A Practical Physiology
by
Albert F. Blaisdell
Part 9 out of 9
Vowel sounds
Walking, jumping, and running
Waste and repair
Waste material, Nature of
Waste products, Elimination of
Water as food
Whispering
Wounds, Incised and lacerated
Yawning
Footnotes:
[1] The Value of Physiological Knowledge. "If any one doubts the
importance of an acquaintance with the fundamental principles of
physiology as a means to complete living, let him look around and see how
many men and women he can find in middle life, or later, who are
thoroughly well. Occasionally only do we meet with an example of vigorous
health continued to old age; hourly do we meet with examples of acute
disorder, chronic ailment, general debility, premature decrepitude.
Scarcely is there one to whom you put the question, who has not, in the
course of his life, brought upon himself illness from which a little
knowledge would have saved him. Here is a case of heart disease consequent
on a rheumatic fever that followed a reckless exposure. There is a case of
eyes spoiled for life by overstudy.
"Not to dwell on the natural pain, the gloom, and the waste of time and
money thus entailed, only consider how greatly ill health hinders the
discharge of all duties,--makes business often impossible, and always more
difficult; produces irritability fatal to the right management of
children, puts the functions of citizenship out of the question, and makes
amusement a bore. Is it not clear that the physical sins--partly our
ancestors' and partly our own--which produce this ill health deduct more
from complete living than anything else, and to a great extent make life a
failure and a burden, instead of a benefaction and a pleasure?"--Herbert
Spencer.
[2] The word protoplasm must not be misunderstood to mean a substance of a
definite chemical nature, or of an invariable morphological structure; it
is applied to any part of a cell which shows the properties of life, and
is therefore only a convenient abbreviation for the phrase "mass of living
matter."
[3] "Did we possess some optic aid which should overcome the grossness of
our vision, so that we might watch the dance of atoms in the double
process of making and unmaking in the living body, we should see the
commonplace, lifeless things which are brought by the blood, and which we
call food, caught up into and made part of the molecular whorls of the
living muscle, linked together for a while in the intricate figures of the
dance of life, giving and taking energy as they dance, and then we should
see how, loosing hands, they slipped back into the blood as dead, inert,
used-up matter."--Michael Foster, Professor of Physiology in the
University of Cambridge, England.
[4] "Our material frame is composed of innumerable atoms, and each
separate and individual atom has its birth, life, and death, and then its
removal from the 'place of the living.' Thus there is going on a
continuous process of decay and death among the individual atoms which
make up each tissue. Each tissue preserves its vitality for a limited
space only, is then separated from the tissue of which it has formed a
part, and is resolved into its inorganic elements, to be in due course
eliminated from the body by the organs of excretion."--Maclaren's
_Physical Education_.
[5] The periosteum is often of great practical importance to the surgeon.
Instances are on record where bones have been removed, leaving the
periosteum, within which the entire bone has grown again. The importance
of this remarkable tissue is still farther illustrated by experiments upon
the transplantation of this membrane in the different tissues of living
animals, which has been followed by the formation of bone in these
situations. Some years ago a famous surgeon in New York removed the whole
lower jawbone from a young woman, leaving the periosteum and even
retaining in position the teeth by a special apparatus. The entire jawbone
grew again, and the teeth resumed their original places as it grew.
[6] The mechanism of this remarkable effect is clearly shown by an
experiment which the late Dr. Oliver Wendell Holmes used to take delight
in performing in his anatomical lectures at the Harvard Medical College.
He had a strong iron bar made into a ring of some eight inches in
diameter, with a space left between the ends just large enough to be
filled by an English walnut. The ring was then dropped to the floor so as
to strike on the convexity just opposite to the walnut, which invariably
was broken to pieces.
[7] For the treatment of accidents and emergencies which may occur with
reference to the bones, see Chapter XIII.
[8] "Besides the danger connected with the use of alcoholic drinks which
is common to them with other narcotic poisons, alcohol retards the growth
of young cells and prevents their proper development. Now, the bodies of
all animals are made up largely of cells, ... and the cells being the
living part of the animal, it is especially important that they should not
be injured or badly nourished while they are growing. So that alcohol in
all its forms is particularly injurious to young persons, as it retards
their growth, and stunts both body and mind. This is the theory of Dr.
Lionel S. Beale, a celebrated microscopist and thinker, and is quite
generally accepted."--Dr. Roger S. Tracy, of the New York Board of Health.
