till developed in the simplest bit of living matter. To learn their
significance, therefore, we have turned to the study of the simplest
form of matter in which these fundamental properties are manifested.
This led us at once to the study of the so-called protoplasm, for
protoplasm is the simplest known form of matter that is alive.
Protoplasm itself at first seemed to be a homogeneous body, and was
looked upon as a chemical compound of high complexity. If this were true
its properties would depend upon its composition and would be explained
by the action of chemical forces. Such a conception would have quickly
solved the problem, for it would reduce living properties to chemical
powers. But the conception proved to be delusive. Protoplasm, at least
the simplest form known to possess the fundamental life properties, soon
showed itself to be no chemical compound, but a machine of wonderful
intricacy.

The fundamental phenomena of life and of protoplasm have proved to be
both chemical and mechanical. Metabolism is the result of the oxidation
of food, and motion is an instance of transference of force. Our problem
then resolved itself into finding the power that guides the action of
these natural forces. Food will not undergo such an oxidation except in
the presence of protoplasm, nor will the phenomena of metabolism occur
except in the presence of _living_ protoplasm. Clearly, then, the living
protoplasm contains within itself the power of guiding this play of
chemical force in such a way as to give rise to vital phenomena, and our
search must be not for chemical force but for this guiding principle.
Our study of protoplasm has told us clearly enough that we must find
this guiding principle in the interaction of the machinery within the
protoplasm. The microscope has told us plainly that these fundamental
principles are based upon machinery. The cell division (reproduction) is
apparently controlled by the centrosomes; the heredity by the
chromosomes; the constructive metabolism by the nucleus in general,
while the destructive metabolism is also seated in the cell substance
outside the nucleus. Whether these statements are strictly accurate in
detail does not particularly affect the general conclusion. It is
clearly enough demonstrated that the activities of the protoplasmic body
are dependent upon the relation of its different parts. Although we have
got rid of the complicated machinery of the organism in general, we are