onceptions of time as in widening their conceptions of space. It is
here and thus that, in my judgment, the subject of life in other worlds
has been hitherto incorrectly dealt with. Men have given up as utterly
idle the idea that the existence of worlds is to be limited to the
special domain of space to which our earth belongs; but they are content
to retain the conception that the domain of time to which our earth's
history belongs, 'this bank and shoal of time' on which the life of the
earth is cast, is the period to which the existence of other worlds than
ours should be referred.

This, which is to be noticed in nearly all our ordinary treatises on
astronomy, appears as a characteristic peculiarity of works advocating
the theory of the plurality of worlds. Brewster and Dick and Chalmers,
all in fact who have taken that doctrine under their special protection,
reason respecting other worlds as though, if they failed to prove that
other orbs are inhabited _now_, or are at least _now_ supporting life in
some way or other, they failed of their purpose altogether. The idea
does not seem to have occurred to them that there is room and verge
enough in eternity of time not only for activity but for rest. They must
have all the orbs of space busy at once in the one work which they seem
able to conceive as the possible purpose of those bodies--the support of
life. The argument from analogy, which they had found effective in
establishing the general theory of the plurality of worlds, is forgotten
when its application to details would suggest that not _all_ orbs are
_at all times_ either the abode of life or in some way subserving the
purposes of life.

We find, in all the forms of life with which we are acquainted, three
characteristic periods--first the time of preparation for the purposes
of life; next, the time of fitness for those purposes; and thirdly, the
time of decadence tending gradually to death. We see among all objects
which exist in numbers, examples of all these stages existing at the
same time. In every race of living creatures there are the young as yet
unfit for work, the workers, and those past work; in every forest there
are saplings, seed-bearing trees, and trees long past the seed-bearing
period. We know that planets, or rather, speaking more generally, the
orbs which people space, pass through various stages of development,
during some only of which they can reasonably be regarded as the abode
of life or