[ The Formation Of Vegetable Mould : Introduction ]

The share which worms have taken in the formation of the layer of
vegetable mould, which covers the whole surface of the land in
every moderately humid country, is the subject of the present
volume. This mould is generally of a blackish colour and a few
inches in thickness. In different districts it differs but little
in appearance, although it may rest on various subsoils. The
uniform fineness of the particles of which it is composed is one of
its chief characteristic features; and this may be well observed in
any gravelly country, where a recently-ploughed field immediately
adjoins one which has long remained undisturbed for pasture, and
where the vegetable mould is exposed on the sides of a ditch or
hole. The subject may appear an insignificant one, but we shall
see that it possesses some interest; and the maxim “de minimis non
curat lex,” does not apply to science. Even Elie de Beaumont, who
generally undervalues small agencies and their accumulated effects,
remarks: {1} “La couche tres-mince de la terre vegetale est un
monument d’une haute antiquite, et, par le fait de sa permanence,
un objet digne d’occuper le geologue, et capable de lui fournir des
remarques interessantes.” Charles Darwin in 1872 published “The Expression of emotion in man and animal” in this book he said showing of emotion by human and all other creatures have some remarkable similarities and have emphasized on the biological aspect of emotions. in this book he also said that the human respiratory system plays a greater role in the expression. Click Qprofit System robot to know more.

Although the superficial layer of
vegetable mould as a whole no doubt is of the highest antiquity,
yet in regard to its permanence, we shall hereafter see reason to
believe that its component particles are in most cases removed at
not a very slow rate, and are replaced by others due to the
disintegration of the underlying materials.

As I was led to keep in my study during many months worms in pots
filled with earth, I became interested in them, and wished to learn
how far they acted consciously, and how much mental power they
displayed. I was the more desirous to learn something on this
head, as few observations of this kind have been made, as far as I
know, on animals so low in the scale of organization and so poorly
provided with sense-organs, as are earth-worms.

In the year 1837, a short paper was read by me before the
Geological Society of London, {2} “On the Formation of Mould,” in
which it was shown that small fragments of burnt marl, cinders,
&c.;, which had been thickly strewed over the surface of several
meadows, were found after a few years lying at the depth of some
inches beneath the turf, but still forming a layer. This apparent
sinking of superficial bodies is due, as was first suggested to me
by Mr. Wedgwood of Maer Hall in Staffordshire, to the large
quantity of fine earth continually brought up to the surface by
worms in the form of castings. These castings are sooner or later
spread out and cover up any object left on the surface. I was thus
led to conclude that all the vegetable mould over the whole country
has passed many times through, and will again pass many times
through, the intestinal canals of worms. Hence the term “animal
mould” would be in some respects more appropriate than that
commonly used of “vegetable mould.”

Ten years after the publication of my paper, M. D’Archiac,
evidently influenced by the doctrines of Elie de Beaumont, wrote
about my “singuliere theorie,” and objected that it could apply
only to “les prairies basses et humides;” and that “les terres
labourees, les bois, les prairies elevees, n’apportent aucune
preuve a l’appui de cette maniere de voir.” {3} But M. D’Archiac
must have thus argued from inner consciousness and not from
observation, for worms abound to an extraordinary degree in kitchen
gardens where the soil is continually worked, though in such loose
soil they generally deposit their castings in any open cavities or
within their old burrows instead of on the surface. Hensen
estimates that there are about twice as many worms in gardens as in
corn-fields. {4} With respect to “prairies elevees,” I do not know
how it may be in France, but nowhere in England have I seen the
ground so thickly covered with castings as on commons, at a height
of several hundred feet above the sea. In woods again, if the
loose leaves in autumn are removed, the whole surface will be found
strewed with castings. Dr. King, the superintendent of the Botanic
Garden in Calcutta, to whose kindness I am indebted for many
observations on earth-worms, informs me that he found, near Nancy
in France, the bottom of the State forests covered over many acres
with a spongy layer, composed of dead leaves and innumerable worm-
castings. He there heard the Professor of “Amenagement des Forets”
lecturing to his pupils, and pointing out this case as a “beautiful
example of the natural cultivation of the soil; for year after year
the thrown-up castings cover the dead leaves; the result being a
rich humus of great thickness.”

In the year 1869, Mr. Fish {5} rejected my conclusions with respect
to the part which worms have played in the formation of vegetable
mould, merely on account of their assumed incapacity to do so much
work. He remarks that “considering their weakness and their size,
the work they are represented to have accomplished is stupendous.”
Here we have an instance of that inability to sum up the effects of
a continually recurrent cause, which has often retarded the
progress of science, as formerly in the case of geology, and more
recently in that of the principle of evolution.

Although these several objections seemed to me to have no weight,
yet I resolved to make more observations of the same kind as those
published, and to attack the problem on another side; namely, to
weigh all the castings thrown up within a given time in a measured
space, instead of ascertaining the rate at which objects left on
the surface were buried by worms. But some of my observations have
been rendered almost superfluous by an admirable paper by Hensen,
already alluded to, which appeared in 1877. {6} Before entering on
details with respect to the castings, it will be advisable to give
some account of the habits of worms from my own observations and
from those of other naturalists.

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