136. _SENNA is a drug, the dried leaves of an annual plant_ (Cassia
senna) _which grows in various parts of Africa and Asia._
_The stems of this plant are woody, and not unlike those of a shrub. The
leaves are winged, and the leaflets oval, smooth, and pointed. The
flowers, which grow in lengthened clusters, and are of pale yellow
colour, are succeeded by oblong, compressed, and kidney-shaped pods._
The cultivation of senna is carried on to considerable extent in Ethiopia,
Arabia, Persia, and Upper Egypt, from several of which countries it has,
from time immemorial, been brought by the caravans to Alexandria, as the
most convenient port whence it could be shipped or sold into Europe. From
this circumstance, it is sometimes denominated _Alexandrian senna_. The
process of stripping and drying the leaves is perfectly simple. When dried,
they are of a yellowish green colour, have a faint, though not unpleasant
smell, and a somewhat acrid, bitterish, and nauseous taste.
These leaves have long been in use in Eastern countries as a medicine; and
their repute, though not so great as in the East, is very considerable in
Europe. They are administered in various ways; and the _pods_ have the same
effect as the leaves.
A kind of senna has of late been cultivated, with success, in Italy and
some of the southern parts of France.
137. _The OFFICINAL CASSIA is a somewhat cylindrical pod, about an inch
in diameter, and a foot or more in length, the fruit of a tree_ (Cassia
fistula) _which is cultivated in Egypt, the East and West Indies, and
South America._
_This tree is forty or fifty feet high, and much branched. Its leaves are
winged, with five pair of leaflets, somewhat oval, pointed, smooth, and
of pale green colour. The flowers are large, yellow, and grow in oblong
clusters. The pods are divided, by transverse partitions, into numerous
cells, each containing one seed._
These pods are in request on account of the black, sweetish, but somewhat
acid _pulp_, which is contained in their cells, and which is used, in many
cases, as a mild opening medicine. It is customary in Egypt to pluck the
pods before they are quite ripe, and to place them in a house, from which
the external air is, as much as possible, excluded. They are then laid in
beds about six inches deep, having palm leaves interposed betwixt them. On
the two following days the whole are sprinkled with water; and, in the
course of about six weeks, they are in a fit state to be packed for sale.
The East Indian and West Indian cassia somewhat differ, both in appearance
and qualities. Of the former the pods are smoother, smaller, and have a
thinner rind; and the pulp is of a deeper shining black colour, sweeter,
and more agreeable to the taste. In choosing cassia, those pods should be
selected which are the heaviest, and in which the seeds do not rattle on
being shaken.
138. _LIGNUM VITÆ and GUIACUM are the wood and resin of a large West
Indian tree_ (Guiacum officinale, Fig. 77) _which has winged leaves in
two sets upon one footstalk, and regular flowers of five petals._
_The usual height of this tree is between thirty and forty feet. The
leaves consist of two, three, and sometimes four pairs of leaflets, which
are somewhat oval, and of shining dark green colour. The flowers spring,
in clusters, from the division of the smaller branches; the petals are of
a rich blue colour, and the stamens are crowned with yellowish anthers._
The _wood_, resin, bark, and even the flowers of this tree, are all of use
either in the mechanical arts or in medicine. The former, which is yellow
towards the outside, of deep blackish brown colour in the centre, and so
compact and heavy as to sink, when immersed in water, is chiefly employed
in the West Indies for the wheels and cogs of sugar mills. It is also
formed into mortars, bowls, and domestic utensils of various kinds, for
which, on account of its hardness, and not being liable to warp, it is
peculiarly valuable. Lignum vitae is chiefly imported into this country
from Jamaica, in logs or pieces of four or five hundred pounds' weight
each, and is in great request for school-boys' rulers, and numerous
articles of turnery ware. A decoction of the wood, when rasped, is
occasionally administered as a medicine in rheumatic and gouty affections.
