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Gums True
gums are formed from the disintegration of internal plant tissues, mostly
from the decomposition of cellulose in a process called gummosis. Gums contain high amounts of sugar and are
closely allied to the pectins. They
are colloidal and soluble in water, either dissolving entirely or swelling,
but they are insoluble in alcohol and ether.
They exude naturally from the stems or in response to wounding of the
plant. Commercial gums arrive in the
market in the form of dried exudations.
Gums are especially common in plants of dry regions. They are used primarily as adhesives, and
are also used in printing and finishing textiles, as a sizing for paper, in
the paint and candy industries and as drugs.
Three important commercial plant gums are gum arabic, gum tragacanth
and karaya gum. A dried gummy exudate obtained
from Acacia
senegal
and
related acacias. These are small
native trees of arid northern Africa and are extensively cultivated in the
Sudan. The trees are tapped between
February and May when the fruits are ripe.
Transverse incisions are made with a small ax and thin strips of the
outer bark are torn off. The gum
slowly exudes as a viscous liquid, collects in a drop and hardens. After 3-8 weeks these “tears” are
collected. The sun bleaches them, and
the impurities are removed before marketing.
The Egyptians used gum arabic as early as 2,000 B.C. Sudan gum has been an article of commerce
since 100 A.D. Several kinds reach
world markets. Kordofan or Hashab gum
has been exported from the region around Cairo and Port Sudan, while Senegal
gum originates north of the Senegal River.
Gum arabic is slowly and completely soluble in cold water and has a
high degree of adhesiveness and viscosity.
Most has been used in textile, mucilage, paste, polish and
confectionery industries and as a glaze in painting. In medicine it has been used as an
emulsifying agent and as a demulcent. This is formed by a
transformation of the pith and medullary-ray cells into a mucilaginous substance
that exudes naturally or after the bark has been punctured or excised. It comes from Astrangalus gummifer and other species of
that genus. They are thorny shrubs of
the arid regions of Western Asia and Southeaster Europe. The gum is allowed to dry on the bark
before it is collected. It reaches
the market in one of three forms:
tears, which are the dried natural exudate; vermiform gum, which
consists of narrow twisted coils or strings; and flakes, which are ribbonlike
pieces. Most of the commercial supply
originates in Iran and Turkey. Gum
tragacanth has been used in calico printing and for other industrial
purposes. It is one of the oldest
drugs and was known since 300 B.C. In
modern medicine it has served as an adhesive agent for pills and troches and
for the suspension of insoluble powders. Karaya gum has been used as a
substitute for gum tragacanth, and several million pounds were imported
annually from India by the mid 1900’s.
It is used in the textile, cosmetic, cigar, past and ice cream
industries. It is obtained from Sterculia urens, a large tree in
central India. Incisions are made
into the heartwood and the gum oozes into these and accumulates as large
irregular knobs. They are then
collected, sorted and graded. The gum
enters the trade in the Other Gums There are many other plants, which
produce gums of some commercial importance.
Gum ghatti, obtained from Anogeissus latifolia, a large tree native
to India and Ceylon, is used as a substitute for gum arabic. The leaves are used for tanning. Feronia limonia and Cochlospermum religiosum in India, Burma and
Java yield gums that are also used in place of gum arabic. The Asiatic Cycas ciccinalis is the source of cycas
gum. The carob, Ceratonia siliqua, produces tragasol, a
mucilaginous hemi cellulose occurring in the pods. Mesquite gum in North America is obtained fro Posopis juliflora, P. glandulosa and other species,
while cherry gum is found in various species of Prunus. Resins are formed as oxidation products of various
essential oils and are very complex and varied in chemical composition. The resin is usually secreted in definite
cavities or passages. It frequently
oozes out through the bark and hardens on exposure to air. Tapping is usually necessary in order to
obtain a sufficient amount to be of commercial value. Commercial resins are also frequently
collected from fossil material.
Resinous substances may occur alone or in combination with essential
oils or gums. Resins, unlike gums,
are insoluble in water, but they dissolve in ether, alcohol and other
solvents. Resin production is
widespread in nature, but only a few families are of commercial
importance. These include the
Anacardiaceae, Burseraceae, Dipterocarpaceae, Guttiferae, Hammamelidaceae,
Leguminosae, Liliaceae, Pinaceae, Styracaceae and Umbelliferae. The exact botanical origin of a resin is
often hard to trace, especially in the case of fossil and semi fossil types. Resins probably serve the plant by
preventing decay, which is due to their high antiseptic qualities. They may also lower the amount of water
lost from the plant tissues. Resins have certain
characteristics that render them important to industry. Their ability to harden gradually, as the
oil that they contain evaporates, makes possible commercial varnishes. The resins are dissolved in solvents and
surfaces are painted with the mixture.
