(seq. 151)

71

Lect 5

To convery sensations, & another to perform
Muscular Motion - A question arises here in what
Manner are sensations produced? This is not known
& perhaps never will. Some suppose, they are produced by
Vibration, the constituent nerves being solid Chords & ima=
gine, that when they are to convey the Influence of the Mind
to the Muscle, the Vibration begins in their Origin being
produced in the Brain by the Mind, but in carrying Sensa=
tions to the Brain, it is vibrated from without & it was
thought, that the Vibratory Motion of the Nerves was the
most likely to account for the Sympathy of Parts. It is ob=
jected then of what Use is the Brain, but it may be said, to
be necesary for the Residence of the Mind. In Answer to this
M.r In. Hunter observes that the brain is not affected by acids
nor has it ^{as lange a Proportion of} Earth ^{in the Composition} as other parts. The material objections are
the Unfitness of the extremities of the nerves to receive a vibra
tory motion as they termeniate in a soft pulpy substance,
but there is no proof of this, tho' it is thought they do end in a
tender substance. their course also is until for this purpose
they are soft & lie in Contact with other Parts & are