The weekly herald. [volume] (Cleveland, Tenn.) 1876-1888, 1881-01-21
A Machine That Measures Thought,

A Machine That Measures Thought
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 fac
that thought creates nervous action
which consumes in its performance ;
certain quantity OF blood, and tha
quantity may be measured. IL nm ad-
dress before the American Association
of Science, Professor e.. +. Barker de
Cribes the machine and its working a
follows:
The forearm, for example, being th'
organ TO be experimental on, is placed
in cylinder of water, and tightly In
closed. A rubb tube connects the in
terror of the cylinder with the recording
apparatus. With the electric circuit By
which the stimulus was applied to pro
duce contraction were two keys, one o.
which was a dummy. 1t was noticed
that, after using the active key severa
times, producing varying current
strengths, the curve sank as before OF
pressing down the inactive key. Since
no real effect was produced, the result
was caused solely ~ the imagination
blood passing from tue body to the brain
in the act.
To test further the effect of menta
action, Doctor Pagliani, whose arm was
in the apparatus, was requested TO mul.
tiply two hundred and siXty-seven by
eight mentally, and to make n sign when
he had finished. The recorded curve
showed vCry distinctly how much more
blood the brain took TO perform the
operation. Hence the plethysmograpk
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
apparatus was set up in his room in
Turin, a classical man came in
to see him. He looked very con-
temptuously upon it, and asked of what
use it could be, saying that it couldn't
do anybody any good.
Doctor Mosso replied: "Well, low
| can tell you by that whether you read
Greek as easily as you can Latin"
As tue classicist would not believe it,
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 Greek book was given to him.
This produced Immediately q much
deeper curve.
He had asserted before that it was
quite as easy for him to 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
as to be useful for ascertaining how
much a person is dreaming. When
Doctor Pagliani went to sleep in the ap-
paratus, the effect upon the resulting
curve was very marked indeed. He said
afterward that lie 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
dog, and even the knocking down of a
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
axtremities.