76 VISION. 
nerves in which your consciousness resides, or would 
even know that you had such things unless those to 
whom the interior of the body is known by dissec- 
tion had told you. 
It is very startling, and to the unscientific very 
confusing. I do not care at the present moment to 
press the inquiry further. All the length which I 
wish to lead you just yet is to appreciate that even 
in touch, which is the simplest of our senses, there 
is no immediate contact of the mind with external 
objects. At most, you are only aware of the posi- 
tions in which your various sensations are felt : you 
are not conscious of the things which cause those 
sensations. 
Let us turn now from common sensation to vision. 
Vision is the most subtile and most complex of all 
the senses. It is produced by the vibrations of 
light, vibrations vastly more minute than those of 
sound ; and even sonorous vibrations are for the 
most part incapable of affecting the sense of touch ; 
although, no doubt, if one stands near a piano with a 
tense parchment in his hand, he will feel the notes 
producing vibrations in his fingers. Further, we 
not only appreciate light and darkness by vision, 
but the exact relative position of very numerous 
spots of light, with their various degrees of intensity 
and their differences of colour, all at the one time. 
