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unequally developed in different races, and that a large natural gift of
the visionary faculty might become characteristic not only of certain
families, as among the second-sight seers of Scotland, but of certain
races, as that of the gypsies.

It happens that the mere acts of fasting, of want of sleep, and of
solitary musing, are severally conducive to visions. I have myself
been told of cases in which persons accidentally long deprived of food
became subject to them. One was of a pleasure-party driven out to
sea, and not being able to reach the coast till nightfall, at a place
where they got shelter but nothing to eat. They were mentally at
ease and conscious of safety, but they were all troubled with visions,
half dreams and half hallucinations. The cases of visions following
protracted wakefulness are well known, and I also have collected a
few. As regards the effect of solitariness, it may be sufficient to allude
to the recognized advantages of social amusements in the treatment of
;:ie insane. It follows that the spiritual discipline undergone for pur-
|ioses of self-control and self -mortification has also the incidental
effect of producing visions. It is to be expected that these should
often bear a close relation to the prevalent subjects of thought, and,

* I have latterly much improved the process, and hope shortly to describe it else-
where.

VOL. XIX. — 34



^^■^



530



TBI; POPULAR SCIENCE MONTHLY.



although they may be really no more than the products of one portion
of the brain, which another portion of the same brain is engaged in
contemplating, they often, through error, receive a religious sanction.
This is notably the case among half-civilized races.

The number of great men who have been once, twice, or more fre-
quently subject to hallucinations is considerable. A list, to which it
would be easy to make large additions, is given by Brierre de Bois-
mont ('• Hallucinations," etc., 1862), from whom I translate the fol-
lowing account of the star of the first Napoleon, which he heard,
second-hand, from General Rapp :

In 1806, General Rapp, on his return from the siege of Dantzic, having occa-
sion to speak to the Emperor, entered bis study witliout being announced. He
found him so absorbed that his entry was unperceived. The General, seeing the
Emperor continue motionless, thouglit he might be ill, and purposely made a
noise. Napoleon immediately roused himself, and without any preamble, seizing
Rapp by the arm, said to him, pointing to the sky, " Look there, up tbere." The
General remained silent, but, on being asked a second time, he answered that he
perceived nothing. " What! " replied the Emperor, " you do not see it? It ia
my star, it is before you, brilliant " ; then animating by degrees, he cried out,
" It has never abandoned me, I see it on all great occasions, it commands me to
go forward, and it is a constant sign of good fortune to me."

It appears that stars of this kind, so frequently spoken of in his-
tory, and so well known as a metaphor in language, are a common
hallucination of the insane. Brierre de Boismont has a chapter on the
stars of great men. I can not doubt that fantasies of this description
were in some cases the basis of that firm belief in astrology which not
a few persons of eminence formerly entertained.

The hallucinations of great men may be accounted for in part by
their sharing a tendency which we have seen to be not uncommon in
the human race, and which, if it happens to be natural to them, is
liable to be developed in their overwrought brains by the isolation of
their lives. A man in the position of the first Napoleon could have
no intimate associates ; a great philosopher who explores M^ays of
thought far ahead of his contemporaries must have an inner world in
which he passes long and solitary hours. Great men are also apt to
have touches of madness ; the ideas by which they are haunted, and
to whose pursuit they devote themselves, and by which they rise to
eminence, have much in common with the monomania of insanity.
Striking instances of great visionaries may be mentioned, who had
almost beyond doubt those very nervous seizures with which the ten-
dency to hallucinations is intimately connected. To take a single in-
stance, Socrates, whose daimon was an audible not a visual appearance,
was subject to what admits of hardly any other interpretation than
cataleptic seizure, standing all night through in a rigid attitude.

It is remarkable how largely the visionary temperament has mani-
fested itself in certain periods of history and epochs of national life.



