_Balsam of Tolu_; F. _Baume de Tolu_; G. _Tolubalsam_.
=Botanical Origin=—_Myroxylon Toluifera_ H B K. (_Toluifera Balsamum_
Miller, _Myrospermum toluiferum_ A. Rich.),[786] an elegant and lofty
evergreen tree with a straight stem, often as much as 40 to 60 feet
from the ground to the first branch. It is a native of Venezuela, and
New Granada,—probably also of Ecuador and Brazil.
=History=—The first published account of Balsam of Tolu, is that of the
Spanish physician Monardes, who in his treatise on the productions of
the West Indies, which in its complete form first appeared at Seville
in 1574,[787] relates how the early explorers of South America observed
that the Indians collected this drug by making incisions in the trunk
of the tree. Below the incisions they affixed shells of a peculiar
black wax to receive the balsam, which being collected in a district
near Cartagena called _Tolu_, took its name from that place. He adds
that it is much esteemed both by Indians and Spaniards, that the latter
buy it at a high price, and that they have lately brought it to Spain,
where it is considered to be as good as the famous Balsam of Mecca.
Francisco Hernandez, who lived in 1561-1577 in Mexico, stated[788] that
the balsam of the province of Tolu was thought to be quite as useful
as, if not superior to, “balsamum indicum,” _i.e._ peruvianum.
A specimen agreeing with this description was given to Clusius[789]
in 1581 by Morgan, apothecary to Queen Elizabeth, but the drug was
certainly not common till a much later period. In the price-list of
drugs of the city of Frankfort of 1669, _Balsamus tolutanum_ (sic)
is expressly mentioned,[790] but there can be but little doubt
that _Balsamum Americanum resinosum_[791] or _siccum_ or _durum_
as occurring in many other tariffs of the 17th century, printed in
Germany, was also the balsam under notice;[792] in a similar list
emanating from the city of Basle in 1646,[793] we noticed _B. indicum
album_, _B. peruvianum_ and _B. siccum_,—the last with the explanatory
words, “_trockner Balsam in der Kürbsen_” (_i.e._ in gourds), meaning
probably balsam of Tolu.
[786] Fig. in Bentley and Trimen, _Med. Plants_, part 23 (1877)
under the name of _Toluifera Balsamum_. Though the change of names
may be justified by the strict rules of priority, we are of opinion
that at present it would be fraught with more of inconvenience than
advantage.—_Myroxylon punctatum_ Klotzsch, a tree stated to grow nearly
all over the northern part of South America, is referred to the same
species by Bentley and Trimen.
[787] _Historia de las cosas que se traen de nuestras Indias
occidentales_, cap. del Balsamo de Tolu.
[788] _Nova Plantarum, animal. et mineral. mexicanorum. Historia_,
Reccho’s edition, Romæ, 1651. fol. 53.
[789] _Exoticor._ etc. 1605. lib. x. fol. 305.
[790] _Pharm. Journ._ vi. (1876) 102.
[791] Pharmaceutical tariff (“Taxa”) of the city of Wittenberg 1632 (in
the Hamburg library).
[792] Flückiger, _Documente zur Geschichte der Pharmacie_, Halle, 1876.
49. 50. 53.—Balsamum _Peruvianum_ first occurs in the tariff of the
city of Worms of 1609.—_Documente_, p. 39; _Pharm. Journ. l. c._
[793] Contained in the _Medicine Tariffs_, in the library of the
British Museum, bound together in one volume ({777. c.}/5). They
include Schweinfurt 1614, Bremen 1644, Basle 1647, Rostock 1659,
Quedlinburg 1665, Frankfort on Main 1669 (quoted above).
As to the tree, of which Monardes figured a broken pod, leaflets of it,
marked 1758, exist in Sloane’s herbarium. Humboldt and Bonpland saw
it in several places in New Granada during their travels (1799-1804),
but succeeded only in gathering a few leaves. Among recent collectors,
Warszewicz, Triana, Sutton Hayes, and Seemann were successful only in
obtaining leaves. Weir in 1863 was more happy, for by causing a large
tree of nearly 2 feet diameter to be felled, he procured good herbarium
specimens including pods, but no flowers. Owing to this tree having
been much wounded for balsam, its foliage and fruits were singularly
small and stunted, and its branches overgrown with lichens.
That which botanists had failed to do, has been accomplished by an
ornithologist, Mr. Anton Goering, who, travelling in Venezuela to
collect birds and insects, made it a special object, at the urgent
request of one of us (H.), to procure complete specimens of the
Balsam of Tolu tree. By dint of much perseverance and by watching for
the proper season, Mr. Goering obtained in December 1868 excellent
flowering specimens and young fruits, and subsequently mature seeds
from which plants have been raised in England, Ceylon and Java.