As the solvents and oils evaporate, a thin waterproof layer of resin
remains. Resinous substances have
been utilized for waterproof coatings, and also for decorative coatings for
millennia. Ancient Egyptians
varnished their mummy cases and the utilization of lacquer in the arts has
been practiced in China and Japan for centuries. The Greeks and Romans were familiar with many of the same
resinous materials that are used today (e.g., mastic, amber, sandarac). Another property of resins that is of
industrial importance is their ability to dissolve in alkalis to form
soap. Resins are also used in
medicine; for sizing paper; as a stiffening material for mats; in the
preparation of sealing wax, incense and perfumes; and for many other purposes
as well. It is difficult to classify resins
because the same term is often used for very diverse materials. In commerce, resins are often referred to
as gums, while such terms as varnish resins, hard resins, spirit varnishes,
balsams, gum resins, damar resins, soft resins, and many others are used
quite indiscriminately. The chemical
differences between the various groups are much more definite. In this section three groups that will be
distinguished are Hard Resins, Oleoresins and Gum Resins. These contain only a
little if any essential oil. They are
usually solid, quite transparent, brittle substances with no particular odor
or taste. They are readily fusible
and burn in air with a smoky flame.
They are nonvolatile and very poor conductors of electricity. They become negatively charged with
friction. The hard resins constitute
the best source of varnishes, due to their low oil content and the readiness
with which they dissolve in alcohol.
The most important commercial resins, such as the copals and damars,
belong to this group. Hard resins are
also used in paints, inks, plastics, sizing, adhesives, fireworks and other
products. Courbaril <bot777> Courbaril (Hymenea courbaril L.)
(fruit, seed pulp; resin, treat lung infections; wood products) [Mexico-Cent. America]
Copals comprise a considerable group of resins of recent, semi fossil
and fossil origin that are found in many tropical and subtropical areas of
the world. The word “copal” is of
Mexican origin. Many of the harder copals
are called animes, especially in northern Europe. The copals insignificant quantities of oil and they yield a
hard elastic varnish, which has been widely used for outdoor work. Several types are know which are diverse
in character and source Zanzibar copal and the
closely related Madagascar and Mozambique copals are derived from Trachylobium verrucosum. Zanzibar copal is the hardest of all
resins except amber and is very valuable.
The resin exudes naturally from the trunk, branches and fruit. However, most of the commercial supply was
obtained from semi fossil material derived from still living trees, and
fossil material from trees that no longer exist. Fossil copal when removed from the ground is covered with a
crust of oxidized material. After
this has been removed, the copal shows a typical surface known as “goose
skin,” which consists of large and small excrescences. The interior is clear and transparent and
varies from yellow to brownish red in color. Inhambane Copal is obtained from Copaifera conjugata, a valuable timber
tree in coastal Southeast Africa; but it is of little commercial value. There are a large number of hard resins
among the West African copals. They
are usually designated by the name of the region from which they were
obtained. The most important of these
are the Congo, Angola, Sierra Leone, Acere and Benin copals. Congo copal is the most important
because it is very hard and has been extensively exploited in the 20th
Century. It is derived from Copaifera demeusii and C. mapane, which are
characteristic trees of the Congo Basin.
Although living trees have furnished some of the supply, the greater
part was obtained from the ground or from watercourses, and was more or less
fossil in nature. The white and red
Angola copals are derived from the same two species. Sierra Leone copal is a
light-yellow, hard and brittle resin that is obtained from Copaifera copallifera and C. salikounda. Live trees are wounded and the resin
exudes and hardens in the form of globular tears. Some fossil material is also obtained. Because of the value of this copal, the
Sierra Leone government has protected the trees. Accra and Benin copals are
probably derived from Daniella ogea and
related species. These large trees
are found in the coastal forests of Liberia, the Gold Coast and Nigeria. The resinous exudation, known locally as
ogea gum, has gained prominence as a varnish resin. This copal is one of the most
valuable of the hard resins. It is
obtained from the kauri pine, Agathis australis, which is the largest and most important tree in New
Zealand. The copal is chiefly fossil
in nature and is dug up on ridges and in swamps and bogs. “Swamp gum” furnishes the bulk of the
supply, and ranges in size from pieces that are 1-2 inches in diameter to
lumps weighing 100 lbs. “Range gum”
yields the best grade of kauri.
