26 HABIT AND INTELIJGENCE. [chap. 



and if the consciousness of a sensation is a distinct thing 

 from the sensation itself, as I think I have shown in the 

 preceding chapter ; it is as probable as analogy can make 

 Conscious- it, that the consciousness of the sensation is also due to a 

 thus pro- nerve-current, like that of the sensation, but in a different 

 duced. fibre ; and if so, all the evidence we have leads to the 

 Nerves conclusion, that the nerve-currents of consciousness are 

 currenT7^' forced in the fibres that connect the sensory ganglia with 

 of con- the ganglionic substance of the cerebrum. I consequently 



ScioUSneSS. ^ Z.^ n^ j.1 -C ■ ■ t- 



regard these fibres as the nerves of consciousness, just as 

 the nerves which connect the organs of sense with the 

 sensory ganglia are the nerves of sensation. A sensation is 

 due to a current entering the sensory ganglia from a nerve 

 of sensation ; and I believe that the consciousness of the 

 sensation is due to a secondary current being set in motion 

 by the first, and flowing out of the sensory ganglia along 

 the nerves of consciousness. Sensation is due to the action 

 of the nerves of sense on the sensory ganglia, and I believe 

 that consciousness is due to the action of the sensory 

 ganglia on the nerves of consciousness, which are cerebral 

 nerves. 



A question arises here. Sensation and, as I have no 



doubt, consciousness also are due to the mutual action of 



a nerve-fibre and a ganglion. The nerves of sensation have 



ganglia at only one end ; their other ends are in connexion 



with the organs of sense — with the eye, the ear, the skin, 



&c. But the nerves of consciousness have ganglia at both 



ends ; at one end are the sensoiy ganglia, at the other is 



Is con- the ganglionic substance of the cerebrum. Is the con- 



^°^*di^"eT sciousness of sensation due to the action of the sensory 



in the ganglia in sending out the current of consciousness along 



^In^aiil tlie cerebral nerve-fibres ? or is it due to the action of the 



or the ganglionic substance of the brain, at the other end of the 



cerebrum? '^ ° . . , l n k 



fibres, receiving the current ? An answer to this question 

 might appear impossible, and of course there is no direct 

 evidence ; nevertheless, I believe the same analogical 

 reasoning which has guided us so far, will enable us to 

 give at least a probable answer to this question also. 



I have as yet spoken only of the consciousness of 