SCHOOL-ROOM VENTILATION. 531

My interpretation of the matter, to a certain extent, is this : That the
visionary tendency is much more common among sane people than is
generally suspected. In early life, it seems to be a hard lesson to an
imaginative child to distinguish between the real and visionary world.
If the fantasies are habitually laughed at, the power of distinguishing
them becomes at length learned ; any incongruity or nonconformity is
noted, the vision is found out and discredited, and is no further at-
tended to. In this way the tendency to see them is blunted by repres-
sion. Therefore, when popular opinion is of a matter-of-fact kind, the
seers of visions keep quiet ; they do not like to be thought fanciful
or mad, and they hide their experiences, which only come to light
through inquiries such as these that I have been making. But let the
tide of opinion change and grow favorable to supematuralism, then
the seers of visions come to the front. It is not that a faculty previ-
ously non-existent has been suddenly evoked, but one that had been
long smothered is suddenly allowed expression and to develop, with-
■ ut safeguards, under the free exercise of it. — Fortnightly Review.



SCHOOL-EOOM YEXTILATIOX.

Br P. J. IIIGGINS, M. D.

'XT'EXTILATION is the supply of fresh air to an apartment, and
V the removal of impure or vitiated air therefrom. An adequate
supply of free oxygen is absolutely necessary to animal life ; and, the
higher we ascend in the scale of that life, the greater the quantity of
oxygen consumed, and the more urgent the necessity for its consunip-
tion. In the atmosphere this oxygen exists in a free state — in mechani-
cal solution — and in the form and proportion in which it is most easily
assimilable. From the atmosphere, the animal absorbs it by means of
its breathing apparatus which provides for its absorption by the blood,
and the blood carries it to the tissues. Pure air consists of a mechani-
cal mixture of about four fifths nitrogen and one fifth oxygen, with
traces of ammonia, and about one part in two thousand of carbonic-acid
gas (COJ. These latter (ammonia and COJ, from their small amount,
may be neglected.

Air becomes vitiated for breathing purposes by holding in solution
other gases or substances whose presence interferes with the appropria-
tion of oxygen by the animal, or, being themselves absorbed, exert a
toxic influence upon the vital fluid and tissues of the body. Hence to
secure an adequate supply of fresh air, and the removal of impurities
that accumulate therein, are the objects of ventilation. In this paper
school-room ventilation only will be considered.

A full-grown person breathes on an average about twenty times



'^



THE POPULAR SCIENCE MONTHLY.



per minute, and takes in over twenty cubic inches of air at each inspi-
ration. Boys and girls inspire somewhat less than twenty cubic inches,
but breathe more rapidly than an adult — say twenty-five times per
minute. In five minutes each will breathe over a cubic foot of air, and
in a two-hours session nearly twenty-five cubic feet : so that, in a
school of forty pupils, one thousand cubic feet will be inhaled every
two hours. This is under, rather than above, the average.

Oxygen to the amount of nearly five per cent, of the quantity
inhaled disappears at every breath, being absorbed by the blood — or
twenty cubic inches per minute, for each individual — representing a
total of fifty cubic feet for a school of forty pupils during a two-hours
session. But, in addition to the consumption of oxygen, the air is fur-
ther deteriorated by the exhalation of nearly as much carbonic-acid
gas (COj) as there is oxygen consumed — say forty -five cubic feet in
two hours, about one fortieth of the total amount produced being
thrown off by the cutaneous surface of the body. Each cubic foot of
carbonic-acid gas contains nearly half an ounce of pure carbon, or
twenty-three ounces in all : so that, by breathing, forty mouths — like
veritable little chimneys — puff out in two hours an amount equal to
about a pound and a half of solid carbon. This is injurious in two
ways, each of which will be examined in the proper place.

The air occasionally contains many impurities, but only those usu-
ally found in the school-room will here be enumerated. They are car-
bonic oxide (CO), carbonic-acid gas (CO,), ammonia (NHJ, sulphur
(S), sulphuretted hydrogen (H3S) — all in the gaseous form ; to which
must be added aqueous vapor, organic matters, inorganic matters,
epithelial cells, and animal exhalations.