Tapping living trees gets an inferior “Bush Gum”. Kauri is yellow, transparent and very
hard. It is an exceedingly valuable
varnish resin, especially for marine and outside work. It was also used in making linoleum. Kauri constituted one of the chief exports
of New Zealand in the mid 20th Century. The first shipments of this
important copal were made from Manila and the name persisted, although by mid
20th Century 75 percent of the product was shipped from Indonesia. The source of all the East Indian,
Philippine and Malayan copals, of which there are many different kinds, is Agathis alba. This is a tall conifer reaching a height
of 200 ft. The resin exudes
naturally, and is also obtained by systematic tapping. Some of the supply was derived from fossil
material and consisted of large, irregular, angular, milky pieces with a
yellowish interior. Hard, semi hard
and soft copals are included among the many different kinds in the
trade. Pontianak copal, a semi fossil
type from Borneo, is the hardest variety and was especially popular in the
United States. Manila copal varnishes
are durable, but they do not adhere strongly to surfaces and they are not
very brilliant. They are used chiefly
for interior work and enamels. These
copals are often erroneously called damars, although they are quite distinct
from the true damars. The tall locust tree in South
America, Hymenaea
courbaril,
which is found in Brazil and other portions of Neotropical America, is the
main source of this copal. The stems,
twigs and even the fruits exude a large amount of resin, which trickles to
the ground. The commercial resin is
collected from the base of living trees, and former trees as well, and is
marked as Demerara or Para Copal. It
is the softest of all copals and therefore the least valuable. There is confusion in the term
“damar.” The word is of Malayan origin
and is used by the natives to indicate a torch made of decayed wood and bark,
mixed with oil and powdered resin, wrapped in leaves and bound with strips of
rattan. At one time it did not refers
to any specific tree or resin.
However, the word came to be a collective term for a great variety of
hard resins of different origin, and included even kauri and manila
copal. In the commercial trade the
term “damar” restricted to resins that re obtained from members of the
Dipterocarpaceae. A few resins from
species of the Burseraceae are also included. This distinction should be maintained for the true damars are
very different chemically from the various coniferous resins. Unlike Manila copal, damar is insoluble in
chloral hydrate, but completely soluble in alcohol and turpentine. The trees that yield damars are
characteristic of all Southeastern Asia, and are particularly abundant in
Malaya and Sumatra. Although all
members of the Dipterocarpaceae secrete resin, only a few species are of commercial
importance. These are found mainly in
the genera Balanocarpus, Hopea and Shorea. Damars are especially important in Malaya
and are obtained by tapping the trees.
The most important Malayan varieties are Damar Mata Kuching from Hopea micrantha and related species.
Damar Penak from Balanocarpus
heimii,
and Damar Temak from Shorea hypochra. The principal damars
of India are saldamar from Shorea robusta, white damar from Vateria indica, and black damar from Canarium strictum. Damars also come from Borneo, Java,
Sumatra, Thailand and Cochin China. Batavian damar, a product of Shorea wiesneri, is the best
commercial variety. The so-called East India resins
are products of the same trees that yield damars. They are older and harder and are often gathered from the
ground or from watercourses. Damars were used principally in
spirit varnishes and the manufacture of nitrocellulose lacquers. Damar varnishes adhere better than Manila
copal varnishes, but are softer and less durable. They are particularly well adapted for varnishing paper because
of their luster and light color. They
have also been used for indoor work and in histology. Amber is a fossil resin found
mainly along the shore of the Baltic Sea. and to a lesser extent in Mexico,
Central America and Caribbean Islands.
The principal source of Baltic amber was the now extinct pine, Pinus succinifera that flourished on the
shores of a former sea in the Eocene.
Amber is very hard and brittle.
It occurs in several forms, the most important of which is
succinite. Some of these forms are
transparent and others are almost opaque.
The color varies from yellow to brown and even black. Amber assumes a high polish and becomes
negatively charged when rubbed. It
also gives off a characteristic aromatic odor. This substance has been known for thousands of years. The Swiss Lake Dwellers were familiar with
it and it was highly prized by the Greeks and Romans. It has always been used for beads and
other ornamental purposes and is often carved. The chief use of amber is for the
mouthpieces of pipes and cigarette and cigar holders. The darker grades yield a valuable
varnish, but this is too costly for general use. Amber is also used to increase the elasticity of rayon fibers
and as the source of an essential oil.
