leads us to ask for the reasons which call for this new theory
of transmutation. The beginning of things must needs lie in
obscurity, beyond the bounds of proof, though within those of
conjecture or of analogical inference. Why not hold fast to the
customary view, that all species were directly, instead of
indirectly, created after their respective kinds, as we now behold
them,--and that in a manner which, passing our comprehension, we
intuitively refer to the supernatural? Why this continual striving
after "the unattained and dim,"--these anxious endeavors, especially
of late years, by naturalists and philosophers of various schools and
different tendencies, to penetrate what one of them calls "the
mystery of mysteries," the origin of species? To this, in general,
sufficient answer may be found in the activity of the human
intellect, "the delirious yet divine desire to know," stimulated as
it has been by its own success in unveiling the laws and processes of
inorganic Nature,--in the fact that the principal triumphs of our age
in physical science have consisted in tracing connections where none
were known before, in reducing heterogeneous phenomena to a common
cause or origin, in a manner quite analogous to that of the reduction
of supposed independently originated species to a common ultimate
origin,--thus, and in various other ways, largely and legitimately
extending the domain of secondary causes. Surely the scientific mind
of an age which contemplates the solar system as evolved from a
common, revolving, fluid mass,--which, through experimental research,
has come to regard light, heat, electricity, magnetism, chemical
affinity, and mechanical power as varieties or derivative
and convertible forms of one force, instead of independent
species,--which has brought the so-called elementary kinds of matter, such
as the metals, into kindred groups, and raised the question, whether the
members of each group may not be mere varieties of one species,--and
which speculates steadily in the direction of the ultimate unity of
matter, of a sort of prototype or simple element which may be to the
ordinary species of matter what the _protozoa_ or component cells of
an organism are to the higher sorts of animals and plants,--the mind
of such an age cannot be expected to let the old belief about species
pass unquestioned.

It will raise the question, how the diverse sorts of plants and
animals came to be as they are and where they a