CONSCIOUSNESS AND SENSATION. 109 
manner, is perfectly aware of the site of irritation 
when a nerve-trunk in the stump is touched, and it 
seems reasonable to suppose therefore that the 
sense of the presence of the removed part is some- 
how to be explained by habit, the reversion of 
consciousness to previous conditions, and is com- 
parable with other waking illusions of the phantom 
sort. The production of pain in the temple from 
toothache may be explained on the supposition 
that intensity of the impressed condition sufficient 
to produce pain is conducted to a nerve-centre and 
spread centrifugally, just as I have suggested that 
the alteration in an ulnar nerve struck at the elbow 
spreads down to the fingers. 
If I have put forward these views of sensation 
simply as a suggestion I should be still more 
unwilling to be dogmatic in applying them to the 
motor nerves. Yet it may be mentioned that one 
of the most inscrutable of all phenomena, looked at 
from the received point of view, is the circumstance 
that the will is able to regulate delicately the 
movements of the limbs by adjusting the contrac- 
tions of complicated muscles of which the mind is 
wholly unconscious; and the difficulty in this 
matter will be greatly simplified if we can see 
our way to believe that, when a motor nerve is set 
in action from the brain, the mind is brought into 