It is of scientific interest that there are often found imbedded in
amber the remains of plants, insects and other objects that existed at the
time the fresh resin was exuded from the pine trees. Lacquer is a natural varnish that
exudes from various trees in Asia, and great quantities of it are used in the
Orient for ornamental purposes. The
principal source is the lacquer tree, Rhus verniciflua, native to China but
cultivated in Japan. The trees are
systematically tapped. The exudate is
a milky liquid, which darkens and thickens rapidly on exposure to air. However, it can remain unchanged for long
periods by storage in closed containers.
It is filtered before use.
When applied as a varnish, the thin film rapidly hardens in a moist
atmosphere, in part due to oxidation.
Lacquer impart5s a remarkable protection as it is unchanged by acids,
alkalis, and alcohol or heat up to 160 deg. Fahrenheit. Pigments may be mixed with the lacquer
before drying. The lacquering process originated
in China many centuries before Christ, and reached its highest development
during the Ming dynasty (A.D. 1368-1644).
In Japan the first records are from the 4th Century, when lacquer was
used for many purposes. The earliest
examples known belong to the 6th Century.
The art reached its height during the 17th Century, although much fine
work was produced as late as the 19th Century. In Japan the quality of lacquered goods is of the highest
excellence. Gold has often been used
as a coloring. The process of
lacquering is very complicated and tedious.
Sometimes 300-400 coats are applied and the whole operation requires
several years to complete. This
technique was kept secret for many years. In Burma lacquer is obtained from Melanorrhoea usitata. It dries more slowly than Japanese
lacquer, but has been used in an attempt to build an industry in Burma. Natural lacquers are also obtained in
Taiwan and Vietnam, with Rhus succedanea being the source in the
latter. True shellac is not a direct plant
product but deserves discussion here.
It is made from stick-lac, a resinous substance secreted on the twigs
of many trees by an insect, Tachardia lacca. The lack insect
derives its food from the sap of the trees and secretes the resin as a kind
of cocoon for its own protection and that of its offspring. Although there are about 40 species that
may serve as hosts for the insect, only seven are of importance. These are often cultivated. They include Butea monosperma,
Schleichera oleosa, Zizyphus xylopyrus, Ficus religiosa, Acacia nilotica, Cajanus cajan, and
Zizyphus jujuba. Butea monosperma was used as a host as
early as 250 A.D. At first a valuable
red dye, which was obtained from the insect, was the only sought after
product. However, since 1590 A.D. the
resinous excretions have been more important. Native workers prepare most of the shellac of industry. India furnished over 97 percent of the
total output by the mid 1950’s, the rest being from Burma, Thailand and
Vietnam. The crude stick-lac is
removed from the twigs and soaked in water to extract the red dye. It is then dried and powdered to a
granular consistency. This seed-lac
is melted and thin sheets of it are hardened. These are broken into the semitransparent, brittle, orange-red
flakes which make-up shellac. If the
melted seed-lac is poured out in droplets, it hardens into the thick round
pieces known as button-lac. Shellac
is often bleached. At one time shellac had many
industrial uses, but synthetic substitutes made from petroleum have greatly
competed with it. True shellac can be
molded readily and was the most satisfactory material for the manufacture of phonograph
records. It is an insulator of the
highest grade and was once extensively used in the electrical industry. It was the principal spirit-varnish resin
yielding a tough film with a smooth finish, which is also capable of a high
polish. Shellac varnishes cannot be
used out-of-doors because they are not water resistant. Shellac was also used in making sealing
wax, drawing inks, some watercolors and nitrocellulose lacquers; for sizing
papers; for stiffening felt hats; and, in India, for many ornamental
purposes. These are grass-tree resins
obtained from Australian trees belonging to the genus Xanthorrhoea. These plants are among the few
monocotyledons, other than palms, which have an arboreal habit. They consist of a short woody stem,
composed of the old leaf bases, surmounted by a tuft of long rush like
leaves. The resin collects around the
bases of the old leaves and is removed by beating the stem. The yellow acaroid resins reach the market
in the form of elongated or round reddish-brown pieces. They are obtained chiefly from Xxanthorrhoea hastilis. Red acaroid resins from X. tateana, X. australis, and related species
are much more common. They consist of
uneven pieces of a brownish color.