[9] "In its action on the system nicotine is one of the most powerful
poisons known. A drop of it in a concentrated form was found sufficient to
kill a dog, and small birds perished at the approach of a tube containing
it."--Wood's _Materia Medica_.
"Tobacco appears to chiefly affect the heart and brain, and I have
therefore placed it among cerebral and cardiac poisons."--Taylor's
_Treatise on Poisons_.
[10] "Certain events occur in the brain; these give rise to other events,
to changes which travel along certain bundles of fibers called nerves, and
so reach certain muscles. Arrived at the muscles, these changes in the
nerves, which physiologists call nervous impulses, induce changes in the
muscles, by virtue of which these shorten contract, bring their ends
together, and so, working upon bony levers, bend the arm or hand, or lift
the weight."--Professor Michael Foster.
[11] The synovial membranes are almost identical in structure with serous
membranes (page 176), but the secretion is thicker and more like the
white of egg.
[12] "Smoking among students or men training for contests is a mistake. It
not only affects the wind, but relaxes the nerves in a way to make them
less vigorous for the coming contest. It shows its results at once, and
when the athlete is trying to do his best to win he will do well to avoid
it." Joseph Hamblen Sears, Harvard Coach, and Ex-Captain of the Harvard
Football Team, Article in _In Sickness and in Health_.
[13] "There is no profession, there is no calling or occupation in which
men can be engaged, there is no position in life, no state in which a man
can be placed, in which a fairly developed frame will not be valuable to
him; there are many of these, even the most purely and highly
intellectual, in which it is essential to success--essential simply as a
means, material, but none the less imperative, to enable the mind to do
its work. Year by year, almost day by day, we see men (and women) falter
and fail in the midst of their labors; ... and all for want of a little
bodily stamina--a little bodily power and bodily capacity for the
endurance of fatigue, or protracted unrest, or anxiety, or
grief."--Maclaren's _Physical Education_.
[14] "One half the struggle of physical training has been won when a boy
can be induced to take a genuine interest in his bodily condition,--to
want to remedy its defects, and to pride himself on the purity of his
skin, the firmness of his muscles, and the uprightness of his figure.
Whether the young man chooses afterwards to use the gymnasium, to run, to
row, to play ball, or to saw wood, for the purpose of improving his
physical condition, matters little, provided he accomplishes that
object."--Dr. D. A. Sargent, Director of the Hemenway Gymnasium at Harvard
University.
[15] "It is _health_ rather than _strength_ that is the great requirement
of modern men at modern occupations; it is not the power to travel great
distances, carry great burdens, lift great weights, or overcome great
material obstructions; it is simply that condition of body, and that
amount of vital capacity, which shall enable each man in his place to
pursue his calling, and work on in his working life, with the greatest
amount of comfort to himself and usefulness to his fellowmen."--Maclaren's
_Physical Education_.
[16] To this classification may be added what are called albuminoids, a
group of bodies resembling proteids, but having in some respects a
different nutritive value. Gelatine, such as is found in soups or table
gelatine is a familiar example of the albuminoids. They are not found to
any important extent in our raw foods, and do not therefore usually appear
in the analyses of the composition of foods. The albuminoids closely
resemble the proteids, but cannot be used like them to build up
protoplasm.
[17] The amount of water in various tissues of the body is given by the
following table in parts of 1000:
Solids. Liquids.
Enamel, 2 Blood, 791
Dentine, 100 Bile, 864
Bone, 486 Blood plasma, 901
Fat, 299 Chyle, 928
Cartilage, 550 Lymph, 958
Liver, 693 Serum, 959
Skin, 720 Gastric juice, 973
Brain, 750 Tears, 982
Muscle, 757 Saliva, 995
Spleen, 758 Sweat, 995
Kidney, 827
Vitreous humor, 987
[18] The work of some kinds of moulds may be apparent to the eye, as in
the growths that form on old leather and stale bread and cheese. That of
others goes on unseen, as when acids are formed in stewed fruits.
Concerning the work of the different kinds of moulds. Troussart says:
"_Mucor mucedo_ devours our preserves; _Ascophora mucedo_ turns our bread
mouldy; _Molinia_ is nourished at the expense of our fruits; _Mucor
herbarium_ destroys the herbarium of the botanist; and _Choetonium
chartatum_ develops itself on paper, on the insides of books and on their
bindings, when they come in contact with a damp wall."--Troussart's
_Microbes, Ferments, and Moulds_.
