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Title: A Handbook of Health
Author: Hutchinson, Woods, 1862-1930
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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The Woods Hutchinson Health Series

A HANDBOOK OF HEALTH

by

WOODS HUTCHINSON, A. M., M. D.

Sometime Professor of Anatomy, University of Iowa; Professor of
Comparative Pathology and Methods of Science Teaching, University of
Buffalo; Lecturer, London Medical Graduates' College and University of
London; and State Health Officer of Oregon. Author of "Preventable
Diseases," "Conquest of Consumption," "Instinct and Health," etc.



Houghton Mifflin Company
Boston New York Chicago
Copyright, 1911, by Woods Hutchinson
All Rights Reserved
Tenth Impression



PREFACE


Looking upon the human body from the physical point of view as the most
perfect, most ingeniously economical, and most beautiful of living
machines, the author has attempted to write a little handbook of
practical instruction for the running of it.

And seeing that, like other machines, it derives the whole of its energy
from its fuel, the subject of foods--their properties, uses, and methods
of preparation--has been gone into with unusual care. An adequate supply
of clean-burning food-fuel for the human engine is so absolutely
fundamental both for health and for efficiency--we are so literally what
we have eaten--that to be well fed is in very fact two-thirds of the
battle of life from a physiological point of view. The whole discussion
is in accord with the aim, kept in view throughout the book, of making
its suggestion and advice positive instead of negative, pointing out
that, in the language of the old swordsman, "attack is the best
defense." If we actively do those things that make for health and
efficiency, and which, for the most part, are attractive and agreeable
to our natural instincts and unspoiled tastes,--such as exercising in
the open air, eating three square meals a day of real food, getting nine
or ten hours of undisturbed sleep, taking plenty of fresh air and cold
water both inside and out,--this will of itself carry us safely past all
the forbidden side paths without the need of so much as a glance at the
"Don't" and "Must not" with which it has been the custom to border and
fence in the path of right living.

On the other hand, while fully alive to the undesirability, and indeed
wickedness, of putting ideas of dread and suffering into children's
minds unnecessarily, yet so much of the misery in the world is due to
ignorance, and could have been avoided if knowledge of the simplest
character had been given at the proper time, that it has been thought
best to set forth the facts as to the causation and nature of the
commonest diseases, and the methods by which they may be avoided. This
is peculiarly necessary from the fact that most of the gravest enemies
of mankind have come into existence within a comparatively recent period
of the history of life,--only since the beginning of civilization, in
fact,--so that we have as yet developed no natural instincts for their
avoidance.

Nor do we admit that we are adding anything to the stock of fears in the
minds of children--the nurse-maid and the bad boys in the next alley
have been ahead of us in this respect. The child-mind is too often
already filled with fears and superstitions of every sort, passed down
from antiquity. Modern sanitarians have been accused of merely
substituting one fear for another in the mind of the child--bacilli
instead of bogies. But, even if this be true, there are profound and
practical differences between the two terrors. One is real, and the
other imaginary. A child cannot avoid meeting a bacillus; he will never
actually make the acquaintance of a bogie. Children, like savages and
ignorant adults, believe and invent and retail among themselves the most
extraordinary and grotesque theories about the structure and functions
of their bodies, the nature and causation of their illnesses and aches
and pains. A plain and straightforward statement of the actual facts
about these things not only will not shock or repel them, or make them
old before their time, but, on the contrary, will interest them greatly,
relieve their minds of many unfounded dreads, and save them from the
commonest and most hurtful mistakes of humanity--those that are
committed through ignorance.

                                                             THE AUTHOR.



CONTENTS


                                                                    PAGE

     I. RUNNING THE HUMAN AUTOMOBILE                                   1

    II. WHY WE HAVE A STOMACH                                          4
        What Keeps Us Alive                                            4
        The Digestive System                                           7
        The Journey down the Food Tube                                 9

   III. THE FOOD-FUEL OF THE BODY-ENGINE                              21
        What Kind of Food should We Eat?                              21
        The Three Great Classes of Food-Fuel                          25

    IV. THE COAL FOODS                                                27
        Proteins, or "Meats"                                          27

     V. THE COAL FOODS (_Continued_)                                  40
        Starches                                                      40
        Sugars                                                        48

    VI. THE COAL FOODS (_Continued_)                                  51
        Animal Fats                                                   51
        Nuts                                                          55

   VII. KINDLING AND PAPER FOODS--FRUITS AND VEGETABLES               56

  VIII. COOKING                                                       62

    IX. OUR DRINK                                                     69
        Filling the Boiler of the Body-Engine                         69
        Where our Drinking Water Comes from                           72
        Causes and Dangers of Polluted Water                          75
        Methods of Obtaining Pure Water                               81
        Home Methods of Purifying Water                               87

     X. BEVERAGES, ALCOHOL, AND TOBACCO                               89
        Alcohol                                                       93
        Tobacco                                                      103

    XI. THE HEART-PUMP AND ITS PIPE-LINE SYSTEM                      108
        The Blood Vessels                                            108
        The Heart                                                    115

   XII. THE CARE OF THE HEART-PUMP AND ITS PIPE LINES                120

  XIII. HOW AND WHY WE BREATHE                                       130

   XIV. HOW TO KEEP THE LUNG-BELLOWS IN GOOD CONDITION               139
        The Need of Pure Air                                         139
        Colds, Consumption, and Pneumonia                            152
        How to Conquer Consumption                                   156
        Pneumonia                                                    165

    XV. THE SKIN                                                     167
        Our Wonderful Coat                                           167
        The Glands in the Skin                                       170
        The Nails                                                    172
        The Blood-Mesh of the Skin                                   174
        The Nerves in the Skin                                       177

   XVI. HOW TO KEEP THE SKIN HEALTHY                                 179
        Clothing                                                     179
        Baths and Bathing                                            184
        Care of the Nails                                            188
        Diseases and Disturbances of the Skin                        189

  XVII. THE PLUMBING AND SEWERING OF THE BODY                        196

 XVIII. THE MUSCLES                                                  202

   XIX. THE STIFFENING RODS OF THE BODY-MACHINE                      210

    XX. OUR TELEPHONE EXCHANGE AND ITS CABLES                        216

   XXI. THE HYGIENE OF BONES, NERVES, AND MUSCLES                    228
        How to Get and Keep a Good Figure                            228
        Our Feet                                                     230
        Sleep and Rest                                               232
        Disorders of Muscles and Bones                               233
        Troubles of the Nervous System                               235

  XXII. EXERCISE AND GROWTH                                          241

 XXIII. THE LOOKOUT DEPARTMENT                                       252
        The Nose                                                     253
        The Tongue                                                   257
        The Eye                                                      259
        The Ear                                                      266
        Our Spirit-Levels                                            269

  XXIV. THE SPEECH ORGANS                                            271

   XXV. THE TEETH, THE IVORY KEEPERS OF THE GATE                     277

  XXVI. INFECTIONS, AND HOW TO AVOID THEM                            286

 XXVII. ACCIDENTS AND EMERGENCIES                                    314

        QUESTIONS AND EXERCISES                                      331

        GLOSSARY AND INDEX                                           343



ILLUSTRATIONS


                                                                    PAGE
TO ATTEMPT TO RUN AN AUTOMOBILE WITHOUT KNOWING HOW WOULD BE
REGARDED AS FOOLHARDY                                                  2

WHERE SUN-POWER IS MADE INTO FOOD FOR US                               6

THE FOOD ROUTE IN THE DIGESTIVE SYSTEM                                 8

THE SALIVARY GLANDS                                                   10

A SECTION OF THE LINING SURFACE OF THE STOMACH                        14

A LONGITUDINAL SECTION OF STOMACH, OR PEPTIC, GLANDS                  15

A CHEAP HOME-MADE ICE BOX                                             23

A BABY-MILK STATION                                                   30

CLEAN, DRY SUNNING YARDS AT A MODEL DAIRY                             33

CLEANLINESS BEFORE MILKING                                            34

THE MILKING HOUR AT A MODEL DAIRY                                     35

MILKING BY VACUUM PROCESS                                             36

WASHING THE BOTTLES AT A MODEL DAIRY                                  37

BACTERIA IN CLEAN AND IN DIRTY MILK                                   38

DANGER FROM DIPPED MILK                                               38

MILK INSPECTION AT THE RETAIL STORE                                   39

A THOROUGH BAKING, AND A VALUABLE CRUST                               44

AN IDEAL BAKERY WITH LIGHT, AIR, AND CLEANLINESS                      45

A BASEMENT BAKERY--A MENACE TO THE PUBLIC HEALTH                      46

CANDY, LIKE OTHER FOODS, SHOULD BE CLEAN                              50

A SMALL STORE, CLEANLY AND HONEST                                     54

THE JOY OF HIS OWN GARDEN PATCH                                       61

THE KITCHEN SHOULD BE CARED FOR AS ONE OF THE MOST IMPORTANT
ROOMS IN THE HOUSE                                                    63