The acaroid resins are used in the manufacture of sealing was, gold,
size, and spirit varnishes for use in coating metals; as a substitute for
rosin in paper sizing and inks; as a mahogany stain; as a source of picric
acid; and in medicine. <bot200> Grass Trees (Xanthorrhoea preissil) & Eucalyptus
spp., central New South Wales, Australia This is a soft pale-yellow resin
obtained mainly from Tetraclinis articulata (= Callistris quadrivalis), a small
tree in Northern Africa. Australian
species of Callitris are also a source of
sandarac. The resin is formed between
the inner and outer layers of the bark, and is excreted inn the form of small
tears, which quickly become opaque. Sandarac
yields a hard, white, rather brittle spirit varnish that is especially useful
for coating labels, negatives, cardboard, leather and metals. It was once used in medicine and was well
known to previous civilizations. This is a very old resin that was
known at least as far back as 400 B.C.
The most useful variety is Chios mastic, derived from Pistacia lenticus, a small tree from the
Mediterranean area. Although the
resin exudes naturally, removing strips of bark enhances the flow. Some of the resin adheres to the trunk in
the form of long, ovoid, pale-yellow, brittle tears, while the remainder
falls to the ground. Bombay mastic,
which consists of large irregular pieces of a dull, milky color, is from P.
cabulica. Mastic yields a pale
varnish used for coating metals and pictures, both oils and watercolors. It is also used in lithographic work, in
perfumery, in medicine, and as cement for dental work. It is one of the most expensive and
high-grade resins. Included here are various deep red materials of a
resinous nature. Sumatra dragon’s
blood is from Daemonorops
draco, a
climbing rattan palm of Eastern Asia.
The dark reddish-brown resin forms as small granules on scaly
fruits. It is used mainly in the
manufacture of red spirit varnishes for metals and in making zinc line
engravings. During the 18th Century
Italian violinmakers used dragon’s blood in their varnishes. Socotra dragon's blood is a resin that
exudes from the stem of Dracaena cinnabari of Western Asia. It has been also used for varnishes, dyes
and stains. Dragon’s blood is
sometimes secured from tropical American species of Dracaena and other
Asiatic species of Daemonorops. Gum kinos are produced by several
plant species. Malabar kino is
derived from the dried juice of Pterocarpus marsupium, a large tree in India. Trees are tapped and the juice is boiled
down. It reaches the market in the
form of small, brownish-red, brittle pieces.
West African kino is a red resin from P. erinaceus. Bengal kino is from Butea monosperma. Some Australian species of Eucalyptus are also sources of
gum kino, but mainly Eucalyptus camaldulensis.
The kino is secreted in cavities between the wood and bark, and oozes
out after incisions have been made.
In the air the resin hardens into a solid reddish mass. Several tropical American trees, mainly
Dipteryx odorata and Cocoloba uvifera, also yield kinos. Kinos have found their main use in
medicine for throat disorders, and are sometimes used in tanning.
A considerable amount of essential oils are contained in oleoresins in
addition to the resinous materials.
Thus, they are often liquid in nature. They have a distinct aroma and flavor. Among the oleoresins we find the
turpentines, balsams and elemis.
There is only a very slight distinction between these groups and often
a confusion of names.
These are oleoresins that had been obtained almost exclusively from coniferous
trees prior to a general switch to petroleum distillates. They are viscous, honey like liquids or
soft and brittle solids. The resin is
secreted and stored in ducts near the cambium layer and exudes naturally as a
soft, sticky substance, often called pitch.
For commercial use crude turpentine is obtained by tapping the
trees. On distillation turpentines
yield the essential oil or spirits of turpentine, and rosin, both of which
are useful products around which an important industry had been built in the
20th Century. The turpentine or
navel-stores industry was one of the oldest of the forest industries. The Trojans and Greeks were familiar with
pitch and its uses, and it is mentioned in the Bible. The industry was valued at 35-40 million
US dollars annually by the mid 20th Century.
The United States led in production with over half of the total
output. Turpentine and rosin were also
produced in Europe and India and Vietnam. <bot400> Turpentine from
Longleaf Yellow Pine, Pinus australis Michx. f.(= palustris Mill.).,
in Florida Turpentines of Minor Importance
Turpentines from various species of conifers have been frequently used
in their natural state for purposes other than the production of naval
stores. Some of them have been
important in industry, in the arts and particularly in medicine for over five
centuries. Among the more common are
the following: This is actually turpentine rather
than a balsam, as the name seems to indicate. It is secreted by the balsam fir, Abies balsamea, of northeastern North
America. The resin collects in
elongated blisters on the bark and only small amounts are obtainable. It was estimated that a tree could yield
from 8-10 oz. per year. Collectors
use a pot with a spout cut at an angle.
