24. Mr. Mudie on 
latter is a very abundant genus, and the gum which it affords 
is astringent, like kino or myrrh; while that of the Acacia is 
more mucilaginous, and approaches nearer to gum arabic or 
the gums of the genus Prunus, as common in this country. . 
One species of Eucalyptus affords a substance, of which the 
medicinal properties have been tried in Australia, and which, 
should it be found to suffer no injury or decomposition dur- 
ing the voyage, might materially reduce the price of manna, 
which still retains its rank as a medicine. 
Until the substance itself, which appears rather difficult to 
preserve, be laid before the Society for their examination and 
decision, it may not be altogether useless to offer a few notes 
on the plant, as even that is but imperfectly known, and has 
not, it is believed, been figured or described in any scientific 
work. The following are the characters, and a few points in 
the description: 
Generic character of Eucalyptus. Calyx superus, per- 
sistens, truncatus ante anthesin tectus. Operculo integer- 
rimo, deciduo. Corollanulla. Capsula quadrilocularis, apice 
dehiscens, polysperma. 
Natural order: Myrtacee. 
Specific name: Eucalyptus mannifera. (Manna gum tree.) 
Specific character: Operculo hemispherico acutiusculo, 
umbellis axillaribus terminalibusve 4-6 floris, cortice albo- 
cinereo. 
The principal habitat of this tree is upon the elevated 
downs into which the Blue Mountains subside, and upon the 
adjoining slopes. It grows to the height of from thirty to 
forty feet, of irregular growth, and having a number of 
slender branches. As is the case with almost all the 
genus, the leaves, which are simple, lanceolate, and entire, 
are placed vertically, by a peculiar twist of the footstalk. 
From the accounts given of it, it does not appear that the 
manna produced by this Eucalyptus is very different from 
that yielded by the Fraxinus, on the coast of the Mediter- 
ranean; though, as common report describes it as having less 
of the nauseous taste, it may be less efficient as a medicine. 
Like the manna of Europe, it is reported to contain a sac- 
charine and a mucous ingredient, both of which are easily 
soluble in water, and partially so likewise in the atmosphere, 
when moist. It obviously arises from a rupture in the cortical 
vessels of the tree, produced not by the puncture of insects, 
but by atmospheric action, as it is produced only in the dry 
season, and the quantity varies with the degree and duration 
of the drought. . 
Toward the close of along dry season, it is found so abun- 