=Extraction=—The most authentic information we possess on this
subject is derived from Mr. John Weir, plant collector to the Royal
Horticultural Society of London, who when about to undertake a journey
to New Granada in 1863, received instructions to visit the locality
producing Balsam of Tolu. After encountering considerable difficulties,
Mr. Weir succeeded in observing the manner of collecting the balsam in
the forest near Plato, on the right bank of the Magdalena. Mr. Weir’s
information[794] may be thus summarized:—
The balsam tree has an average height of 70 feet with a straight trunk,
generally rising to a height of 40 feet before it branches. The balsam
is collected by cutting in the bark two deep sloping notches, meeting
at their lower ends in a sharp angle. Below this =V=-shaped cut, the
bark and wood is a little hollowed out, and a calabash of the size and
shape of a deep tea-cup is fixed. This arrangement is repeated, so that
as many as twenty calabashes may be seen on various parts of the same
trunk. When the lower part has been too much wounded to give space for
any fresh incisions, a rude scaffold is sometimes erected, and a new
series of notches made higher up. The balsam-gatherer goes from time to
time round the trees with a pair of bags of hide, slung over the back
of a donkey, and empties into them the contents of the calabashes. In
these bags the balsam is sent down to the ports where it is transferred
to the cylindrical tins in which it reaches Europe. The bleeding of
the trees goes on for at least eight months of the year, causing them
ultimately to become much exhausted, and thin in foliage.
In some districts, as we learn from another traveller, it is customary
to let the balsam flow down the trunk into a receptacle at its base,
formed of the large leaf of a species of _Calathea_.
[794] _Journ. of the R. Hort. Soc._, May 1864; _Pharm. Journ._ vi.
(1865) 60.
From the observations of Mr. Weir, it appears that the balsam tree is
plentifully scattered throughout the Montaña around Plato and other
small ports on the right bank of the Magdalena. He states that he saw
at least 1,500 lb. of the drug on its way for exportation. From another
source, we know that it is largely collected in the valley of the
Sinu, and in the forests lying between that river and Cauca. None is
collected in Venezuela.
=Description=—Balsam of Tolu freshly imported is a light brown,
slow-flowing resin, soft enough to be impressible with the finger,
but viscid on the surface.[795] By keeping, it gradually hardens so
as to be brittle in cold weather, but it is easily softened by the
warmth of the hand. Thin layers show it to be quite transparent and
of a yellowish brown hue. It has a very agreeable and delicate odour,
suggestive of benzoin or vanilla, especially perceptible when the resin
is warmed, or when its solution in spirit is allowed to evaporate
on paper. Its taste is slightly aromatic with a barely perceptible
acidity, though its alcoholic solution decidedly reddens litmus.
In very old specimens, such as those which during the last century
reached Europe in little calabashes[796] of the size and shape of an
orange, the balsam is brittle and pulverulent, and exhibits when broken
a sparkling, crystalline surface. This old balsam is of a fine deep
amber tint and superior fragrance.
When Balsam of Tolu is pressed between two warmed plates of glass so
as to obtain it in a thin even layer, and then examined with a lens,
it exhibits an abundance of crystals of cinnamic acid. Balsam of Tolu
dissolves easily and completely in glacial acetic acid, acetone,
alcohol, chloroform or solution of caustic potash; it is less soluble
in ether, scarcely at all in volatile oils, and not in benzol or
bisulphide of carbon. The solution in acetone is devoid of rotatory
power in polarized light.
=Chemical Composition=—The balsam consists partly of an _amorphous
resin_, not soluble in bisulphide of carbon, which is supposed to be
the same as the dark resin precipitated by the bisulphide from balsam
of Peru. Scharling (1856) assigned the formula C₁₈H₂₀O₅ to that part of
the balsam which is soluble in potash.
If Tolu balsam is boiled with water, it yields to it cinnamic and
benzoic acid, which we have (1877) perfectly succeeded in separating by
repeated recrystallization from water; we have before us good specimens
of either, showing not only different melting points (133° C. and 121°
C.), but as to our crystals of benzoïc acid, isolated from the balsam
as stated above, we find that they also do _not_ evolve bitter almond
oil when mixed with sulphuric acid and chromate of potassium. The acids
may also be removed by boiling bisulphide of carbon.
Busse[797] showed that _benzylic_ ethers of both benzoic and cinnamic
acid are also constituents of the balsam, the cinnamate of benzyl being
present in larger quantity.
Upon distilling the balsam with water, it affords 1 per cent. of
_Tolene_, C₁₀H₁₆, boiling at about 170° C. This liquid rapidly absorbs
oxygen from the air. By destructive distillation, the balsam affords
the same substances as those obtainable from balsam of Peru, among
which _Phenol_ and _Styrol_ have been observed.
[795] I have seen it imported very fluid into London by way of New
York.—Sept. 1878.—F. A. F.
[796] The gourds, “Kürbsen,” of the list of Basle of 1647.
[797] _Berichte der Deutschen Chemischen Gesellschaft_, 1876. 833.
=Commerce=—The balsam is exported from New Granada, packed in
cylindrical tins holding about 10 lb. each. The quantity shipped from
Santa Marta in 1870 was 2,002 lb.; in 1871, 2,183 lb.; in 1872, 1,206
lb. In 1876 from the port of Savanilla 27,180 kilogrammes are stated to
have been exported.
=Uses=—Balsam of Tolu has no important medicinal properties. It is
chiefly used as an ingredient in a pleasant-tasting syrup and in
lozenges.
=Adulteration=—We have twice met with spurious Balsam of Tolu, but in
neither instance did the fraudulent drug bear any great resemblance to
the genuine.
Colophony, which might be mixed with the balsam, can be detected by
warm bisulphide of carbon which dissolves it, but removes from the pure
drug almost exclusively cinnamic and benzoic acid.