This is forced into the blisters and held in place while the balsam
drains out. The balsam is a viscid
yellowish or greenish substance. It
main use has been as a mounting medium for microscopic work and as cement for
optical lenses. It is very
transparent and has a high refractive index, which results in a minimum of
dispersed light. The medicinal value
of Canada balsam was known as early as 1607.
It was used as an irritant, stimulant and antiseptic, and is a
component of collodion and some plasters.
It has also been used as a fixative for soap and perfumes. Oregon Balsam is obtained from the
Douglas fir and it has similar properties and uses. This is the natural exudation of
various species of spruce of North America, with Picea rubens being the main
source. It is usually the result of
an injury to the sapwood. The thin,
clear, bitter, sticky oleoresin is secreted in blister like cavities in the
bark or in longitudinal fissures in the wood. It hardens on exposure to the air and is collected when hard or
semi soft. Before the advent of
chewing gum about 500,000 lb. were used each year as a substitute. The gum softens in the mouth and assumes a
reddish color. It has a pleasing
resinous taste. This turpentine is obtained from
the European larch, Larix decidua, a widespread tree in the mountains of Central Europe. Unlike other conifers, the resin ducts are
located in the heart of the tree so that holes are bored in order to obtain
the resin. The trees are tapped in
the spring. Venetian turpentine has
been an important product since the middle of the 18th Century. It is a yellowish or greenish liquid with
a typical odor and taste. It has been
used in varnishes, histology, lithographic work and veterinary medicine. Turpentines of small importance
include Bordeaux turpentine from Pinus pinaster, Strasbourg turpentine
from Abies
alba and Jura turpentine
from Picea
abies. In he first two of these European
turpentines, the crude exudation is used to some extent, but generally it is
strained and filtered through cloth.
The residue, known as Burgundy pitch, is a stimulant and
counterirritant, and has been used in plasters, ointments and other
pharmaceutical preparations.
These are technically oleoresins that contain benzole or cinnamic acid
and therefore are highly aromatic.
However, the term “balsam” is frequently applied in error to much
different substances, such as Canada balsam, copaiba balsam, etc. The true balsams contain much less oil
than the turpentines and are more viscous.
They yield essential oils on distillation. Balsams are used in medicines and as fixatives in the perfume
industry. This balsam is from Myroxylon pereirae, a tall tree in
Central America. It was cultivated in
many tropical and subtropical areas.
The wood resembles mahogany and is valuable. The balsam is a dark, reddish-brown, thick, syrupy, viscous
liquid, and is a pathological product formed as a result of wounding the
tree. The tree trunks are beaten with
a blunt instrument and the injured bark is then charred. It falls off naturally or is removed. Sometimes small “windows” are cut in the
bark. The balsam exudes from the
exposed surface of the wood and is collected on cloths. These cloths are later boiled to free the
purified balsam. Balsam of Peru has
been used in medicine for healing wounds and skin diseases. During World War II it was used in field
dressings for quick applications of a protective covering to the surface of
wounds. It has also been used in the
treatment of coughs, bronchitis and similar ailments, because of its
simulative and antiseptic effect on the mucous membranes. It is utilized in perfumes as a fixative
for the heavier odors and has served as a substitute for vanilla. Its common name is a misnomer because the
tree does not grow in Peru. The main supply
for the United States had been El Salvador. This balsam is a pathological
product obtained from Myroxylon balsamum, a tree of Venezuela, Colombia and Peru. Incisions with a V-shape are made in the
trunk and the balsam exudes slowly and is collected in gourds. It is a brown or yellowish-brown plastic
substance with a pleasant aromatic taste and odor. It has been used for salves and ointments and as an expectorant
and antiseptic in the treatment of coughs, colds and bronchitis. It is sometimes used to flavor cough
syrups. Considerable amounts have
been used as fixatives in the perfume and soap industries. Styrax, or storax, occurs in two
forms. The most important type, the
styrax of antiquity, is known as Levant styrax. This is obtained from Liquidambar orientalis, a small tree found
along the coasts of southwestern Asia Minor.
The balsam issues as a pathological product from a wound. The outer bark is bruised and soon the
balsam exudes into the inner bark.