The _resin_ of this tree is sometimes obtained by wounding the bark in
different parts. It exudes through the wounds; and, when sufficiently
hardened by exposure to the sun, is taken off, and packed in small kegs for
exportation. Sometimes it is obtained by sawing the wood into billets, each
about three feet in length, which are then bored with an augur
longitudinally, and laid upon a fire, in such position that the melted
resin, which flows through the hole as the wood burns, may be received into
a vessel placed for the purpose of containing it. This resin, which is
frequently called _gum guiacum_, is of a greenish colour, but has sometimes
a reddish hue. Its taste is pungent and acrid. From the bark of the tree
there is frequently a spontaneous exudation: this has the name of _native
gum_, and is imported in small, irregular, bright pieces, which are much
more pure than the gum obtained in any other way. Guiacum is used as a
strengthening medicine, and a warm aromatic; it is employed as a remedy
against rheumatic and other pains, and as an ingredient in many officinal
preparations. On its first introduction, which was soon after the discovery
of America, it was in such repute as to have been sold for seven crowns a
pound.
In the West Indies, the _bark_, _flowers_, and _fruit_, are each employed
in medicine; and of these the former is frequently used instead of soap for
washing, in which process it gives a good lather.
139. _BALSAM OF TOLU is a reddish yellow, thick, and pellucid substance,
of fragrant odour, which is obtained from a tree_ (Toluifera balsamum)
_which grows in South America._
_This tree is of considerable height; and has somewhat oval leaves, each
on a short foot-stalk. The flowers are numerous, and in lateral branches;
and the fruit is a round berry._
The name of this balsam has been obtained from its being chiefly procured
from the province of Tolu, on the north coast of South America, near the
isthmus of Panama. Incisions are made in the bark of the trees, at a
particular season of the year, and a resinous fluid of yellowish white
colour oozes out. This is collected in small gourd shells. At first it is
about the consistence of treacle, but it thickens by being kept; and by age
it becomes hard and brittle. Its smell is peculiarly grateful, somewhat
resembling that of lemons; and its taste is warm and sweetish. On being
chewed, it adheres to the teeth.
This balsam is used in medicine both in the form of a tincture, and a
syrup; and, in its medicinal virtues, it agrees with most other balsams.
The syrup of Tolu is used in several medicines; and is also made into
lozenges, which may be procured of almost any chemist, and which are
considered serviceable in appeasing the irritation occasioned by severe
coughing.
140. _BENZOIN or GUM BENJAMIN, is a concrete or solid and fragrant
balsamic substance, the produce of a tree_ (Styrax benzoe) _which grows
chiefly in the island of Sumatra._
_This tree has oblong leaves which taper to a pointy and are smooth on
the upper surface, and downy beneath. The flowers are in loose bunches;
they usually hang all on the same side; and are generally closed, which
gives them the appearance of buds._
In some of the northern parts of Sumatra, particularly near the sea coast,
there are several extensive plantations of Benzoin trees. The seeds or nuts
are sown in the rice fields, and they afterwards require no other attention
than that the surrounding shrubs should be cleared away from about the
young plants.
When the trees have attained the age of six or seven years, incisions are
made into the bark; and from these the balsam exudes, in the form of a
thick, whitish, resinous juice. By exposure to the air, this juice soon
hardens; it is then pared from the bark with a knife or chisel. For the
first three years the trees yield the purest resins: this is of a white
colour inclining to yellow, is soft and fragrant. Afterwards, for the next
seven or eight years, an inferior sort is yielded; this is of reddish
yellow colour, degenerating to brown. At length the trees, unable to bear a
repetition of the process, are cut down, and split into pieces. From these
is procured by scraping, a still worse sort of benzoin, which is
dark-coloured, hard, and mixed, more or less, with parings of the wood and
other impurities.
The inferior sorts of benzoin are exported to Arabia, Persia, and some
parts of India, where they are burned, to perfume, with their smoke, the
temples and the houses of the inhabitants; to expel troublesome insects,
and obviate the pernicious effects of unwholesome air or noxious
exhalations.
Benzoin is brought for sale to the mercantile parts of Sumatra, in large
cakes, covered with mats. In order to pack it in chests, it is necessary to
break these cakes, and to expose it to the heat of the sun. The greater
part of the benzoin which is brought to England is re-exported to countries
where the Roman Catholic and Mahometan religions prevail; to be there
burned as incense in the churches and temples. The annual exportation of
benzoin from London to Mogadore only has been estimated at 30,000 pounds'
weight per annum.
That which is consumed in England is chiefly employed in medicine, in
perfumes, and as cosmetics. It constitutes the basis of what are called
_Turlington's_ or _Friar's balsam_, and _Jesuit's drops_; the salutary
effects of which, particularly in healing recent wounds, is well known.