The most toxic of all these is undoubtedly carbon monoxide (CO).
It is a product of the incomplete combustion of carbon (C), but hap-
pily it is not usually found in the school-room in any large amount. A
fire is the result of the chemical combination of the carbon of coal, or
other combustible, with the oxygen (O) of the air ; the atoms of the
gas rush into combination with those of the carbon, and the arrested
motion is transformed into heat — aqueous vapor (H^O), carbon monox-
ide (CO), and carbonic-acid gas (COJ, being produced. If a suffi-
cient supply of air has free access to the loxcer portions of the fire,
carbonic-acid gas is directly formed ; but this in its passage upward
through the central portion of the fire, where the temperature is
higher, takes up another atom of carbon (C0, + C=C04-C0) and
becomes carbon monoxide, or carbonic oxide, as it is commonly called.
This carbonic oxide, on reaching the upper surface of the fire, takes
up an additional atom of oxygen from the air, and, burning with a
bluish flame, becomes carbonic - acid gas once more, and makes its
escape by the chimney. But usually a portion of the carbonic oxide
fails to take up the additional atom of oxygen ; and, when the sup-
ply of air is limited, the amount is increased, so that more or less car-



SCHOOL-ROOM VENTILATION.



533



bonic oxide passes up the chimney along with the other gases of com-
bustion. As the products of combustion are much lighter than the
surrounding atmosphere — volume for volume — on account of their
much higher temperature, and as the expansibility of gases is very
great, they exert a pressure upon the sides of the pipe or flue through
which they ascend. This being the case, these gases will escape
through chinks, holes, or defective joints, along their course, like steam
through a leaky conduit. Downward air-currents in the flue, and lat-
eral currents from open windows, etc., occasionally blow large quan-
tities of the gases of combustion through the open door of the stove,
or through seams or cracks therein ; and in these two ways — through
stove and flue — sulphur, carbonic oxide, and carbonic-acid gas, may find
their way into the room. It is claimed by some physicists that carbonic
oxide will make its way through heated iron, and thus escape through
the sides of the stave, but the quantity given out in this way — if, in-
deed, any is so given out, of which there is a reasonable doubt — must
be so small that it is practically of no account, while quantities large
enough to be decidedly injurious may issue through the door and other
openings. Of course, these remarks apply only to schools heated by
stoves ; but it must not be forgotten that in rural districts, and many
cities, all the schools are still heated in this way.

Carbonic oxide is a deadly poison, fixing itself in the blood-cor-
puscles and paralyzing them so that they can not carry on the func-
tion of respiration. To the inhalation of this gas is chiefly due the pale
color of those who spend much time in apartments heated by stoves and
poorly ventilated. Its presence can not be recognized by the senses, as
it is tasteless, colorless, and inodorous.

Carbonic acid is produced in two ways, as before explained — by
combustion and by breathing. The quantity thrown off in breathing
is very much increased — often nearly doubled — during active diges-
tion. As the fullest meal is taken at dinner, and digestion is most
active soon after, it follows that the exhalation of carbonic-acid gas is
greatest during the early part of the afternoon, and therefore during
this time ventilation needs more attention. Of all the impurities
found in the school-room, this is vastly the largest in amount, and
popularly considered the most important. It is once and a half as
heavy as air. At first sight, it might be supposed that, being heavier
than air, it would sink to the floor and settle there in a layer of uni-
form height and density, like so much water. But this is not the case,
for it is even more expansible than air. (Coefficient of expansion of
air = -00366; of CO, = -00371.) Now, the law Avhich governs the
mixtures of gases is this :

The mixture of gases in free communication, whatever their den-
sity, takes place rapidly, and is homogeneous — that is, the mixture
contains the gases in the same proportion; so that the percentage of
carbonic-acid gas is about the same in all parts of the room.



534 THE POPULAR SCIENCE MOXTHLY.

If ample provision is not made for the removal of the vitiated air,
the proportion of carbonic-acid gas continues to increase; and, as it
is much heavier than air, the density becomes greater. Nou*, this
increase of the air's density interferes with and retards the diffusion
between the impure gases held in solution in the blood and the oxy-
gen of the atmosphere — in other words, interferes with respiration.
The consequence is, that the blood is not purified of the carbonic-acid
gas which it holds in solution and combination. Not being removed
as fast as it is formed in the body, it accumulates in the blood; the
blood carries it throughout the system, circulating it through the deli-
cate tissues of the brain. As the brain is the organ of the mind, it
is by and through the brain that we think, reason, memorize, learn.
For its healthy and vigorous action, a full supply of pure blood is an
imperious necessity. The effects produced by this gas, when circu-
lating through the brain in excess, are drowsiness, dizziness, dull head-
ache, an inability to fix the attention, a dislike for application, a weaken-
ing of the memory, and a general torpor of the intellectual powers. An
explanation of how and why these effects are produced would involve
certain principles of mental physiology — a subject not within the scope
of this paper.

