Evening star., 1906-02-05
THE PHYSIOLOGICAL ZERO.
at Which Human Body
Feels No Sensation.
From the Literary Digest.

From the Literary Digest.
This name is given, by certain writers on
the subject, to the temperature at which
the human body feels no sensation of heat
or cold. 1t might be supposed that 1t would
coincide in all cases with that of the body
itself, but, according to the recent expert
ments of MIR. Maurei. a French phystolo-
gist, it Is several degrees lower. and varies
with the nature Of the surrounding me-
dium, being lower in air than In water.
Mr. Maurel determined his physiological
zero by immersing his body in baths of
different temperatures, but he does not
seem to have measured his own body. sur
face temperature directly. relying. instead.
on the records OF measurements made by
divers earlier authorftfes. This and the
fact that he has neglected to take yarfoas
necessary precautions makes his results
somewhat doubtful in the opinion of Mr..
Henry Pteron, who .criticises them thus in
the Revue Scientifque:
"Mr. Maurel placed himself in baths of
water or air at divers temperatures, and
noted between what degrees he realized
the sought-for state of indifference. He did
the same for the variations OF temperature
between the skin and the clothes, which he
calls the tsubvestial temperature and for
the temperature of the body in bed. which
he names 'cubilial temperature And he
finds that the cutaneous physiological zero
lies practically between 30 degrees and 33
degrees (S6 degrees and OIL degrees F.); he
even seeks to differentiate the trunk and
the lower limbs. whose physiological zero
ne finds to be slightly lower. In general
the range of zero Is / degree to degrees
e degrees to degrees F.).
He also concludes that there is a relation
between the physiological zero and the sur
face temperature OF each organ. which lat
ter Is about degrees t5h degrees F.) high
er than zero. But were any new expert
ments necessary to show that the sensation
of Indifference depends on the surface tenn
perature of the body?
THE same medium should appear Icy or
broiling to the fever patient as his sur
face temperature oscHIates. And as the
exit or entrance Of heat, the contact that
assures thermic equilibrium should assure
also a state of sensorial indifference
AT first sight 1t would appear odd that
one should experience sensation OF heat
when the external temperature is identical
with his own surface temperature. And. In
fact, exact experiments in thermo-esthesi-
ometry have shown that In certain spots on
the hand, for instance, a drop OF water at
the same temperature is not felt. But the
surface temperature Is only cross be-
tween the internal and external tempera-
ture, adapting itself to this double tnfiu-
ence by capricious regulating mechanism
under the direct but obscure action of the
nervous system.
Hence the phenomena of caloriic radi-
ton toward the exterior or interior, which
provoke our sensations of heat or cold. may
respond to numerous and imperfectly deter
mined factors, Influenced by pressure. hu-
n;dity ETC., from outside, and by bodily
chemical actions the eonductibiiity of the
tissues. etc, from inside
Thus. though rather astonishing, Maui
rcFs conclusion that the physiological zero
is lower than the surface temperature can
not be attacked. except on the basis of new
experiments"