a focus before they reach the retina; if too flat, they will reach the
retina before coming to a focus. In either case, the sight will be
indistinct. A more common defect, however, is in the shape of the globe of
the eye, which is either flattened or elongated. In the former case (see
_G_, Fig. 67), objects at a distance can be seen most distinctly--
hence that is called farsightedness. [Footnote: This should not be
confounded with the long sight of old people, which is caused by the
stiffness of the ciliary muscles, whereby the lens can not adapt itself to
the varying distances of objects.] In the latter, objects near by are
clearer, and hence this is termed nearsightedness. Farsightedness is
remedied by convex glasses; nearsightedness, by concave. When glasses will
improve the sight they should be worn; [Footnote: Dr. Henry W. Williams,
the celebrated ophthalmologist, says that, in some cases, glasses are more
necessary at six or eight years of age than to the majority of healthy
eyes at sixty. Sometimes children find accidentally that they can see
better through grandmother's spectacles. They should then be supplied with
their own.] any delay will be liable to injure the eyes, by straining
their already impaired power. Cataract is a disease in which there is an
opacity of the crystalline lens or its capsules, which obscures the
vision. The lens may be caused to be absorbed, or may be removed by a
skillful surgeon and the defect remedied by wearing convex glasses.
FIG. 66.
[Illustration: _Adjustment of the Crystalline Lens._--A, _for far
objects, and_ B, _for near._]
FIG. 67.
[Illustration: _Diagram illustrating the position of the Retina._--B,
_in natural sight;_ G, _in far sight; and_ C, _in near sight._]
COLOR-BLIND PERSONS receive only two of the three elementary color
sensations (green, red, violet). The spectrum appears to them to consist
of two decidedly different colors, with a band of neutral tint between.
The extreme red end is invisible, and a bright scarlet and a deep green
appear alike. They are unable to distinguish between the leaves of a
cherry tree and its fruit by the color of the two, and see no difference
between blue and yellow cloth. Whittier, the poet, it is said, could not
tell red from green unless in direct sunlight. Once he patched some
damaged wall paper in his library by matching a green vine in the pattern
with one of a bright autumnal crimson. This defect in the eye is often
unnoticed, and many railway accidents have doubtless happened through an
inability to detect the color of signal lights.
CARE OF THE EYES.--The shape of the eye can not be changed by rubbing and
pressing it, as many suppose, but the sight may thus be fatally injured.
Children troubled by nearsightedness should not lean forward at their
work, as thereby the vessels of the eye become overcharged with blood.
They should avoid fine print, and try, in every possible way, to spare
their eyes. If middle age be reached without especial difficulty of sight,
the person is comparatively safe. Most cases of squinting are caused by
longsightedness, the muscles being strained in the effort to obtain
distinct vision. In childhood, it may be cured by a competent surgeon, who
will generally cut the muscle that draws the eye out of place.
After any severe illness, especially after measles, scarlatina, or typhoid
fever, the eyes should be used with extreme caution, since they share in
the general debility of the body, and recover their strength slowly.
Healthy eyes even should never be used to read fine print or by a dim
light. Serious injury may be caused by an imprudence of this kind. Reading
upon the cars is also a fruitful source of harm. The lens, striving to
adapt itself to the incessantly varying distance of the page, soon becomes
wearied. Whenever the eyes begin to ache, it is a warning that they are
being overtaxed and need rest.
Objects that get into the eye should be removed before they cause
inflammation; rubbing in the meantime only irritates and increases the
sensitiveness. If the eye be shut for a few moments, so as to let the
tears accumulate, and the upper lid be then lifted by taking hold of it at
the center, the cinder or dust is often washed away at once. Trifling
objects can be removed by simply drawing the upper lid as far as possible
over the lower one; when the lid flies back to its place, the friction
will detach any light substance. If it becomes necessary, turn the upper
lid over a pencil, and the intruder may then be wiped off with a
handkerchief. "Eye-stones" are a popular delusion. When they seem to take
out a cinder, it is only because they raise the eyelid, and allow the
tears to wash it out. No one should ever use an eyewash, except by medical
advice. The eye is too delicate an organ to be trifled with, and when any
disease is suspected, a reliable physician should be consulted. This is
especially necessary, since, when one eye is injured, the other, by
sympathy, is liable to become inflamed, and perhaps be destroyed.
