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gen. At every inhalation, a portion of the oxygen permeates
the veiictdar membrane, and unites with the blood, which, at
the same time, emits a certain amount of carbonic acid gas,
which unfits the air to be respired a second time.

A simple experiment will elucidate the vitiation of exhaled
air. Breathe into a cup containing lime-water, and in a
short time a white film will be seen on the surface of the
water. This is called the carbonate of lime, and this alkaline
salt is formed by the carbonic acid gas, from the exhaled air,
uniting with the lime.

It is a well-known fact, that a taper will not bum where
carbonic acid alone exists ; and another proof that exhaled
fdr contains carbonic acid gas, or will not support combustion,
may be seen by the following experiment.

Tbke a glass recei^'er, to which is attached a stop-cock ;
sink it in water until it displaces the air by filling the receiver.

In whom is respii-ation most frequent ? How is it in diseases ? How
often do we respire in a minute ? How often does the heart beat at every
rtspiration ? How many cubic feet of air do we inhale in twenty-four
hours ? How much oxygen should the inhaled air contain ? Why ? Why
is air unfit to be re-inhaled ? How can it be proved that the air exhaled
contains oarfoonio aeid gas ? What experiment shows that exhaled air will
not support combustion ?

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Ghradni^y raise it, and respire into it, avoiding as much as
possible toe ingress of atmospheric air ; then inhale the same
air and sink the vessel into the water. Repeat this several
times. Fill the receiver with the air that has been inhaled
several times, and slide a plate upon which a sheet of paper
is placed, under it, while the open mouth of the receiver is
kept below the surface of the water. By turaing the stop-
cock, and keeping it on the plate filled with water, no atmos-
pheric air will pass into the receiver. After a taper is light-
ed, raise and invert the jar suddenly, being careful to keep
the mouth of the jar covered with the paper ; then raise the
paper and pass the burning taper into it ; the flame will be
immediately extinguished, for want of oxygen to support com-
bustion, and in consequence of the presence of carbonic gas.

In crowded rooms, which are not ventilated, the air is soon
vitiated by the abstraction of oxygen, and the deposition of
carbonic acid gas, by the audience. The lamps, under such
eircumstances, emit but a feeble light. Let the oxygen gas
be more and more expended, and the lamps will bum more
and more feebly until nearly extinguished. Air in which
lamps will not burn with brilliancy, is unfitted for respiration.
For this reason, before entering wells or subterranean pas-
sages, a lighted taper should be passed into them, and if the
flame be extinguished, it shows the presence of carbonic gas,
and if such places are entered before this deleterious gas is
removed, instant death will follow. Nor should persons sleep
in rooms where charcoal is in a state of ignition, without some
aperture to permit the carbonic acid gas to escape.

In addition to the above-mentioned sources, which render
the air unfit for respiration a second time, there is passing from
the skin and lungs, more than two pounds of waste matter
every twenty-four hours. This is difiused through the air in
the room, and if this impure air be not changed, it will be ia-
haled into the lungs.

Let the air become vitiated, whether from the abstraction
of oxygen, an excess of carbonic gas, or the exhalations from
the lungs and skin, and it will have a deleterious effect on the
system, by rendering the circulating fluid impure. For this
reason, in workshops, churches, and dwelling houses, pure air

What effeftt ha« vitiated air upon burning lamps ? What caution U giv«
en on entering subterranean passages ? lu sleeping in a close room w^eio
ignited charcMl is placed ?

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should be admitted freely and constaDtly, and the ii^pure Mad
vitiated air permitted to escape. This is of mpre importance
than the warming of houses. We can compensate for the de*
ficiency of a stove, by an extra garment or an increased quan-
tity of food ; but neither garment, exercise, nor food, will com-
pensate for pure air.

The brain of the scholar must be stimulated by pure bloody
or its proper functions will not be performed. If the school-
house be not ventilated, the pupils will complain of inability
to study, defective memory, and headache, caused by a want
of pure oxygenated blood, and an excess of carbonic acid

Above all, 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
mprning headaches, and the want of appetite, so commoor
among the feeble. JSvery room should be so constructed thai
pure air can be admitted freely, as impure air tends to
weaken and destroy the system. The impure air oi sleeping
roon^s is probably more ruinous 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
flpcks, are found to be the most healthy and robust Head-
aches, liver complaints, and coughs, are almost unknown to
them ; not so with those who spend their days and pights in
rooms, in which the sashes of the windows are caulked, or
perchance doubled, to prevent the keen but healthy air of win-
ter from entering their apartments. Disease and suffering are
their constant companions. The one breathes pure air, the
other does. not.

