HYGIENE OF THE RESPIRATORY ORGANS.
495. For man to enjoy the highest degree of health, it is necessary
that the impure "venous" blood be properly changed. As this is
effected in the lungs by the action of the air, it follows that this
element, when breathed, should be pure, or contain twenty-one per
cent. of oxygen to about seventy-nine per cent. of nitrogen.
496. The volume of air expelled from the lungs is somewhat less than
that which is inspired. The amount of loss varies under different
circumstances. An eightieth part of the volume taken into the lungs,
or half a cubic inch, may be considered an average estimate.
497. _The quality and purity of the air is affected by every
respiration._ 1st. The quantity of oxygen is diminished. 2d. The
amount of carbonic acid is increased. 3d. A certain proportion of
watery vapor is ejected from the lungs in the expired air. Of the
twenty-one parts of oxygen in the inspired air, only eighteen parts
are expired, while the carbonic acid and watery vapor are increased
about four per cent. The quantity of nitrogen is nearly the same in
the expired as in the inspired air.
_Observation._ It is now fully ascertained that while the chemical
composition of the blood is essentially changed, its weight remains
the same, as the carbon and hydrogen discharged are equal to the
united weight of the oxygen and nitrogen absorbed.
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495-546. _Give the hygiene of the respiratory organs._ 495. What is
necessary that man enjoy the highest degree of health? 496. How does
the volume Of expired air compare with that which was inspired? Does
this loss vary, and what is an average estimate? 497. How is the
purity of the air affected by respiration? How is the inhaled oxygen
affected? What effect on the carbonic acid and watery vapor? On the
nitrogen? What is said respecting the weight of the blood?
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498. If one fourth part of the volume of air received by the lungs at
one inspiration is decomposed at one "beat" of the heart, it might be
supposed that if the expired air be again received into the lungs, one
half of the oxygen would be consumed, and, in a similar ratio, if
re-breathed four times, all the oxygen would be consumed. But it does
not follow, if the air is thus re-breathed, that the same changes will
be effected in the lungs. For air that has been inspired does not part
with its remaining oxygen as freely as when it contains the proper
amount of this life-giving element, and thus the changes in the impure
blood are not so completely effected.
_Illustration._ In the process of dyeing, each successive article
immersed in the dye weakens it; but it does not follow that the dye
each time is affected in the same degree, or that the coloring matter
by repeated immersions can be wholly extracted. The same principle
applies to the exchange of oxygen and carbonic acid gas in the lungs.
499. _If the inspired air is free from moisture and carbonic acid,
these substances contained in the blood will be more readily imparted
to it._ When the air is loaded with vapor, they are removed more
slowly; but if it is saturated with moisture, no vapor will escape
from the blood through the agency of the lungs. This may be
illustrated by the following experiment: Take two and a half pounds of
water, add to it half a pound of common salt, (chloride of sodium,)
and it will readily mix with the water; and to this solution add the
same quantity of salt, and it will be dissolved more slowly. Again,
add more salt, and it will remain undissolved, as the water has become
saturated by the pound before dissolved.
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498. Does air that is re-breathed freely impart its oxygen? Why? 499.
What is the effect on the blood when the air is free from vapor and
carbonic acid? When loaded with vapor? When saturated? How is this
illustrated?
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500. The principle in this experiment is analogous to that of the
union between carbonic gas and atmospheric air. Allen and Pepy showed
by experiment, that air which had been once breathed, contained eight
and a half per cent. of carbonic acid. They likewise showed, that no
continuance of the respiration of the same air could make it take up
more than ten per cent. This is the point of saturation.
_Experiment._ Sink a glass jar that has a stop-cock, or one with a
glass stopper, into a pail of water, until the air is expelled from
the jar. Fill the lungs with air, and retain it in the chest a short
time, and then breathe into the jar, and instantly close the
stop-cock. Close the opening of the jar that is under the water with a
piece of paper laid on a plate of sufficient size to cover the
opening, invert the jar, and sink into it a lighted candle. The flame
will be extinguished as quickly as if put in water.[15] Remove the
carbonic acid by inverting the jar, and place a lighted candle in it,
and the flame will be as clear as when out of the jar.
[15] As a substitute for a jar with a stop-cock, take a piece of lead
pipe bent in the form of a siphon, and insert it in the mouth
of a reversed jar. This experiment is as conclusive whether the
air is inhaled once only or breathed many times.