This balsam is composed of benzoin, balsam of Tolu (139), Socotrine aloes
(107), and rectified spirit of wine. Benzoin is also used in the
preparation of what is called _ladies' court plaster_; but in this it is
supposed to be unnecessary if not prejudicial; not only as it renders the
plaster more difficult to be moistened, previously to its application, but
as the irritating quality of the benzoin may in some instances dispose a
fresh wound to fester. The mode of making court plaster is very simple.
Five ounces of isinglass are dissolved in a pint of water. A quantity of
thin black sarsnet being then stretched on a frame, a warm solution of the
isinglass is applied with a brush equally over the surface; and, when dry,
this is repeated a second or third time. It is finally brushed over with a
weak solution of benzoin in spirits of wine, which communicates to it a
pleasant aromatic smell.
If powdered benzoin be put into an earthen vessel over a slow fire, and the
fumes of it be made to sublime into a paper cone fixed to the top of the
pot, the substance thus formed is the _flowers of benzoin_ of the shops, or
_Benzoic acid_, as it is termed, by chemists.
141. _STORAX is a fragrant, concrete, or solid balsam, that is obtained
from a tree_ (Styrax officinalis) _which grows in the Levant, and in some
parts of Italy._
_This tree grows to the height of twenty feet and upwards: it is much
branched, and has broad, alternate, oval leaves, somewhat pointed, smooth
above, and downy beneath. The flowers are large, white, in clusters on
short footstalks, and terminate the branches._
The best storax is obtained from Asiatic Turkey, in small transparent
masses, of pale red or yellowish colour, and generally abounding in whitish
tears, resembling those of benzoin. The drug, however, which is commonly
sold in the shops as storax, consists of large, light pieces, very impure,
from the saw-dust with which it is mixed.
The mode of obtaining this balsam is similar to that employed for benzoin
(140): incisions are made in the trees, and, on its oozing from the wound,
it is scraped off, and collected together to be packed for sale. It was
formerly customary to enclose it in reeds.
Storax is one of the most fragrant of the balsams, and is much used in some
countries in perfumes, and for fumigation. It is also compounded in various
ways with other substances, for medicinal use.
142. _LOG-WOOD is a dark red wood, chiefly used in dyeing; and imported
from Honduras, and some of the islands of the West Indies._
_The log-wood tree_ (Hæmatoxylon campechianum, Fig. 43) _is from sixteen
to twenty-four feet high, and, both in the trunk and branches, is
extremely crooked. The branches are spinous, and the leaves winged, with,
in general, four or five pair of leaflets, which are somewhat
heart-shaped. The flowers are if a reddish yellow colour, small, and
numerous._
The district of Honduras in North America has long been celebrated for the
production of log-wood, which grows wild chiefly in forests where the soil
is moist, or near the banks of rivers and lakes. The cutting of it occupies
a great number of hands, and is an unpleasant and very unhealthy pursuit.
In the year 1715 some seeds of the log-wood tree were introduced into the
island of Jamaica; and this wood is now chiefly employed in that island as
a fence against cattle. As an article of commercial export, it does not
appear to answer so fully as could have been wished; yet, in morassy parts
of the island, it grows in considerable luxuriance.
Few kinds of wood are of more solid texture than this. Hence arises its
weight, which is so great that it will sink in water. Its predominant
colour is red, tinged with orange and black; and its hardness such that it
is capable of being polished, and is scarcely susceptible of decay. For
exportation to Europe, it is cut into billets or logs, each about three
feet in length.
The chief use of log-wood in this country is for dyeing green, purple,
blue, and black colours, according to the different ingredients with which
it is employed. It gives a purplish tinge to watery and spirituous
infusions; but all the colours which can be prepared from it are fugitive,
and cannot, by any art, be rendered so durable as those prepared from other
materials.
Independently of its use as a dyeing drug, log-wood possesses considerable
utility as an astringent medicine, chiefly under the form of a decoction,
or of an extract boiled down to a proper consistence.
The price of logwood at Honduras is so low as not usually to exceed 12_l._
or 14_l._ Jamaica currency per ton.
