Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1875-12-08

0CLkNIkIC.

The Relation of Food to Work.-Dr.
Du ChaumOnt, in recent lecture, said
that up to q quite late date there was
an absence OF any satisfactory theory
as to the relation of food to work, and
it was supposed that bodily force was
due to a chemical change in the mus
cles themselves, and that the nitrOge-
nous matter in food repaired the waste.
But the researches of JOule, Playfair,
Frankland. and others, on the cOnser-
walton of energy. have led to the con-
clusion that active force is produced
chiefly by the potential energy stored
up in the carboniferous food, and set
free by oxidation. Hence it was seen
that to credit the chemical changes in
the muscles with the Originati0n of
force in the body was not more philO-
sophical than to credit the force exer-
ted by a steam engine to the wearing
away of its wheels and pistOns.
The lecturer then proceeded through
q large number of elaborate calcula-
tiOns, based upon actual observation.
for the purpose of showing the ordinary
amount of productive work of which a
man of average height is capable, and
its equivalent in foot tuns-a foot tun
representing the amount of force re-
Quired to raise one tun one foot high.
1t appears that the work done in walk
ing three miles an hour is equal to
about one tenth the work done by di-
rect ascent. Three hundred foot tuns
is a fair days work for q man of ave-
rage height. This would be equiva-
lent to walking fifteen miles in little
over five hours. A hard days work
would be equal to walking twenty-fOur
miles in eight hours. DR.. Parkes men-
tiOns an extreme case, in which man
in copper mill did as much as 723 foot
tuns in a day, his average work being
443 foot tuns. The ordinary work of a
military prisoner is 80 foot tuns. The
velocity at which work was done, and
the consequent resistance, greatly af-
feet the quantity of potential energy
required for its accomplishment. Fer
the production of any amount of what
may be termed productive work, "a much
larger amount of potential energy has
to be expended. Professor HaughtOn,
of Dublin, has calculated that. of the
total potential energy produced in the
body, 260 foot tuns are required for
the action of the heart. Then the ami
NAL heat absOrbs from 1900 to {, 800
foot tuns, or more.
According to HelmhOltz, about five
times as much energy is Used In the in
ternal work of the body as is expended
in ordinary productive work. In the
case of severe work, the proportion
of internal work to productive work is
still greater. SuppOsing the work per-
formed by man to consist of walking,
the most economical rate, both as re-
CARDS the amount of food required to
sustain it, and the amount of potential
e. -ergy expended ON the body itself, is
about three miles an hour. Both
above and below that speed there is a
decrease in the amount of active work
as compared with the non-prOductive
energy. A man walking fifteen or six
teen miles day, or doing an equiva-
lent amount of work in another form,
would require % Ozs. of food, composed
of albuminates 4'6 Ozs., fat Ozs. starch
1913 ozs., and salts II. oZs. This would
yield a potential energy of 4.430 foot
tuDs, and 800 foot tuns for productive
work. A mere subsistence diet for a
man at rest would be 10 Ozs.. but with
this amount man would lose weight.
About 1000 foot tuns a day of pOten-
tial energy is about the greatest amount
which is pOssibleas apermanency. This
would yield 600 foot tuns of productive
work. These calculations apply only
to men in health.