cannot make a fly, a midge, or blade of grass. He is an ingenious
compiler, but not a creator; and his powers of manufacture and
conversion are restricted within narrow boundaries. He cannot wander far
in the indulgence of his fancies without being recalled, and compelled
to return to the first models set by the Great Architect. The further he
strays from primitive types in the effort to improve, by crossing,
cutting, and grafting, and proportionably less becomes the procreative
force. Hybrids are notoriously sterile. Garden fruit is not permanent,
and requires to be renewed from seed. The law seems universal in plants
and animals, that the vital energy or germ is less forcible and prolific
in the pampered and artificial, than in the natural and wild races.


HYPOTHESIS OF THE VITAL PRINCIPLE.

It is ascertained that the basis of all vegetable and animal substances
consists in nucleated cells--that is, cells having granules within them.
Nutriment is converted into these before being assimilated by the
system. It has likewise been noted that the globules of the blood are
reproduced by the expansion of contained granules; "they are, in short,"
says the _Vestiges_, "_distinct organisms multiplied by the same
fissiporous generation_. So that all animated nature may be said to be
based on this mode of origin; _the fundamental form of organic being is
a globule, having a new globule forming within itself_, by which it is
in time discharged, and which is again followed by another and another,
in endless succession. It is of course obvious, that if these globules
could be produced by any process from inorganic elements, we should be
entitled to say that the fact of a transit from the inorganic to the
organic had been witnessed." (p. 176.) "Globules," the author
continues, "can be produced in albumen by electricity. _If_, therefore,