856 The Relations of Mind and Matter. (September, 
one substance, now on another; its different parts irregularly 
rising into activity or sinking into quiescence ; and its energies 
continuing unchanged and inexhausted through all this varied 
outflow of motor activity. No instance of the kind was ever 
seen or can be imagined to exist. The existence of such arbi- 
trary and seemingly voluntary activity irresistibly leads to the 
inference of a separate agent overruling the action of the machine, 
and now calling this, now that part into activity. On the theory 
of self-action of any instrument it is impossible to admit the 
existence of arbitrary and irregular variations of activity like 
those of the mind. On the opposite theory that the mind is an 
organism separate from the brain, and using the latter as its 
instrument, we can readily comprehend the varying action of the 
instrument. If the two be in close but not in constant connec- 
tion; if the mind now makes contact with one group of brain 
cells, now with another, and now withdraws from all contact, the 
difficulty diminishes. Why these varying contacts takes place is 
a question of a different character. They may be due to influ- 
ences of affinity or polarization, which are subject to change 
under the changes in cerebral conditions which they induce. Or 
they may be otherwise produced. It is difficult to understand 
the cause of such seemingly arbitrary contacts; but this diffi- 
culty is not an impossibility like that attending the brain-mind 
theory. And underthe idea that the mind is a separate organ- 
ism we can understand the vagaries of consciousness, which can-, 
not possibly be done under the brain-mind hypothesis. This 
subject will be considered later. 
There is one more consideration to which we may briefly 
advert. The cerebrum is subject to pathological changes. It 
frequently becomes incapable of doing its duty properly. In 
many instances of cerebral disorder the mind seems to disappear. 
A whole series of mental conditions may utterly vanish, and 
remain lost for years. A new series of mental conditions may 
be built up. Or every trace of intelligence and consciousness 
may disappear and the body act as a mere automaton, governed 
by reflex action only, or possibly by the deeply based hereditary 
-Or instinctive mental powers. And yet, after years of this mental 
_ obliteration, there are instances on record where the brain recov- 
ered its normal condition and the mind reappeared with all its 
rme - contents of memories, opinions and ideas. Such a cif 
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