condition, the _Aethalium_ is an actively locomotive creature, and takes
in solid matters, upon which, apparently, it feeds, thus exhibiting the
most characteristic feature of animality. Is this a plant; or is it an
animal? Is it both; or is it neither? Some decide in favour of the last
supposition, and establish an intermediate kingdom, a sort of biological
No Man's Land for all these questionable forms. But, as it is admittedly
impossible to draw any distinct boundary line between this no man's land
and the vegetable world on the one hand, or the animal on the other, it
appears to me that this proceeding merely doubles the difficulty which,
before, was single.

Protoplasm, simple or nucleated, is the formal basis of all life. It is
the clay of the potter: which, bake it and paint it as he will, remains
clay, separated by artifice, and not by nature, from the commonest brick
or sun-dried clod.

Thus it becomes clear that all living powers are cognate, and that all
living forms are fundamentally of one character. The researches of the
chemist have revealed a no less striking uniformity of material
composition in living matter.

In perfect strictness, it is true that chemical investigation can tell
us little or nothing, directly, of the composition of living matter,
inasmuch as such matter must needs die in the act of analysis,--and upon
this very obvious ground, objections, which I confess seem to me to be
somewhat frivolous, have been raised to the drawing of any conclusions
whatever respecting the composition of actually living matter, from that
of the dead matter of life, which alone is accessible to us. But
objectors of this class do not seem to reflect that it is also, in
strictness, true that we know nothing about the composition of any body