The brain is located in the head for the sake of the eyes, and the
other senses on account of the brain.
The head is not just an aggregation and collection of these parts that
guard the eyes, though they cannot exist without the head. What need therefore
was there that the other parts, whose structure earns it the name “head,” be
assembled here also? Each of the organs of sense—vision, smell, taste, and
hearing—requires a soft nerve
[nervus sensorius]: a nerve, in
fact, to be the instrument of sense:
soft, since it should be affected and displaced in some way.
Indeed, it is quite fitting that the
organs undergo some
stimulus coming from outside in
order for sensation to occur. And so because the eyes needed the soft nerves of
the brain, and if they extend too far all soft things are soon pulled apart,
broken, or damaged,
it was right that the brain be located not far from the eyes.
These things being as they are, we now discover what was sought
from the beginning about the reason for the structure of the head.
It may be inferred that the brain is located in the head
because of the eyes, and the organs of smell, hearing, and taste on account of
the brain. But there are other reasons why these organs are properly allotted
the topmost place. For since the ears should perceive sound, which is by nature
they are rightly
located high in the body. Similarly the nostrils, because every odor is taken
upward, are deservedly high; and because much judgement of food and drink also
belongs to the nostrils, it is not without cause that they seek the vicinity of
the mouth. Now taste, which should sense the kinds of things we eat,
conveniently dwells in that part of the mouth where Nature has opened the path
for food and drink. Touch, on the other hand, is evenly distributed throughout
the body, so that we may feel all blows and all excessive onsets of cold and