tiplied without a distinct and essential difference of
meaning.

The five senses, together with some auxiliaries, which will be the
subjects of future notice, may be considered as the instruments or
agents, by which the edifice of mind is constructed. In the act of
perceiving by the different senses, there are some circumstances, which
are particularly deserving of attention. In order that perception may
fully and certainly take place, it is necessary that the person should
be undisturbed; he ought to be exempt from external intrusions, and
internal perturbation. During this process the respiration is in general
more slowly drawn, the body endeavours to maintain a perfect quietude,
and its position becomes fixed. When we perceive objects by the eye,
this organ becomes fixed and the lips are usually closed. During our
examinations by the touch, the eye is also fixed, the breathing is
suspended, and the lips brought into contact: the fingers are separated,
and their more delicately tangent surfaces applied to the object with
their utmost expansion. In the exercise of audible perception, the neck
is stretched forth, and the ear applied to the quarter from whence the
sound appears to issue; the mouth is partly open to conduct the
vibrations to the Eustachian tube. When we acquire intelligence by the
smell, the lips are very firmly closed, the nostrils become dilated, and
the inspiration of air through them is conducted by short and successive
inhalations. From the connection between the smell and organs of taste,
(and this association is more remarkable in some animals than in man,)
it is difficult to describe the process, which, however, principally
consists, when minutely tasting, in moving the tongue (the principal
discriminator) on the palate:--but when urged by strong appetite as in
the act of feeding, and when divested of the restraints which refined
society imposes; the nostrils are widely expanded, the eye is keenly
directed to the portion, and the hands are busily employed.

Experience has sufficiently informed us that the organs of sense must be
in a healthy state, in order to the due conveyance of perception. When
the function of any organ is altogether defective, as when a person is
born blind, he is cut off from all perception of light and of visible
objects. If by nature deaf, from the intonation of sounds; and many
unhappy instances of such connate defects abound among our species. In
one particular subject,