the opposite distribution of heat in the east and the west of Europe and
North America, see Dove, 'Repertorium der Physik', bd. iii., s. 392-395.
The simultaneous thermic and hygrometric modifications of the upper regions
of the air can only be learned (when direct observations on mountain
stations or aerostatic ascents are impracticable) from hypothetical
combinations, by making the barometer serve both as a thermometer and an
hygrometer. Important changes of weather are not owing to merely local
causes, situated at the place of observation, but are the consequence of a
disturbance in the equilibrium of the aerial currents at a great distance
from the surface of the Earth, in the higher strata of the atmosphere,
bringing cold or warm, dry or moist air, rendering the sky cloudy or serene,
and converting the accumulated masses of clouds into light feathery 'cirri'.
As, therefore, the inaccessibility of the phenomenon is added to the
manifold nature and complication of the disturbances, it has always appeared
to me that meteorology must first seek its foundation and progress in the
torrid zone, where the variations of the atmospheric pressure, the course of
hydro-meteors, and the phenomena of electric explosion, are all of periodic
occurrence.
As we have now passed in review the whole sphere of inorganic terrestrial
life, and have briefly considered our planet with reference to its form, its
internal heat, its electro-magnetic tension, its phenomena of polar light,
the volcanic reaction of its interior on its variously composed solid crust,
and, lastly, the phenomena of its two-fold envelopes -- the aerial and
liquid ocean -- we might, in accordance with the older method of treating
physical geography, consider that we had completed our descriptive history
of the globe. But the nobler aim I have proposed to myself, of raising the
contemplation of nature to a more elevated point of view, would be defeated,
and this delineation of nature would appear to lose its most attractive
charm, if it did not also include the sphere of organic life in the many
stages of its typical development. The idea of vitality is so intimatey
associated with the idea of the existence of the active, ever-blending
natural forces which animate the terrestrial sphere, that the creation of
plants and animals is ascribed in the most ancient mythical representations
of many nations to these forces, while the condition of the surface of our
planet, before it was animated by vital forms, is regarded as coeval with
the epoch of a chaotic conflict of the struggling elements. But the
empirical domain of objective contemplation, and the delineation of our
planet in its present condition, do not include a consideration
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of the mysterious and insoluble problems of origin and existence.
A cosmical history of the universe, resting upon facts as its basis, has,
from the nature and limitations of its sphere, necessarily no connection
with the obscure domain embraced by a 'history of organisms',* if we
understand the word 'history' in its broadest sense.
[footnote] *The 'history of plants', which Endlicher and Unger have
described in a most masterly manner ('Grundzuge der Botanik', 1843, s.
449-468), I myself separated from the 'geography of plants' half a century
ago. In the aphorisms appended to my 'Subterranean Flora', the following
passage occurs: "Geognosia naturam animantem et inanimam vel, ut vocabulo
minus apto, ex antiquitate saltem haud petito, utar, corpora vitur capita:
Geographia oryctologica quam simpliciter Geognosiam vel Geologiam dicunt,
virque acutissimus Wernerus egregie digessit; Geographia zoologica, cujus
doctrinae fundamenta Zimmermannus et Treviranus jecerunt; et Geographic
plantarum quam aequales nostri diu intactam reliquerunt. Geographia
plantarum vincula et cognationem tradit, quibus omnia vegetabilia inter se
connexa sint, terraetractur quos teneant, in aerem atmosphaericum quae sit
eorum vis ostendit, saxa atque rupes quibus potissimum algarum primordiis
radicibusque destruantur docet, et quo pacto in telluris superficie humus
nascatur, commemorat. Est itaque quod differat inter Geognosiam et
Physiographiam, 'historia naturalis' perperam nuncupatam quum Zoognosia,
Phytognosia, et Oryctognosia, quae quidem omnes in naturae investigatione
versantur, non nisi singulorum animalium, plantarum, rerum metallicarum vel
(venia sit verbo) fossilium formas, anatomen, vires scrutautur. Historia
Telluris, Geognosiae magis quam Physiographiae affinis, nemini adhuc tenata,
plantarum animaliumque genera orbem inhabitantia primaevum, migrationes
eorum compluriumque interitum, ortum quem montes, valles, saxorum strata et
vemae metalliferae ducunt, aerem, mutatis temporum vicibus, modo purum, modo
vitiatum, terrae superficiem humo plantisque paulatim obtectam, fluminum
inundantium impetu denuo nudatam, iterumque siccatam et gramine vestitam
commemorat. Igitur Historia zoolopgica, Historia plantarum et Historia
oryctologica, quae non nisi pristinum orbis terrae statum indicant, a
Geognosia probe distinguendae." -- Humboldt, 'Flora Friburgensis
Subterranea, cui accedunt Aphorismi ex Physiologia Chemica Plantarum', 1793,
p. ix.-x. Respecting the "spontaneous motion." which is referred to in a
subsequent part of the text, see the remarkable passage in Aristotle, 'De
Coelo,' ii., 2, p. 284, Bekker, where the distinction between animate and
inanimate bodies is made to depend on the internal or external position of
the seat of the determining motion. "No movement," says the Stagirite,
"proceeds from the vegetable spirit, because plants are buried in a still
sleep, from which nothing can arouse them" (Aristotle, 'De Generat.