When reading or working, the _light should be at the left side, or at
the rear; never in front_.
The constant increase of defective eyesight among the pupils in our
schools is an alarming fact. Dr. Agnew considers that our schoolrooms are
fast making us a spectacle-using people. Nearsightedness seems to increase
from class to class, until in the upper departments, there are sometimes
as high as fifty per cent of the pupils thus afflicted. The causes are
(1), desks so placed as to make the light from the windows shine directly
into the eyes of the scholars; (2), cross lights from opposite windows;
(3), insufficient light; (4), small type that strains the eyes; and (5),
the position of the pupil as he bends over his desk or slate, causing the
blood to settle in his eyes. All these causes can be remedied; the
position of the desks can be changed; windows can be shaded, or new ones
inserted; books and newspapers that try the eyes can be rejected; and
every pupil can be taught how to sit at study.
PRACTICAL QUESTIONS.
1. Why does a laundress test the temperature of her flatiron by holding it
near her cheek?
2. When we are cold, why do we spread the palms of our hands before the
fire?
3. What is meant by a "furred tongue"?
4. Why has sand or sulphur no taste?
5. What was the origin of the word palatable?
6. Why does a cold in the head injure the flavor of our coffee?
7. Name some so-called flavors that are really sensations of touch.
8. What is the object of the hairs in the nostrils?
9. What use does the nose subserve in the process of respiration?
10. Why do we sometimes hold the nose when we take unpleasant medicine?
11. Why was the nose placed over the mouth?
12. Describe how the hand is adapted to be the instrument of touch.
13. Besides being the organ of taste, what use does the tongue subserve?
14. Why is not the act of tasting complete until we swallow?
15. Why do all things have the same flavor when one's tongue is "furred"
by fever?
16. Which sense is the more useful--hearing or sight?
17. Which coat is the white of the eye?
18. What makes the difference in the color of eyes?
19. Why do we snuff the air when we wish to obtain a distinct smell?
20. Why do red-hot iron and frozen mercury (-40°) produce the same
sensation?
21. Why can an elderly person drink tea which to a child would be
unbearably hot?
22. Why does an old man hold his paper so far from his eyes?
23. Would you rather be punished on the tips of your fingers than on the
palm of your hand?
24. What is the object of the eyelashes? Are the hairs straight?
25. What is the use of winking?
26. When you wink, do the eyelids touch at once along their whole length?
Why?
27. How many rows of hairs are there in the eyelashes?
28. Do all nations have eyes of the same shape?
29. Why does snuff taking cause a flow of tears?
30. Why does a fall cause one to "see stars"?
31. Why can we not see with the nose, or smell with the eyes?
32. What causes the roughness of a cat's tongue?
33. Is the cuticle essential to touch?
34. Can one tickle himself?
35. Why does a bitter taste often produce vomiting?
36. Is there any danger in looking "crosseyed" for fun?
37. Should schoolroom desks face a window?
38. Why do we look at a person to whom we are listening attentively?
39. Do we really feel with our fingers?
40. Is the eye a perfect sphere? (See Fig. 61.)
41. How often do we wink?
42. Why is the interior of a telescope or microscope often painted black?
43. What is "the apple of the eye"?
44. What form of glasses do old people require?
45. Should we ever wash our ears with cold water?
46. What is the object of the winding passages in the nose?
47. Can a smoker tell in the dark, whether or not his cigar is lighted?
48. Will a nerve reunite after it has been cut?
49. Will the sight give us an idea of solidity? [Footnote: A case occurred
a few years ago, in London, where a friend of my own performed an
operation upon a young woman who had been born blind, and, though an
attempt had been made in early years to cure her, it had failed. She was
able just to distinguish large objects, the general shadow, as it were,
without any distinct perception of form, and to distinguish light from
darkness. She could work well with her needle by the touch, and could use
her scissors and bodkin and other implements by the training of her hand,
so to speak, alone Well, my friend happened to see her, and he examined
her eyes, and told her that he thought he could get her sight restored; at
any rate, it was worth a trial. The operation succeeded; and, being a man
of intelligence and quite aware of the interest of such a case, he
carefully studied and observed it; and he completely confirmed all that
had been previously laid down by the experience of similar cases. There
was one little incident which will give you an idea of the education which
is required for what you would suppose is a thing perfectly simple and
obvious. She could not distinguish by sight the things that she was
perfectly familiar with by the touch, at least when they were first
presented to her eyes. She could not recognize even a pair of scissors.