Due atCenUon has not been given to the proper ventUation
of rooms. '1st. Air can and should be introduced into our
apartments pure and warm. This caii be done by the use of
hot-air furnaces, or by converting the box and air-tight stoves,
into hot-air iurnaces. The common air-tight stoves are very
objectionable, especially for sick rooms.

2d. Provision should be made for the escape of the vitiated
air, as well as the introduction of pure air. This can be done

Is the ventilation of rooms of as much importance as the warming of
them? Why should every inhabited room be well ventilated? How
•hotttd pure air be introduced into apartments ? How should tiis impure
ahr b« oarried firom rooms ?

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bj constructing a ventilating due in the chimney. This
should be in contact with the dues for the escape of smoke,
but separated from them by a thin brick partition. The heat
of the current of air in the smoke dues will warm the sepa-
rating 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 regu-
lated, by well-adjusted registers. Open fire places and open
grates favor the escape of vitiated air, and are more conducive
to health, than any of the ordinary stoves.

EffecU of impure Uood upon the system will now he stated.
The blood may be rendered impure by each of the influences
before described, or by all of them combined. We will note
the effect it has upon the bones. As one condition of health
and strength, they require pure blood. If it be not supplied
to them, they will become soft and brittle ; their vitality will be
impaired ; disease will be the ultimate result The four hun-
dred muscles receive another portion of the blood. These
organs are attached to, and act upon the bones. Upon the
health and contractile energy of the muscles depends the
ability to labor. Give these organs of motion impure blood,
which is an unhealthy stimulus, and they will become enfee-
bled, the step will lose its elasticity, the movement of the arm
will be inefficient, and every muscle will be incapacitated to
perform its usual amount of labor.

The stomach, liver, and other organs subservient to the
digestion of food, are supplied with this impure blood.
This impairs the digestive process, causing a faintness of the
stomach, loss of appetite, and a deranged state of the in-
testines, and, in general, all the symptoms of dyspepsia, or
liver complaint. This impure blood goes also to th# lungs, in
the nutrient arteries. The delicate structure of these organs,
in which the blood is, or should be purified, needs the requi-
site amount of pure blood to give them vigor and health.
The blood not becoming of that character, the lungs themselves
lose their tone, and even if permitted to expand freely, have
not power fully to change in inspiration the impure quality of
the blood. This dark, sluggish fluid also passes to the skin,
the health and beauty of which require well-purified blood.

Mention how impure blood affects the bones and muscles of the s^rstem.
The digestive organs. Does this impure blood aiTect the structure of tho
lungs ? How conveyed ?

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This not existing, the surface becomes covered with pimples
and blotches, and the individual suffers from ^' humors " as
they are called. Drinks, made of various kinds of herbs, and
pills and powders, are taken for this disease. These will never
have any good effect, while the causes of impure blood exist.

This impure blood is sent to the brain. If this important
organ be stimulated by impure blood, the nervous headache,
bilious headache, and all kinds of aches, confusion of ideas,
loss of memory, impaired intellect, dimness of vision, and
dullness of hearing, will be experienced. Often, in process of
time, the brain becomes disorganized, and the brittle thread of
life is broken.

The free movements of the ribs and diaphragm, with an
abundant supply of pure air, are of the ntmost importance
to feeble and scrofulous individuals. A common cause of
scrofula, so prevalent in the densely populated sections of
our country, is the inhalation of vitiated air. Due renova-
tion of the air which we breathe, is really influential in
protecting us against the inroads of disease. A constant cir-
culation of air is one^of the most effectual means of prevent-
ing contagion from fever. It is no unusual practice in some
communities, when a child or an adult is sick of an acute dis-
ease, to prevent the ingress of pure air, simply from the ap-
prehension of the attendants, that the patient will contract a
cold. Again, the prevalent custom of several individuals sit-
ting 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 have
pqye air to breathe, for the purer the blood, the greater the
power of rtie system to remove disease, and the less the liabil-
ity to contract colds.

Fig. 122 represents the thoracic and abdominal organs, in
their relative positions. Let the pupil, from this figure, re-
view the sections upon the anatomy and physiology of the
digestive and respiratory organs, giving the location of each
part, describing its structure, use, and the laws upon which
health depends.

