INTELLECTUAL WORK OF THE BLIND—VILLEY. 685 
Notwithstanding, one should reflect that sight is not necessary to 
the free action of thought. If the disease that destroys it is confined 
to the eye and its immediate adjuncts, and does not reach the brain, 
the integrity of the intellect is secure. There are in the world very 
few ideas that the blind man (I mean, blind from birth) may not 
acquire, because there is very little that comes to us through the 
eyes alone. If we analyze the elements of visual sensation, we per- 
ceive that nearly all of it is within the reach of the tactile sense. Let 
us suppose that you look at a ruler which is in front of you on your 
table. The color strikes you first. That is a sensation which a 
person born blind never has. Although he may feel carefully all 
the surfaces of the ruler, his fingers will never tell him that it is 
black. But all the rest—its length, breadth, thickness, the form of 
the extremities, the sharpness of the angles and the edges, the polish 
of the surfaces, the place which it occupies on your table, the dis- 
tance which separates it from you—all these other ideas will be given 
him by his exploring hand. Everything is, in fact, brought back to 
the elementary ideas, extension and solidity, which touch furnishes as 
well as, and even more exactly than sight. There are without doubt 
objects too far removed from us and of too small dimensions to be felt, 
but all the ideas regarding them which sight gives to man go back 
to those which we have indicated. All things, therefore, except the 
idea of color, are conceivable to an individual who is endowed with 
the sense of touch. In order to construct an idea of an object, and 
produce an exact image of it, it suffices to multiply and combine the 
ideas of space and extent given by touch. Sight is a kind of touch 
of long reach, with the sensation of color added. Touch is a kind of 
sight minus color and plus the sensation of roughness. The two 
senses give us sensations of the same order. 
Those who see are not able to compass the earth in a single glance. 
For all that, however, they construct an idea from the data given 
them by geometers. In the same way the blind form ideas of objects 
they can not touch from the accounts of those who see, which can 
always be translated into tactile language. 
The person born blind is, however, deprived of the notion of color. 
It is an elementary notion which no other sense can give, no lan- 
guage can render comprehensible, and no analogy can make intelli- 
gible to those who can not see. I will add also the idea of light, 
which is similar. These ideas, however, are of very slhght im- 
portance from an intellectual point of view. They concern only the 
surface of objects. They do not enter at all into the composition 
of the essential ideas of human thought, such as space, time, cause, ete. 
The blind man is without those impressions of pleasure or pain 
which certain combinations of form and color cause the mind. He 
