Dr Neil Arnott has addressed a letter on this subject to the 'Times'
newspaper. Any expression of opinion by him on such a subject, and more
particularly with reference to the prevailing epidemics, must be deemed
of so much importance, that we are anxious, as far as in our power, to
keep it before the world. He commences by assuming, what will readily
be granted, that fresh air for breathing is one of the essentials to
life, and that the respiration of air poisoned by impure matter is
highly detrimental to health, insomuch that it will sometimes produce
the immediate destruction of life. The air acquires impurities from
two sources in chief--solid and liquid filth, and the human breath.
Persons exposed to these agencies in open places, as the manufacturers
of manure in Paris, will suffer little. It is chiefly when the
poison is caught and retained under cover, as in close rooms, that it
becomes notedly active, its power, however, being always chiefly shown
upon those whose tone of health has been reduced by intemperance, by
improper food or drink, by great fatigue and anxiety, and, above all,
by a habitual want of fresh air.
Dr Arnott regards ventilation not only as a ready means of rendering
harmless the breath of the inmates of houses, as well as those living
in hospitals and other crowded places, but as a good interim-substitute
for a more perfect kind of draining than that which exists. 'To
illustrate,' he says, 'the efficacy of ventilation, or dilution with
fresh air, in rendering quite harmless any aërial poison, I may adduce
the explanation given in a report of mine on fevers, furnished at the
request of the Poor-Law Commissioners in 1840, of the fact, that the
malaria or infection of marsh fevers, such as occur in the Pontine
marshes near Rome, and of all the deadly tropical fevers, affects
persons almost only in the night. Yet the malaria or poison from
decomposing organic matters which causes these fevers is formed during
the day, under the influence of the hot sun, still more abundantly
than during the colder night; but in the day the direct beams of the
sun warm the surface of the earth so intensely, that any air touching
that surface is similarly heated, and rises away like a fire balloon,
carrying up with it of course, and much diluting, all poisonous
malaria formed there. During the night, on the contrary, the surface
of the earth, no longer receiving the sun's rays, soon radiates away
its heat, so that a thermometer lying on the ground is found to be
several degrees colder than one hanging in the air a few feet above.
The poison formed near the ground, therefore, at night, instead of
being heated and lifted, and quickly dissipated, as during the day,
is rendered cold, and comparatively dense, and lies on the earth a
concentrated mass, which it may be death to inspire. Hence the value in
such situations of sleeping apartments near the top of a house, or of
apartments below, which shut out the night air, and are large enough to
contain a sufficient supply of the purer day air for the persons using
them at night, and of mechanical means of taking down pure air from
above the house to be a supply during the night. At a certain height
above the surface of the earth, the atmosphere being nearly of equal
purity all the earth over, a man rising in a balloon, or obtaining air
for his house from a certain elevation, might be considered to have
changed his country, any peculiarity of the atmosphere below, owing
to the great dilution effected before it reached the height, becoming
absolutely insensible.
'Now, in regard to the dilution of aërial poisons in houses by
ventilation, I have to explain that every chimney in a house is what
is called a sucking or drawing air-pump, of a certain force, and
can easily be rendered a valuable ventilating-pump. A chimney is a
pump--first, by reason of the suction or approach to a vacuum made at
the open top of any tube across which the wind blows directly; and,
secondly, because the flue is usually occupied, even when there is no
fire, by air somewhat warmer than the external air, and has therefore,
even in a calm day, what is called a chimney-draught proportioned to
the difference. In England, therefore, of old, when the chimney breast
was always made higher than the heads of persons sitting or sleeping
in rooms, a room with an open chimney was tolerably well ventilated
in the lower part, where the inmates breathed. The modern fashion,
however, of very low grates and low chimney openings, has changed the
case completely; for such openings can draw air only from the bottom of
the rooms, where generally the coolest, the last entered, and therefore
the purest air, is found; while the hotter air of the breath, of
lights, of warm food, and often of subterranean drains, &c., rises and
stagnates near the ceilings, and gradually corrupts there. Such heated,
impure air, no more tends downwards again to escape or dive under the
chimneypiece, than oil in an inverted bottle, immersed in water, will
dive down through the water to escape by the bottle's mouth; and such a
bottle, or other vessel containing oil, and so placed in water with its
open mouth downwards, even if left in a running stream, would retain
the oil for any length of time. If, however, an opening be made into
a chimney flue through the wall near the ceiling of the room, then
will all the hot impure air of the room as certainly pass away by that
opening as oil from the inverted bottle would instantly all escape
upwards through a small opening made near the elevated bottom of the
bottle. A top window-sash, lowered a little, instead of serving, as
many people believe it does, like such an opening into the chimney
flue, becomes generally, in obedience to the chimney draught, merely
an inlet of cold air, which first falls as a cascade to the floor, and
then glides towards the chimney, and gradually passes away by this,
leaving the hotter impure air of the room nearly untouched.
