Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 1 - By Alexander Von Humboldt And Aime Bonpland.
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Yet We Are Far From Affirming, That, Throughout The
Whole Of The Eastern Part Of South America, From Porto Bello To
Cayenne, Or From The Equator To The 10th Degree Of North Latitude
Between The Meridians Of 54 And 71 Degrees, The Cinchona Absolutely
Does Not Exist.
How can we be expected to know completely the flora
of so vast an extent of country?
But, when we recollect, that even
in Mexico no species of the genera cinchona and exostema has been
discovered, either in the central table-land or in the plains, we
are led to believe, that the mountainous islands of the West Indies
and the Cordillera of the Andes have peculiar floras; and that they
possess particular species of vegetation, which have neither passed
from the islands to the continent, nor from South America to the
coasts of New Spain.
It may be observed farther, that, when we reflect on the numerous
analogies which exist between the properties of plants and their
external forms, we are surprised to find qualities eminently
febrifuge in the bark of trees belonging to different genera, and
even different families.* (* It may be somewhat interesting to
chemistry, physiology, and descriptive botany, to consider under
the same point of view the plants which have been employed in
intermittent fevers with different degrees of success. We find
among rubiaceous plants, besides the cinchonas and exostemas, the
Coutarea speciosa or Cayenne bark, the Portlandia grandiflora of
the West Indies, another portlandia discovered by M. Sesse at
Mexico, the Pinkneia pubescens of the United States, the berry of
the coffee-tree, and perhaps the Macrocnemum corymbosum, and the
Guettarda coccinea; among magnoliaceous plants, the tulip-tree and
the Magnolia glauca; among zanthoxylaceous plants, the Cuspare of
Angostura, known in America under the name of Orinoco bark, and the
Zanthoxylon caribaeum; among leguminous plants, the geoffraeas, the
Swietenia febrifuga, the Aeschynomene grandiflora, the Caesalpina
bonducella; among caprifoliaceous plants, the Cornus florida and
the Cuspa of Cumana; among rosaceous plants, the Cerasus virginiana
and the Geum urbanum; among amentaceous plants, the willows, oaks,
and birch-trees, of which the alcoholic tincture is used in Russia
by the common people; the Populus tremuloides, etc.; among
anonaceous plants, the Uvaria febrifuga, the fruit of which we saw
administered with success in the Missions of Spanish Guiana; among
simarubaceous plants, the Quassia amara, celebrated in the feverish
plains of Surinam; among terebinthaceous plants, the Rhus glabrum;
among euphorbiaceous plants, the Croton cascarilla; among composite
plants, the Eupatorium perfoliatum, the febrifuge qualities of
which are known to the savages of North America. Of the tulip-tree
and the quassia, it is the bark of the roots that is used. Eminent
febrifuge virtues have also been found in the cortical part of the
roots of the Cinchona condaminea at Loxa; but it is fortunate, for
the preservation of the species, that the roots of the real
cinchona are not employed in pharmacy. Chemical researches are yet
wanting upon the very powerful bitters contained in the roots of
the Zanthoriza apiifolia, and the Actaea racemosa: the latter have
sometimes been employed with success as a remedy against the
epidemic yellow fever in New York.) Some of these barks so much
resemble each other, that it is not easy to distinguish them at
first sight. But before we examine the question, whether we shall
one day discover, in the real cinchona, in the cuspa of Cumana, the
Cortex Angosturae, the Indian swietenia, the willows of Europe, the
berries of the coffee-tree and uvaria, a matter uniformly diffused,
and exhibiting (like starch, caoutchouc, and camphor) the same
chemical properties in different plants, we may ask whether, in the
present state of physiology and medicine, a febrifuge principle
ought to be admitted. Is it not probable, that the particular
derangement in the organization, known under the vague name of the
febrile state, and in which both the vascular and the nervous
systems are at the same time attacked, yields to remedies which do
not operate by the same principle, by the same mode of action on
the same organs, by the same play of chemical and electrical
attractions? We shall here confine ourselves to this observation,
that, in the species of the genus cinchona, the antifebrile virtues
do not appear to belong to the tannin (which is only accidentally
mingled in them), or to the cinchonate of lime; but in a resiniform
matter, soluble both by alcohol and by water, and which, it is
believed, is composed of two principles, the cinchonic bitter and
the cinchonic red.* (* In French, l'amer et le rouge cinchoniques.)
May it then be admitted, that this resiniform matter, which
possesses different degrees of energy according to the combinations
by which it is modified, is found in all febrifuge substances?
Those by which the sulphate of iron is precipitated of a green
colour, like the real cinchona, the bark of the white willow, and
the horned perisperm of the coffee-tree, do not on this account
denote identity of chemical composition;* and that identity might
even exist, without our concluding that the medical virtues were
analogous. (* The cuspare bark (Cort. Angosturae) yields with iron
a yellow precipitate; yet it is employed on the banks of the
Orinoco, and particularly at the town of St. Thomas of Angostura,
as an excellent cinchona; and on the other hand, the bark of the
common cherry tree, which has scarcely any febrifuge quality,
yields a green precipitate like the real cinchonas. Notwithstanding
the extreme imperfection of vegetable chemistry, the experiments
already made on cinchonas sufficiently show, that to judge of the
febrifuge virtues of a bark, we must not attach too much importance
either to the principle which turns to green the oxides of iron, or
to the tannin, or to the matter which precipitates infusions of
tan.) We see that specimens of sugar and tannin extracted from
plants, not of the same family, present numerous differences: while
the comparative analysis of sugar, gum, and starch; the discovery
of the radical of the prussic acid (the effects of which are so
powerful on the organization), and many other phenomena of
vegetable chemistry, clearly prove that substances composed of
identical elements, few in number and proportional in quantity,
exhibit the most heterogeneous properties, on account of that
particular mode of combination which corpuscular chemistry calls
the arrangement of the particles.
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