_Observations._ 1st. It is familiarly known that a taper will not burn
where carbonic acid exists in any considerable quantity, or when there
is a marked deficiency of oxygen. From this originated the judicious
practice of sinking a lighted candle into a well or pit before
descending into it. If the flame is extinguished, respiration cannot
there be maintained, and life would be sacrificed should a person
venture in, until the noxious air is removed.
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500. What did the experiments of Allen and Pepy show? How can the
presence of carbonic gas in the expired air be demonstrated? State
observation 1st. Observation 2d.
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2d. It is the action of carbonic acid upon the respiratory organs,
that gives rise to a phenomenon frequently seen in mines and caves. A
man may enter these subterranean rooms, and feel no inconvenience in
breathing; but the dog that follows him, falls apparently dead, and
soon dies if not speedily removed to pure air. This arises from the
fact that this gas is heavier than air, and sinks to the bottom of the
room or cave.
3d. While it is true that carbonic acid possesses properties that
render it unfit to be breathed, it is, notwithstanding, productive of
very agreeable effects, when conveyed into the stomach. It forms the
sparkling property of mineral waters, and fills the bubbles that rise
when beer or cider is fermenting.
501. _Pure atmospheric air is best adapted to a healthy action of the
system._ As the air cannot be maintained pure under all circumstances,
the question may be asked, To what degree may the air be vitiated and
still sustain life? and what is the smallest quantity of pure air a
person needs each minute to maintain good health? Birnan says, that
air which contains more than three and a half per cent. of carbonic
acid is unfit for respiration, and, as air once respired contains
eight and a half per cent. of carbonic acid, it clearly shows that it
is not fitted to be breathed again.
502. No physiologist pretends that less than seven cubic feet of air
are adequate for a man to breathe each minute, while Dr. Reid allows
ten feet. The necessity of fifteen or twenty times the amount of air
actually taken into the lungs, arises from the circumstance, that the
expired air mixes with and vitiates the surrounding element that has
not been inhaled.
503. _The quantity of air which different persons actually need,
varies._ The demand is modified by the size, age, habits, and
condition of the body. A person of great size who has a large quantity
of blood, requires more air than a small man with a less amount of
circulating fluid. Individuals whose labor is active, require more air
than sedentary or idle persons, because the waste of the system is
greater. On the same principle, the gormandizer needs more of this
element than the person of abstemious habits. So does the growing lad
require more air than an adult of the same weight, for the reason that
he consumes more food than a person of mature years. Habit also exerts
a controlling influence. A man who works in the open air suffers more
when placed in a small, unventilated room, than one who is accustomed
to breathe the confined air of workshops.
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Observation 3d. 501. What questions may be asked respecting the
inspired air? Give the remark of Birnan. 502. How many cubic feet of
air are adequate for a man to breathe each minute? How much does Dr.
Reid allow? 503. Mention some reasons why different persons do not
require the same amount of air.
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504. _Air, in which lamps will not burn with brilliancy, is unfitted
for respiration._ In crowded rooms, which are not ventilated, the air
is vitiated, not only by the abstraction of oxygen and the deposition
of carbonic acid, but by the excretions from the skin and lungs of the
audience. The lamps, under such circumstances, emit but a feeble
light. Let the oxygen gas be more and more expended, and the lamps
will burn more and more feebly, until they are extinguished.
_Illustrations._ 1st. The effects of breathing the same air again and
again, are well illustrated by an incident that occurred in one of our
halls of learning. A large audience had assembled in an ill-ventilated
room, to listen to a lecture; soon the lamps burned so dimly that the
speaker and audience were nearly enveloped in darkness. The
oppression, dizziness, and faintness experienced by many of the
audience induced them to leave, and in a few minutes after, the lamps
were observed to rekindle, owing to the exchange of pure air on
opening the door.
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How is it with the laborer? With the gormandizer? With the person that
works in the open air? 504. What effect has impure air on a burning
lamp? Give the illustration of the effects of impure air on lighted
lamps.
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2d. In the "Black Hole of Calcutta," one hundred and forty-six
Englishmen were shut up in a room eighteen feet square, with only two
small windows on the same side to admit air. On opening this dungeon,
ten hours after their imprisonment, only twenty-three were alive. The
others had died from breathing impure air.
505. _Air that has become impure from the abstraction of oxygen, an
excess of carbonic acid, or the excretions from the lungs and skin,
has a deleterious effect on the body._ When this element is vitiated
from the preceding causes, it prevents the proper arterialization, or
change in the blood. For this reason, pure air should be admitted
freely and constantly into work-shops and dwelling-houses, and the
vitiated air permitted to escape. This is of greater importance than
the warming of these apartments. We can compensate for the deficiency
of a stove, by an extra garment or an increased quantity of food; but
neither garment, exercise, nor food will compensate for pure air.