'For years past I have recommended the adoption of such ventilating
chimney openings as above described, and I devised a balanced metallic
valve, to prevent, during the use of fires, the escape of smoke to
the room. The advantages of these openings and valves were soon so
manifest, that the referees appointed under the Building Act added
a clause to their bill, allowing the introduction of the valves,
and directing how they were to be placed, and they are now in very
extensive use. A good illustration of the subject was afforded in
St James's parish, where some quarters are densely inhabited by the
families of Irish labourers. These localities formerly sent an enormous
number of sick to the neighbouring dispensary. Mr Toynbee, the able
medical chief of that dispensary, came to consult me respecting the
ventilation of such places, and on my recommendation had openings
made into the chimney flues of the rooms near the ceilings, by
removing a single brick, and placing there a piece of wire gauze
with a light curtain flap hanging against the inside, to prevent the
issue of smoke in gusty weather. The decided effect produced at once
on the feelings of the inmates was so remarkable, that there was an
extensive demand for the new appliance, and, as a consequence of its
adoption, Mr Toynbee had soon to report, in evidence given before the
Health of Towns Commission, and in other published documents, both an
extraordinary reduction of the number of sick applying for relief, and
of the severity of diseases occurring. Wide experience elsewhere has
since obtained similar results. Most of the hospitals and poor-houses
in the kingdom now have these chimney-valves; and most of the medical
men, and others who have published of late on sanitary matters, have
strongly commended them. Had the present Board of Health possessed the
power, and deemed the means expedient, the chimney openings might, as a
prevention of cholera, almost in one day, and at the expense of about
a shilling for a poor man's room, have been established over the whole
kingdom.
'Mr Simpson, the registrar of deaths for St Giles's parish, an
experienced practitioner, whose judgment I value much, related to me
lately that he had been called to visit a house in one of the crowded
courts, to register the death of an inmate from cholera. He found five
other persons living in the room, which was most close and offensive.
He advised the immediate removal of all to other lodgings. A second
died before the removal took place, and soon after, in the poor-house
and elsewhere, three others died who had breathed the foul air of that
room. Mr Simpson expressed to me his belief that if there had been the
opening described above into the chimney near the ceiling, this horrid
history would not have been to tell. I believe so too, and I believe
that there have been in London lately very many similar cases.
'The chimney-valves are part of a set of means devised by me for
ventilation under all circumstances. My report on the ventilation of
ships, sent at the request of the Board of Health, has been published
in the Board's late Report on Quarantine, with testimony furnished to
the Admiralty as to its utility in a convict ship with 500 prisoners.
My observations on the ventilation of hospitals are also in the hands
of the Board, but not yet published. All the new means have been freely
offered to the public, but persons desiring to use them should be
careful to employ competent makers.'
Having seen Dr Arnott's ventilators in operation in London and
elsewhere, we can venture to recommend them as a simple and very
inexpensive machinery for ventilating rooms with fires. The process
is indeed generally known, and would be more extensively applied if
people knew where to procure the ventilators. We have had many letters
of inquiry on this subject, and could only refer parties to 'any
respectable ironmongers.' But unfortunately, as it appears, there are
hundreds of respectable ironmongers who never heard of the article
in question, and our recommendation goes pretty much for nothing.
Curious how a little practical difficulty will mar a great project!
We trust that the worthy doctor will try to let it be known where his
ventilators are to be had in town and country.