Special attention is requested to this statement by Dr. Routh:*
*' Experiment has shown that if an animal be kept confined in a narrow,
closed apartment, so that the air supplied is always more or less vitiated
by the carbonic acid which it expires, however well fed that animal may
be, tubercle (consumption) will be developed in about three months."
If this be the case, a large percentage of cases of consumption should
be met with among the inmates of badly ventilated schools. But,
fortunately, the disease is comparatively infrequent under the age of
fifteen, and added to this is the protecting influence of the active ex-
ercise in the open air usually indulged in by school-children. It is
upon the teachers that its blighting effects are most apparent, as they
are predisposed by age, they neglect exercise in the open air, and their
mental labor is severe, and xrorry of mind exhausting. Of eleven
teachers who died during the last eight years within the limits of one
county in Pennsylvania, two died of acute disease, one of an overdose
of an habitual narcotic, and of nine attacked by consumption, eight
died — six ladies and one gentleman ; the other, a gentleman, will re-
cover, at least for a time.

The organic matters suspended in the air are derived {a) from the
body ; {h) from other sources. Epithelial cells or scales, very minute,
arise by desquamation from the external cutaneous surface, and also
from the mouth, pharynx, and bronchi. Being exceedingly light, they
float in the air, and are inhaled, lodging in the throat, trachea, and
even deep in the lungs. It is not pleasant to contemplate the fact that

*" Infant Feeding," Part IT, chapter iv.



SCHOOL-ROOM VENTILATION. 535

we inhale minute portions of each other's bodies, but it is true neverthe-
less. In diphtheria, scarlatina, small-pox, measles, etc., these epithelial
scales come off in vastly greater quantities than in health, carrying
with them, in greater or less virulence, the peculiar infection in the
body whence they have arisen. The greater their number and the
more favorable the nidus in which they become deposited, the more
likely they are to become transplanted as primary centers of infection.
Hence it is important to prevent their accumulation, as the greater
their numbers the greater the probability of their successful trans-
plantation ; and as they float in the air they follow its currents, and
are thus removed by ventilation. Other sources of organic matters are
various and numerous, but, with the following exception, of little im-
portance in the present connection.

The cutaneous surface and the lungs give out certain odors, sui
generis, which are designated " animal exhalations." It is to these
that the heavy, sickening smell noticed on first entering a crowded
room is due. Odors being volatile and exceedingly light, these ex-
halations rise to the highest portions of the room ; and, if not allowed
to escape, accumulate there, saturating the air from above downward,
and finally reaching the floor. Of all the noxious matters in the fouled
air of a poorly ventilated school or public building, these are at once
the most perceptible, the most offensive, and the most rapidly pros-
trating. They produce a sensation of stifling by their irritation of the
branches of the pneumogastric nerve distributed to the lungs and
•larynx, and nauseate, probably by reflex action, through branches of
the same nerve distributed to the stomach. A distinguished physi-
cian, writing of an infant nursery under his charge where the chil-
dren did not thrive, and many died of diseases of the digestive or-
gans, says : " One remarkable circumstance observed was that there
was a faint odor always present in the room. Yet it was a large room,
about fifty feet in length. One side of the room was made up of win-
dows which went up about ten feet where the roof or ceiling beveled
up in an inverted A shape, which raised the room in the center seven
or eight feet more. Do what I would, I could not get rid of this smell.
One day, being much annoyed thereat, I procured some long steps
which extended about three feet above the upper ledge of the windows.
On walking up, no sooner had I got ray head one foot above their
level, than I found a terrible odor that made me feel giddy and sick ;
and I was glad enough to come down. I instantly sent for a work-
man, and desired him to remove three or four tiles at each end of the
room, on a level with the highest point of the roof. He did so. In ten
minutes all odor had disappeared ; but his work was no sooner ended
than he was taken very giddy and practically sick, so completely
Lad he been overcome by the pestilential atmosphere." This incident
will again be referred to in speaking of ventilators.