A KNOWLEDGE OF COOKING IS A VALUABLE PART OF A GOOD EDUCATION         66

BOYS, AS WELL AS GIRLS, SHOULD KNOW HOW TO COOK                       67

THE CHAINED CUP                                                       71

THE SPOUTING FOUNTAIN                                                 72

NATURE'S FILTER-BED                                                   74

AN EXAMPLE OF GOOD FARM DRAINAGE                                      76

THE DANGER SPOT ON THE FARM                                           78

TYPHOID EPIDEMIC IN THE MOHAWK-HUDSON VALLEY                          80

ARTESIAN WELL BORINGS                                                 82

A CITY WATER SUPPLY BROUGHT FROM THE FAR HILLS                        84

A RESERVOIR AND COSTLY DAM                                            86

SCRAPING THE SEDIMENT FROM THE BOTTOM OF A RESERVOIR                  87

THE DOMESTIC FILTER IN USE                                            88

A MILK STATION IN A CITY PARK                                         92

PROPORTION OF ALCOHOL IN LIGHT WINE, IN BEER, IN WHISKEY              95

A BOARD OF HEALTH EXAMINATION FOR WORKING PAPERS                     105

A TEST OF CLEAR HEAD AND STEADY NERVES                               106

BLOOD CORPUSCLES                                                     109

SURFACE VEINS AND DEEP-LYING ARTERIES OF INNER SIDE OF RIGHT
ARM AND HAND                                                         112

DIAGRAM OF ARTERY, CAPILLARIES, AND VEIN                             114

THE EXTERIOR OF THE HEART                                            116

DIAGRAM OF VALVES IN THE VEINS AND HEART                             117

THE BLOOD-ROUTE TROUGHT THE HEART                                    118

THE SCHOOL PHYSICIAN EXAMINING HEART AND LUNGS                       121

ROWING IS A SPLENDID EXERCISE FOR HEART AND LUNGS                    127

THE GREAT ESSENTIAL TO LIFE--AIR                                     131

DIAGRAM OF THE AIR TUBES AND LUNGS                                   134

"IMPROVING THEIR WIND"                                               137

THE "DARK ROOM" DANGER OF THE TENEMENTS                              145

VENTILATING THE PUPILS, AS WELL AS THE CLASSROOM                     146

A WELL-AIRED CLASSROOM                                               147

A HEALTHFUL ARRANGEMENT OF WINDOWS AND SHADES                        148

A HEALTHFUL BEDROOM                                                  151

DISEASE GERMS                                                        152

A VACUUM CLEANER                                                     153

EXERCISE IN THE COLD IS A GOOD PREVENTIVE OF COLDS                   155

A YEAR OF CONSUMPTION ON MANHATTAN ISLAND                            156

CONSUMPTION IN CHICAGO                                               157

A REPORT-FORM FROM A HEALTH DEPARTMENT LABORATORY                    159

A SIGN THAT OUGHT NOT TO BE NECESSARY                                160

A COMPARATIVE DEATH-RATE FROM CONTAGIOUS DISEASES                    161

A TUBERCULOSIS TENT COLONY IN WINTER                                 163

AN OUTDOOR CLASSROOM FOR TUBERCULOUS CHILDREN                        165

THE LAYERS OF THE SKIN                                               169

THE GLANDS IN THE SKIN                                               171

RESULTS OF TIGHT CLOTHING                                            181

A COMFORTABLE DRESS FOR OUTDOOR STUDY IN COLD WEATHER                183

AS A TONIC, SWIMMING IS THE BEST FORM OF BATHING                     185

THE URINARY SYSTEM                                                   200

THE MUSCLE-SHEET                                                     205

USE OF MUSCLES IN BOWLING                                            206

USE OF MUSCLES IN FOOTBALL                                           207

PATELLA AND MUSCLE                                                   207

THE HUMAN SKELETON                                                   211

THE SPINAL COLUMN                                                    212

A BALL-AND-SOCKET JOINT                                              213

A HINGE JOINT                                                        213

LENGTHWISE SECTION OF BONE                                           214

CROSS SECTION OF BONE                                                214

THE NERVOUS SYSTEM                                                   218

THE POSITION OF THE BODY IS AN INDEX TO ITS HEALTH                   229

IMPRINT OF (1) ARCHED FOOT AND (2) FLAT FOOT                         230

THE RESULT OF WEARING A FASHIONABLE SHOE                             231

CALLUS FORMED AROUND A FRACTURE                                      234

A TRAINED BODY                                                       242

TUG OF WAR                                                           245

THE GIANT STRIDE                                                     246

SCHOOL GARDENING                                                     248

A WASTED CHANCE FOR PUBLIC HEALTH                                    249

AN OBSTACLE RACE                                                     250

THE HIGH JUMP                                                        251

ADENOIDS                                                             256

MOUTH-BREATHERS                                                      257

THE APPARATUS OF VISION                                              260

A SCHOOL EYE-TEST                                                    263

DISINFECTING A BABY'S EYES AT BIRTH                                  265

THE APPARATUS OF HEARING                                             267

THE VOCAL CORDS                                                      272

TEETH--A QUESTION OF CARE                                            278

A TOOTH                                                              279

THE REPLACING OF THE MILK TEETH                                      282

A TOOTH-BRUSH DRILL                                                  284

THE WINNING FIGHT                                                    290

DEATH-RATE FROM MEASLES                                              291

DEATH-RATE FROM DIPHTHERIA AND CROUP                                 294

BILL OF HEALTH                                                       298

GERMS OF MALARIA                                                     301

CULEX                                                                302

ANOPHELES                                                            302

OILING A BREEDING GROUND OF MOSQUITOES                               304

AN EDUCATIONAL FLY POSTER                                            310

A BREEDING PLACE OF FLIES AND FILTH                                  311

A TOURNIQUET                                                         321

POISON IVY                                                           325

THE NEW METHOD OF ARTIFICIAL BREATHING                               328


PLATES IN COLOR

DIAGRAM OF THE CIRCULATORY SYSTEM                         _facing_   110

DIAGRAM SHOWING GENERAL PLAN AND POSITION OF
BODY-MACHINERY                                            _facing_   198



A HANDBOOK OF HEALTH



CHAPTER I

RUNNING THE HUMAN AUTOMOBILE


The Body-Automobile. If you were to start to-morrow morning on a
long-distance ride in an automobile, the first thing that you would do
would be to find out just how that automobile was built; how often it
must have fresh gasoline; how its different speed gears were worked;
what its tires were made of; how to mend them; and how to cure engine
troubles. To attempt to run an automobile, for even a ten-mile ride,
with less information than this, would be regarded as foolhardy.

Yet most of us are willing to set out upon the journey of life in the
most complicated, most ingenious, and most delicate machine ever
made--our body--with no more knowledge of its structure than can be
gained from gazing in the looking-glass; or of its needs, than a
preference for filling up its fuel tank three times a day. More
knowledge than this is often regarded as both unnecessary and
unpleasant. Yet there are few things more important, more vital to our
health, our happiness, and our success in life, than to know how to
steer and how to road-repair our body-automobile. This we can learn only
from physiology and hygiene.

The General Plan of the Human Automobile is Simple. Complicated as our
body-automobile looks to be, there are certain things about the plan
and general build of it which are plain enough. It has a head end, where
fuel supplies are taken in and where its lamps and other look-out
apparatus are carried; a body in which the fuel is stored and turned
into work or speed, and into which air is drawn to help combustion and
to cool the engine pipes. It has a pair of fore-wheels (the arms) and a
pair of hind-wheels (the legs), though these have been reduced to only
one spoke each, and swing only about a quarter of the way around and
back again when running, instead of round and round. It has a steering
gear (the brain), just back of the headlights, and a system of nerve
electric wires connecting all parts of it. It gets warm when it runs,
and stops if it is not fed.

[Illustration: TO ATTEMPT TO RUN AN AUTOMOBILE WITHOUT KNOWING HOW WOULD
BE REGARDED AS FOOLHARDY]

There is not an unnecessary part, or unreasonable "cog," anywhere in the
whole of our bodies. It is true that there are a few little remnants
which are not quite so useful as they once were, and which sometimes
cause trouble. But for the most part, all we have to do is to look long
and carefully enough at any organ or part of our bodies, to be able to
puzzle out just what it is or was intended to do, and why it has the
shape and size it has.

Why the Study of Physiology is Easy. There is one thing that helps to
make the study of physiology quite easy. It is that you already know a
good deal about your body, because you have had to live with it for a
number of years past, and you can hardly have helped becoming somewhat
acquainted with it during this time.