[19] "The physiological wear of the organism is constantly being repaired
by the blood; but in order to keep the great nutritive fluid from becoming
impoverished, the matters which it is constantly losing must be supplied
from some source out of the body, and this necessitates the ingestion of
articles which are known as food."--Flint's _Text-book of Human
Physiology_.
[20] Glands. Glands are organs of various shapes and sizes, whose
special work it is to separate materials from the blood for further use in
the body, the products being known as secretion and excretion.
The means by which secretion and excretion are effected are, however,
identical. The essential parts of a gland consist of a basement membrane,
on one side of which are found actively growing cells, on the other is the
blood current, flowing in exceedingly thin-walled vessels known as the
capillaries. The cells are able to select from the blood whatever material
they require and which they elaborate into the particular secretion. In
Fig. 47 is illustrated, diagrammatically, the structure of a few typical
secreting glands. The continuous line represents the basement membrane.
The dotted line represents the position of the cells on one side of the
basement membrane. The irregular lines show the position of the
blood-vessels.
[21] Tablets and other material for Fehling and additional tests for sugar
can be purchased at a drug store. The practical details of these and other
tests which assume some knowledge of chemistry, should be learned from
some manual on the subject.
[22] The Peritoneum. The intestines do not lie in a loose mass in the
abdominal cavity. Lining the walls of this cavity, just as in a general
way, a paper lines the walls of a room, is a delicate serous membrane,
called the peritoneum. It envelops, in a greater or less degree, all
the viscera in the cavity and forms folds by which they are connected with
each other, or are attached to the posterior wall. Its arrangement is
therefore very complicated. When the peritoneum comes in contact with the
large intestine, it passes over it just as the paper of a room would pass
over a gas pipe which ran along the surface of the wall, and in passing
over it binds it down to the wall of the cavity. The small intestines are
suspended from the back wall of the cavity by a double fold of the
peritoneum, called the mesentery. The bowels are also protected from
external cold by several folds of this membrane loaded with fat. This is
known as the _great omentum_.
The peritoneum, when in health, secretes only enough fluid to keep its
surface lubricated so that the bowels may move freely and smoothly on each
other and on the other viscera. In disease this fluid may increase in
amount, and the abdominal cavity may become greatly distended. This is
known as _ascites_ or dropsy.
[23] The human bile when fresh is generally of a bright golden red,
sometimes of a greenish yellow color. It becomes quite green when kept,
and is alkaline in reaction. When it has been omited it is distinctly
yellow, because of its action on the gastric juice. The bile contains a
great deal of coloring matter, and its chief ingiedients are two salts of
soda, sodium taurocholate and glycocholate.
[24] Nansen emphasizes this point in his recently published work,
_Farthest North_.
[25] We should make it a point not to omit a meal unless forced to do so.
Children, and even adults, often have the habit of going to school or to
work in a hurry, without eating any breakfast. There is almost sure to be
a fainting, or "all-gone" feeling at the stomach before another mealtime.
This habit is injurious, and sure to produce pernicious results.
[26] The teeth of children should be often examined by the dentist,
especially from the beginning of the second dentition, at about the sixth
year, until growth is completed. In infancy the mother should make it a
part of her daily care of the child to secure perfect cleanliness of the
teeth. The child thus trained will not, when old enough to rinse the mouth
properly or to use the brush, feel comfortable after a meal until the
teeth have been cleansed. The habit thus formed is almost sure to be
continued through life.
[27] "If the amount of alcohol be increased, or the repetition become
frequent, some part of it undergoes acid fermentation in the stomach, and
acid eructations or vomitings occur. With these phenomena are associated
catarrh of the stomach and liver with its characteristic symptoms,--loss
of appetite, feeble digestion, sallowness, mental depression, and
headache."--James C. Wilson, Professor in the Jefferson Medical College,
Philadelphia.
"Man has recourse to alcohol, not for the minute quantity of energy which
may be supplied by itself, but for its powerful influence on the
distribution of the energy furnished by other things. That influence is a
very complex one."--Professor Michael Foster.
[28] "When constantly irritated by the direct action of alcoholic drinks,
the stomach gradually undergoes lasting structural changes. Its vessels
remain dilated and congested, its connective tissue becomes excessive, its
power of secreting gastric juice diminishes, and its mucous secretions
abnormally abundant."--H. Newell Martin, late Professor of Physiology in
Johns Hopkins University.
"Chemical experiments have demonstrated that the action of alcohol on the
digestive fluids is to destroy its active principle, the pepsin, thus
confirming the observations of physiologists that its use gives ride to
the most serious disorders of the stomach and the most malignant
aberrations of the entire economy."--Professor E. C. Youmans, author of
standard scientific works.
