EUCALYPTUS

The Eucalypti , of which there are many species, belong to the natural order Myrtaceæ , and are natives of Australia, where they are known under the names of “gum-trees,” or as “stringy-bark trees.” The most interesting and important characteristic of these plants is the power they undoubtedly po e of correcting, if not of removing, the pestilential exhalations which are regarded as the origin of the fevers that occur in marshy localities. This discovery is due to M. Ramel, and was made by him in 1856. M. Gimbert, amongst other cases, cites one of a farm, twenty miles from Algiers, the atmosphere surrounding which was of a very pestilential character. In the spring of 1867 13,000 eucalyptus trees were planted on the farm, and M. Gimbert states that since then not a single case of fever has taken place, the freedom from disease occurring the same year the plants were placed in the ground, and the good effects commencing whilst the trees were only two or three mètres in height. The following is extracted from ‘Les Mondes’ (1876):—“Between Nice and Monaco there is a locality so unhealthy that the Paris, Lyons, and Mediterranean Railway Company have been obliged to change every two or three months the watchman at a cro ing there. “Plantations of the eucalyptus have been formed there, and at present the same watchman has resided there for several months with his family without experiencing the least inconvenience.” Again:—“In the Campagna, about three miles from Rome, there stand some deserted church buildings and a monastery, the latter having been abandoned because of the mortality amongst the monks caused by the noxious exhalations. Some six years since a company of French trappists, having obtained permi ion from the Italian Government, planted the grounds in and around the monastery with eucalyptus trees, and the result is stated to have been so total an immunity of the building from fever, although situated in the worst part of the Campagna, that the monastery is now tenanted, the health of the occupants being, it is said, unimpaired.” The writer in the ‘Pharmaceutical Journal,’ who contributes this statement, adds:—“Whether this grand result has been obtained through the efficacy of the extract of the eucalyptus taken each morning with their cup of black coffee, or whether it is to be attributed to the effects of the plantations, I leave to scientific men to determine.” [284] [284] Bentley. It seems very probable that the effects above described are due to the eucalyptus having such extensive and far-spreading roots, which suck up and appropriate the moisture of the surrounding soil, the presence of which, aided by heat, giving rise to vegetable decomposition, is believed to be the cause of malarial poisoning. The avidity of the plant for water is very great; it has been computed that one tree will absorb ten times its weight of moisture from the soil. [285] It is most likely owing, at any rate in very large measure, to this cause, rather than to the supposed antiseptic and disinfecting odours exhaled by its leaves, that the salubrious effects of the eucalyptus are due. The blue gum tree, or Eucalyptus globulus (so distinguished because of the rounded form of the lid which covers its unexpanded flower bud), has been succe fully introduced into Asia, Africa, and Southern Europe. If, as a erted, it can only exist in a climate where the temperature is never lower than the freezing point, its domestication (save in hot-houses) is impo ible in our own country. [285] ‘Pharm. Journal,’ February 5th, 1876. IMG:596405606043057898_i684.png: Eucalyptus Globulus (from the ‘Archiv der Pharm.,’ 1873, p. 129.) The Eucalyptus globulus is a very rapidly-growing tree, and attains to great proportions. “In some cases it has been known to attain the colo al dimensions of 350 feet in height and a 100 in circumference.” [286] [286] Bentley. This magnitude is entirely out of proportion to the size of the seed, which is very minute; so minute that it has been computed one pound weight of the seed could produce 162,000 trees. Various preparations of the leaves and bark of the eucalypti have been introduced into medicine, which will be found under the respective pharmaceutical preparations. They were a erted to be specially serviceable in intermittent fevers and bronchitis. The idea that their efficacy in the former cla of disease was due to the presence in the barks of the eucalypti of an alkaloid similar to, if not the same as, quinine, has been shown to be an erroneous one, from the experiments of the Government chemist of Ootacamund (Mr Brought on), who, after a most careful chemical analysis, failed to discover either quinine, quinidine, cinchonine, cinchonidine, or the least trace of any one of the cinchona alkaloids. When the leaves of the Eucalyptus globulus are held to the light they reveal the presence of little semi-transparent dots, which are found to be receptacles for a volatile oil, that may be obtained in large quantity by submitting the plant to aqueous distillation. This volatile oil has been examined by Cloez, who found it to consist chiefly of a substance allied in chemical characters to camphor, which substance he named eucalyptol . [287] Any therapeutic power po e ed by the eucalyptus may be referred to this substance, since, as just stated, it cannot be due to a bark alkaloid. [287] Me rs Faust and Homeyer state that Cloez’s “Eucalyptol” is a mixture of terpen and cymol. Before finishing our notice of the reputed curative effects of the eucalyptus we may mention that Dr Gimbert employs the leaves instead of lint for dre ing wounds and fetid ulcers, and says he has found them, when thus used, excellent deodorisers; that another method of employing the leaves of the eucalyptus consists in having them made into cigarettes, which are reported to be useful in asthma and bronchial complaints. Lastly, let us state that another species of eucalyptus exudes a very astringent substance, which, from its appearance and properties, being so analogous to kino, has been denominated Botany Bay kino . (See Eucalypt in .) The e ential oil of eucalyptus, which, according to the species of the plant from which it is obtained, varies in colour from light yellow to light blue, is now largely employed as a diluent for the more delicate volatile oils used in perfumery. Many species of the eucalyptus yield excellent timber, po e ed of great hardne and durability, and little affected by moisture. This timber has the power of resisting the attacks of insects. The wood of the eucalyptus is also very rich in potash. The maple and the elm, which are regarded as yielding a large per-centage of this substance, afford only about half as much as can be obtained from the eucalyptus, this latter tree yielding 21 per cent. of potash. The barks of different species have also been advantageously utilised for paper making, as well as for tanning. In this country eucalyptus seeds are reared in a greenhouse. They may be sown in a mixture of loam, peat, and ordinary soil, with a sprinkling of sand on the surface. The following directions for the cultivation of the eucalyptus in England were communicated to the ‘Medical Times and Gazette’ of 1873 by Mr Bennett Stanford, of Pyt House, Tisbury:—“I have succe fully reared from seed two dozen of these trees, and they are now growing well out of doors. I obtained the seed five years ago from South Australia, and forced it in a hothouse; in one year it was four feet high, and now, in its fifth year, it is growing rapidly in a sheltered position in the park, having attained a height of thirty feet. The first three years the tree must be taken under cover in the winter, and the fourth and fifth years should be protected for several feet up with wisps of hay or straw. When the trees are kept indoors in winter it should be in an orangery or very high greenhouse, with plenty of light and a little water.”