You have, also, another advantage, which will help you in this study.
While your ideas of how to take care of your body are rather vague, and
some of them wrong, most of them are in the main right, or at least lead
you in the right direction. You all know enough to eat when you are
hungry and to drink when you are thirsty, even though you don't always
know when to stop, or just what to eat. You like sunny days better than
cloudy ones, and would much rather breathe fresh air than foul. You like
to go wading and swimming when you are hot and dusty, and you don't need
to be told to go to sleep when you are tired. You would much rather have
sugar than vinegar, sweet milk than sour milk; and you dislike to eat or
drink anything that looks dirty or foul, or smells bad.

These inborn likes and dislikes--which we call _instincts_--are the
forces which have built up this wonderful body-machine of ours in the
past and, if properly understood and trained, can be largely trusted to
run it in the future. How to follow these instincts intelligently, where
to check them, where to encourage them, how to keep the proper balance
between them, how to live long and be useful and happy--this is what the
interesting study of physiology and hygiene will teach you.



CHAPTER II

WHY WE HAVE A STOMACH


WHAT KEEPS US ALIVE

The Energy in Food and Fuel. The first question that arises in our
mind on looking at an engine or machine of any sort is, What makes it
go? If we can succeed in getting an answer to the question, What makes
the human automobile go? we shall have the key to half its secrets at
once. It is fuel, of course; but what kind of fuel? How does the body
take it in, how does it burn it, and how does it use the energy or power
stored up in it to run the body-engine?

Man is a bread-and-butter-motor. The fuel of the automobile is gasoline,
and the fuel of the man-motor we call food. The two kinds of fuel do not
taste or smell much alike; but they are alike in that they both have
what we call _energy_, or power, stored up in them, and will, when set
fire to, burn, or explode, and give off this power in the shape of heat,
or explosions, which will do work.

Food and Fuel are the Result of Life. Fuels and foods are also alike
in another respect; and that is, that, no matter how much they may
differ in appearance and form, they are practically _all the result of
life_. This is clear enough as regards our foods, which are usually the
seeds, fruits, and leaves of plants, and the flesh of animals. It is
also true of the cord-wood and logs that we burn in our stoves and
fireplaces. But what of coal and gasoline? They are minerals, and they
come, as we know, out of the depths of the earth. Yet they too are the
product of life; for the layers of coal, which lie sixty, eighty, one
hundred and fifty feet below the surface of the earth, are the
fossilized remains of great forests and jungles, which were buried
millions of years ago, and whose leaves and branches and trunks have
been pressed and baked into coal. Gasoline comes from coal oil, or
petroleum, and is simply the "juice" which was squeezed out of these
layers of trees and ferns while they were being crushed and pressed into
coal.

How the Sun is Turned into Energy by Plants and Animals. Where did the
flowers and fruits and leaves that we now see, and the trees and ferns
that grew millions of years ago, get this power, part of which made them
grow and part of which was stored away in their leaves and branches and
seeds? From the one place that is the source of all the force and energy
and power in this world, the sun.

That is why plants will, as you know, flourish and grow strong and green
only in the sunlight, and why they wilt and turn pale in the dark. When
the plant grows, it is simply sucking up through the green stuff
(_chlorophyll_) in its leaves the heat and light of the sun and turning
it to its own uses. Then this sunlight, which has been absorbed by
plants and built up into their leaves, branches, and fruits, and stored
away in them as energy or power, is eaten by animals; and they in turn
use it to grow and move about with.

Plants can use this sun-power only to grow with and to carry out a few
very limited movements, such as turning to face the sun, reaching over
toward the light, and so on. But animals, taking this power at
second-hand from plants by eating their leaves or fruits, can use it not
merely to grow with, but also to run, to fight, to climb, to cry out,
and to carry out all those movements and processes which we call life.

Plants, on the other hand, are quite independent of animals; for they
can take up, or drink, this sun-power directly, with the addition of
water from the soil sucked up through their roots, and certain salts[1]
melted in it. Plants can live, as we say, upon non-living foods. But
animals must take their supply of sun-power at second-hand by eating the
leaves and the fruits and the seeds of plants; or at third-hand by
eating other animals.

[Illustration: WHERE SUN-POWER IS MADE INTO FOOD FOR US]

All living things, including ourselves, are simply bundles of sunlight,
done up in the form of cabbages, cows, and kings; and so it is quite
right to say that a healthy, happy child has a "sunny" disposition.

Plants and Animals Differ in their Way of Taking Food. As plants take
in their sun-food and their air directly through their leaves, and their
drink of salty water through their roots, they need no special opening
for the purpose of eating and drinking, like a mouth; or place for
storing food, like a stomach. They have mouths and stomachs all over
them, in the form of tiny pores on their leaves, and hair-like tubes
sticking out from their roots. They can eat with every inch of their
growing surface.

But animals, that have to take their sun-food or nourishment at
second-hand, in the form of solid pieces of seeds, fruits, or leaves of
plants, and must take their drink in gulps, instead of soaking it up all
over their surface, must have some sort of intake opening, or mouth,
somewhere on the surface; and some sort of pouch, or stomach, inside the
body, in which their food can be stored and digested, or melted down. By
this means they also get rid of the necessity of staying rooted in one
place, to suck up moisture and food from the soil. One of the chief and
most striking differences between plants and animals is that animals
have mouths and stomachs, while plants have not.


THE DIGESTIVE SYSTEM

How the Food Reaches the Stomach. Our body, then, has an opening,
which we call the _mouth_, through which our food-fuel can be taken in.
A straight delivery tube, called the _gullet_, or _esophagus_, runs down
from the mouth to a bag, or pouch, called the _stomach_, in which the
food is stored until it can be used to give energy to the body, just as
the gasoline is stored in the automobile tank until it can be burned.

The mouth opening is furnished with _lips_ to open and close it and
assist in picking up our food and in sucking up our drink; and, as much
of our food is in solid form, and as the stomach can take care only of
fluid and pulpy materials, nature has provided a mill in the mouth in
the form of two arches, of semicircles, of _teeth_, which grind against
each other and crush the food into a pulp.

[Illustration: THE FOOD ROUTE IN THE DIGESTIVE SYSTEM

In this diagram the entire alimentary canal is shown enlarged, and the
small intestine greatly shortened, in order to show distinctly the
course of the food in the process of digestion.]

In the bottom or floor of the mouth, there has grown up a movable bundle
of muscles, called the _tongue_, which acts as a sort of waiter, handing
the food about the mouth, pushing it between the teeth, licking it out
of the pouches of the cheeks to bring it back into the teeth-mill again,
and finally, after it has been reduced to a pulp, gathering it up into a
little ball, or _bolus_, and shooting it back down the throat, through
the gullet, into the stomach.

The Intestines. When the food has been sufficiently melted and
partially digested in the stomach, it is pushed on into a long tube
called the _intestine_, or _bowel_. During its passage through this part
of the food tube, it is taken up into the veins, and carried to the
heart. From here it is pumped all over the body to feed and nourish the
millions of little cells of which the body is built. This bowel tube, or
intestine, which, on account of its length, is arranged in coils,
finally delivers the undigested remains of the food into a somewhat
larger tube called the _large intestine_, in the lower and back part of
the body, where its remaining moisture is sucked out of it, and its
solid waste material passed out of the body through the _rectum_ in the
form of the _feces_.


THE JOURNEY DOWN THE FOOD TUBE

The Flow of Saliva and "Appetite Juice." We are now ready to start
some food-fuel, say a piece of bread, on its journey down our food tube,
or _alimentary canal_. One would naturally suppose that the process of
digestion would not begin until the food got well between our teeth;
but, as a matter of fact, it begins before it enters our lips, or even
before it leaves the table. If bread be toasted or freshly baked, the
mere smell of it will start our mouths to watering; nay, even the mere
sight of food, as in a pastry cook's window, with the glass between us
and it, will start up this preparation for the feast.

This flow of saliva in the mouth is of great assistance in moistening
the bread while we are chewing it; but it goes farther than this. Some
of the saliva is swallowed before we begin to eat; and this goes down
into the stomach and brings word to the juices there to be ready, for
something is coming. As the food approaches the mouth, a message also is
telegraphed down the nerves to the stomach, which at once actively sets
to work pouring out a digestive juice in readiness, called the "appetite
juice." This shows how important are, not merely a good appetite, but
also attractive appearance and flavor in our food; for if this appetite
juice is not secreted, the food may lie in the stomach for hours before
the proper process of digestion, or melting, begins.

The Salivary Glands. Now, where does this saliva in the mouth come
from? It is poured out from the pouches of the cheeks, and from under
the tongue, by some little living sponges, or juice factories, known as
_salivary glands_.[2]

[Illustration: THE SALIVARY GLANDS

In this diagram are shown the three glands (_G_) of the left side. The
duct (_D_) from the parotid gland empties through the lining of the
cheek; those from the lower glands empty at the front of the mouth under
the tongue (_T_). _N_, nerve; _A_, artery; _V_, vein.]

