nitrogen,
and to speak of the various powers and activities of these substances as
the properties of the matter of which they are composed.

When hydrogen and oxygen are mixed in a certain proportion, and an
electric spark is passed through them, they disappear, and a quantity of
water, equal in weight to the sum of their weights, appears in their
place. There is not the slightest parity between the passive and active
powers of the water and those of the oxygen and hydrogen which have
given rise to it. At 32 deg. Fahrenheit, and far below that temperature,
oxygen and hydrogen are elastic gaseous bodies, whose particles tend to
rush away from one another with great force. Water, at the same
temperature, is a strong though brittle solid, whose particles tend to
cohere into definite geometrical shapes, and sometimes build up frosty
imitations of the most complex forms of vegetable foliage.

Nevertheless we call these, and many other strange phaenomena, the
properties of the water, and we do not hesitate to believe that, in some
way or another, they result from the properties of the component
elements of the water. We do not assume that a something called
"aquosity" entered into and took possession of the oxide of hydrogen as
soon as it was formed, and then guided the aqueous particles to their
places in the facets of the crystal, or amongst the leaflets of the
hoar-frost. On the contrary, we live in the hope and in the faith that,
by the advance of molecular physics, we shall by and by be able to see
our way as clearly from the constituents of water to the properties of
water, as we are now able to deduce the operations of a watch from the
form of its parts and the manner in which they are put together.

Is the case in any way changed when carbonic acid, water, and ammonia
disappear, and in their place, under the influence of pre-existing
living protoplasm, an equivalent weight of the matter of life makes its
appearance?

It is true that there is no sort of parity between the properties of the
components and the properties of the resultant, but neither was there in
the case of the water. It is also true that what I have spoken of as the
influence of pre-existing living matter is something quite
unintelligible; but does anybody quite comprehend the _modus operandi_
of an electric spark, which traverses a mixture of oxygen and hydrogen?

What justification is there, then, for the assumption of the existence
in the livin