"The structural changes induced by habitual use of alcohol and the action
of this agent on the pepsin, seriously impair the digestive power. Hence
it is, that those who are habitual consumers of alcoholic fluids suffer
from disorders o digestion."--Robert Bartholow, recently Professor of
Materia Medica in the University of Pennsylvania.
"Alcohol in any appreciable quantity diminishes the solvent power of the
gastric fluid so as to interfere with the process of digestion instead of
aiding it."--Professor W. B. Carpenter, the eminent English physiologist.
[29] "Cirrhosis of the liver is notoriously frequent among drunkards, and
is in fact almost, though not absolutely, confined to them."--Robert T.
Edes, formerly Professor of Materia Medica in Harvard Medical College.
"Alcohol acts on the liver by producing enlargement of that organ, and a
fat deposit, or 'hob-nailed' liver mentioned by the English
writers."--Professor W. B. Carpenter.
[30] Preparation of Artificial Gastric Juice. _(a)_ Take part of the
cardiac end of the pig's stomach, which has been previously opened and
washed rapidly in cold water, and spread it, mucous surface upwards, on
the convex surface of an inverted capsule. Scrape the mucous surface
firmly with the back of a knife blade, and rub up the scrapings in a
mortar with fine sand. Add water, and rub up the whole vigorously for some
time, and filter. The filtrate is an artificial gastric juice.
_(b)_ From the cardiac end of a pig's stomach detach the mucous membrane
in shreds, dry them between folds of blotting-paper, place them in a
bottle, and cover them with strong glycerine for several days. The
glycerine dissolves the pepsin, and on filtering, a glycerine extract with
high digestive properties is obtained.
These artificial juices, when added to hydrochloric acid of the proper
strength, have high digestive powers.
Instead of _(a)_ or _(b)_ use the artificial pepsin prepared for the
market by the wholesale manufacturers of such goods.
[31] The cause of the clotting of blood is not yet fully understood.
Although the process has been thoroughly investigated we have not yet a
satisfactory explanation why the circulating blood does not clot in
healthy blood-vessels. The ablest physiologists of our day do not, as
formerly, regard the process as a so-called vital, but a purely chemical
one.
[32] Serous Membranes.--The serous membranes form shut sacs, of which
one portion is applied to the walls of the cavity which it lines; the
other is reflected over the surface of the organ or organs contained in
the cavity. The sac is completely closed, so that no communication exists
between the serous cavity and the parts in its neighborhood. The various
serous membranes are the _pleura_ which envelops the lungs; the
_pericardium_ which surrounds the heart; the _peritoneum_ which invests
the viscera of the abdomen, and the _arachnoid_ in the spinal canal and
cranial cavity. In health the serous membranes secrete only sufficient
fluid to lubricate and keep soft and smooth the opposing surfaces.
[33] A correct idea may be formed of the arrangement of the pericardium
around the heart by recalling how a boy puts on and wears his toboggan
cap. The pericardium encloses the heart exactly as this cap covers the
boy's head.
[34] "Alcohol taken in small and single doses, acts almost exclusively on
the brain and the blood-vessels of the brain, whereas taken in large and
repeated doses its chief effects are always nervous effects. The first
effects of alcohol on the function of inhibition are to paralyze the
controlling nerves, so that the blood-centers are dilated, and more blood
is let into the brain. In consequence of this flushing of the brain, its
nerve centers are asked to do more work."--Dr. T. S. Clouston, Medical
Superintendent of the Royal Asylum, Edinburgh.
"Alcoholic drinks prevent the natural changes going on in the blood, and
obstruct the nutritive and reparative functions."--Professor E. L.
Youmans, well-known scientist and author of _Class Book of Chemistry_.
[35] The word "cell" is not used in this connection in its technical
signification of a histological unit of the body (sec. 12), but merely in
its primary sense of a small cavity
[36] "The student must guard himself against the idea that arterial blood
contains no carbonic acid, and venous blood no oxygen. In passing through
the lungs venous blood loses only a part of its carbonic acid; and
arterial blood, in passing through the tissues, loses only a part of its
oxygen. In blood, however venous, there is in health always some oxygen;
and in even the brightest arterial blood there is actually more carbonic
acid than oxygen."--T. H. Huxley.
