labourer who wields the spade or the pickaxe
becomes thicker and harder by friction.

The bearing of these remarks upon our present point will soon be
obvious: we multiply examples, in order to shew in what an important
sense we use the word _control_, with regard to the relation of reason
with imagination. As we have seen, chemistry overrules the mechanical
laws; vegetation suspends the laws of chemistry; a superior department
of animal life controls influences which are laws in a lower
department; again, mind controls the effects of physical influences;
and, lastly, one power of the mind controls, and in a great measure
suspends, the natural activity of another power--_reason controls
imagination_. A second fact with regard to the action of reason must
be noticed--that _it requires a wakeful condition of the brain_. Some
may suppose that they have reasoned very well during sleep; but we
suspect that, if they could recollect their syllogisms, they would
find them not much better than Mickle's poetry composed during sleep.
Mickle, the translator of the _Lusiad_, sometimes expressed his regret
that he could not remember the poetry which he improvised in his
dreams, for he had a vague impression that it was very beautiful.
'Well,' said his wife, 'I can at least give you two lines, which I
heard you muttering over during one of your poetic dreams. Here they
are:

"By Heaven! I'll wreak my woes
Upon the cowslip and the pale primrose!"'

If we required proof that the operation of reason demands a wakeful
and active condition of the brain, we might find it in the fact, that
all intellectual efforts which imply sound reasoning are prevented
even by a partial sleepiness or dreaminess. A light novel may be read
and enjoyed while the mind is in an indolent and dreamy state; music
may be enjoyed, or even composed, in the same circumstances, because
it is connected rather with the imaginative than with the logical
faculty; but, not to mention any higher efforts, we cannot play a game
of chess well unless we are 'wide awake.'

Now we come to our point:--Supposing that, by any means, the brain can
be deprived of that wakefulness and activity which is required for a
free exercise of the reasoning powers, then what would be the effect
on the imagination? For an answer to this query, we shall not refer to
the phenomena of natural sleep and dreaming, because it is evident
that the subjects of the experiments we have to expla