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66
same room, while there are great differences between the rooms and the corridors,
and the amount of carbonic acid present may be two or three times that to be
found in the open air, but may it not be contended that, when we are not dealing
with the hospital ward, but with the problem of rearing a number of young
people so as to be vigorous in body and alert in mind, the very imperfect but
varying conditions incidental to a moderately efficient system of natural
ventilation provide better conditions than a chemically, mechanically and
physically perfect system or forced draught?
“If this is not the case, why is the open air regarded as so hygienic? Does
anyone believe that the difference is merely due to the amount of poisonous
matter in the atmosphere of an ordinarily well ventilated room? There may
be in the outer air actinic rays about which we know little, and which are incapable
of penetrating glass, and these may be entirely absent in our closed classrooms.
The rays which gradually turn to a violet colour the window glass of
a century ago through the liberation of metallic manganese within the glass
may be rays of this kind. On the other hand, it may be the constant adaptation
of the body to varying conditions which constitutes the major part of the
health giving influences of the open air. My main point is, ought we on the
one hand to be running open air classes, and on the other to be adopting a
system of forced draught and closed windows? The two appear to be very
inconsistent.”
This letter is worthy of being put upon record if only for the remarkable insight
which enabled Dr. Garnett to suggest the existence of actinic rays which cannot
penetrate glass, which might have a decided effect upon health. At that time
nothing was known scientifically of the effect of ultra violet rays upon health. It
is only in the past six years that the very important and definite health giving
properties of these rays have been demonstrated, and it is the fact that they are
obstructed by ordinary glass.
The memorandum to which Dr. Garnett alluded in his letter, contained the
following paragraph relating to the complaints of the teachers:—
“I do not think that teachers will ever take kindly to the “plenum”
system. In the first instance, any system of heating by warm air is unpleasant.
It causes a deposit of the solid particles in the air on all surfaces which are
cooler than the air itself, and gives a sense of stuffiness. For comfort the air
should be colder than the furniture and walls of the room. This gives a feeling
of crispness to the air, which is experienced to perfection in the sunshine of a
high mountain.
“In the second place, I think that in a building in which the windows
can never be opened to admit the fresh air directly from the outside, a nervous
depression is produced. I do not think that the supply of chemically pure air,
perfect as regards its hygrometric condition and its temperature, in a closed
building would ever have the health giving effect of open air life, at least as far
as its effect on the nervous system is concerned.
“In the third place, it is very much open to question whether there is not
a considerable refreshment when different parts of the room are at slightly
different temperatures whereby eddy currents are naturally produced. In a
room which is heated entirely by air at a uniform temperature, there is liability
to a production of the sense of lassitude and oppression which would be at
once relieved either by opening a window or coming to the front of a bright
fire. I am not in a position to explain all these phenomena on physiological
grounds.”
It will be seen that the opinion which the medical staff has independently formed
coincides with that of Dr. Garnett, and an attempt has been made to give the physiological
explanation which Dr. Garnett felt himself unable to do.