Now, you would have supposed that a pair of scissors, of all things in the
world, having been continually used by her, and their form having become
perfectly familiar to her hands, would have been most readily recognized
by her sight; and yet she did not know what they were; she had not an idea
until she was told, and then she laughed, as she said, at her own
stupidity. No stupidity at all; she had never learned it, and it was one
of those things which she could not know without learning. One of the
earliest cases of this kind was related by the celebrated Cheselden, a
surgeon of the early part of last century. Cheselden relates how a youth
just in this condition had been accustomed to play with a cat and a dog;
but for some time after he attained his sight he never could tell which
was which, and used to be continually making mistakes. One day, being
rather ashamed of himself for having called the cat the dog, he took up
the cat in his arms and looked at her very attentively for some time
stroking her all the while; and in this way he associated the impression
derived from the touch, and made himself master (so to speak) of the whole
idea of the animal. He then put the cat down, saying: "Now, puss, I shall
know you another time."--CARPENTER.]
50. Why can a skillful surgeon determinate the condition of the brain and
other internal organs by examining the interior of the eye? [Footnote:
This is done by means of an instrument called the ophthalmoscope. Light is
thrown into the eye with a concave mirror, and the interior of the organ
examined with a lens.]
51. Is there any truth in the idea that the image of the murderer can be
seen in the eye of the dead victim?
52. What is the length of the optic nerve? _Ans_. About three fourths
of an inch.
53. Why does an injury to one eye generally affect the other eye?
_Ans_. The optic nerves give off no branches in passing from their
origin in two ganglia situated between the cerebrum and the cerebellum,
and their termination in the eyeballs; but, in the middle of their course,
they _decussate_, or unite in one mass. The fibers of the two nerves
here pass from side to side, and intermingle. The two ganglia are also
united directly by fibers. Thus the eyes are not really separate organs of
sight, but a kind of double organ to perform, a single function.
IX.
HEALTH AND DISEASE.--DEATH AND DECAY.
"Health is the vital principle of bliss."
THOMSON.
"There are three wicks to the lamp of a man's life: brain, blood, and
breath. Press the brain a little, its light goes out, followed by both the
others. Stop the heart a minute, and out go all three of the wicks. Choke
the air out of the lungs, and presently the fluid ceases to supply the
other centers of flame, and all is soon stagnation, cold, and darkness."
O. W. HOLMES.
"Calmly he looked on either Life, and here
Saw nothing to regret, or there to fear;
From Nature's temp'rate feast rose satisfy'd,
Thank'd Heaven that he had lived, and that he died."
POPE.
HEALTH AND DISEASE.--DEATH AND DECAY.
VALUE OF HEALTH.--The body is the instrument which the mind uses. If it be
dulled or nicked, the effect of the best labor will be impaired. The
grandest gifts of mind or fortune are comparatively valueless unless there
be a healthy body to use and enjoy them. The beggar, sturdy and brave with
his outdoor life, is really happier than the rich man in his palace with
the gout to twinge him amid his pleasures. The day has gone by when
delicacy is considered an element of beauty. Weakness is timid and
irresolute; strength is full of force and energy. Weakness walks or
creeps; strength speeds the race, wins the goal, and rejoices in the
victory.
FALSE IDEAS OF DISEASE.--It was formerly supposed that diseases were
caused by evil spirits, who entered the body, and deranged its action.
Incantations, spells, etc., were resorted to in order to drive them out.
By others, disease was thought to come arbitrarily, or as a special
visitation of an overruling power. Hence, it was to be removed by fasting
and prayer. Modern science teaches us that disease is not a thing, but a
state. When our food is properly assimilated, the waste matter promptly
excreted, and all the organs work in harmony, we are well; when any
derangement of these functions occurs, we are sick. Sickness is discord,
as health is concord. If we abuse or misuse any instrument, we impair its
ability to produce a perfect harmony. A suffering body is simply the
penalty of violated law.