[37] "Consumption is a disease which can be taken from others, and is not
simply caused by colds. A cold may make it easier to take the disease. It
is usually caused by germs which enter the body with the air breathed. The
matter which consumptives cough or spit up contains these germs in great
numbers--frequently millions are discharged in a single day. This matter
spit upon the floor, wall, or elsewhere is apt to dry, become pulverized,
and float in the air as dust. The dust contains the germs, and thus they
enter the body with the air breathed. The breath of a consumptive does not
contain the germs and will not produce the disease. A well person catches
the disease from a consumptive only by in some way taking in the matter
coughed up by the consumptive."--Extract from a circular issued by the
Board of Health of New York City.
[38] "The lungs from the congested state of their vessels produced by
alcohol are more subject to the influence of cold, the result being
frequent attacks of bronchitis. It has been recognized of late years that
there is a peculiar form of consumption of the lungs which is very rapidly
fatal and found only in alcohol drinkers."--Professor H. Newell Martin.
[39] "The relation to Bright's Disease is not so clearly made out as is
assumed by some writers, though I must confess to myself sharing the
popular belief that alcohol is one among its most important
factors."--Robert T. Edes, M.D.
[40] Thus the fibers which pass out from the sacral plexus in the loins,
and extend by means of the great sciatic nerve and its branches to the
ends of the toes, may be more than a yard long.
[41] Remarkable instances are cited to illustrate the imperative demand
for sleep. Gunner boys have been known to fall asleep during the height of
a naval battle, owing to the fatigue occasioned by the arduous labor in
carrying ammunition for the gunner. A case is reported of a captain of a
British frigate who fell asleep and remained so for two hours beside one
of the largest guns of his vessel, the gun being served vigorously all the
time. Whole companies of men have been known to sleep while on the march
during an arduous campaign. Cavalrymen and frontiersmen have slept soundly
in the saddle during the exhausting campaigns against the Indians.
[42] According to the Annual Report of New York State Reformatory, for
1896, drunkenness among the inmates can be clearly traced to no less than
38 per cent of the fathers and mothers only.
Drunkenness among the parents of 38 per cent of the prisoners in a
reformatory of this kind is a high and a serious percentage. It shows that
the demoralizing influence of drink is apt to destroy the future of the
child as well as the character of the parent.
"There is a marked tendency in nature to transmit all diseased conditions.
Thus the children of consumptive parents are apt to be consumptive. But,
of all agents, alcohol is the most potent in establishing a heredity that
exhibits itself in the destruction of mind and body. There is not only a
propensity transmitted, but an actual disease of the nervous system."--Dr.
Willard Parker.
[43] "It is very certain that many infants annually perish from this
single cause."--Reese's _Manual of Toxicology_.
[44] If an eye removed from its socket be stripped posteriorly of the
sclerotic coat, an inverted image or the field of view will be seen on the
retina; but if the lens or other part of the refractive media be removed,
the image will become blurred or disappear altogether.
[45] This change in the convexity of the lens is only a slight one, as the
difference in the focal point between rays from an object twenty feet
distant and one four inches distant is only one-tenth of an inch. While
this muscular action is taking place, the pupil contracts and the eyeballs
converge by the action of the internal rectus muscles. These three acts
are due to the third nerve (the motor oculi). This is necessary in order
that each part should he imprinted on the same portion of the retina,
otherwise there would be double vision.
[46] The Germans have a quaint proverb that one should never rub his eyes
except with his elbows
[47] "The deleterious effect of tobacco upon eyesight is an acknowledged
fact. The Belgian government instituted an investigation into the cause of
the prevalence of color-blindness. The unanimous verdict of the experts
making the examination was that the use of tobacco was one of the
principal causes of this defect of vision.
"The dimness of sight caused by alcohol or tobacco has long been
clinically recognized, although not until recently accurately understood.
The main facts can now be stated with much assurance, since the
publication of an article by Uhthoff which leaves little more to be said.
He examined one thousand patients who were detained in hospital because of
alcoholic excess, and out of these found a total of eye diseases of about
thirty per cent.
"Commonly both eyes are affected, and the progress of the disease is slow,
both in culmination and in recovery.... Treatment demands entire
abstinence."--Henry D. Noyes, Professor of Otology in the Bellevue
Hospital Medical College, New York.
