e vegetative dynamo. From each viscus,
from the stomach and intestine, from the kidneys and bladder, from
the liver and spleen, from the blood-vessels, from all the glands
of external and internal secretion, there flow along the vegetative
nerves, to and from the brain, energies of various qualities and
intensities. All the members of the vegetative apparatus are more or
less active, and so all our wishes are all more or less active. All
our working hours we are aware of hunger, satiety or indifference, of
a desire to empty the intestine or bladder, or of a lack of necessity
of doing so, of a state of tranquillity of the blood-vessels and sweat
glands, or of a perturbation of them, of a varying tensity of even the
muscles that are, as we say, under the control of the will, of the
state, in fact, of all the elements of the vegetative complex. The
stream of feeling which constitutes the undertow of consciousness
originates outside of the brain altogether, and is composed of
currents arising from viscera, muscles, blood-vessels and glands.

Now the component currents are of different sizes and positions and
variable degrees of warmth. That is another way of saying that whether
or not a current is to become the center of the stream, or to approach
it, or whether it is to be hot, cold, or tepid, depends upon the
degree of activity of the various parts of the vegetative apparatus.
A convenient name for this is _tonus_. Tonus can be experimentally
watched and measured. Thus hunger, the most primitive of the
wish-feelings, has been found to be simultaneous with certain
characteristic contractions of the stomach. Stop those contractions,
and you stop the hunger. The contractions begin slowly and weakly,
and no awareness of them occurs in the mind. As they grow stronger,
consciousness becomes a sensation rather like an itch somewhere in
the upper abdomen, and accompanied sometimes by a sense of general
weakness. The vegetative activity going on as a current almost on the
outside of the stream of feeling has swelled and warmed, and so forced
itself, in a manner of speaking, into the center of the stream. Or if
you will, the rest of the stream has to arrange itself around it as
the center. A similar mechanism for the tonus of the other members
of the vegetative system, and how they determine consciousness and
behaviour is understandable. It has been shown that when the bladder
tone and the intestinal tone are of a definitely measur