All the juices poured out by these glands, indeed nearly all the fluids
or juices in our bodies, are either _acid_ or _alkaline_. By acid we
mean sour, or sharp, like vinegar, lemon juice, vitriol (_sulphuric
acid_), and _carbonic acid_ (which forms the bubbles in and gives the
sharp taste to plain soda-water). By alkaline we mean "soap-like" or
flat, like soda, lye, lime, and soaps of all sorts. If you pour an acid
and an alkali together--like vinegar and soda--they will "fizz" or
effervesce, and at the same time _neutralize_ or "kill" each other.

The Use of the Saliva. As the chief purpose of digestion is to prepare
the food so that it will dissolve in water, and then be taken up by the
cells lining the food-tube, the saliva, like the rest of the body
juices, consists chiefly of water. Nothing is more disagreeable than to
try to chew some dry food--like a large, crisp soda cracker, for
instance--which takes more moisture than the salivary glands are able to
pour out on such short notice. You soon begin to feel as if you would
choke unless you could get a drink of water. But it is not altogether
advisable to take this short cut to relief, because the salivary juice
contains what the drink of water does not--a _ferment_, or digestive
substance (_ptyalin_), which possesses the power of turning the _starch_
in our food into _sugar_. As starch is only very slowly soluble, or
"meltable," in water, while sugar is very readily so, the saliva is of
great assistance in the process of melting, known as _digestion_. The
changing of the starch to sugar is the reason why bread or cracker,
after it has been well chewed, begins to taste sweetish.

This change in the mouth, however, is not of such great importance as
we at one time thought, because even with careful mastication, a certain
amount of starch will be swallowed unchanged. Nature has provided for
this by causing another gland farther down the canal, just beyond the
stomach, called the _pancreas_, to pour into the food tube a juice which
is far stronger in sugar-making power than the saliva, and this will
readily deal with any starch which may have escaped this change in the
mouth. Moreover, this "sugaring" of starch goes on in the stomach for
twenty to forty minutes after the food has been swallowed.

Starchy foods, like bread, biscuit, crackers, cake, and pastry, are
really the only ones which require such thorough and elaborate chewing
as we sometimes hear urged. Other kinds of food, like meat and
eggs--which contain no _starch_ and consequently are not acted upon by
the saliva--need be chewed only sufficiently long and thoroughly to
break them up and reduce them to a coarse pulp, so that they can be
readily acted upon by the acid juice of the stomach.

Down the Gullet. When the food has been thoroughly moistened and
crushed in the mouth and rolled into a lump, or bolus, at the back of
the tongue, it is started down the elevator shaft which we call the
gullet, or esophagus. It does not fall of its own weight, like coal down
a chute, but each separate swallow is carried down the whole nine inches
of the gullet by a wave of muscular action. So powerful and closely
applied is this muscular pressure that jugglers can train themselves,
with practice, to swallow standing on their heads and even to drink a
glass of water in that position; while a horse or a cow always drinks
"up-hill." This driving power of the food tube extends throughout its
entire length; it is carried out by a series of circular rings of
muscles, which are bound together by other threads of muscle running
lengthwise, together forming the so-called _muscular coat_ of the tube.
By contracting, or squeezing down in rapid succession, one after
another, they move the food along through the tube. The failure of these
little muscles to act properly is one of the causes of constipation and
biliousness. Sometimes the action of the muscles is reversed, and then
we get a gush of acid, or bitter, half-digested food up into the mouth,
which we call "heart-burn" or "water-brash."

The Stomach--its Shape, Position, and Size. By means of muscular
contraction, then, the gullet-elevator carries the food into the
stomach. This is a comparatively simple affair, merely a ballooning out,
or swelling, of the food tube, like the bulb of a syringe, making a
pouch, where the food can be stored between meals, and where it can
undergo a certain kind of melting or dissolving. This pouch is about the
shape of a pear, with its larger end upward and pointing to the left,
and its smaller end tapering down into the intestine, or bowel, on the
right, just under the liver. The middle part of the stomach lies almost
directly under what we call the "pit of the stomach," though far the
larger part of it lies above and to the left of this point, going right
up under the ribs until it almost touches the heart, the diaphragm only
coming between.[3] This is one of the reasons why, when we have an
attack of indigestion, and the stomach is distended with gas, we are
quite likely to have palpitation and shortness of breath as well,
because the gas-swollen left end of the stomach is pressing upward
against the diaphragm and thus upon the heart and the lungs. Most cases
of imagined heart trouble are really due to indigestion.

The Lining Surface of the Stomach. Now let us look more carefully at
the lining surface of the stomach, for it is very wonderful. Like all
other living surfaces, it consists of tiny, living units, or "body
bricks" called _cells_, packed closely side by side like bricks in a
pavement. We speak of the _mucous membrane_, or lining, of our food
tube, as if it were one continuous sheet, like a piece of calico or
silk; but we must never forget that it is made up of living ranks of
millions of tiny cells standing shoulder to shoulder.

These cells are always actively at work picking out the substances they
need, and manufacturing out of them the ferments and acids, or alkalies,
needed for acting upon the food in their particular part of the tube,
whether it be the mouth, the stomach, or the small intestine.

[Illustration: A SECTION OF THE LINING SURFACE OF THE STOMACH

(Greatly magnified)

Showing the mouths of the stomach glands, and the furrows, or folds, of
the lining.]

The Peptic Juice. The cells of the stomach glands manufacture and pour
out a slightly sour, or acid, juice containing a ferment called
_pepsin_. The acid, which is known as _hydrochloric acid_, and the
pepsin together are able to melt down pieces of meat, egg, or curds of
milk, and dissolve them into a clear, jelly-like fluid, or thin soup,
which can readily be absorbed by the cells lining the intestine.[4]

You can see now why you shouldn't take large doses of soda or other
alkalies, just because you feel a little uncomfortable after eating.
They will make your stomach less acid and perhaps relieve the
discomfort, but they stop or slow down digestion. Neither is it well to
swallow large quantities of ice-water, or other very cold drinks, at
meal times, or during the process of digestion. As digestion is largely
getting the food dissolved in water, the drinking of moderate quantities
of water, or other fluids, at meals is not only no hindrance, but rather
a help in the process. The danger comes only when the drink is taken so
cold as to check digestion, or when it is used to wash down the food in
chunks, before it has been properly ground by the teeth.

[Illustration: A LONGITUDINAL SECTION OF STOMACH, OR PEPTIC, GLANDS

(Greatly magnified)

The long duct of each gland is but a deep fold of the stomach lining
(see note, p. 11). Into this duct the ranks of cells around it pour out
the peptic juice.]

Digestion in the Stomach. Although usually a single, pear-shaped
pouch, the stomach, during digestion, is practically divided into two
parts by the shortening, or closing down, of a ring of circular muscle
fibres about four inches from the lower end, throwing it into a large,
rounded pouch on the left, and a small, cone-shaped one on the right.
The gullet, of course, opens into the large left-hand pouch; and here
the food is stored as it is swallowed until it has become sufficiently
melted and acidified (mixed with acid juice) to be ready to pass on into
the smaller pouch. Here more acid juice is poured out into it, and it is
churned by the muscles in the walls of the stomach until it is changed
to a jelly-like substance.

Digestion in the Small Intestine. The food-pulp now passes on into the
_small intestine_, where it is acted upon by two other digestive
juices--the _bile_, which comes from the _liver_, and the _pancreatic
juice_, which is secreted by the pancreas.

The liver and the pancreas are a pair of large glands which have budded
out, one on each side of the food tube, about six inches below where the
food enters the small intestine from the stomach. The liver[5] weighs
nearly three pounds, and the pancreas about a quarter of a pound.

Of these two glands, the pancreas, though the smaller, is far more
important in digestion. In fact, it is the most powerful digestive gland
in the body. Its juice, the pancreatic juice, can do everything that any
other digestive juice can, and do it better. It contains a ferment for
turning starch into sugar, which is far more powerful than that of the
saliva; also another (_trypsin_), which will dissolve meat-stuffs nearly
twice as fast as the pepsin of the stomach can; and still another, not
possessed by either mouth or stomach glands, which will melt fat, so
that it can be sucked up by the lining cells of the intestine.

What does this great combination of powers in the pancreas mean? It
means that we have now reached the real centre and chief seat of
digestion, namely, the small intestine, or upper bowel. This is where
the food is really absorbed, taken up into the blood, and distributed to
the body. All changes before this have been merely preparatory; all
after it are simply a picking up of the pieces that remain.

In general appearance, this division of the food tube is very
simple--merely a tube about twenty feet long and an inch in diameter,
thrown into coils, so as to pack into small space, and slung up to the
backbone by broad loops of a delicate tissue (_mesentery_). It looks not
unlike twenty feet of pink garden hose.

The intestine also is provided with glands that pour out a juice known
as the _intestinal juice_, which, although not very active in digestion,
helps to melt down still further some of the sugars, and helps to
prevent putrefaction, or decay, of the food from the bacteria[6] which
swarm in this part of the tube.