How is the skin affected by it ? How does it affect the brain ? What it
a common cause of scrofula ? What is one of the means of preventinff
contagion from fever 7 What custom prevalent in many siek-rooma tbonra
be abandoned ? What does fig. 122 exhibit ?

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Fig. 122.

Vlg. 133- A view of the jorgana of the cl
M glveo by the removal of the anterior y/
the side of the chest. 3, The fatty tissue i
tion of the pieura of each side. 6, The
rapertor lobe of the right lung. 7, The inl
that separates them. 8, The upper lobe <
left long. 11, The fissure between them.
IS, The upper face of the right lube of th
The end of the gall bladder. 16. The stona
19, 19. 19, 19, The omentum. 20, 20, The
through the omentum. 21, The spleen, i
walla of the abdomen turned down.

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The voice consists in the production of a particular sound,
by the aid of the air which escapes from the lungs. It is
chiefly formed in that portion of the respiratory organs named
the larynx. Incidentally, the other portions of the respira-
tory organs are subservient to phonation or 3ound. The
tongue, nasal passages, muscles of the fauces and face, are
agents which aid in the intonations of the voice. The me-
chanism and function of the larynx, will be the topics exam-
ined in this chapter.

rig. 128. Fig. 124.

^ Fig. 128. Bepreronta a lateral view of ttie eartUages and ligaments of the larynx.
1, The OS hyomcs. 2, A ligament which connects the hvoid l)one with the thyroid
cartilage. 8, The large horn of the thyroid cartUwe. 4. The angle and side of this
cartilage. 5, The small horn of this cartilage. 6. The lateral portion of the criccld
cartilage. 7, Sings of the trachea.

What 18 the voice? In what organ is it chiefly formed ? Nam© oth«r
organs that are siibservient to soand. What do Figs. 123 and 124 repre-

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FIff. 134. S«pre8«nt8 a posterior view of the cartOages and Ilwients of the larynx;
1. The posterior face of the epiglottis. 2. 2, The appendages of the os hyoides. 8, 9.
Its comoa, or horns. 4, 4, The lateral ligaments which connect the os hyoides and
thyroid cartilage. 5, 6, The posterior face of the thyroid cartilage. 6, 6, I'he aryte«
noid cartilages. 7, The cricoid cartilage. 8, The articulation of the cricoid and
arytenoid cartilages. 9, 9, The posterior ligament that connects the cricoid and thy.
Toid cartilages. 10, The small horn of the thyroid cartilage. 11, The anterior li«u
Qient that connects the cricoid and thyroid cartilage. 12, The ligamentous portion
of the first ring of the trachea.

The LARYNX is a kind of cartilaginous tube, which, taken
as a whole, has the general form of a hollow reversed cone^
with its base upward toward the tongue, in the shape of an
expanded triangle. It opens into the pharynx, and unites
inferiorily to the trachea.

The \^alls of the larynx are chiefly formed by the union
of five eartilages, viz : the ihyroid^ cricoid, the two arytenoidj
and the epiglottis. These are bound together by ligaments,
and moved by muscles.

Fig. 125. rig. IM.

Fig. 195. Bepresents a vertical Section of the idrynx. 1, A section of the root of
tiie tongue. 2, The os hroides. 8, The muciparons glands of the epiglottis. 4, Tht
top of the epiglottis cartilage. 5, A section of its anterior face. 6, A fold of macona
membrane. 7, The superior vocal ligament. 8, A section of the thyroid cartilage.
9, The ventricle of the larynx. 10. The lower vocal ligament. 11, The arytenoid
eartilages. 12, Inside of the cricoid cartilage. 18, Its posterior portion. 14, The
liniiig membrane of the trachea. 16, The end of the comu major of the os hyoides.
16, The comu major of the thyroid cartilage. 17, The mucous membrane of tha
phar3nix. 18, The oesophagus. 19, The thyroid gland.

Fig. 126. Represents a view of the larynx t^om above, showing the vocal Ugamenta.
1, The superior edge of the larynx.' '2, 2, Its anterior face. 3, 8, The cornua major

Describe the lamix. Hoitf »t its wcOls farmed ? How are tiiese a»i
tUages bound togeuer and moved?

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of tlie ttarroid eartUage. 4, The poAtorlor foce of the thyroid cartUags. 0, 5, Th*
•rytenoia cartUages. 6, 6, The yocal ligaments. 7, Their origin, witfiln fbe aofde
of the thyroid cartilage. 9, Their termination, at the base or the arytenoid cartU-
agM. 8, 10, The glottic.

