Centre Democrat. [volume] (Bellefonte, Pa.) 1848-1989, 1880-12-02

A Machine That Measures Thoughts.
A machine has been invented by Doc
tor Mosso, of Turin, which measures
thought. II IS called the plethysmograph,
and its revelations are based on the fact
that thought creates nervous action,
which consumes in its performance Il
certain quantity OF blood, and that
quantity may be measured. In an ad-
dress before the American Association
of Science, Professor G.. +. Barker de-
cribes the machine and its working as
follows:
The forearm, for example, being the
organ TO be experimental on, Is placed
in cylinder Of water, and tightly in
closed. A rubb,r tube connects the in
terror of the cylinder with the recording
apparatus. With the electric circuit by
which the stimulus was applied 10 pro.
duce contraction were two keys. one of
which was dummy. IL was noticed
that, after using the active key several
times, producing varying current
hlINHENilSs lilt wi Nt b1tlh ID JtAOIf Oll
pressing down the inactive key. Since
no real effect was produced, the result
was caused solely by the imagination,
blood passing from the body TO the brain
in the act.
To test further the effect Of mental
action, Doctor Pagliani, whose arm was
in the apparatus, was requested 10 null
tiply two hundred and sixty-seven by
eight mentally, and TO make sign when
lie had finished. The recorded curve
showed very distinctly how much more
blood the brain took 10 perform the
operation. Hence the plcthysmograph
is capable OF measuring the relative
amount OF mental power required by
| different persons to work out the same
! mental problem. Indeed, Mr.. Gaskel
suggests the use of this instrument in
the examination room, TO find out, in
addition TO the amount OF knowledge a
man possesses, how much effort il
causes him to produce any particular
result Of brain work.
Doctor Mosso relates that, while the
| alphl aAuo was eft up III hIs lbOul III
Turin. classical man came in
TO see him. He looked very con-
temptuously upon it, and asked of what
use it could be, saying tha. it couldn't
do anybody any good.
Doctor Mosso replied: well, .1w
| can tell YOU by that whether you rea.
Greek as easily as you can Latin"
AS tIe ciassicist would not believe Il,
his own arm was put into the apparatus.
and he was given a Latin book TO read
Avery slight sinking OF the curve was
the result.
The Latin book was then taken away,
and a Greek book was given 10 him
This produced Immediately a much
deeper curve.
He had asserted before that i: was
quite as easy for him 10 read Greek as
Latin. and that there was no difficulty
in doing either. Doctor Mosso. how
ever, was able to show him that he was
laboring under delusion.
Again, this apparatus is so sensitive
rs be useful for asccrtaiuing how
much person is dreaming. When
Doctor Pagiiani went TO sleep in the ap-
daratus, tae effect upon the resulting
curve was very marked indeed. He said
afterward that he had been in a sound
sleep, and remembered nothing of what
| passed in the room-that he had been
absolutely unconscious; and yet, every
little movement in the room, such as
the slamming OF door. the barking of
a dog, and even the knocking down Of n
piece of glass, were all marked on the
curves. Sometimes he moved his lips,
and gave other evidences that he was
dreaming. They were all recorded on
the curve, the amount of blood required
for dreaming diminishing that in the
extremeties.