Animal.', v. i., p. 778, Bekker); and again, "because plants have no desires
which incite them to spontaneous motion." (Arist., 'De Somno et Vigil'.,
cap. i., p. 455, Bekker.)
It must, however, be remembered, that the inorganic crust of the Earth
contains within it the same elements that enter into the structure of animal
and vegetable organs. A physical cosmography would therefore be incomplete
p 341
if it were to omit a consideration of these forces, and of the substances
which enter into solid and fluid combinations in organic tissues, under
conditiions which, from our ignorance of their actual nature, we designate
by the vague term of 'vital forces', and group into various systems in
accordance with more or less perfectly conceived analogies. The natural
tendency of the human mind involuntarily prompts us to follow the physical
phenomena of the Earth, through all their varied series, until we reach the
final stage of the morphological evolution of vegetable forms, and the
self-determining powers of motion in animal organisms. And it is by these
links that 'the geography of organic beings -- of plants and animals' -- is
connected with the delineation of the inorganic phenomena of our terrestrial
globe.
Without entering on the difficult question of 'spontaneous motion', or, in
other words, on the difference between vegetable and animal life, we would
remark, that if nature had endowed us with microscopic powers of vision, and
the integuments of plants had been rendered perfectly transparent to our
eyes, the vegetable world would present a very different aspect from the
apparent immobility and repose in which it is now manifested to our senses.
The interior portion of the cellular structure of their organs is
incessantly animated by the most varied currents, either rotating, ascending
and descending, remifying, and ever changing their direction, as manifested
in the motion of the granular mucus of marine plants (Naiades, Characeae,
Hydrocharidae), and in the hairs of phanerogamic land plants; in the
molecular motion first discovered by the illustrious botanist Robert Brown,
and which may be traced in the ultimate portions of every molecule of
matter, even when separated from the organ; in the gyratory currents of the
globules of cambium ('cyclosis') circulating in their peculiar vessels; and,
finally, in the singularly articulated self-unrolling filamentous vessels in
the antheridia of the chara, and in the reproductive organs of liverworts
and algae, in the structural conditions of which Meyen, unhappily too early
lost to science, believed that he recognized an analogy with the spermatozoa
of the animal kingdom.*
[footnote] *["In certain parts, probably, of all plants, are found peculiar
spiral filaments, having a striking resemblance to the spermatozoa of
animals. They have been long known in the organs called the antheridia of
mosses, Hepaticcae, and Characeae, and have more recently been discovered in
peculiar cells on the germinal frond of ferns, and on the very young leaves
of the buds of Phanerogamia. They are found in peculiar cells, and when
these are placed in water they are torn by the filament, which commences an
active spiral motion. The signification of these organs is at present quite
unknown; they appear, from the researches of Nägeli, to resemble the cell
mucilage, or proto-plasma, in composition, and are developed from it.
Schleiden regards them as mere mucilaginous deposits, similar to those
connected with the circulation in cells, and he contends that the movement
of these bodies in water is analogous to the molecular motion of small
particles of organic and inorganic substances, and depends on mechanical
causes." -- 'Outlines of Structural and Physiological Botany', by A.
Henfrey, F.L.S., etc., 1846, p. 23.] -- Tr.