506. _School-rooms should be ventilated._ If they are not, the pupils
will be restless, and complain of languor and headache. Those
unpleasant sensations are caused by a want of pure air, to give an
adequate supply of oxygen to the lungs. When pupils breathe for a
series of years such vitiated air, their life is undoubtedly
shortened, by giving rise to consumption and other fatal diseases.
_Illustration._ A school-room thirty feet square and eight feet high,
contains 7200 cubic feet of air. This room will seat sixty pupils,
and, allowing ten cubic feet of air to each pupil per minute, all the
air in the room will be vitiated in twelve minutes.
_Observation._ In all school-rooms where there is not adequate
ventilation, it is advisable to have a recess of five or ten minutes
each hour. During this time, let the pupils breathe fresh air, and
open the doors and windows, so that the air of the room shall be
completely changed.
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Of the effects of breathing impure air. 505. In preserving health,
what is of greater importance than warming the room? 506. Why should a
school-room be ventilated? Give the illustration.
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507. _Churches, concert halls, and all rooms designed for a collection
of individuals, should be amply ventilated._ While the architect and
workmen are assiduous in giving these public rooms architectural
beauty and splendor, by adorning the ceiling with Gothic tracery,
rearing richly carved columns, and providing carefully for the warming
of the room, it too frequently happens that no direct provision is
made for the change of that element which gives us beauty, strength,
and life.
_Illustration._ A hall sixty feet by forty, and fifteen feet high,
contains 36,000 cubic feet of air. A hall of this size will seat four
hundred persons; by allowing ten cubic feet of air to each person per
minute, the air of the room will be rendered unfit for respiration in
nine minutes.
508. _Railroad cars, cabins of steam and canal-boats, omnibuses, and
stage-coaches, require ample ventilation._ In the construction of
these public conveyances, too frequently, the only apparent design is,
to seat the greatest number of persons, regardless of the quantity and
character of the air to maintain health and even life. The character
of the air is only realized when, from the fresh, pure air, we enter a
crowded cabin of a boat or a closed coach; then the vitiated air from
animal excretions and noxious gases is offensive, and frequently
produces sickness.
509. The influence of habit is strikingly expressed by Birnan, in the
"Art of Warming and Ventilating Rooms:" "Not the least remarkable
example of the power of habit is its reconciling us to practices
which, but for its influence, would be considered noxious and
disgusting. We instinctively shun approach to the dirty, the squalid,
and the diseased, and use no garment that may have been worn by
another. We open sewers for matters that offend the sight or the
smell, and contaminate the air. We carefully remove impurities from
what we eat and drink, filter turbid water, and fastidiously avoid
drinking from a cup that may have been pressed to the lips of a
friend. On the other hand, we resort to places of assembly, and draw
into our mouths air loaded with effluvia from the lungs, skin, and
clothing of every individual in the promiscuous crowd--exhalations
offensive, to a certain extent, from the most healthy individuals; but
when arising from a living mass of skin and lungs, in all stages of
evaporation, disease, and putridity,--prevented by the walls and
ceiling from escaping--they are, when thus concentrated, in the
highest degree deleterious and loathsome."
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What suggestion when a school-room is not ventilated? 507. What is
said in regard to ventilating churches, concert halls, &c.? State the
illustration. 508. What remarks relative to public conveyances? 509.
State the influence of habit by Birnan.
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510. _The sleeping-room should be so ventilated that the air in the
morning will be as pure as when retiring to rest in the evening._
Ventilation of the room would prevent morning headaches, the want of
appetite, and languor--so common among the feeble. The impure air of
sleeping-rooms probably causes more deaths than intemperance. Look
around the country, and those who are most exposed, who live in huts
but little superior to the sheds that shelter the farmer's flocks, are
found to be the most healthy and robust. Headaches, liver complaints,
coughs, and a multitude of nervous affections, are almost unknown to
them; not so with those who spend their days and nights in rooms in
which the sashes of the windows are calked, or perchance doubled, to
prevent the keen but healthy air of winter from entering their
apartments. Disease and suffering are their constant companions.
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510. What is said of the ventilation of sleeping-rooms? What would
adequate ventilation prevent? Give a common observation.
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_Illustration._ By many, sleeping apartments twelve feet square and
seven feet high, are considered spacious for two persons, and good
accommodations for four to lodge in. An apartment of this size
contains 1008 cubic feet of air. Allowing ten cubic feet to each
person per minute, two occupants would vitiate the air of the room in
fifty minutes, and four in twenty-five minutes. When lodging-rooms are
not ventilated, we would strongly recommend early rising.