The outer layers are discarded and the balsam is recovered by boiling
the inner layers in seawater. The
residual bark is dried and used for fumigation. Styrax is a semi liquid, grayish-brown, sticky, opaque
substance with a pronounced aromatic odor.
It has been used in soaps and cosmetics; as a fixative for the heavy
oriental type of perfume; in adhesives, lacquers, and incense; as a flavoring
for tobacco; and in medicine as a stimulant to the mucous membranes and for
the treatment of scabies. American styrax has been obtained
from the sweet gum, Liquidambar styraciflua. This is a solid balsam that is
often classified as a resin or balsamic resin. It is the pathological product obtained from several species of
Styrax in Southeastern Asia
and the East Indies. The balsam oozes
from incisions made in the trunk and branches. Two varieties are known in commerce. Siam benzoin is from Styrax tonkinense and S. benzoides and occurs as yellowish
or brownish pebble like tears with a milky white center. The tears are hard and brittle at room
temperature and occur separately or adhere together slightly. Sumatra benzoin, from Styrax benzoin, occurs in reddish or
grayish-brown blocks or lumps, composed of masses of tears stuck
together. Benzoin is exceedingly
aromatic with a vanilla like odor. It
is used in medicine as a stimulant and expectorant; and in the preparation of
heavy sweet perfumes, soap, toilet waters, lotions, tooth powders, incense
and fumigating materials.
Oleoresins that do not belong to either the turpentines or balsams are
such products as copaiba, elemi and Mecca balsam. Also known as copaiba balsam or
copaiba, this product is a natural oleoresin obtained from several species of
Copaifera from tropical South
America. The copaiba trees are small
with strong, tough, durable wood, which contains resin ducts of a large
size. So much oleoresin is secreted
and stored in cavities that sometimes the pressure causes the trunks to
burst. Copaiba is obtained by boring
holes into the heartwood. The
secretion flows out very rapidly. It
is a thin, clear, colorless liquid at first, but turns yellow and becomes
more viscid with age. It has a
peculiar aromatic odor and a persistent bitter taste. Several commercial varieties occur, which
differ in the amount of resins and essential oils present as well as inn the
source. The most important are
Maracaibo copaiba from Venezuela, obtained from Copaifera officinalis, which contains much
resin and is rather thick; and Para copaiba, a very fine grade from Brazil,
obtained from C.
reticulata. Copaiba has been used in making varnishes,
lacquers, and tracing paper, as a fixative in scenting soaps and perfumes,
and in photography to emphasize half tones and shadows. In medicine it was used as a disinfectant,
laxative, diuretic, and mild stimulant.
Amerindians used it for its healing properties. It became known in Europe early in the
16th Century. Substitutes for copaiba are Gurjun
Balsam and Illurin Balsam. Gurjun Balsam is obtained from Dipterocarpus turbinatus and related species
from India and the East Indies. The
thick, opaque, grayish oleoresin is obtained by cutting holes in the trunk. Illurin Balsam or African Copaiba
is a very fragrant oleoresin with a thick pungent, pepperlike odor that
originates from a West African tree, Daniella thurifera. This species is sometimes called Sierra
Leone Frankincense. It is found in
the drier open forests and savannahs of Upper Guinea. The resin exudes in a copious flow from
the base of the trees. A similar
product comes from D.
oliveri,
a species of the denser moist forests.
This oleoresin, under the name of wood oil, was once one of the chief
products of Nigeria. This name is used as a collective
for several oleoresins of different origin.
It is also used in error as a synonym for some of the soft
copals. Elemis differ considerably in
their characteristics. These
oleoresins exude as clear pale liquids, but they tend to harden on exposure. Some remain soft, while others become very
hard. Manila Elemi is the most important
and the best know of the elemis. Its
source is the pili tree, Canarium luzonicum, of the Philippines.
The oleoresin is secreted in the bark and oozes from the trunk in
fragrant white masses. Native people
have used elemi for torches and for caulking their boats. Manila elemi has been used in lithographic
work and in the manufacture of inks, adhesives, and cements; in the varnish
industry to give toughness and elasticity to the products; in perfumes; and
in medicine in plasters and ointments. Of lesser importance is African
Elemi from Boswellia
frereana;
Mexican Elemi from Amyris
elemifera,
A.
balsamifera
and
other species; and Brazilian Elemi from Protium heptaphyllum, Bursera gummifera and other trees. This is a greenish turbid
oleoresin with the odor of rosemary.
It is obtained from Commiphora
opobalsamum, in Arabia. This material has long been used in
incense and for perfumes of an oriental type. It has some medicinal value.