By the time the food has gone a third of the way down the small
intestine, a good share of the starches in it have been turned into
sugar and absorbed by the blood vessels in its wall; and the meats,
milk, eggs, and similar foods have been digested in the same way.

There still remains the bulk of the fats to be disposed of. These fats
are attacked by the pancreatic juice and the bile, and made ready for
digestion. Like other foods, they are then eaten by the cells of the
intestinal wall; but instead of going directly into the blood vessels,
as the sugars and other food substances do, they are passed on into
another set of little tubes or vessels, called the _lymphatics_. In
these they are carried through the _lymph glands_ of the abdomen into
the great _lymph duct_, which finally pours them into one of the great
veins not far from the heart. Tiny, branching lymphatic tubes are found
all over the body, picking up what the cells leave of the fluid which
has seeped out of the arteries for their use and returning it to the
veins through the great lymph duct.

All these different food substances, in the process of digestion, do not
simply soak through the lining cells of the food tube, as through a
blotting paper or straining cloth, but are actually eaten by the cells
and very much changed in the process, and are then passed through the
other side of the cells, either into the blood vessels of the wall of
the intestine or into the lymph vessels, practically ready for use by
the living tissues of the body. It is in the cells then that our food is
turned into blood, and it is there that what we have eaten becomes
really a part of us. It may even be said that we are living upon the
leavings of the little cell citizens that line our food tube; but they
are wonderfully decent, devoted little comrades of the rest of our body
cells, and generous in the amount of food they pass on to the blood
vessels.

As the food-pulp is squeezed on from one coil to another through the
intestine, it naturally has more and more of its nourishing matter
sucked out of it; until, by the time it reaches the last loop of the
twenty feet of the small intestine, it has lost over two-thirds of its
food value.

The Final Stage--the Journey through the Large Intestine. From the
small intestine what remains of the food-pulp is poured into the last
section of the food tube, which enlarges to from two to three inches in
diameter. It is known as the large intestine, or large bowel. This
section is only about five feet long. The first three-fourths of it is
called the _colon_; the last or lowest quarter, the rectum, the
discharge-pipe of the food tube. The principal use of the colon is to
suck out the remaining traces of nourishing matter from the food and the
water in which it is dissolved, thus gradually drying the food-pulp down
to a solid or pasty form, in which condition it collects in a large "S"
shaped loop of the bowel just above the rectum, until discharged.

The Waste Materials. By the time that the remains of the food-pulp
have reached the middle of the large intestine, they have lost all their
nutritive value and most of their water. All the way down from the upper
part of the small intestine they have been receiving solid waste
substances poured out by the glands of the intestines; indeed, the bulk
of the feces is made up of these intestinal secretions, not, as is
generally supposed, of the undigested remains of the food. Ninety-five
per cent of our food is absorbed; the body-engine burns up its fuel very
clean. The next largest part of the feces is bacteria, or germs; and the
third and smallest, the indigestible fragments and remainders of food,
such as vegetable fibres, bran, fruit skins, pits, seeds, etc. Hence the
feces are not only worthless from a food point of view, but full of all
sorts of possibilities for harm; and the principal interest of the body
lies in getting rid of them as promptly and regularly as possible.

It can easily be seen how important it is that a habit should be formed,
which nothing should be allowed to break, of promptly and regularly
getting rid of these waste materials. For most persons, once in
twenty-four hours is normal; for some, twice or even three times in the
day. Whatever interval is natural, it should be attended to, beginning
at a fixed hour every morning.

Constipation, and how to Prevent It. Constipation should not be
treated by the all too common method of swallowing salts, which will
cause a flood of watery matters to be poured through the food tube and
sluice it clean of both poisons and melting food at the same time,
leaving it in an exhausted and disturbed condition afterwards; nor by
taking some irritating vegetable cathartic, generally in the form of
pills, which sets up a violent action of the muscles of the food tube,
driving its contents through at headlong speed; nor by washing out the
lower two or three feet of the bowel with injections of water; although
any or all of these may be resorted to occasionally for temporary
relief. A very large portion of the food eaten is sucked out of the food
tube into the blood vessels, passes through a large area of the body,
and is poured out again as waste through the glands of the lining of the
lower third of the bowel. Constipation, therefore, is caused by
disturbances which interfere with these processes _all over the body_,
not only in the stomach and bowels. Its only real and permanent cure is
through exercise in the open air, sleep, and proper ventilation of
bedrooms, with abundance of nourishing food, including plenty of green
vegetables and fresh fruits.

The Appendix and Appendicitis. The beginning of the large bowel, where
the small bowel empties into it, is the largest part of it, and forms a
curious pouch called the _cecum_, or "blind" pouch. From one side of
this projects a little wormlike tube, twisted and coiled upon itself,
from three to six inches long and of about the size of a slate pencil.
This is the famous _appendix vermiformis_ (meaning, "wormlike tag"),
which is such a frequent source of trouble. It is the shrunken and
shriveled remains of a large pouch of the intestine which once opened
into the cecum, and was used originally as a sort of second stomach for
delaying and digesting the remains of the food. The reason why it gives
rise to so much trouble is that it is so small--scarcely larger than
will admit a knitting-needle--and so twisted upon itself that germs or
other poisonous substances swallowed with the food may get into it,
start a swelling or inflammation, get trapped in there by the closing of
the narrow mouth of the tube, and form an abscess, which leaks through,
or bursts into, the cavity of the body, called the _peritoneum_. This
causes a very serious and often fatal blood poisoning.

Fortunately, _appendicitis_, or inflammation of the appendix, is not a
very common disease, causing only one in one hundred of all deaths that
occur; and these are mostly cases that were not treated promptly. Yet,
if you have a severe, constant pain, rather low down in the right-hand
corner of your abdomen, and if, when you press your hand firmly down in
that corner, it hurts, or you feel a lump, it is decidedly safest to
call a doctor and let him see what the condition really is, and advise
you what to do.


FOOTNOTES:

[1] The term _salts_ includes, as will be explained later, a large
number of substances, like ordinary table salt, baking soda, and the
laxative salts.

[2] There are three pairs of these: one just below the ears and behind
the angles of the jaw, known as the _parotid_; one under the middle of
the lower jaw known as the _submaxillary_; and a small pair just under
the tip of the tongue, called the _sublingual_. These glands have grown
up from the very simplest of beginnings. At first there was just a
little pocketing or pouching down of the mucous lining, like the finger
of a glove; then a couple of smaller hollow fingers budded off from the
bottom of the first finger; then four smaller fingers from the bottom of
these; and so on, until a regular little hollow tree or shrub of these
tiny tubes was built up, all discharging through the original hollow
stem, which has now become what we call the _duct_ of the gland. Every
secreting gland in the body--the stomach (or peptic) glands, the
salivary glands, the liver, the pancreas--is built up upon this simple
plan. The saliva and the juice of the pancreas and that of the liver
(bile) are alkaline, as are also the blood and most juices of the body.
The stomach juice is acid, as also are the urine and the perspiration.

[3] It is wonderfully elastic and constantly changing in size,
contracting till it will scarcely hold a quart when empty, and
expanding, as food or drink is put into it, until it will easily hold
two quarts, or even a gallon or more when greatly distended, as by gas.

[4] If you take some pepsin which has been extracted from the stomach of
a pig or a calf, melt it in water in a glass tube, then drop one or two
little pieces of meat or hard-boiled white of egg into it, you can see
them slowly melt away like sugar in a cup of coffee. If you add a few
drops of hydrochloric acid, the melting will go on much faster; and if
you warm up the tube to about the heat of the body, it will proceed
faster still. So nature knew just what she was doing when she provided
pepsin and acid and warmth in the stomach.

[5] The liver and the bile are more fully described in chapter XVII.

[6] Tiny plant cells, known also as _germs_, which cause fermentation,
decay, and many diseases.



CHAPTER III

THE FOOD-FUEL OF THE BODY-ENGINE


WHAT KIND OF FOOD SHOULD WE EAT?

Generally speaking, our Appetites will Guide us. Our whole body is an
ingenious machine for catching food, digesting it, and turning the
energy, or fuel value, which it contains, into life, movement, and
growth.

Naturally, two things follow: first, that the kind and amount of food
which we eat is of great importance; and second, that from the millions
of years of experience that the human body has had in trying all sorts
of foods, it has adapted itself to certain kinds of food and developed
certain likes and dislikes which we call _appetites_. Those who happened
to like unhealthy and unwholesome foods were poisoned, or grew thin and
weak and died off, so that we are descended solely from people who had
sound and reliable food appetites; and, in the main, what our instincts
and appetites tell us about food is to be depended upon.

The main questions which we have to consider are: How much of the
different kinds of food it is best for us to eat, and in what
proportions we should use them. Both men and animals, since the world
began, have been trying to eat and digest almost everything that they
could get into their mouths. And what we now like and prepare as foods
are the things which have stood the test, and proved themselves able to
yield strength and nourishment to the body. So practically every food
that comes upon our tables has some kind of real food value, or it
wouldn't appear there.

