The Past Condition of Organic Nature | Page 4

and that, eventually, the
constituent materials of the whole structure of both animals and plants
were thus returned to their original source: there was a constant passage
from one state of existence to another, and a returning back again.
Lastly, when we endeavoured to form some notion of the nature of the
forces exercised by living beings, we discovered that they--if not
capable of being subjected to the same minute analysis as the
constituents of those beings themselves--that they were correlative

with--that they were the equivalents of the forces of inorganic
nature--that they were, in the sense in which the term is now used,
convertible with them. That was our general result.
And now, leaving the Present, I must endeavour in the same manner to
put before you the facts that are to be discovered in the Past history of
the living world, in the past conditions of organic nature. We have,
to-night, to deal with the facts of that history--a history involving
periods of time before which our mere human records sink into utter
insignificance--a history the variety and physical magnitude of whose
events cannot even be foreshadowed by the history of human life and
human phenomena--a history of the most varied and complex character.
We must deal with the history, then, in the first place, as we should
deal with all other histories. The historical student knows that his first
business should be to inquire into the validity of his evidence, and the
nature of the record in which the evidence is contained, that he may be
able to form a proper estimate of the correctness of the conclusions
which have been drawn from that evidence. So, here, we must pass, in
the first place, to the consideration of a matter which may seem foreign
to the question under discussion. We must dwell upon the nature of the
records, and the credibility of the evidence they contain; we must look
to the completeness or incompleteness of those records themselves,
before we turn to that which they contain and reveal. The question of
the credibility of the history, happily for us, will not require much
consideration, for, in this history, unlike those of human origin, there
can be no cavilling, no differences as to the reality and truth of the facts
of which it is made up; the facts state themselves, and are laid out
clearly before us.
But, although one of the greatest difficulties of the historical student is
cleared out of our path, there are other difficulties--difficulties in
rightly interpreting the facts as they are presented to us--which may be
compared with the greatest difficulties of any other kinds of historical
study.
What is this record of the past history of the globe, and what are the
questions which are involved in an inquiry into its completeness or
incompleteness? That record is composed of mud; and the question
which we have to investigate this evening resolves itself into a question
of the formation of mud. You may think, perhaps, that this is a vast

step--of almost from the sublime to the ridiculous--from the
contemplation of the history of the past ages of the world's existence to
the consideration of the history of the formation of mud! But, in nature,
there is nothing mean and unworthy of attention; there is nothing
ridiculous or contemptible in any of her works; and this inquiry, you
will soon see, I hope, takes us to the very root and foundations of our
subject.
How, then, is mud formed? Always, with some trifling exception,
which I need not consider now--always, as the result of the action of
water, wearing down and disintegrating the surface of the earth and
rocks with which it comes in contact--pounding and grinding it down,
and carrying the particles away to places where they cease to be
disturbed by this mechanical action, and where they can subside and
rest. For the ocean, urged by winds, washes, as we know, a long extent
of coast, and every wave, loaded as it is with particles of sand and
gravel as it breaks upon the shore, does something towards the
disintegrating process. And thus, slowly but surely, the hardest rocks
are gradually ground down to a powdery substance; and the mud thus
formed, coarser or finer, as the case may be, is carried by the rush of
the tides, or currents, till it reaches the comparatively deeper parts of
the ocean, in which it can sink to the bottom, that is, to parts where
there is a depth of about fourteen or fifteen fathoms, a depth at which
the water is, usually, nearly motionless, and in which, of course, the
finer particles of this detritus, or mud as we call it, sinks to the bottom.
Or, again, if you take a river, rushing down