PREVENTION OF DISEASE.--Doubtless a large proportion of the ills which now
afflict and rob us of so much time and pleasure might easily be avoided. A
proper knowledge and observance of hygienic laws would greatly lessen the
number of such diseases as consumption, catarrh, gout, rheumatism,
dyspepsia, etc. There are parts of England where one half the children die
before they are five years old. Every physiologist knows that at least
nine tenths of these lives could be saved by an observance of the simple
laws of health. Professor Bennet, in a lecture at Edinburgh, estimated
that one hundred thousand persons die annually in Great Britain from
causes easily preventable.
With the advance of science, the causes of many diseases have been
determined. Vaccination has been found to prevent or mitigate the ravages
of smallpox. Scurvy, formerly so fatal among sailors that it was deemed "a
mysterious infliction of Divine Justice against which man strives in
vain," is now entirely avoided by the use of vegetables or lime juice.
Cholera, whose approach still strikes dread, and for which there is no
known specific, is but the penalty for filthy streets, bad drainage, and
overcrowded tenements, and may be controlled, if not prevented, by
suitable sanitary measures. It was, no doubt, the intention that we should
wear out by the general decay of all the organs, [Footnote: So long as the
phenomena of waste and repair are in harmony--so long, in other words, as
the builder follows the scavenger--so long man exists in integrity and
repair--just, indeed, as houses exist. Derange nutrition, and at once
degeneration, or rather let us say, alteration begins. Alas! that we are
so ignorant that there are many things about our house, which, seeing
them, weaken, we know not how to strengthen. About the brick and the
mortar, the frame and the rafters, we are not unlearned; but within are
many complexities, many chinks and crannies, full in themselves of
secondary chinks and crannies, and these so small, so deep, so recessed,
that it happens every day that the destroyer settles himself in some place
so obscure, that, while he kills, he laughs at defiance. You or I meet
with an accident in our watch. We consult the watchmaker, and he repairs
the injury. If we were all that watchmakers, like ourselves, should be, a
man could be made to keep time until he died from old age or annihilating
accident. This I firmly and fully believe.--_Odd Hours of a
Physician_.] rather than by the giving out of any single part, and that
all should work together harmoniously until the vital force is exhausted.
CURE OF DISEASE.--The first step in the cure of any disease is to obey the
law of health which has been violated. If medicine be taken, it is not to
destroy the disease, since that is not a thing to be destroyed, but to
hold the deranged action in check while nature repairs the injury, and
again brings the system into harmonious movement. This tendency of nature
is our chief reliance. The best physicians are coming to have diminished
confidence in medicine itself, and to place greater dependence upon
sanitary and hygienic measures, and upon the efforts which nature always
makes to repair injuries and soothe disordered action. They endeavor only
to give to nature a fair chance, and sometimes to assist her by the
intelligent employment of proper medicines. The indiscriminate use of
patent nostrums and sovereign remedies of whose constituents we know
nothing, and by which powerful drugs are imbibed at haphazard, can not be
too greatly deprecated. When one needs medicine, he needs also a competent
physician to advise its use.
DEATH AND DECAY.--By a mystery we can not understand, life is linked with
death, and out of the decay of our bodies they, day by day, spring afresh.
At last the vital force which has held death and decay in bondage, and
compelled them to minister to our growth, and to serve the needs of our
life, faints and yields the struggle. These powers which have so long time
been our servants, gather about our dying couch, and their last offices
usher us into the new life and the grander possibilities of the world to
come. This last birth, we who see the fading, not the dawning, life, call
death.
"O Father! grant Thy love divine,
To make these mystic temples Thine,
When wasting age and wearying strife
Have sapp'd the leaning walls of life;
When darkness gathers over all,
And the last tottering pillars fall,
Take the poor dust Thy mercy warms,
And mold it into heavenly forms."
HOLMES.
HINTS ABOUT THE SICK ROOM
A SICK ROOM should be the lightest and cheeriest in the house. A small,
close, dark bedroom or a recess is bad enough for one in health, but
unendurable for a sick person. In a case of fever, and in many acute
diseases, it should be remote from the noise of the family; but when one
is recovering from an accident, and in all attacks where quiet is not
needed, the patient may be where he can amuse himself by watching the
movements of the household, or looking out upon the street.
_The ventilation must be thorough._ Bad air will poison both the sick
and the well. A fireplace is, therefore, desirable. Windows should open
easily. By carefully protecting the patient with extra blankets, the room
may be frequently aired. If there be no direct draught, much may be done
to change the air, by simply swinging an outer door to and fro many times.