The most careful study and analysis have shown that almost every known
food has some peculiar advantage, such as digestibility, or cheapness,
or pleasant taste as flavoring for other more nutritious, but less
interesting, foods. But some foods have much higher degrees of
nutritiousness or digestibility or wholesomeness than others; so that
our problem is to pick out from a number of foods that "taste good" to
us, those which are the most nutritious, the most digestible, and the
most wholesome, and to see that we get plenty of them. It is not that
certain foods, or classes of food, are "good," and should be eaten to
the exclusion of all others; nor that certain foods, or classes of food,
are "bad," and should be excluded from our tables entirely; but that
certain foods are more nutritious, or more wholesome, than others; and
that it is best to see that we get plenty of the former before indulging
our appetites upon the latter.

Beware of Tainted Food. The most dangerous fault that any food can
have is that it shall be tainted, or spoiled, or smell bad. Spoiling, or
tainting, means that the food has become infected by some germs of
putrefaction, generally _bacteria_ or _moulds_ (see chapter XXVI). It is
the poisons--called _ptomaines_, or _toxins_--produced by these germs
which cause the serious disturbances in the stomach, and not either the
amount or the kind of food itself. Even a regular "gorge" upon early
apples or watermelon or cake or ice cream will not give you half so bad,
nor so dangerous, colic as one little piece of tainted meat or fish or
egg, or one cupful of dirty milk, or a single helping of cabbage or
tomatoes that have begun to spoil, or of jam made out of spoiled berries
or other fruit. This spoiling can be prevented by strict cleanliness in
handling foods, especially milk, meat, and fruit; by keeping foods
screened from dust and flies; and by keeping them cool with ice in
summer time, thus checking the growth of these "spoiling" germs. The
refrigerator in the kitchen prevents colic or diarrhea, ice in hot
weather is one of the necessaries of life. Smell every piece of food to
be eaten, in the kitchen before it is cooked, if possible; but if not,
at the table avoid everything that has an unpleasant odor, or tastes
queer, and you will avoid two-thirds of the colic, diarrhea, and bilious
attacks which are so often supposed to be due to eating too much.

[Illustration: A CHEAP HOME-MADE ICE BOX

This should not cost over twenty-five cents. The sketch shows an
ordinary soap box; inside is a tin pail surrounded by a sheet of tin, so
that there is a circular air space between the pail and the sheet of
tin. Sawdust is packed around the tin, and cracked ice (two cents a day)
fills the tin pail around the milk bottle. The newspapers inside the
cover help to keep out the warmth of the outside air. Recommended by the
Boards of Health of New York City and Chicago.]

Variety in Food is Necessary. Man has always lived on, and apparently
required, a great variety of foods, animal and vegetable--fish and
flesh, nuts, fruit, grains, fat, sugar, and vegetables. Indeed, it was
probably because man could live on anything and everything that he was
able to survive in famines and to get so far ahead of all other sorts of
animals.

We still need a great variety of different sorts of food in order to
keep our health; so our tendency to become tired of a certain food,
after we have had it over and over and over again, for breakfast,
dinner, and supper, is a sound and healthy one. There is no "best food";
nor is there any one food on which we can live and work, as an engine
will work all its "life" on one kind of coal, wood, or oil. No one kind
of food contains all the stuffs that our body is made of and needs, in
exactly the right proportions. It takes a dozen or more different kinds
of food to supply these, and the body picks out what it wants, and
throws away the remainder.

Even the best and most nutritious and digestible single food, like meat,
or bread and butter, or sugar, is not sufficient by itself; nor will it
do for every meal in the day, or every day in the week. We must eat
other things with it; and we must from time to time change it for
something which may even be not quite so nutritious, in order to give
our body the opportunity to select from a great variety of foods the
particular things which its wonderful instincts and skill can use to
build it up and keep it healthy. This is why every grocery store, every
butcher shop, every fish market, and every confectioner's shows such a
great variety of different kinds of foods put up and prepared in all
sorts of ways. Although nearly two-thirds of the actual fuel which we
put into our body-boilers is in the form of a dozen or fifteen great
staple foods, like bread, meat, butter, sugar, eggs, milk, potatoes, and
fish, yet all the lighter foods, also, are needed for perfect health.

It is possible, by careful selection, and by taking a great deal of
trouble, to supply all the elements of the body from animal foods alone,
or from vegetable foods alone. But practically, it has everywhere, and
in all ages, been found that the best and most healthful diet is a
proper combination of animal and vegetable foods. Our starches, for
instance, which furnish most of our fuel,--though they give us
_comparatively little_ to _build up_, or _repair_, the body with,--are
found, as we have seen, in the vegetable kingdom, in grains and fruits;
while most of our proteins and fats, which chiefly give us the materials
with which to build up, or repair, the body, are found in the animal
kingdom. There is no advantage whatever in trying to exclude either
animal food or vegetable food from our dietary. Both animal and
vegetable foods are wholesome in their proper place, and their proper
place is on the table together.

Those nations which live solely, or even chiefly, upon one or two kinds
of staple foods, such as rice, potatoes, corn-meal, or yams, do so
solely because they are too poor to afford other kinds of food, or too
lazy, or too uncivilized, to get them; and instead of being healthier
and longer-lived than civilized races, they are much more subject to
disease and live only about half as long.


THE THREE GREAT CLASSES OF FOOD-FUEL

Food is Fuel. Now what is the chief quality which makes one kind of
food preferable to another? As our body machine runs entirely upon the
energy or "strength" which it gets out of its food, _a good food must
have plenty of fuel value_; that is to say, it must be capable of
burning and giving off heat and steaming-power. Other things being
equal, the more it has of this fuel value, the more desirable and
valuable it will be as a food.

From this point of view, foods may be roughly classified, after the
fashion of the materials needed to build a fire in a grate or stove, as
Coal foods, Kindling foods, and Paper foods. Although coal, kindling,
and paper are of very different fuel values, they are all necessary to
start the fire in the grate and to keep it burning properly. Moreover,
any one of them would keep a fire going alone, after a fashion, provided
that you had a grate or furnace large enough to burn it in, and could
shovel it in fast enough; and the same is true, to a certain degree, of
the foods in the body.

How to Judge the Fuel Value of Foods. One of the best ways of roughly
determining whether a given food belongs in the Coal, the Kindling, or
the Paper class, is to take a handful or spoonful of it, dry it
thoroughly by some means,--evaporating, or driving off the water,--and
then throw what is left into a fire and see how it will burn. A piece of
beef, for instance, would shrink a good deal in drying; but about
one-third of it would be left, and this dried beef would burn quite
briskly and would last for some time in the fire. A piece of bread of
the same size would not shrink so much, but would lose about the same
proportion of its weight; and it also would burn with a clear, hot
flame, though not quite so long as the beef. A piece of fat of the same
size would shrink very little in drying and would burn with a bright,
hot flame, nearly twice as long as either the beef or the bread. These
would all be classed as Coal foods.

Then if we were to dry a slice of apple, it would shrink down into a
little leathery shaving; and this, when thrown into the fire, would burn
with a smudgy kind of flame, give off very little heat, and soon
smoulder away. A piece of raw potato of the same size would shrink even
more, but would give a hotter and cleaner flame. A leaf of cabbage, or a
piece of beet-root, or four or five large strawberries would shrivel
away in the drying almost to nothing and, if thoroughly dried, would
disappear in a flash when thrown on the fire. These, then, except the
potato, we should regard as Kindling foods.

But it would take a large handful of lettuce leaves, or a big cup of
beef-tea, or a good-sized bowl of soup, or a big cucumber, or a gallon
of tea or coffee, to leave sufficient solid remains when completely
dried, to make more than a flash when thrown into the fire. These, then,
are Paper foods, with little fuel value.



CHAPTER IV

THE COAL FOODS


Kinds of Coal Foods. There are many different kinds of Coal foods,
such as pork, mutton, beef, bread, corn-cakes, bacon, potatoes, rice,
sugar, cheese, butter, and so on. But when you come to look at them more
closely, and to take them to pieces, or, as we say, analyze them, you
will see that they all fall into three different kinds or classes: (1)
_Proteins_, such as meat, milk, fish, eggs, cheese, etc. (2)
_Starch-sugars_ (_carbohydrates_), found pure as laundry starch and as
white sugar; also found, as starch, making up the bulk of wheat and
other grains, and of potatoes, rice, peas; also found, as sugar, in
honey, beet-roots, sugar cane, and the sap of maple trees. (3) _Fats_,
found in fat meats, butter, oil, nuts, beeswax, etc.

This whole class of Coal foods can be recognized by the fact that
usually some one of them will form the staple, or main dish, of almost
any regular meal, which is generally a combination of all three
classes--a protein in the shape of meat; a starch-sugar in the form of
bread, potatoes, or rice; and a fat in the form of butter in northern
climates, or of olive oil in the tropics.


