155 
To wliicli I replied :— 
There is a small quantity of Caoutchouc in the leaves of (at least) the members of the Corymbose 
section of the genus. It is particularly observable in the widely-distributed E. corymbose/, Sm. (Blood- 
wood). It is a common thing to see small boys pull apart the young leaves of that species, and a thin 
membrane, mainly consisting of Caoutchouc, is at once obtained. (23/5/03.) 
The quantity of caoutchouc in Eucalyptus leaves has not been ascertained, 
so far as I am aware, but it is not likely ever to he a commercial source of that 
article. 
The leaves of the Lemon-scented Gum are used to a limited extent for 
perfumery purposes when dry ; they are, however, of far greater importance as 
yielders of essential oil. As regards ordinary Spotted Gum, I am not aware that 
the leaves are distilled for commercial purposes. Eollowing are some references to 
the oils of the Spotted Gum and its variety, emanating from the laboratory of the 
leading essential oil firm of the world, Messrs. E. Schimmel & Co., Miltitz, Saxony :— 
Oil of Eucalyptus mar.ulata. —The Spotted Gum-tree ( Eucalyptus maculata ) closely related to E. 
citriodora, Hook., grows in New South Wales and Queensland, but has also been transplanted to Ceylon 
and Algiers. The oil, of citronellal-like odour,* * * § has the sp. gr. 0-900, boils from 210-220°, and cannot be 
distinguished from the following oil (E. citriodora.). f 
Oil of Eucalyptus citriodora.—Eucalyptus citriodora , Hook., is probably only a variety of E. 
maculata, Hook., and is for this reason sometimes designated as E. maculata, Hook., var. citriodora. The 
tree grows best in strong ground. It is indigenous to Queensland, and has also been planted with succcess 
in India, in Zanzibar, and on the Magdalene River. | The fresh leaves are distilled in Gladstone (Queens¬ 
land) and give, in the fresh state, 1-T5 per cent. ; in the dried state, 3-4 per cent, of oil. 
The oil, distinguished through its pleasant citronellal-like odour, is much used as a perfume for 
soap. Sp. gr. 0-870-0-905. It is inactive or slightly dextrogyrate (a D up to + 2°), and is soluble in 4 or 
5 parts of 70 per cent, alcohol. 
It consists to the extent of 80-90 per cent, of citronellal, C J0 H, 8 O. The remainder of the oil, 
judging from the odour, consists of geraniol and citronellal. Cineol is not contained in it § (The above 
extract is also taken from Gildemeister and Hoffman’s work, p. 537.) 
An oil of Eucalyptus citriodora, recently obtained by us, via London, showed properties which 
differed somewhat from those observed in other cases, viz., specific gravity 0-865 ; a D = -15° 52' at 19°. 
Soluble in 7 and more parts of 70 per cent, alcohol. The aldehyde-content, found by Tiemann-Parry’s 
cyanacetic-acid method, was 87 per cent. The determination can be made with this oil without difficulty, 
as it is free from slimy and wax-like substances, which, as in the case of oil of lemon, make it difficult or 
totally impossible to read the scale correctly. 
Some oils previously examined in our laboratory had specific gravities from 0-870 to 0-905, were 
either inactive or slightly dextrogyre, and formed already clear solutions with 5 parts of 20 per cent, 
alcohol. (Schimmel Co., April-May, 1901, p. 35.) 
The Chemist and Druggist, of Australasia, 1890, in noticing a sample of oil 
of the Lemon-scented Gum, received from Mr. A. J. Timbury, of Gladstone, Q., 
says :— 
The odour strongly recalls that of citronella, so that in its commercial career the oil will have to face 
the competition of one of the lowest priced of essential oils. For external medicinal use this resemblance 
• Bericht von 8. & Co., April, 1888, p. 19. 
+ “ The Volatile Oils ” (Gildemeister and Hoffmann, p. 536). 
t v. Mueller, Select Extra-Tropical Plants, 1, 9th ed., p. 187. 
§ Bericht von Schimmel & Co., Apr., 1888, p. 20 ; October, 1890, pp. 16 and 20 ; April, 1891, p. 19 ; April, 1893, 
l age 27 ; October, 1893, page 17. 