[48] "The student who will take a little trouble in noticing the ears of
the persons whom he meets from day to day will be greatly interested and
surprised to see how much the auricle varies. It may be a thick and clumsy
ear or a beautifully delicate one; long and narrow or short and broad, may
have a neatly formed and distinct lobule, or one that is heavy, ungainly,
and united to the cheek so as hardly to form a separate part of the
auricle, may hug the head closely or flare outward so as to form almost
two wings to the head. In art, and especially in medallion portraits, in
which the ear is a marked (because central) feature, the auricle is of
great importance"--William W. Keen, M.D., editor of Gray's _Anatomy_
[49] The organ of Corti is a very complicated structure which it is
needless to describe in this connection. It consists essentially of
modified ephithelial cells floated upon the auditory epithelium, or
basilar membrane, of the cochlea. There is a series of fibers, each made
of two parts sloped against each other like the rafters of a roof. It is
estimated that there are no less than 3000 of these arches in the human
ear, placed side by side in a continuous series along the whole length of
the basilar membrane. Resting on these arches are numbers of conical
epithelial cells, from the free surface of which bundles of stiff hairs
(cilia) project. The fact that these hair-cells are connected with the
fibers of the cochlear division of the auditory nerve suggests that they
must play an important part in auditory sensation.
[50] The voices of boys "break," or "change," because of the sudden growth
or enlargement of the larynx, and consequent increase in length of the
vocal cords, at from fourteen to sixteen years of age. No such enlargement
takes place in the larynxes of girls: therefore their voices undergo no
such sudden change.
[51] This experiment and several others in this book, are taken from
Professor Bowditch's little book called _Hints for Teachers of
Physiology_, a work which should be mastered by every teacher of
physiology in higher schools.
[52] The teacher or student who is disposed to study the subject more
thoroughly and in more detail than is possible in a class text-book, will
find all that is needed in the following excellent books, which are
readily obtained by purchase, or may be found in the public libraries of
larger towns: Dulles' _Accidents and Emergencies;_ Pilcher's _First Aid in
Illness and Injury_; Doty's _Prompt Aid to the Injured;_ and Johnston's
"Surgical Injuries and Surgical Diseases," a special article in
Roosevelt's _In Sickness and in Health_.
[53] "A tourniquet is a bandage, handkerchief, or strap of webbing, into
the middle of which a stone, a potato, a small block of wood, or any hard,
smooth body is tied. The band is tied loosely about the limb, the hard
body is held over the artery to be constricted, and a stick is inserted
beneath the band on the opposite side of the limb and used to twist the
band in such a way that the limb is tightly constricted thereby, and the
hard body thus made to compress the artery (Fig. 160).
"The entire circumference of the limb may be constricted by any sort of
elastic band or rubber tube, or any other strong elastic material passed
around the limb several times on a stretch, drawn tight and tied in a
knot. In this way, bleeding may be stopped at once from the largest
arteries. The longer and softer the tube the better. It requires no skill
and but little knowledge of anatomy to apply it efficiently." Alexander B.
Johnson, Surgeon to Roosevelt Hospital, New York City.
[54] Corrosive sublimate is probably the most powerful disinfectant known.
A solution of one part in 2000 will destroy microscopic organisms. Two
teaspoonfuls of this substance will make a solution strong enough to kill
all disease germs.
[55] The burning of sulphur produces sulphurous acid, which is an
irrespirable gas. The person who lights the sulphur must, therefore,
immediately leave the room, and after the lapse of the proper time, must
hold his breath as he enters the room to open the windows and let out the
gas. After fumigation, plastered walls should be white-washed, the
woodwork well scrubbed with carbolic soap, and painted portions repainted.
[56] Put copperas in a pail of water, in such quantity that some may
constantly remain undissolved at the bottom. This makes a saturated
solution. To every privy or water-closet, allow one pint of the solution
for every four persons when cholera is about. To keep privies from being
offensive, pour one pint into each seat, night and morning.
[57] "While physiology is one of the biological sciences, it should be
clearly recognized that it is not, like botany or zoology, a science of
observation and description; but rather, like physics or chemistry, a
science of experiment. While the amount of experimental instruction (not
involving vivisection or experiment otherwise unsuitable) that may with
propriety be given in the high school is neither small nor unimportant,
the limitations to such experimental teaching, both as to kind and as to
amount, are plainly indicated.
"The obvious limitations to experimental work in physiology in the high
school, already referred to, make it necessary for the student to acquire
much of the desired knowledge from the text-book only. Nevertheless, much
may be done by a thoughtful and ingenious teacher to make such knowledge
real, by the aid of suitable practical exercises and
demonstrations."--_Report of the Committee of Ten on Secondary School
Studies_.
[58] This ingenious and excellent experiment is taken from the _New York
School Journal_ for May, 1897, for which paper it was prepared by Charles
D. Nason, of Philadelphia.
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