The geographical distribution of myrrh-yielding plants is, of course, similarly indefinite. Four distinct districts may be named as the probable sources :—(l) Somali-land, extending southwards from Cape Gardaful and Berbera ; (2) the triangle included between Tajura, Harrar, and Shoo.; (3) the neighbourhood of Ghizan, ou the Atabian shore of the Red. Sea, opposite Masowa; (4) the Arabian coast country stretching E. of Aden. The variety of the gum-resin yielded by each locality is not a matter of certainty. It is generally supposed, however, that true myrrh (hira-b61) is obtained from the first-named diatrict, and brought from the Wady Nogal, Mal cyan, Ogadain, and Agahora, many trees being found also on the hot sunny declivities of the coabt range called Ahl or Serrat mountains, at 1500-3000 ft., and a few on the hills behind Bunder Mareyeh. The bissa-bol variety would seem to be chiefly the product of Harrar and the country lying W. of it, notably the district S.-W. of Zeila, the Adal desert, and the jungle of the Hawash. The Ghizan plant has been called B. Ehrenbergianum, and identified by Oliver witla B. Opobalsannon, a myrrh yielding plant found by Schweinfurth on the Bisharrin mountains of Abysbinia, but Schweinfurth does not admit the identity. The " Arabian " myrrh is produced in the Fadthli country, some 40-60 miles E. of Aden. The article locally known as hotai or hodthai, derived from 13. Pluyfairii, is a bdelliuna rather than a myrrh, and has been described under tho former name (see p. 1637). It must be admitted that future researcla may prove the varieties of myrrh to be due to differences in soil, climate, and time aud mode of collection, as much as to specific dissimilmity in the plants themselves.
The sucietion of the gurn-rain, according tu Marchand's examination of B. Illyrrha, is mainly in the cortical layers, with a little in the medulla. Exudation takes place spontaneously, inciaions never being made in the plants, though bruising with stones is sometimes resorted to, according to Johnston. It escapes from the bark aftir the manner of cherry-gun:1, having at first an oily and then u buttery consistence, and changing its colour while hardening from yellowish-white to golden and finally reddish. It is brought into commerce thiefly by way of Berbera, an E. African port nearly opposite Aden, where it is bought by Banian traders at the great menial fair in November-January, and shipped largely to Bombay. The crude article thus exported, having been collected by ignorant and eareless natives, eontaias all qualities of myrrh, mixed with bdelliums and other foreign resins and gums, and various impurities such as bark and stones. At Bombay, a certain amount of sorting is done, the best samples coming to Europe, the commoner going to China for burning as ine,euse ; this sorting is carelessly performed, and needs to be supple mented by a seeond one here. The article is first sifted to remove the small fragments, and is then
hand-picked, yet the greatest care cannot prevent the occasional presence of spurious gums, even in the best grade.
Myrrh may be distinguished from its impurities by its fraeture,, odour, and flavour. Com mercial myrrh (hira-beil) may be conveniently divided into " soft " and " dry," though brokers do not recognize any such distinction. The soft kiad occurs iu irregularly roundish masses, varying in size from small grains to pieces as large as hens' eggs ; it has a dull, waxy fracture, and is readily impressed by the finger-nail, emitting aa oily exudation. The fracture ofteu shows whitish markings, either in narrow curves concentric to the side which was attached to the tree, or broad streaks, hut never exhibiting cracks filled with transparent resin, characteristic of bissa-bol. The fragrant odour of myrrh is quite sui generis ; the flavour is similar, aromatic and slightly bitter; the colour varies from deep reddish-brown to almost colourless, the palest being most esteemed. Tiny transparent tears sometimes appear on the usually powdery surface ; they am due to the resinification of oil which bas been exuded. Seft myrrh, beaten in a mortar for some time, forms a greasy paste, and cannot be powdered. Dry myrrh exists in irtegular lumps; its fracture is conehoidal and shiny, resisting the finger-nail, and giving uo oily exudation ; in odour and flavour, it sgreos precisely with soft myrrh ; the white markings of the latter are abseut. It contains a much larger proportion of gum (75 per cent.). It is possible that the same tree may afford both soft and dry myrrh at different seasons. Parker has shown that the oue is not converted into the other by long exposure to the air. In external appearance, bissa-bN is much like soft myrrh ; the fracture is waxy, yielding to the fiager-nail, and exuding an oily matter ; but the whitish markings are traversed by angular interstie,es filled with transparent reddish brown resin or gum-resin ; and its powerful aromatic odour is quite unlike that of true myrrh, and has been compared with the odour of apples and of " lemon-lollipop," and with the flavour of the spring mushroom. It is possible that this is the addi or " false myrrh " of a recent traveller in Somali Land (Georges Revoil), which he describes as being of the same colour, but more powerful odour, and easy of recognition from its always appealing oily. The maiu constitueets of myrrh are some 40-75 per cent. of gum, 23-45 per cent. of resin, and a very uacertaie quautity of essential oil. The gum is soluble in water ; the resin partially iu alkalies and carbon bisulphide, completely in chloroform and alcohol. The gum beparated in making tincture may bo used tor malting a common mucilage.