This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The nutmeg tree, Myristica fragrans, Van Houtte (N.O. Myristicaceoe), is indigenous to the Molucca Islands and a few neighbouring islands, as well as north-western New Guinea, but has been introduced into Penang, Sumatra, Malacca, Java, the West Indies, and Ceylon, nutmegs and mace being exported from the Malay Archipelago, the Straits Settlements, the West Indies, and Ceylon.
The use of the spice was introduced into Europe probably during the twelfth century. The Banda Islands, where they were produced, were discovered about 1506, and passed into the possession of the Portuguese, and finally of the Dutch, who, in this case as in that of cloves and cinnamon, made every endeavour to restrict the cultivation of the trees to the islands of Banda and Amboyna, and thus create a profitable monopoly. The nutmeg trees of adjacent islands were destroyed, and the nutmegs themselves soaked in a mixture of slaked lime and water to render them, it was said, incapable of germination, a precaution that was quite unnecessary, as the vitality of the seed is destroyed by the simple process of drying. For some time these efforts were successful, and the nutmeg trade remained in the hands of the Dutch; but eventually the trees were successfully introduced into Malacca, Ceylon, and Jamaica.
The fruit is a fleshy drupe resembling a small peach in size and shape. As it ripens the fleshy pericarp splits longitudinally and discloses a crimson, lobed arillus surrounding a brown seed (fig. 97). The fruits are collected, the pericarps removed, and the crimson arillus (mace) stripped off in a single piece (double blade) or in two halves (single blade), flattened, and dried, during which the crimson colour changes to a reddish yellow.
The seeds are then carefully dried, usually over a charcoal fire, a process that requires several weeks. When quite dry the kernel rattles in the thin, brittle, brown shell. The latter is broken and the kernel removed. They are frequently dusted over with slaked lime, or washed in milk of lime and dried, before they are exported; this protects them from the attacks of insects, to which they are otherwise very liable. Very probably the original ' liming ' of nutmegs was intended to protect them from insects and not to destroy the vitality of the seeds, as has been often assumed (Tschirch, 1898). They are usually imported in cases which, on arrival in this country, are opened and the contents bulked. The nutmegs are then thrown on to a coarse iron riddle, the broken and otherwise damaged picked out and the sound ones sorted according to their size which is indicated by the number (65, 80, 110, etc.) required to make up a pound weight. Some of these are sold without further treatment, but many are limed (or re-limed), limed nutmegs being preferred in Holland and in the United States. The damaged nutmegs are sold for the production of the volatile and expressed oil.
Fig. 97. - Nutmeg. A, fruiting branch of Myristica fragrans, showing fruit dehiscing. B, stamens of staminate flower; magnified. C, pistillate flower cut longitudinally; p, perianth; g, ovary; magnified. D, Nutmeg surrounded by the arillus (mace). E, the same cut longitudinally, showing the embryo, e. (Luerssen).
Nutmegs are broadly ovoid in shape and about 2.5 cm. in length; they are usually of a greyish brown colour and marked with shallow reticulate furrows. The hilum lies in a little circular depression surrounded by a raised ring, and from it the raphe can usually be traced in a furrow extending to the chalaza at the apex. When examined with a powerful lens the surface is seen to be very finely pitted and marked with minute reddish points and larger dark reddish brown lines and irregularly elongated spots. The section exhibits dark, reddish brown, wavy lines alternating with pale brownish or greyish interspaces. The greater portion of the nutmeg consists of the ruminated albumen, the ruminations being produced by the infolding of part of the perisperm and deposition in its cells of dark colouring matter. These infoldings occur near the fibro-vascular bundles, and produce the depressed lines on the surface of the nutmeg corresponding to the branching bundles.
The cut surface easily yields oil when indented with the nail. The odour is strong and aromatic, the taste aromatic and bitterish.
The chief constituents of nutmegs are volatile oil (8 to 15 per cent.) and solid fat (about 40 per cent.); they contain in addition as reserve material amylodextrin, a substance intermediate between starch and dextrin.
The volatile oil (sp. gr. 0.870 to 0.925; O.R.+ 13° to + 30°) consists chiefly of terpenes together with myristicin which possesses an intense odour of mace and passes over in the last portions of the distillate.
Expressed oil of nutmeg is a yellowish, very aromatic solid, melting at 25° to 43°, obtained from imperfect or broken nutmegs by hot pressure; it contains about 12 per cent, of the volatile oil together with the glycerides of myristic, palmitic, and oleic acids.
Amylodextrin occurs in granules of irregular shape which are coloured reddish brown by iodine (distinction from starch); it can be obtained in a crystalline form, and appears to be an intermediate product between starch and maltose (or dextrose).
Myristicin, C11H1203, is crystalline and toxic; it is more easily absorbed in the presence of the other constituents of nutmegs and is less toxic to lower animals than to human beings.
Penang nutmegs are broadly ovoid and very aromatic. Singapore nutmegs are more deeply and minutely wrinkled and frequently show marks of scorching.
West Indian nutmegs are somewhat elongated and frequently have dark marks on them.
All the above varieties may, however, be of small size, shrivelled, or otherwise defective.
Of the other species of Myristica yielding seeds resembling nutmegs, only one, viz. M. argentea, Warburg, the Macassar or Papua nutmeg, yields an aromatic seed (wild, Papua, Macassar or long nutmeg; exported from New Guinea); this is long, narrower and less aromatic than the official, and has a uniform, brown, scurfy surface and a distinctly acrid taste.
Bombay nutmegs (M. malabarica, Lamarck) are also long and narrow, but are destitute of aroma.
Factitious nutmegs, made from exhausted or damaged nutmegs mixed with mineral matter (clay) and pressed into moulds, have several times been detected; they yield from 11 to 18 per cent, of ash, whereas genuine nutmegs do not afford over 4 per cent.; they also yield less volatile oil (1.76 per cent.), and the section is not regularly reticulated.
Nutmegs have stimulant and carminative properties; in large doses they are toxic, producing convulsions, an action due to the myristicin contained in them. The expressed and volatile oils have been used externally in chronic rheumatism.