370 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ May 7,1891. 
examination, in whicli the efforts of the botanist, chemist, physician, 
and physiologist have been combined. One of the directions in which 
science has made important progress of recent years is in the investi¬ 
gation of plant products with the view to their use in medicine, and 
some of this activity is being extended to Australian plants, each year 
advancing our knowledge in this direction. The products of Eucalyptus 
will be alluded to presently, and I will confine myself, in this brief 
sketch, to little more than an enumeration of our native drugs to which 
most attention has been given. Bitter barks seem to obtain most notice 
in all parts of the world. We have several of these, such as Alstonia, 
Tabernsemontana, Petalostigma, Chionanthus, &c., which usually go 
under such names as Quinine, cr Fever Barks. The first one (A. con- 
stricta)has been most worked at, and has rewarded scientific chemists with 
a number of interesting alkaloids ; but so much Cinchona and so many 
Cinchona substitutes are offering from all parts of the world, that bitter 
barks are a drug in the market in a double sense. With the aromatic 
barks, such as the Sassafrases (Atherosperma, Doryphora, Nesodaphne, 
&c.), the case will probably be different, although they can yet scarcely 
be said to have passed the experimental stage. They will probably be 
presented to the pharmacist in the form of essential oils. I will allude 
to but one other class of barks—the pungent, peppery bark of Drimys. 
The true Winter’s Bark of the Straits of Magellan belongs to this genus, 
and was in high repute in medicine for over two centuries until the 
supply fell off. We have two species, and their bark is at present under 
examination with a view to its substitution for the better known one. 
Glancing for a moment at herbs and leaves, we have the Duboisia 
(D. myoporoides), which has been before ophthalmic surgeons for some 
years, but partly because of the intermittent supply, and partly because 
the active principle is deemed by some to present no advantages over 
Atropine, it has not come largely into use. A species of Euphorbia 
(E. pilulifera) has received much attention in Australia as a cure for 
asthma, but while marvellous results are said to have followed its use, 
it can only be held forth as an important palliative in this distressing 
complaint. We have a Native Centaury (Erythrma australis), exten¬ 
sively distributed in Australia, and one of the best known of our native 
plants by country people as a simple bitter, and also for use in 
diarrhoea, &:c. Like all countries we have a multitude of plants pos¬ 
sessing nasty tastes of one kind and another, which possess local 
reputations more or less deserved, but whether they will come into 
more extended use remains to be seen. 
We now come to an important group of substances—namely, the 
exudations, i.e., gums and allied substances yielded by our native 
plants. 
The only true gums in which we do any export trade, or are likely 
to do, are Wattle Gums, which form a low grade gum arable, and are 
used for calico printing and other purposes. The Araucarias yield 
beautifully clear resins, which may have a limited application in varnish 
making, while those of Frenela (Callitris), known as Cypress Pines, 
yield resins which cannot be distinguished from Sandarach. A species 
of Myoporum yields a dark coloured, easily fusible resin, while the best 
known of all, erroneously known as grass-tree “ gum,” and obtained 
from various species of Xanthorrhma, is chiefly used as an inferior 
substitute for shellac. The reddish astringent exudations of our gum 
trees are of much more promise, and, since they are so abundant, a 
trade in them could readily be established. They contain a high per¬ 
centage of tannic acid, and many of them are in every way fit to 
replace the expensive Kino of the Pharmacopoeia. 
Australia is as remarkable for its fewness of plants yielding fixed 
oils in any quantity, as for its wealth of plants yielding essential oils. 
As far as i am aware, not a single indigenous species actually yields, in 
this continent, fruit or seeds for the oil press. 
Chief amongst Australian essential oils, of course, come those of 
Eucalyptus. Every tree of the countless myriads of “ gum trees ” in 
this continent contains essential oil in its leaves, but comparatively few 
species yield it in quantity sufficiently large for its extraction to be 
profitable commercially. 
