mass of cells, out
of which the harmonious diversity of the organs arranges itself, worm or
man, as God has willed from the beginning.

This differentiation having been effected, each several part assumes its
special office, having a life of its own adjusted to that of other parts
and the whole. "Just as a tree constitutes a mass arranged in a definite
manner, in which, in every single part, in the leaves as in the root,
in the trunk as in the blossom, cells are discovered to be the ultimate
elements, so is it also with the forms of animal life. Every animal
presents itself as a sum of vital unities, every one of which manifests
all the characteristics of life."

The mechanism is as clear, as unquestionable, as absolutely settled and
universally accepted, as the order of movement of the heavenly bodies,
which we compute backward to the days of the observatories on the plains
of Shinar, and on the faith of which we regulate the movements of war
and trade by the predictions of our ephemeris.

The mechanism, and that is all. We see the workman and the tools, but
the skill that guides the work and the power that performs it are as
invisible as ever. I fear that not every listener took the
significance of those pregnant words in the passage I quoted from
John Bell,--"thinking to discover its properties in its form." We have
discovered the working bee in this great hive of organization. We have
detected the cell in the very act of forming itself from a nucleus, of
transforming itself into various tissues, of selecting the elements of
various secretions. But why one cell becomes nerve and another muscle,
why one selects bile and another fat, we can no more pretend to tell,
than why one grape sucks out of the soil the generous juice which
princes hoard in their cellars, and another the wine which it takes
three men to drink,--one to pour it down, another to swallow it, and a
third to hold him while it is going down. Certain analogies between
this selecting power and the phenomena of endosmosis in the elective
affinities of chemistry we can find, but the problem of force remains
here, as everywhere, unsolved and insolvable.

Do we gain anything by attempting to get rid of the idea of a special
vital force because we find certain mutually convertible relations
between forces in the body and out of it? I think not, any more than we
should gain by getting rid of the idea and expression Magnetism because
of its correlation with