apparatus.

In order to be in a position successfully to change the outer world
through the motility, there is required the accumulation of a large sum
of experiences in the memory systems as well as a manifold fixation of
the relations which are evoked in this memory material by different
end-presentations. We now proceed further with our assumption. The
manifold activity of the second system, tentatively sending forth and
retracting energy, must on the one hand have full command over all
memory material, but on the other hand it would be a superfluous
expenditure for it to send to the individual mental paths large
quantities of energy which would thus flow off to no purpose,
diminishing the quantity available for the transformation of the outer
world. In the interests of expediency I therefore postulate that the
second system succeeds in maintaining the greater part of the occupation
energy in a dormant state and in using but a small portion for the
purposes of displacement. The mechanism of these processes is entirely
unknown to me; any one who wishes to follow up these ideas must try to
find the physical analogies and prepare the way for a demonstration of
the process of motion in the stimulation of the neuron. I merely hold to
the idea that the activity of the first [Greek: Psi]-system is directed
_to the free outflow of the quantities of excitement_, and that the
second system brings about an inhibition of this outflow through the
energies emanating from it, _i.e._ it produces a _transformation into
dormant energy, probably by raising the level_. I therefore assume that
under the control of the second system as compared with the first, the
course of the excitement is bound to entirely different mechanical
conditions. After the second system has finished its tentative mental
work, it removes the inhibition and congestion of the excitements and
allows these excitements to flow off to the motility.