The voccd cordsy or ligaments, are formed of elastic and
parallel fibres, enclosed in a fold of mucous membrane. They
are about two lines in width, and pass from the anterior an-
gle of the thyroid cartilage to the two arytenoid cartilages.
The one is named the superior, and the other ,the inferior
vocal ligament The cavity or depression between the supe-
rior and inferior ligament, is named the ventricle of the lar-
ynx. The aperture or opening between these ligaments or
vocal cords, is named the glottis, or chink of (he glottis. It is
about three fourths of an inch in length, and one fourth of an
inch in diameter, the opening being widest at the posterior
part This opening is enlarged and contracted by the agency
of the different laryngeal musdes.

The cartilages of the larynx have attached to them, and
are acted upon by, eight pairs of small muscles. Several of
, these muscles are well represented in the following engrav-

Fig. 127. Fig. 128.

Pfr. 127. Represents a posterior view of the larynx. 1, The thyroid cartflago. 9,
One of the ascending comua. 3, One of the descending comua. 4, The ertcoia oai^
•tiloge. A, A, Tho arytenoid cartilages. 6, Tlie arytenoideas mascle, eonsistiiicof
obliniie and transvcroe fibres. 7, The crlco-arytenoideus-postici muscles. 8, xbo

Fig. 128. Represents a side rlew of the larynx. I, The thyroid cartilage. S. 0*o
of tlie arytenoid cartilages. 3, One of the comua of the larynx. 4, The cricoid car-
Describe the vocal cords. How named ? What is the name of the cavity
between the superior and inferior ligaments ? Where do we find the chink
of the glottis ? How wide is the glottis ? How long ? How is this open-
ing enlarged and contracted ? How many mosdes act upon tho cartOaget
of the larynx ?

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tnage. 5. Tbe erlco.4U7tenoMl«a8.po8tleas moicto. 6, Tl)« erloo^irtenoldevs-tateiw
aU« mu«cie. 7, The thyro-arytenoidens muscle. 8, The crico-thyroidcftn membrane.
9, The epfelottis. 10, 1'he upper part of tbe trachea.

In fig. 137, The muscle 7 opens the chluk of the glottis. Tbe muscle 6 closes th«
chink uf the glottis.

In flg. 128, TThe muscles 6 and 7 open the chink of the glottis.

The larynx is connected by muscles with the sternum,
oesophagus, base of the skull, hyoid bone, lower jaw, and
tongue. The following engravings illustrate this connection.

In addition to the parts before described, the lar}'nx is
supplied with a larige number of blood-vessels. It likewise
receives nerves from tbe ganglionic system, and two large
nerves from the eighth pair, l^he number and size of the
nervous filaments distributed to the mucous membrane of the
larynx, render it more sensitive than any other portion of
the respiratory passages.

ng. 129.

Flf . 129. A view of the snperflclal muscles of the face and head. 1, The ftmital
portion of the occiplto-frontalis. 2, Its occipital portion. S, Its aponeurosis. 4, Tbe
orbicularis palpebrarum. 6, The pyramldalls nasi. 6, The compressor nasi. 7, The
crblcttlaris oris. 8, The levator labil superiorls alnque nasi. 9, The levator supe-
riorw proprins. 10, The zycomatlcus major. 11, The cygomaticus minor. 12, 'J lie
depressor labil Inferioris. 13, The depressor anguli oris. 14, The levator Jabli infe-
ri? nS:. ''^ *".'* ^^' '^^^ maweter. 17, The attrahens aurem. 18, The buccinator.
19, The anollens aurem. 20, The fascia of the temporal muscle. 21, The retruhcns
aurcm. 22, The belly of the digastric muscle. 23, The stylo-hvoidens muscle. 24,
V'® "iV®J?^'®***®"' musoie. 25, The upper part of the stemo-cleldo-mastoldeus mus-
cle. 26, The upper part of the trapezius.

With what is the larynx connected ? Why is the larynx mora Bensitiv*
than other parts of the respiratory passages 7

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Tb« miiiclM 8 «Bd 9, elCTate the upper lip. W, th« itinscle t^At deprew^ the
lower Up. 10, and 11, The muscleii that elevate the angle of the mouth. 18, The
muscle that depresses the ancle of the month. 7, The muscle that closes the mouth.
15 and 16. The muscles that bring the upper and lower Jaw In opposlUon, in masticef.
lug food. 25, The muscle that brings the head forward In bowlnaf. 4, The muscle
that closes the eye.