If to these
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manifold currents and gyratory movements we add the phenomena of endosmosis,
nutrition, and growth, we shall have some idea of those forces which are
ever active amid the apparent repose of vegetable life.
Since I attempted in a former work, 'Ansichten der Natur' (Views of Nature),
to delineate the universal diffusion of life over the whole surface of the
Earth, in the distribution of organic forms, both with respect to elevation
and depth, our knowledge of this branch of science has been most remarkably
increased by Ehrenberg's brilliant discovery "on microscopic life in the
ocean, and in the ice of the polar regions" -- a discovery based, not on
deductive conclusions, but on direct observation. The sphere of vitality,
we might almost say, the horizon of life, has been expanded before our eyes.
"Not only in the polar regions is there an uninterrupted development of
active microscopic life, where larger animals can no longer exist, but we
find that the microscopic animals collected in the Antarctic expedition of
Captain James Ross exhibit a remarkable abundance of unknown and often most
beautiful forms. Even in the residuum obtained from the melted ice,
swimming about in round fragments in the latitude of 70 degrees 10', there
were found upward of fifty species of silicious-shelled Polygastria and
Coscinodiscae with their green ovaries, and therefore living and able to
resist the extreme severity of the cold. In the Gulf of Erebus, sixty-eight
silicious-shelled Polygastria and Phytolitharia, and only one
calcareous-shelled Polythalamia, were brought up by lead sunk to a depth of
from 1242 to 1620 feet."
The greater number of the oceanic microscopic forms hitherto discovered have
been silicious-shelled, although the analysis of sea water does not yield
silica as the main constituent, and it can only be imagined to exist in it
in a state of suspension. It is not only at particular points in inland
seas, or in the vicinity of the land, that the ocean is densely inhabited by
living atoms, invisible to the naked eye, but samples of
p 343
water taken up by Schayer on his return from Van Diemen's Land (south of the
Cape of Good Hope, in 57 degrees latitude, and under the tropics in the
Atlantic) show that the ocean in its ordinary condition, without any
apparent discoloration, contains numerous microscopic moving organisms,
which bear no resemblance to the swimming fragmentary silicious filaments of
the genus Chaetoceros, similar to the Oscillatoriae so common in our fresh
waters. Some few Polygastria, which have been found mixed with sand and
excrements of penguins in Cockburn Island, appear to be spread over the
whole earth, while others seem to be peculiar to the polar regions.*
[footnote] *See Ehrenberg's treatise 'Ueber das kleinste Leben im Ocean',
read before the Academy of Science at Berlin on the 9th of May, 1844.
[Dr. J. Hooker found Diatomaceae in countless numbers between the parallels
of 70 degrees and 80 degrees south, where they gave a color to the sea, and
also the icebergs floating in it. The death of these bodies in the South
Arctic Ocean is producing a submarine deposit, consisting entirely of the
silicious particles of which the skeletons of these vegetables are composed.
This deposit exists on the shores of Victoria Land and at the base of the
volcanic mountain Erebus. Dr. Hooker accounted for the fact that the
skeletons of Diatomaceae had been found in the lava of volcanic mountains,
by referring to these deposits at Mount Erebus, which lie in such a position
as to render it quite possible that the skeletons of these vegetables should
pass into the lower fissures of the mountain, and then passing into the
stream of lava, be thrown out, unacted upon by the heat to which they have
been exposed. See Dr. Hooker's Paper, read before the British Association
at Oxford, July, 1847.] -- Tr.
We thus find from the most recent observations that animal life predominates
amid the eternal night of the depths of ocean, while vegetable life, which
is so dependent on the periodic action of the solar rays, is most prevalent
on continents. The mass of vegetation on the Earth very far exceeds that of
animal organisms; for what is the volume of all the large living Cetacea and
Pachydermata when compared with the thickly-crosded colossal trunks of
trees, of from eight to twelve feet in diameter, which fill the vast forests
covering the tropical region of South America, between the Orinoco, the
Amazon, and the Rio de Madeira? And although the character of different
portions of the earth depends on the combination of external phenomena, as
the outlines of mountains -- the physiognomy of plants and animals -- the
azure of the sky -- the forms of the clouds -- and the transparency of the
atmosphere -- it must still be admitted that the vegetable mantle with which
the earth is decked constitutes the main feature of the picture. Animal
forms are inferior in mass, and their powers of motion often withdraw them
from our sight. The
p 344
vegetable kingdom, on the contrary, acts upon our imagination by its
continued presence and by the magnitude of its forms; for the size of a tree
indicates its age, and here alone age is associated with the expression of a
constantly renewed vigor.*
[footnote] *Humboldt, 'Ansichten der Natur' (2te Ausgabe, 1826), bd. ii. s.