PROTEINS, OR "MEATS"

Proteins, the "First Foods." There are proteins, or "meats," both
animal and vegetable; and no one can support life without protein in
some form. This is because proteins alone contain sufficient amounts of
the great element called _nitrogen_, which forms a large part of every
portion of our bodies. This is why they are called proteins, meaning
"first foods," or most necessary foods. Whatever we may live on in later
life, we all began on a diet of liquid meat (milk), and could have
survived and grown up on nothing else.

Composition of Proteins. Nearly all our meats are the muscle of
different sorts of animals, made of a soft, reddish, animal pulp called
_myosin_; the other principal proteins being white of egg, curd of milk,
and a gummy, whitish-gray substance called _gluten_, found in wheat
flour. This gluten is the stuff that makes the paste and dough of wheat
flour sticky, so that you can paste things together with it; while that
made from corn meal or oatmeal will fall to pieces when you take it up.
The jelly-like or pulp-like myosin in meat is held together by strings
or threads of tough, fibrous stuff; and the more there is of this
fibrous material in a particular piece or "cut," of meat, the tougher
and less juicy it is. The thick, soft muscles, which lie close under the
backbone in the small of the back, in all animals, have less of this
tough and indigestible fibrous stuff in them, and cuts across them give
us the well-known porter-house, sirloin, or tenderloin steaks, and the
best and tenderest mutton and pork chops.

Fuel Value of Meats. Weight for weight, most of the butcher's
meats--beef, pork, mutton, and veal--have about the same food value,
differing chiefly in the amount of fat that is mixed in with their
fibres, and in certain flavoring substances, which give them, when
roasted, or broiled, their special flavors. The different flavors are
not of any practical importance, except in the case of mutton, which
some people dislike and therefore can take only occasionally, and in
small amounts.

The amount of fat in meats, however, is more important; and depends
largely upon how well the animal has been fed. There is usually the least
amount of fat in mutton, more in beef, and by far the greatest amount
in pork. This fat adds to the fuel value of meat, but makes it a little
slower of digestion; and its presence in large amounts in pork, together
with the fact that it lies, not only in layers and streaks, but also
mixed in between the fibres of the lean as well has caused this meat to
be regarded as richer and more difficult of digestion than either beef
or mutton. This, however is not quite fair to the pork, because smaller
amounts of it will satisfy the appetite and furnish the body with
sufficient fuel and nutrition. If it be eaten in moderate amounts and
thoroughly chewed, it is a wholesome and valuable food.

Veal is slightly less digestible than beef or mutton, on account of the
amount of slippery _gelatin_ in and among its fibres; but if well cooked
and well chewed, it is wholesome.

The other meats--chicken, duck, and other poultry, game, etc.--are of
much less nutritive value than either beef, pork, or mutton, partly
because of the large amount of waste in them, in the form of bones,
skin, and tendons, and partly from the greater amount of water in them.
But their flavors make them an agreeable change from the staple meats.

Fish belongs in the same class as poultry and consists of the same
muscle substance, but, as you can readily see by the way that it shrinks
when dried, contains far more water and has less fuel value. Some of the
richer and more solid fishes, like salmon, halibut, and mackerel,
contain, in addition to their protein, considerable amounts of fat and,
when dried or cured, give a rather high fuel value at moderate cost. But
the peculiar flavor of fish, its large percentage of water, and the
special make-up of its protein, give it a very low food value, and
render it, on the whole, undesirable as a permanent staple food. Races
and classes who live on it as their chief meat-food are not so vigorous
or so healthy as those who eat also the flesh of animals. As a rule, it
is not best to use fish as the main dish of a meal oftener than two or
three times a week.

[Illustration: A BABY-MILK STATION

The milk sold here for a few cents is perfectly clean and pure, and is
variously adapted to the needs of different babies. In many cities such
milk stations have been established.]

Milk. Milk is an interesting food of great value because it combines
in itself all three of the great classes of food-stuffs,--protein,
starch-sugar, and fat. Its protein is a substance called _casein_, which
forms the bulk of curds, and which, when dried and salted, is called
cheese. The fat is present in little tiny globules which give milk its
whitish or milky color. When milk is allowed to stand, these globules of
fat, being lighter, float up to the top and form a layer which is called
cream. When this cream is skimmed off and put into a churn, and shaken
or beaten violently so as to break the little film with which each of
these droplets is coated, they run together and form a yellow mass which
we call butter. In addition to the curd and fat, milk contains also
sugar, called milk-sugar (_lactose_), which gives it its sweetish
taste. And as a considerable part of the casein, or curd, is composed
of another starch-like body, or animal starch, this makes milk quite
rich in the starch-sugar group of food-stuffs.

All these substances, of course, in milk are dissolved in a large amount
of water, so that when milk is evaporated, or dried, it shrinks down to
barely one-sixth of its former bulk. It is, in fact, a liquid meat,
starch-sugar, and fat in one; and that is why babies are able to live
and thrive on it alone for the first six months of their lives. It is
also a very valuable food for older children, though, naturally, it is
not "strong" enough and needs to be combined with bread, puddings, meat,
and fat.

Soups and Broths. Soups, broths, and beef teas are water in which
meats, bones, and other scraps have been boiled. They are about
ninety-eight per cent water, and contain nothing of the meat or bones
except some of their flavor, and a little gelatin. They have little or
no nutritive or fuel value, and are really Paper foods, useful solely as
stimulants to appetite and digestion, enabling us to swallow with relish
large pieces of bread or crackers, or the potatoes, rice, pea-meal,
cheese, or other real foods with which they are thickened. Their food
value has been greatly exaggerated, and many an unfortunate invalid has
literally starved on them. Ninety-five per cent of the food value of the
meat and bones, out of which soups are made, remains at the bottom of
the pot, after the soup has been poured off. The commercial extracts of
meat are little better than frauds, for they contain practically nothing
but flavoring matters.

Protein in Vegetables. Several vegetable substances contain
considerable amounts of protein. One of these has already been
mentioned,--the gluten or sticky part of bread,--and this is what has
given wheat its well-deserved reputation as the best of all grains out
of which to make flour for human food.

There is also another vegetable protein, called _legumin_, found in
quite large amounts in dried beans and peas; but this is of limited food
value, first because it is difficult of digestion, and secondly because
with it, in dried peas and beans, are found a pungent oil and a bitter
substance, which give them their peculiar strong flavor, both of which
are quite irritating to the average person's digestion. So distressing
and disturbing are these flavoring substances to the civilized stomach,
that, after thousands of attempts to use them more largely, it has been
found that a full meal of beans once or twice a week is all that the
comfort and health of the body will stand. This is really a great pity,
for beans and peas are both nourishing and cheap. Nuts also contain much
protein, but are both difficult of digestion and expensive.

Virtues and Drawbacks of Meats. Taken all together, the proteins, or
meats, are the most nutritious and wholesome single class of foods.
Their chief drawback is their expense, which, in proportion to their
fuel value, is greater than that of the starches. Then, on account of
their attractiveness, they may be eaten at times in too large amounts.
They are also somewhat more difficult to keep and preserve than are
either the starches or the fats. The old idea that, when burned up in
the body, they give rise to waste products, which are either more
poisonous or more difficult to get rid of than those of vegetable foods,
is now regarded as having no sufficient foundation. Neither is the
common belief that meats cause _gout_ well founded.

The greatest danger connected with meats is that they may become
tainted, or begin to spoil, or decay, before they are used.
Unfortunately, the ingenious cook has invented a great many ways of
smothering, or disguising, the well-marked bad taste of decayed, or
spoiled, meat by spices, onions, and savory herbs. So, as a general
thing, the safest plan, especially when traveling or living away from
home, is to avoid as far as possible hashes, stews, and other "made"
dishes containing meat. This is one of the ways in which spices and
onions have got such a bad reputation for "heating the blood," or
upsetting the stomach, when it is really the decayed meat which they are
used to disguise that causes the trouble. Highly spiced dishes rob you
of the services of your best guide to the wholesomeness of food--your
nose.

Risks of Dirty Milk. The risks from tainting or spoiling are
particularly great in the case of milk, partly on account of the dusty
and otherwise uncleanly barns and sheds in which it is often handled and
kept, and from which it is loaded with a heavy crop of bacteria at the
very start; and partly because the same delicateness which makes it so
easily digestible for babies, makes it equally easy for germs and
bacteria to grow in it and spoil, or sour, it. You all know how
disagreeable the taste of spoiled milk is; and it is as dangerous as it
is disagreeable. A very large share of the illnesses of babies and young
children, particularly the diseases of stomach and bowels which are so
common in hot weather, are due to the use of spoiled, dirty milk.

