a layer of very small oval cells of a light yellow colour. The last layer, E, eonsists of thick walled cells of an oval form, and containing dark coloured matter and globules of oil. The substance forming the interior of the seed consists of cells, F, filled with the flour of mustard and oil globules.

The outer coat, A, (Fig. 25) of the black mustard seed, consists of large, irregularly formed, colourless, hexagonal cells. The second coat, B, is formed of small angular open cells, similar, except in colour, to those constituting the third layer of white mustard seed. The third coat, C, is made up of very small perforated, reddish-brown coloured cells, somewhat hexagonal in form. These resemble the fourth coat, D, of white mustard, but the absence of colour prevents any difficulty in discriminating between them. The fourth coat, D, is a brown coloured membrane formed of hexagonal cells with well defined walls. The last layer, E, of the testa, formed of oval cells, containing dark, granular matter and globules of oil, is identical with the same coat in white mustard. It should be particularly noted, that neither white nor black mustard seed contains starch.

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