511. _The sick-room, particularly, should be so arranged that the
impure air may escape, and pure air be constantly admitted into the
room._ It is no unusual practice in some communities, when a child or
an adult is sick of an acute disease, to prevent the ingress of pure
air, simply from the apprehension of the attendants, that the patient
will contract a cold. Again, the prevalent custom of several
individuals sitting in the sick-room, particularly when they remain
there for several hours, tends to vitiate the air, and, consequently,
to increase the suffering and danger of the sick person. In fevers or
inflammatory diseases of any kind, let the patient breathe pure air;
for the purer the blood, the greater the power of the system to remove
disease, and the less the liability to contract colds.
_Observation._ Among children, convulsions, or "fits," usually occur
when they are sleeping. In many instances, these are produced by the
impure air which is breathed. To prevent these alarming and
distressing convulsions, the sleeping-room should be ventilated, and
there should be no curtains around the bed, or coverings over the
face, as they produce an effect similar to that experienced when
sleeping in a small, unventilated room. To relieve a child when
convulsed, carry it into the open air.
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What is said of the size of sleeping-rooms? 511. What is said of the
sick-room? Mention some prevailing customs in reference to these
rooms. What is said of convulsions among children?
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512. _While occupying a room, we are insensible of the gradual
vitiation of the air._ This is the result of the diminished
sensibility of the nervous system, and gradual adaptation of the
organs to blood of a less stimulating character. This condition is
well illustrated in the hibernating animals. We are insensible of the
impure air of unventilated sleeping-rooms, until we leave them for a
walk or ride. If they have been closed, we are made sensible of the
character of the air as soon as we reenter them, for the system has
regained its usual sensibility while inhaling a purer atmosphere.
513. _In the construction of every inhabited room, there should be
adequate means of ventilation, as well as warming._ No room is well
ventilated, unless as much pure air is brought into it as the
occupants vitiate at every respiration. This can be effected by making
an aperture in the ceiling of the room, or by constructing a
ventilating flue in the chimney. This should be in contact with the
flues for the escape of smoke, but separated from them by a thin brick
partition. The hot air in the smoke flues will warm the separating
brick partition, and consequently rarefy the air in the ventilating
flue. Communication from every room in a house should be had to such
flues. The draught of air can be regulated by well-adjusted registers,
which in large rooms should be placed near the floor as well as near
the ceiling.
514. While provision is made for the escape of rarefied impure air, we
should also provide means by which pure air may be constantly admitted
into the room, as the crevices of the doors and windows are not always
sufficient; and, if they should be adequate, air can be introduced in
a more convenient, economical, and appropriate manner. There should be
an aperture opposite the ventilating flue, at or near the floor, to
connect with the outer walls of the building or external air. But if
pure heated air is introduced into the room, it obviates the necessity
of the introduction of the external air.[16]
[16] Mr. Frederick Emerson, of Boston, has devised a simple and
effective apparatus for removing vitiated air from a room. It
is successfully used upon all the public school-houses of
Boston. It is now being generally applied to the school-houses
and other public buildings, as well as private dwellings, of
New England.
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512. Why are we insensible to the gradual vitiation of the air of an
unventilated room? 513. What is very important in the building of
every inhabited room? How can a room be well ventilated? 514. What is
said relative to a communication with the external air?
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515. In warming rooms, the hot air furnaces, or box and air-tight
stoves converted into hot air furnaces, should be used in preference
to the ordinary stoves. The air thus introduced into the room is pure
as well as warm. In the adaptation of furnaces to dwelling-houses,
&c., it is necessary that the air should pass over an ample surface of
iron moderately heated; as a red heat abstracts the oxygen from the
contiguous air, and thus renders it unfit to be respired.[17]
[17] Dr. Wyman's valuable work on "Ventilation," and the work of Henry
Barnard, Esq., on "School-house architecture," can be
advantageously consulted, as they give the practical methods of
ventilating and warming shops, school-rooms, dwelling-houses,
public halls, &c.
_Observation_. Domestic animals need a supply of pure air as well as
man. The cows of cities, that breathe a vitiated air, have, very
generally, tubercles. Sheep that are shut in a confined air, die of a
disease called the "rot," which is of a tuberculous character.
Interest and humanity require that the buildings for animals be
properly ventilated.
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515. How should rooms be warmed? What is necessary in the adaptation
of furnaces to dwelling-houses?
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