rms of
the Theory of Development which have been propounded in modern times,
and applied to account for the origin of planets and astral systems, of
vegetable and animal races, and of the different successive systems of
human opinion and belief. We have found that, imposing as it may seem to
be, and high as its pretensions are, that theory has no claim to the
character of a scientific doctrine; that it is a mere hypothesis, and
nothing more; a speculative figment, which may be injurious to those who
thoughtlessly dally with it, but which can have no power to hurt any one
who will resolutely lay hold of it, and examine its claims.

"Gently, softly, touch a nettle,
And it stings you for your pains;
Grasp it, like a man of mettle,
And it soft as silk remains."

It is only necessary to add, that _the same general principle_ seems to
be involved in _all_ the forms of this theory,--the principle, namely,
that we are bound to account for the past _only_ by causes known to be
in actual operation at the present day. M. Comte lays it down in the
following terms: "Our conjectures on the origin, or formation of our
world should evidently be subjected to this indispensable
condition,--not to allow of the interposition of any other natural
agents than those whose influence we clearly discern in our ordinary
phenomena, and whose operations, _then_, would only be on a greater
scale. Without this rule, our work can have no truly scientific
character, and we shall fall into the inconvenience, so justly made a
ground of reproach to the greater number of geological hypotheses,--that
of introducing, for the purpose of explaining the ancient revolutions of
the globe, agencies which do not exist at the present day, and whose
influence it is impossible, for that very reason, to verify or even to
comprehend." The same principle is strongly stated, but with due
limitation, by Sir Charles Lyell, who insists on the explanation of all
terrestrial changes by _means of causes and according to laws known to
be in operation at the present day_: "During the progress of Geology,
there have been great fluctuations of opinion respecting the nature of
the causes to which all former changes in the earth's surface are
referable. The first observers conceived that the monuments which the
Geologist endeavors to decipher relate to a period when the physical
constitution of the earth differed entirely from the present, and that,
even after