21.
In the animal kingdom (and this knowledge is also the result of Ehrenberg's
discoveries), the form which we term microscopic occupy the largest space,
in consequence of their rapid propagation.*
[footnote] *On multiplication by spontaneous division of the
mother-corpuscle and intercalation of new substance, see Ehrenberg 'Van den
jetzt lebenden Thierarten der Kreidebildung', in the 'Abhandl. der Berliner
Akad. der Wiss.', 1839, s. 94. The most powerful productive faculty in
nature is that manifested in the Vorticellae. Estimations of the greatest
possible development of masses will be found in Chrenberg's great work 'Die
Infusionsthierchen als volkommne Organismen', 1838, s. xiii., xix., and 244.
"The Milky Way of these organisms comprises the genera Monas, Vibrio,
Bacterium, and Bodo." The universality of life is so profusely distributed
throughout the whole of nature, that the smaller Infusoria live as parasites
on the larger, and are themselves inhabited by others, s. 194, 211, and 512.
The minutest of the Infusoria, the Monadidae, have a diameter which does not
exceed 1/3000th of a line, and yet these silicious-shelled organisms form in
humid districts subterranean strata of many fathoms in depth.
The strong and beneficial influence exercised on the feelings of mankind by
the consideration of the diffusion of life, throughout the realms of nature
is common to every zone, but the impression thus produced is most powerful
in the equatorial regions, in the land of palms, bamboos, and arborescent
ferns, where the ground rises from the shore of seas rich in mollusca and
corals to the limits of perpetual snow. The local distribution of plants
embraces almost all heights and all depths. Organic forms not only descend
into the interior of the earth, where the industry of the miner has laid
open extensive excavations and sprung deep shafts, but I have also found
snow-white stalactiitic columns encircled by the delicate web of an Usnea,
in caves where meteoric water could alone penetrate through fissures.
Podurellae penetrate into the icy crevices of the glaciers on Mount Rosa,
the Grindelwald, and the Upper Aar; the Chionaea nivalis (formerly known as
Protococcus), exist in the polar snow as well as in that of our high
mountains. The redness assumed by the snow after lying on the ground for
soome time was known to Aristotle, and was probably observed by him on the
mountains of Macedonia.*
[footnote] *Aristot., 'Hist. Animal.', v. xix., p. 552, Bekk.
p 345
While, on the loftiest summits of the Alps, only Lecideae, Parmeliae, and
Umbilicariae cast their colored but scanty covering over the rocks, exposed
by the melted snow, beautiful phanerogamic plants, as the Culcitium
rufescens, Sida pinchinchensis, and Saxifraga Boussingaulti, are still found
to flourish in the tropical region of the chain of the Andes, at an
elevation of more than 15,000 feet. Thermal springs contain small insects
(Hydroporus thermalis), Gallionellae, Oscillatoria and Confervae, while
their waters bathe the root-fibers of phanerogamic plants. As air and water
are aniimated at different temperatures by the presence of vital organisms,
so likewise is the interior of the different portions of animal bodies.
Animalcules have been found in the blood of the frog and the salmon;
according to Nordmann, the fluids in the eyes of fishes are often filled
with a worm that lives by suction (Diplostomum), while in the gills of the
bleak the same observer has discovered a remarkable double aniimalcule
(Diplozoon paradoxum), having a cross-shaped form with two heads and two
caudal extremities.