143. _MAHOGANY is the wood of a well-known tree_ (Swietenia mahagoni,
Fig. 44) _of large dimensions, with winged leaves, and small white
flowers, which grows in Jamaica and Honduras._
_The branches of this tree are numerous and spreading. Its leaves are
alternate and winged, with four or five pair of leaflets, which are
somewhat spear-shaped. The flowers are numerous, small, white, and in
spikes or clusters, which arise at the junction of the leaves with the
branches._
The cutting of mahogany constitutes a principal occupation of the British
settlers in the vicinity of Honduras. The gangs of negroes employed in this
work consist of from ten to fifty each, one of whom is styled the
"huntsman." He is generally selected from the most intelligent of his
companions, and his chief employment is to search for these trees in the
woods, the principal of which lie adjacent to the river Balize. About the
beginning of August, the huntsman is despatched into the woods, and he cuts
his way through the thickest parts, to the highest spots he can find. Here
he climbs the loftiest tree, and thence attentively surveys the surrounding
forest. At this season the leaves of the mahogany trees are of a yellow
reddish hue, and an eye accustomed to them can discover, at a great
distance, the places where they are most abundant. He now descends, and to
such places directs his steps; and, having well marked the way, returns to
his companions, to point out the places to them.
Here they assemble, and erect, against each tree to be felled, a stage so
high as to allow of the tree being cut down at the height of about twelve
feet from the ground. The last day of felling the trees is appropriated to
festivity; and these people have then a short interval of leisure for
comforts in which they seldom can indulge at any other time.
After the branches are lopped, and the useless parts of the wood are cut
off, the operation commences of conveying the trees, by cattle and trucks,
to the water's side, a task of infinite and laborious difficulty. A
sufficient number of pieces to form a raft being here collected, they are
shoved from the bank into the water, and suffered to float singly upon the
current to large cables which are placed across the river at some distance
below. As numerous gangs of mahogany cutters are usually employed near the
banks of the same river, their trees also float to the same spot. Here
therefore the whole are collected, amounting sometimes to more than a
thousand immense logs; and, each party claiming his own, the trees are
formed into separate rafts for their final destinations.
In some instances the profit of cutting mahogany at this settlement has
been very great. A single tree has occasionally been known to contain
12,000 superficial feet, and to have produced upwards of 1000_l._ sterling.
The body of the tree is of course the most valuable; but, for ornamental
purposes, the limbs or large branches, are generally preferred, their grain
being much closer, and their veins being more rich and variegated than
those of the other parts.
The Honduras mahogany is considered inferior to that produced in Jamaica.
In this island mahogany was formerly much more abundant, and consequently
much less expensive than it is now, because the low lands have gradually
been thinned of such trees as could readily be carried to market, or
conveyed on board vessels for exportation.
The date of the introduction of mahogany wood into England is 1724. Since
this period it has been in very general request for making the more
valuable kinds of household furniture. It admits of a high polish, and is
excellently adapted for tables, chairs, desks, and other similar articles.
In Jamaica, mahogany is employed as a strong and durable timber for beams,
joists, planks, boards, &c. Many attempts have been made to stain other
kinds of wood so as to resemble it, but none of these have been attended
with success.
It has been lately discovered that the _bark_ of the mahogany tree may be
advantageously employed in medicine, as a substitute for Peruvian bark
(62).
144. _QUASSIA is a drug, the root of a tree_ (Quassia amara, Fig. 78)
_which grows in the West Indies and South America, but particularly in
the colony of Surinam._
_The leaves of the quassia tree are winged, with two pair of oval and
somewhat pointed leaflets, and an odd one at the end: these are smooth,
deep green above and pale below; and the common footstalk is edged on
each side with a leafy membrane. The flowers are bright red, and
terminate the branches in long clusters._
This drug was first brought into use in Surinam, by a negro whose name was
Quassia, and who employed it with great success in the cure of intermittent
and other malignant fevers, which prevail in that flat and marshy country.
The offer of a valuable consideration induced him to reveal the secret to
Daniel Rolander, a Swede, who carried specimens of the wood, together with
a branch of the tree, the flower, and fruit, to Stockholm, in 1756.
Since this period the drug has been generally employed in Europe; and its
efficacy in the removal of many diseases has been perfectly ascertained.
Dr. Cullen, however, observes, that though it is an excellent bitter, and
that it will do all that any pure or simple bitter can do, yet his
experience of it had not led him to think it would do more. Quassia is said
to possess antiseptic properties, and consequently to have considerable
influence in retarding a tendency to putrefaction. It is also sometimes
used instead of hops in the brewing of malt liquor.
The _root_, _wood_, and _bark_ of the quassia tree are all occasionally
employed in medicine, and the bark is said to be more intensely bitter than
either of the other two.
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