The supply of Mecca balsam has always been limited and thus is a rare
and costly product.
Gum resins are mixtures of both true gums and resins and naturally
combine the traits of both groups.
They often contain small amounts of essential oils and traces of
coloring material. Gum resins occur
naturally as milky exudates and collect in the form of tears or irregular
masses. Injuring or tapping the
plants also produces them. They are
mostly from plants of dry, arid regions, especially species of the
Umbelliferae and Burseraceae. Three
of the umbelliferous species, the sources of ammoniacum, asafetida and
galbanum, are very common in Iran and Afghanistan and furnish the
characteristic aspects of the vegetation of the plains and steppes in those
regions. During the dry season these
plains are barren, but shortly after the rains begin, these plants send up
thick stems from their perennial rootstalks.
When fully grown the plants attain a height of 5-6 ft., and are so
abundant that they from a kind of open forest. This is obtained from Dorema ammonniacum, a tall, stout naked,
hollow-stemmed perennial found in the deserts of Iran, southern Siberia and
other parts of Western Asia. It has a
milky juice, which exudes from the stem and flowering branches and hardens
into tears. Insect injury often
causes the exudation to occur. The
brownish-yellow tears are hard and brittle and occur singly or in
masses. Ammoniacum is used in
medicine as a circulatory stimulant, and in perfumery.
This is derived from Ferula assafoetida
and
allied species, stout perennial herbs of Iran and Afghanistan. The cortex of the thick fleshy roots
exudes a milky juice during the rainy season. The crown of the roots is cut off and protected from the
sun. The gum resin gradually collects
on the surface in the form of tears, or masses of tears of varying colors
imbedded in a thick, gummy, grayish or reddish matrix. Asafetida has a powerful and foul odor and
a bitter acrid taste, due to sulfur compounds present in the essential
oil. Despite this it has been used
throughout the East for flavoring sauces, curries and other foods, and as a
drug. In Europe and America is used
in perfumes and for flavoring only when exceedingly dilute and after certain
impurities have been removed.
Asafetida has may valuable medicinal properties and is used in the
treatment of coughs, asthma, and other nervous disorders and as an aid to
digestion and metabolism. Galbanum is a gum resin excreted
from the lower part of the stems of Ferula galbaniflua, a stout herbaceous
perennial of Northwestern Asia. It
occurs in the form of separate tears or brownish and yellowish-green
masses. It has been used for
centuries in medicine. Galbanum has a
powerful tenacious aromatic odor. This is one of the oldest and most
valuable of the gum resins. There has
been some confusion regarding its source because two forms seem to occur. Herabol Myrrh is derived from Commiphora myrrha, a large shrub or
small tree of Ethiopia, Somaliland and Arabia. The gum resin oozes naturally from the stems or as a result of
wounding. The pale-yellow liquid
gradually solidifies and becomes brown or even black in color. Herabol myrrh is used in perfume
manufacture and for medicinal purposes as a tonic, stimulant, and antiseptic
and is often a constituent of mouthwashes and dentifrices. Bisabol Myrrh or Sweet Myrrh is
from Commiphora
erythraea,
and Arabian species of similar appearance.
This is the myrrh of antiquity and has been used for centuries in
incense, perfumes and embalming.
Myrrh was an important product in Biblical times, ranking with gold in
value. It is still used in perfumes
and incense for religious ceremonies.
It is one of the constituents of Chinese joss sticks. This is also known as Olibanum and is
obtained from Boswellia
carteri
and
related Asiatic and African species.
The clear yellow resin exudes from incisions made in the bark and
hardens as small yellow grains.
Frankincense, like myrrh, has been a valuable material since Biblical
times. It is still an indispensable
ingredient of incense for religious purposes, and is also used in perfumes,
because of its excellent fixative properties, face powders, pastilles and
fumigating powders. These gum resins have been of much
less importance. Opopanax is derived
from two very distinct plants, Commiphora kataf of
the Burseraceae and Opopanax chironium of the Umbelliferae. It is used in perfumery and was formerly
of importance in medicine. Bdellium is a bitter aromatic gum resin obtained from Commiphora mukul of India and C. africana of Africa. It has been used in the perfume industry. There are other resinous
substances, which find no use in industry but are treated under “Medicinal
Plants.” These include aloes, guaiacum, jalap and
podophyllum, and will be treated later.
Gamboge, a gum resin is discussed under “Dye Plants.” |