(F.v.M., in Fragm. x. 54, 1876.) Gimlet Gum.

Systematic. - A tall tree, with a smooth, thin bark, stem usually much twisted. Branchlets often green in colour. Abnormal leaves ovate-lanceolate, petiolate. Normal leaves small, lanceolate, acuminate, shining, older leaves particularly so; venation more prominent in younger leaves, intramarginal vein close to the edge, lateral veins spreading, inclined at about 30° to the mid-rib. Peduncles flattened, about 3 lines long, at first axillary, later lateral, with umbels of three to six flowers. Buds shining; calyx tube about 1 line long, semi-ovoid, pedicel twice as lone: operculum blunt, conoidal, 2 lines in length.

Fruit. - Small, truncate, pyriform, tapering to a short angular pedicel, shining; rim convex; valves slightly exserted; 2 lines long and 2 lines in diameter.

The capsule comes closer in form to that of E. squamosa than perhaps to any other species.

Habitat. - Western Australia.

ESSENTIAL OIL. - Material for distillation was received from Western Australia in July, 1904. It was collected at Hine's Hill, Great Eastern Railway, and consisted of leaves and terminal branchlets cut as would be done for commercial purposes The yield of oil was 1.39 per cent. The crude oil was of a light radish-brown colour, and had a very distinct odour of aromadendral. It contained pinene, which was apparently the dextrorotatory form; phellandrene was absent, as was to be expected in this class of Eucalyptus oils. Cymene was present in some quantity. Cineol was detected, bu it only occurs in the oil of this species in comparatively small amount. Aromadendral was present in considerable quantity, and it was to this constituent that the lævo-rotation of the oil was due.

The esters consisted largely of geranyl-acetate.

It is worthy of note how closely the oil of this species agrees with those from the typical "Boxes" of the eastern coast of Australia, and of many of the "Mallees."

The crude oil had specific gravity at 150 C. = 0.902, rotation aD - 5.8°; refractive index at 200 = 1.4784, and was soluble in 1 volume 80 per cent. alcohol. The saponification number for the esters and free acid was 18.9.

On rectification, the usual amount of volatile aldehydes came over below 1680 C. (corr.). Between 168-1720, 18 per cent, distilled; between 172-1830, 46 per cent, distilled; between 183-2190, 18 per cent, came over, and between 210-240°, 9 per cent, distilled. These fractions gave the following results: -

The cineol, determined by the phosphoric acid method in the second fraction, was 18-8 per cent., representing about 10 per cent. of that constituent in the crude oil.

For the investigation of the aromadendral, see the article in this work, on "The cyclic (aromatic) aldehydes occurring in Eucalyptus oils."

There is little demand for this class of Eucalyptus oil at present, although Dr. Cuthbert Hall has shown that aromadendral has marked bactericidal properties, far greater than those of any other constituent in Eucalyptus oils. If hot suitable for medicinal purposes, such Eucalyptus oils, with a high aromadendral content, might well be utilised for disinfectants, and also for soaps and similar articles.

The results obtained with the oil of this species were published by us in the Pharmaceutical Journal, London, September, 1905.