In regard to the moisture of the air, the following may be said :



.'f' 1



536 THE POPULAR SCIENCE MONTHLY.



The drier the air, the more rapidly are thfe liquids of the body evapo-
rated, and digestion and assimilation carried on, the more nervous is the
temperament, and the more rapid the development. Generally speak-
ing, the air is much drier in the United States than in Europe. This
is the chief reason why our childj-en are less repressible, livelier, and
more nervous and precocious than those of Europe. Another reason is,
that we use here more animal food, which.is far more stimulating both
to body and mind than vegetable. On the other hand, too dry an at-
mosphere is unhealthy. As children drink much water, they exhale
much aqueous vapor — the sweat-glands and capillary circulation being
more active than in the adult — say to the amount of half a pint each,
more or less, during school-hours. As such a large amount of invisible
vapor arises, it serves a useful purpose by adding to the moisture of
our dry air, rather than being injurious. In dwellings it is sometimes
customary to place a vessel of water upon the stove to produce vapor,
so as to diminish the dryness of the air ; but, for the reason given
above, it is perhaps unnecessary in a school-room. However, as water
absorbs equal volumes of carbonic-acid gas, and four hundred and
thirty volumes of ammonia, a shallow vessel of water may in this way
be of some service.

TJie inorganic matters consist of chalk-dust, earth-dust, ashes, etc.
Of late years, owing to the large amount of blackboard work done in
schools, particularly in the primary departments, chalk-dust floats in
large quantities in the air whenever the erasers are used. The parti-
cles of chalk-dust are comparatively large in size. When inhaled, it •
lodges in the posterior portion of the nasal passages and upper portion
of the larynx ; and when settled in large amount in these locations it
gives rise to a good deal of irritation. The effect of this irritation is
the secretion of a tenacious mucus that provokes distressing cough and
unpleasant hawking. It is easy to understand how this exciting cause,
long continued, may produce a chronic catarrh of these regions, espe-
cially in the posterior nasal passages, as they are prone to congestion
and a low grade of chronic inflammation. The same remarks apply,
but in a far less degree, to ash and earth-dust. The frequent cough
and occasional sneeze heard among the audience in theatre, hall, or
church, are provoked by the inhalation of fine dust suspended in the
air, and might be prevented by careful sweeping and dusting after
occupancy. The school-room should be swept every evening, and
dusted at least an hour before opening. The blackboards should be
erased as little as possible, and preferably by the so-called "dustless "
erasers — though, strictly speaking, no eraser is really " dustless," being
simply " less dusty " — and then gently in an up-and-down direction, so
that the dust may not be dispersed through the room. The floor
should not be disturbed by sweeping at any time during the day.
Having examined briefly the different substances that vitiate or foul
the air contained in a school-room, and the sources from which they



SCHOOL-ROOM VENTILATION. 537

are derived, the means of effecting their removal therefrom will next
be discussed.

The chief factors in carrying on ventilation are («) the difference
in temperature between the outside air and that within the room, and
{J)) the diffusibility of gases.

It is the difference in temperature that produces a draught up a
flue or chimney when a fire is lighted below ; for the products of com-
bustion have a very much higher temperature (several hundred degrees
Fahr.) than the surrounding atmosphere. Being so much warmer, they
are lighter in consequence (as will be explained presently), and there-
fore have a constant tendency to ascend — being compelled by the force
of gravity — till, after cooling little by little, they reach a layer of their
own temperature. Upon the same principle an inflated balloon ascends
and a cork immersed in water constantly tends to rise to the surface.
As the coefiicient of expansion for gases equals about ^j — i. e., they
increase about ^-^oi their bulk for every degree centigrade increase in
temperature, thus becoming lighter in proportion to their volume, and,
becoming lighter (some being originally lighter) than the atmosphere,
are compelled by gravitation to ascend. It is important that the pipe
or flue, in rooms heated by stoves or grates, should be vertical or near-
ly so ; also that it be not too wide, otherwise downward currents will
be produced, and these interfere with the draught, and cause the gases
of combustion to escape into the room. In a stove-pipe the elbows



Online LibraryD. S. (David Samuel) MargoliouthThe Popular science monthly (Volume 19) → online text (page 66 of 110)