The analysis of essential oils is surrounded by peculiar difficulties, 
and matters have been complicated by the varying oils w'hich have been 
supplied to different workers, brrt the composition of the principal ones 
is in a fair way to be settled, and the conclusion of the»e researches will 
place commerce in these products on a surer footing. Eucalyptus oils 
are chiefly employed as antiseptics and rubefacients, the chief species 
employed being E. amygdalina, E. oleosa, and other Mallees, and 
E. hfemastoma. Two Queensland species, B. citriodora (the Citron 
scented gum), and E. Staigeriana (the Lemon scented Ironbark), yield 
sweet scented oils, which, in addition to the uses above mentioned, may 
perhaps be emp'oyed for perfumery purposes. Other planis of our 
indigenous vegetation have been distilled for their oils, but their products 
at present remain curiosities of the laboratory. 
As far as is at present known Australia yields no indigenous dye¬ 
stuffs of any consequence in these days of chemical preparations, out 
she makes up for this lack by a great profusion of tanning substances. 
The astringent properties of our Kinos have been briefly referred to, and 
the barks of some Eucalypts (Ironbarks and a few other trees), are 
locally used for tanning; but one genus of plants has made the reputation 
of Australia as a producer of tans. I, of course, allude to the Wattles 
(Acacia), of which this continent is the headquarters. Spread over 
these colonies are over 300 species, varying in size from a few inches in 
height to large trees. The barks of all are more or less astringent, 
though the vast majority are too small in size, too limited in distribution, 
or too poor in tannic acid, for them to enter into commerce. Four 
Wattles deserve particular mention. First comes the Golden Wattle of 
South Australia and part of Victoria (Acacia pycnantha), a small tree 
with a solid bark, which in mature specimens contains from 40 to 50 per 
cent, of tannic acid ; Acacia decurrens Sydney Black Wattle, and 
Acacia mollissima New South Wales Green Wattle, or Victorian and 
Tasmanian Black Wattle, larger trees than the preceding, but not so 
strong in tannic acid (35 to 40 percent, in best specimens) ; and Acacia 
saligna Weeping Wattle, found in Western Australia, and yielding the 
best tan bark (30 per cent, of tannic acid), in that colony. In the early 
days of settlement Wattles were abundant in most of the colonies, but 
the greater number have been got rid of with great prodigality. The 
result is that now there are comparatively few mature Wattle trees of 
tanning value remaining ; trees are stripped before the bark has attained 
its full strength, while the price of good bark has increased to an almost 
prohibitory figure, and export has almost cea.sed, except in one or two 
colonies. The remedy for this is conservation of existing trees and 
replanting. For replanting we have Acacia pycnantha, which prefers 
warm and dry situations ; and Acacia decurrens, and the closely related 
mollissima, for damper and colder localities.—J. H. Maiden, F.L.S.,, 
F.C.S., &c., Curator of the Technological Museum, Sydney; author of 
“ The Useful Native Plants of Australia,” (in the Year BooTt of 
Australia.') 
(To be contiuued.) 
SETTING LAWN MOWERS. 
The term “setting” is well understood by gardeners as adjusting 
the knives, plate, and rollers, so that the machine cu‘s cleanly, smoothly,, 
FIG. 68.—eansome’s lawn mower. 
and evenly. Messrs. Ransomes, Sims, k Co., Ipswich, send the accom¬ 
panying illustrations, the first of which shows the method of setting 
adopted in their machine, and the second the machine set for work. 
We have not received any description of the contrivance, but as we have 
seen the machine are able to say that the method of adjusting the parts 
for working is as simple and satisfactory as anyone could desire, and 
more so than could be imagined by persons who have only had experi¬ 
ence with machines that had to be turned over to work the bottom 
screws, and some of these difficult to reach. So far as we remember, 
and as the engraving shows, one screw only on each side needs turning 
to loosen or tighten as may be required, and this can be done with the 
greatest ease when the machine is in its natural working position. It 
is a good mechanical arrangement. 
AURICULAS AT SLOUGH AND READING. 
These two places are associated in my mind with many floral 
memories. Slough I knew in the days of “ Brown,” but it was not until 
the nursery passed into the hands of my late friend Charles Turner that 
it became a regular place of pilgrimage to me, with the great firm of 
Sutton & Sons—that is, before that time my old friend was then in his 
quiet little cottage at Chalvey, and had not burst forth into the full¬ 
blown florist he afterwards became. But ah 1 how well I recollect his 
frames of Pansies—he had not then begun to grow Auricirlas—and oftem 
do I muse over the pleasant visits paid there when we were both young, 
