theory we have advanced, although unconscious of any such theory, except
that so broadly and unqualifiedly put forth by the "panspermists" as to
meet with a ready refutation. He is laboring, of course, to strengthen his
position that nature eternally works to get rid of her imperfect forms, or
to ensure "the survival of the fittest." But while his facts accomplish
little in this direction, they establish much in another, as the reader
will see. He says: "In Staffordshire, on an estate of a relative, where I
had ample means of investigation, there was a large and extremely barren
heath, which had never been touched by the hand of man; but several
hundred acres of exactly the same nature had been enclosed twenty-five
years before, and planted with scotch fir. The change in the native
vegetation of the planted part of the heath was most remarkable--more than
is generally seen in passing from one quite different soil to another; not
only the proportional numbers of the heath plants were wholly changed,
_but twelve species of plants _ (not including grasses and sedges)
flourished in the plantation which could not be found on the heath."

The attempt is here made, by Mr. Darwin, to convey an altogether different
meaning to his facts than what they will warrant, even as adroitly handled
by him. No heath plants were "wholly changed" in characteristics, but only
in proportional numbers; nor did the "twelve new species of plants" make
their appearance by virtue of any law of variability or selection of the
fittest. The growth of scotch fir had simply changed the conditions of the
soil, so that certain varieties of heath growth disappeared for the want
of "necessary conditions," and certain varieties of forest growth made
their appearance because conditions favored. Similar, if not greater
changes, are constantly occurring in hundreds of localities in New
England, where choked and worn-out pasture lands are left, untouched by
the hand of man, to grow up as best they may into new forests. The
open-field plants and shrubs entirely disappear, as the stronger and more