A bare floor, with strips of carpet here and there to deaden noise, is
cleanest, and keeps the air freest from dust. Cane-bottomed chairs are
preferable to upholstered ones. All unnecessary furniture should be
removed out of the way. A straw bed or a mattress is better than feathers.
The bed hangings, lace curtains, etc., should be taken down. Creaking
hinges should be oiled. Sperm candles are better than kerosene lamps.
_Never whisper in a sick room._ All necessary conversation should be
carried on in the usual tone of voice. Do not call a physician
unnecessarily, but if one be employed, _obey his directions
implicitly_. Never give nostrums overofficious friends may suggest. Do
not allow visitors to see the patient, except it be necessary. Never
bustle about the room, nor go on tiptoe, but move in a quiet, ordinary
way. Do not keep the bottles in the continued sight of the sick person.
Never let drinking water stand in the room.
Do not raise the patient's head to drink, but have a cup with a long
spout, or use a bent tube, or even a straw. Do not tempt the appetite when
it craves no food. Bathe frequently, but let the physician prescribe the
method. Give written directions to the watchers. Have all medicines
carefully marked. Remove all soiled clothing, etc., at once from the room.
Change the linen much oftener than in health. When you wish to change the
sheets, and the patient is unable to rise, roll the under sheet tightly
lengthwise to the middle of the bed; put on the clean sheet, with half its
width folded up, closely to the other roll; lift the patient on to the
newly-made part, remove the soiled sheet, and then spread oat the clean
one.
DISINFECTANTS.
Remember, first, that deodorizers and disinfectants are not the same. A
bad smell, for instance, may be smothered by some more powerful odor,
while its cause remains uninfluenced. Bear also in mind the fact that no
deodorizer and no disinfectant can take the place of perfect cleanliness
and thorough ventilation. No purifyer can rival the oxygen contained in
strong and continued currents of fresh, cold air, and every disinfectant
finds an indispensable ally in floods of scalding water.
An excellent disinfectant may be made by dissolving in a pail of water
either of the following: (1), a quarter of a pound of sulphate of zinc and
two ounces of common salt for each gallon of water; (2), a pound and a
half of copperas, for each gallon of water. Towels, bed linen,
handkerchiefs, etc., should be soaked at least an hour, in a solution of
the first kind, and then be boiled, before washing. [Footnote: It is
_best_ to burn all articles which have been in contact with persons
sick with contagious or infectious diseases.
In using the zinc solution, place the articles in it as soon as they are
removed from the patient, and before they are taken from the room; if
practicable, have the solution boiling hot at the time. In fumigating
apartments, all the openings should be made as nearly air-tight as
possible. The articles to be included in the fumigation should be so
exposed and spread out that the sulphurous vapor may penetrate every
portion of them. For a room about ten feet square, at least two pounds of
sulphur should be used; for larger rooms, proportionally increased
quantities. Put the sulphur in iron pans supported upon bricks placed in
washtubs containing a little water, set it on fire by hot coals or with
the aid of a spoonful of alcohol, or by a long fuse set on train as the
last opening to the room is closed. Allow the apartment to remain sealed
for twenty-four hours. Great care should be taken not to inhale the
poisonous fumes in firing the sulphur. After the fumigation, allow free
currents of air to pass through the apartment; expose all movable articles
for as long time as may be to the sun and the wind out of doors; beat and
shake the carpets, hangings, pillows, etc.
The disinfectants and the instructions for using them, as given above, are
mainly those recommended by the National Board of Health.] Vaults, drains,
vessels used in the sick room, etc., should be disinfected by a solution
of the second kind; chloride of lime may also be used for the same
purpose. Rooms, furniture, and articles that can not be treated with the
solution of the first kind, should be thoroughly fumigated with burning
sulphur. Where walls are unpapered, re-whitewash with pure, freshly
slacked quicklime, adding one pint of the best fluid carbolic acid to
every gallon of the fluid whitewash. Powdered stone lime sprinkled on
foul, wet places, or placed in pans in damp rooms, will absorb the
moisture; and dry, fresh charcoal powder may be combined with it to absorb
noxious gases.
WHAT TO DO TILL THE DOCTOR COMES.