Fig. 130.


In the formation of the voice, each of the portions before
described performs an important part. The cricoid and thy-
roid cartilages give form and stability to the organs; the
arytenoid cartilages by their movement vapy the width of
th6 glottis. Th6 epiglottis is flexible and elastic When it
is erect, the chink of the glottis is open, as in inspiration ;

Which curtilages give ttability and form to the larynx ? Which Tary th«
4lamet«r of the glottis ? What is the function of the epiglottis ?

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when depressed, as in swallowing food and drink, it hoovers
and closes this aperture. This prevents the introduction of
articles of food into the air-passages, and, probabljr, modifies
the sounds as they issue from the glottis.

Fig. 131.

Fig. 181. A Utend view of the tongne, larynx tnd apper part of the trachea. 1,
A portion of the temporal bone of the left side. 2, 2, The right side of the lower Jnw ;
the left Mide has been removed. The white line shows the position of the lower mar-

f In of the Jaw behind the muscles. 8. The tongue. 4, The genlo-hyoldeus muscle.
, The genlo-hvo-glossuR. 6; 7, The hvo-gloMMUR. 8, A portion of the linffUMlls. 9,
The stylo-glossua. 10, The stylo-hyoideus. 11, The 8tvio-pharvngeas. 18» Tho oa.
bvoides. la, The membrane connecting the hvoid bone with the thyroid cartilage.
14, The thyroid cartilage. 15, The thyro-Iiyoideus muscle. 16, The cricoid cartil-
age. 17, The membrane which connects the cricoid and thyroid cartilages. 18, The
trachea. 19, The commencement of the oesophagus.

The muscle 4 elevates the larynjiC, and draws it forward, when the under Jaw la
fixed, or it depresses the under jaw when the larynx is fixed. The muscles 6, 7, eU
•vate the larynx or depress the root of the tongue, when the larynx or tongue oper-
ates as the fixed point. The muscles 10 and 11 draw the larynx npwanl and baclc-
ward. The muscle 9 draws the root of the tongue upward and backward. The
muscle 15 draws the larynx toward the hyold bone, or this bone toward the larynx,
as the one or the other is fixed by the action of other muscles.

The muscles of the neck elevate and depress the larynx;
the laryngeal muscles (Figs. 127, 128) increase or diminish the
width of the glottis ; at the same time, the vocal cords which
vary the vocal sounds, are relaxed or tightened| while the
muscles of the face open and close the mouth.

By what means are the vocal lotmda varied ?

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It is now proved, beyond a doubt, that the vocal cords are
the principal agents in the formation of the voice. The
tongue, which many have supposed to be the most important
organ in speaking, is, not essential to sound, as in some cases
of the removal of the tongue the persons thus mutilated could
speak with fluency.

Sound depends on the forcible ejectment of air from the
chest, through the chink of the glottis. The velocity of the
expelled current of air and the tension of the vocal ligaments,
are the principal circumstances that modify the character of
sound. The size of the larynx, the volume and health of the
lungs, the condition of the fauces and nasal passages, the ele-
vation and depression of the chin and tongue, the development
and freedom of action of the muscles which connect the larynx
with the sternum, hyoid bone, lower jaw, tongue, and the
opening of the mouth, contribute to the modulations of sound.

The development of the vocal organs, their education and
use, will be the subject of the following observations.


The larynx is much more developed and prominent in man
than in woman. In the former, the ianterior angle of the
thyroid cartilage is acute, while in the latter it is rounded,
and the central slope of the superior border of the same car-
tilage is less deep, and the epiglottis smaller and less promi-
nent than in man.

Less striking difference exists in the formation of the larynx
in infancy, but at a later period it is more developed in the
male than in the female. It is very remarkable that this in-
crease is not progressive, like that of other organs, but, on the
contrary, developes itself at once at the period of puberty.

Common observation shows that the voice can be changed
and modified by the habits ; sailors, smiths, and others, who are
engaged in noisy occupations, exert their vocal organs more
strongly than those of more quiet pursuits. This not only
affects the structure of the vocal organs, but varies their

What are the essential agents in speaking? Is the tongue essential m

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Online LibraryCalvin CutterAnatomy and physiology, designed for academies and families → online text (page 14 of 27)