Although the existence of meteoric Infusoria is more than doubtful, it can
not be denied that, in the same manner as the pollen of the flowers of the
pine is observed every year to fall from the atmosphere, minute infusorial
animalcules may likewise be retained for a time in the strata of the air,
after having been passively borne up by currents of aqueous vapor.*
[footnote] *Ehrenberg, op. cit., s. xiv., p. 122 and 403. The rapid
multiplication of microscopic organisms is, in the case of some (as, for
instance, in wheat-eels, wheel-animals, and water-bears or tardigrade
animalcules), accompanied by a remarkable tenacity of life. They have been
seen to come to life from a state of apparent death after being dried for
twenty-eight days in a vacuum with chloride of line and sulphuric acid, and
after being exposed to a heat of 248 degrees. See the beautiful experiments
of Doyere, in 'Mem. sur les Tardigrades et sur leur propriete de revenir a
la vie', 1842, p. 119, 129, 131, 133. Compare, also, Ehrenberg, s. 492-496,
on the revival of animalcules that had been dried during a space of many
years.
This circumstance merits serious attention in reconsidering the old
discussion respecting 'spontaneous generation',* and the
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more so, as Ehrenberg, as I have already remarked, has discovered that the
nebulous dust or sand which mariners often encounter in the vicinity of the
Cape Verd Islands, and even at a distance of 380 geographical miles from the
African shore, contains the remains of eighteen species of silicious-shelled
polygastric animalcules.
[footnote] *On the supposed "primitive transformation" of organized or
unorganized matter into plants and animals, see Ehrenberg, in Poggendorf's
'Annalen der Physik', bd. xxiv., s. 1-48, and also his 'Infusionsthierchen',
s. 121, 525, and Joh. Muller, 'Physiologie des Menschen' (4te Aufl., 1844),
bd. i., s. 8-17. It appears to me worthy of notice that one of the early
fathers of the Church, St. Augustine, in treating of the question how
islands may have been covered with new animals and plants after the flood,
shows himself in no way disinclined to adope the view of the so-called
"spontaneous generation" ('generatio aequivoca, spontanea aut primaria').
"If," says he, "animals have not been brought to remote islands by angels,
or perhaps by inhabitants of continents addicted to the chase, they must
have been spontaneously produced upon the earth; although here the question
certainly arises, to what purpose, then, were animals of all kinds assembled
in the ark?" "Si e terra exort" sunt (bestiae) secundum originem primam,
quando dixit Deus" 'Producat terra animam vivam!' multo clarius apparet,
non tam reparandorum animalium causa, quam figurandarum variarum gentium (?)
propter ecclesiae sacramentumin arca fuisse omnia genera, si in insulis quo
transire non possent, multa animalia terra produxit." Augustinus, 'De
Civitate Dei', lib. xvi., cap. 7: 'Opera, ed. Monach. Ordinis S.
Benedicti', t. vii., Venet., 1732, p. 422. Two centuries before the tiime
of the Bishop of Hippo, we find, by extracts from Trogus Pompeius, that the
'generatio primaria' was brought forward in connection with the earliest
drying up of the ancient world, and of the high table-land of Asia,
precisely in the same manner as the terraces of Paradise, in the theory of
the great Linnaeus, and in the visionary hypotheses entertained in the
eighteenth century regarding the fabled Atlantis: "Quod si omnes quondam
terrae submersae profundo fuerunt, profecto editissilimam quamque partem
decurrentibus aquis primum detectam; humillimo autem solo eandem aquam
diutissime immoratam, et quanto prior quaeque pars terrarum siccata sit,
tanto prius animalia generare coepisse. Porro Scythiam adeo editiorem
omnibus terris esse ut cuncta flumina ibi nata in Maeotium, tum deinde in
Ponticum et Aegyptium mare decurrant." -- Justinus, lib. ii., cap. 1. The
erroneous supposition that the land of Scythia is an elevated table-land, is
so ancient that we meet with it most clearly expressed in Hippocrates, 'De
Aere et Aquis', cap. 6, 96, Coray. "Scythia," says he, "coonsists of high
and naked plains, which, without being crowned with mountains, ascend higher
and higher toward the north."
Vital organisms, whose relations in space are comprised under the head of
the geography of plants and animals, may be considered either according to
the difference and relative numbers of the types (their arrangement into
genera and species), or according to the number of individuals of each
species on a given area. In the mode of life of plants as in that of
animals, an important difference is noticed; they either exist in an
isolated state, or live in a social condition. Those species of plants
which I have termed 'social'* uniformly cover vast extents of land.
[footnote] *Humboldt, 'Aphorismi ex Physiologia Chemica Plantarum', in the
'Flora Fribergensis Subterranea', 1793, p. 178.