ss and not one simply
controlled by physical forces like osmosis. Here our explanation runs
against what we call 'vital power' of the ultimate elements of the
body." Professor Conn next analyzes the processes of circulation, and
his ready-made mechanical concepts carry him along swimmingly, till he
tries to explain by them the beating of the heart, and the contraction
of the small blood-vessels which regulate the blood-supply. Here comes
in play the mysterious vital power again. He comes upon the same power
when he tries to determine what it is that enables the muscle-fibre to
take from the lymph the material needed for its use, and to discard the
rest. The fibre acts as if it knew what it wanted--a very unmechanical
attribute.

Then Professor Conn applies his mechanics and chemistry to the
respiratory process and, of course, makes out a very clear case till he
comes to the removal of the waste, or ash. The steam-engine cannot
remove its own ash; the "living machine" can. Much of this ash takes
the form of urea, and "the seizing upon the urea by the kidney cells is
a vital phenomenon." Is not the peristaltic movement of the bowels, by
which the solid matter is removed, also a vital phenomenon? Is not the
conception of a pipe or a tube that forces semi-fluid matter along its
hollow interior, by the contraction of its walls, quite beyond the reach
of mechanics? The force is as mechanical as the squeezing of the bulb of
a syringe by the hand, but in the case of the intestines, what does the
squeezing? The vital force?

When the mechanical and chemical concepts are applied to the phenomena
of the nervous system, they work very well till we come to mental
phenomena. When we try to correlate physical energy with thought or
consciousness, we are at the end of our tether. Here is a gulf we cannot
span. The theory of the machine breaks down. Some other force than
material force is demanded here, namely, psychical,--a force or
principle quite beyond the sphere of the analytic method.

Hence Professor Conn concludes that there are vital factors and that
they are the primal factors in the organism. The mechanical and chemical
forces are the secondary factors. It is the primal factors that elude
scientific analysis. Why a muscle contracts, or why a gland secretes, or
"why the oxidation of starch in the living machine gives rise to motion,
growth, and reproduction, while if the oxidation occurs in the
chemist's laboratory ... it s