(From Peoples' Health Journal, October, 1885.)
Considerable scientific attention has recently been very profitably
devoted to the question of fabrics for underwear most conducive to
health. Interesting experiments have been made developing facts which
will surprise almost everyone on learning them for the first time. One
of the simplest and most readily understood of these experiments was
that of filling tin cans with hot water and wrapping each one with a
different fabric, and then observing with thermometers the varying
rapidity in the loss of heat. Thus showing accurately the relative
heat preserving value of each fabric. Of two cans surrounded with the
same amount of common cotton batting, in one case the cotton being
compressed, and the other not, the loss of heat was found to be much
more rapid in the former than in the latter. Showing, therefore,
conclusively, that loose open fabrics are warmer than those which
contain less air in their interstices. This accords with the well-known
fact that the new flannel is warmer than old which has undergone the
felting or fulling processes. Assuming that flannel contains 100 units
of air in its interstices, the permeability of other substances have
been found to be as follows: Linen, 58; silk, 40; buckskin, 58; kid,
1; chamois, 51. Doubling the layers of any given material does not
diminish the loss of heat in the same proportion. Assuming the loss
of heat through a single layer to be 100, through a double layer of
the same material it is found to be as follows: Thin silk, 97; gutta
percha, 96; shirtings, 95; stout silk, 94; thick home-spun linen,
91; chamois leather, 88-90; flannel, 86; summer buckskin, 88; winter
buckskin, 86. Thus we see that the loss of heat through two layers of
thin silk is only three per cent. less than through one layer. The
inference is that what the substance is and what its weight, does
not make so much difference as its texture and volume. How the body
may lose heat rapidly by wet clothing, and ill results follow, is
shown by the following experiment: A rabbit was shorn of its fur, its
temperature was then found to be 102 degrees. It was wrapped with a wet
cloth and placed in a room, the temperature of which was 66 degrees. At
the expiration of five hours the temperature of the rabbit was found
to be 76 degrees. The capacity of water to absorb heat is known to be
greater than any other substance. Now, when our clothing is damp from
perspiration or from any other cause, our bodies lose just as much heat
as the moisture in our clothing is capable of absorbing. The importance
of always having dry material next to the skin is evident, and that
material which will retain the least moisture is the best. Woolen
fibre is found to answer this purpose more nearly than any other.
In addition to its well-known filtering capacity, it has a greater
stimulating action upon the skin than any other. On the other hand,
cotton fibre, on account of its great capillary attraction, rapidly
absorbs and retains moisture. A fabric, therefore, so constructed
as to allow a layer of woolen fibre to lie between the skin and a
layer of cotton fibre, and sufficiently open and loose as to contain
the largest possible amount of air is the ideal. _The Jaros Hygienic
Underwear material, a new fabric, seems beautifully adapted to this
end. A layer of woolen fibres, soft and fleecy, is firmly held on one
side of and in the meshes of an exceeding porous cotton fabric, so that
while one extremity of a fibre lies against the skin, the other is
in contact with the cotton; thus admitting of the rapid transference
of all dampness of perspiration to the cotton where it is retained,
and consequently leaving no moisture next to the skin to absorb and
diminish the heat of the body. The importance of this subject, and
the possibilities of this new fabric for the prevention of colds, and
their resultant diseases, can only be appreciated when we remember the
simple fact that it is impossible to take a cold so long as a healthy
condition of the skin, and an even temperature of the surface of the
body, are maintained._