[Illustration: CLEAN, DRY SUNNING YARDS AT A MODEL DAIRY]

There is one sure preventive for all these dangers, and that is
_absolute cleanliness_ from cow to customer. All the changes that take
place in milk are caused by germs of various sorts, usually floating in
the air, that get into it. If the milk is so handled and protected, from
cow to breakfast table, that these germs cannot get into it, it will
remain sweet for several days.

[Illustration: Currying the cow

Washing the udders

CLEANLINESS BEFORE MILKING]

Boards of Health all over the world now are insisting upon absolutely
clean barns and cleanly methods of handling, shipping, and selling milk.
In most of our large cities, milk-men are not allowed to sell milk
without a license; and this license is granted only after a thorough
examination of their cattle, barns, and milk-houses. These clean methods
of handling milk cost very little; they take only time and pains.

Nowadays, in the best dairies, it is required that the barns or sheds in
which cows are milked shall have tight walls and roofs and good
flooring; that the walls and roofs shall be kept white-washed; and the
floor be cleaned and washed before each milking, so that no germs from
dust or manure can float into the milk. Then the cows are kept in a
clean pasture, or dry, graveled yard, instead of a muddy barnyard; and
are either brushed, or washed down with a hose before each milking, so
that no dust or dirt will fall from them into the milk. The men who are
to milk wash their hands thoroughly with soap and water, and put on
clean white canvas or cotton overalls, jackets, and caps. As soon as the
milk has been drawn into the pails, it is carried into the milk-room and
cooled down to a temperature of about forty-two degrees--that is, about
ten degrees above freezing point. This is to prevent the growth of such
few germs as may have got into it, in spite of all the care that has
been taken. Then the milk is drawn into bottles; and the bottles are
tightly capped by a water-proof pasteboard disc, or cover, which is not
removed until the milk is brought into the house and poured into the
glass, or cup, for use.

[Illustration: THE MILKING HOUR AT A MODEL DAIRY]

Milk handled like this costs from two to four cents a quart more to
produce than when drawn from a cow smeared with manure, in a dark,
dirty, strong-smelling barn, by a milker with greasy clothing and dirty
hands; and then ladled out into pitchers in the open street, giving all
the dust and flies that happen to be in the neighborhood a chance to get
into it! But it is doubly worth the extra price, because, besides
escaping stomach and bowel troubles, you get more cream and higher food
value. There is one-third more food value in clean milk than in dirty
milk, because its casein and sugar have not been spoiled and eaten by
swarms of bacteria. How great a difference careful cleanliness of this
sort can make in milk is shown by the difference in the number of
bacteria that the two kinds of milk contain. Ordinary milk bought from
the wagons in the open street, or from the cans in the stores, will
contain anywhere from _a million_ to a _million and a half_ bacteria to
the cubic centimeter (about fifteen drops); and samples have actually
been taken and counted, which showed _five_ and _six millions_.

[Illustration: MILKING BY VACUUM PROCESS

This method is used in many large dairies to avoid handling the udders
or the milk. Its chief drawback is that the long tubes are very
difficult to keep clean.]

Such a splendid food for germs is milk, and so rapidly do they grow in
it, that dirty milk will actually contain more of them to the cubic inch
than sewage, as it flows in the sewers. Now see what a difference a
little cleanliness will make! Good, clean, carefully handled milk,
instead of having a million, or a million and a half, bacteria, will
have less than ten thousand; and very clean milk may contain as low as
three or four hundred, and these of harmless sorts. The whole gospel of
the care of milk can be summed up in two sentences: (1) _Keep dirt and
germs out of the milk._ (2) _Keep the milk cool._

[Illustration: WASHING THE BOTTLES AT A MODEL DAIRY

The inside of the bottle is thoroughly cleansed by the revolving brush.]

Besides the germs of the summer diseases of children, which kill more
than fifty thousand babies every year in the United States, dirty milk
may also contain typhoid germs and consumption germs. The typhoid germs
do not come from the body of the cow, but get into the milk through its
being handled by people who have, or have just recovered from, typhoid,
or who are nursing patients sick with typhoid, and who have not properly
washed their hands; or from washing the cans, or from watering the milk
with water taken from a well or stream infected with typhoid. It is
estimated that about one-eighth of all the half million cases of
typhoid that occur in the United States every year are carried through
dirty milk.

[Illustration: BACTERIA IN CLEAN AND IN DIRTY MILK]

[Illustration: DANGER FROM DIPPED MILK

The milk that spills or spatters over the hand drips back into the can
and may seriously infect the main supply.]

The germs of consumption, or _tuberculosis_, that are present in milk
may come from a cow that has the disease; or from consumptive human
beings who handle the milk; or from the dust of streets or houses--which
often contains disease germs. The latter sources are far the more
dangerous; for, as is now pretty generally agreed, although the
tuberculosis of cattle can be given to human beings, it is not very
actively dangerous to them; and probably not more than three or four per
cent of all cases of tuberculosis come from this source. The idea,
however, of allowing the milk of cows diseased from any cause to be used
for human food, is not to be tolerated for a moment. All good dairymen
and energetic Boards of Health now insist upon dairy herds being tested
for tuberculosis, and the killing, or weeding out, of all cows that
show they have the disease.

[Illustration: MILK INSPECTION AT THE RETAIL STORE

It is well to have the quality and purity of the milk tested just before
it goes to the consumer, but it is far more important that it should be
examined by State Inspectors at the dairy farms.]

Cheese. Cheese is the curd of milk squeezed dry of its liquid
(_whey_), salted, pressed into a mould, and allowed to ferment slowly,
or "ripen," in which process a considerable part of its casein is turned
into fat. It is a cheap, concentrated, and very nutritious food, and in
small amounts is quite appetizing. But unfortunately, the acids and
extracts which have formed in the process of fermentation and ripening
are so irritating to the stomach, that it can usually be eaten only in
small amounts, without upsetting the digestion. Its chief value is as a
relish with bread, crackers, potatoes, or macaroni. In moderate amounts,
it is not only appetizing and digestible, but will assist in the
digestion of other foods; hence the custom of eating a small piece of
"ripe" cheese at the end of a heavy meal.



CHAPTER V

THE COAL FOODS (_Continued_)


STARCHES

Sources of Starch. The starches are valuable and wholesome foods. They
form the largest part, both in bulk and in fuel value, of our diet, and
have done so ever since man learned how to cultivate the soil and grow
crops of grain. The reason is clear: One acre of good land will grow
from ten to fifteen times the amount of food in the form of starch in
grains or roots, as of meat in the shape of cattle or sheep.
Consequently, starch is far cheaper, and this is its great advantage.

Our chief supply of starch is obtained from the seed of certain most
useful grasses, which we call wheat, oats, barley, rye, rice, and corn,
and from the so-called "roots" of the potato. Potatoes are really
underground buds packed with starch, and their proper name is tubers.

Starch, when pure or extracted, is a soft, white powder, which you have
often seen as cornstarch, or laundry starch. As found in grains, it is
mixed with a certain amount of vegetable fibre, covered with husks, or
skin, and has the little germ or budlet of the coming plant inside it.
It has been manufactured and laid down by little cells inside their own
bodies, which make up the grains; so that each particular grain of
starch is surrounded by a delicate husk--the wall of the cell that made
it. This means that grains and other starch foods have to be prepared
for eating by grinding and cooking. The grinding crushes the grains into
a powder so that the starch can be sifted out from the husks and
coating of the grain, and the fibres which hold it together; and the
cooking causes the tiny starch grain to swell and burst the cell wall,
or bag, which surrounds it.

Starches as Fuel. The starches contain no nitrogen except a mere trace
in the framework of the grains or roots they grow in. They burn very
clean; that is, almost the whole of them is turned into carbon dioxid
gas and water.[7]

This burning quality makes the starches a capital fuel both in the body
and out of it. You may have heard of how settlers out on the prairies,
who were a long way from a railroad and had no wood or coal, but plenty
of corn, would fill their coal scuttles with corn and burn that in their
stoves; and a very bright, hot fire it made.

One of the chief weaknesses of the starches is that they burn up too
fast, so that you get hungry again much more quickly after a meal made
entirely upon starchy foods, like bread, crackers, potatoes, or rice,
than you do after one which has contained some meat, particularly fat,
which burns and digests more slowly.

How Starch is Changed into Sugar. As we learned in chapter II, the
starches can be digested only after they are turned into sugars in the
body. If you put salt with sugar or starch, although it will mix
perfectly and give its taste to the mixture, neither the salt nor the
starch nor the sugar will have changed at all, but will remain exactly
as it was in the first place, except for being mixed with the other
substances. But if you were to pour water containing an acid over the
starch, and then boil it for a little time, your starch would entirely
disappear, and something quite different take its place. This, when you
tasted it, you would find was sweet; and, when the water was boiled off,
it would turn out to be a sugar called _glucose_. Again, if you should
pour a strong acid over sawdust, it would "char" it, or change it into
another substance, _carbon_. In both of these cases--that of the starch
and of the sawdust--what we call a _chemical change_ would have taken
place between the acid and the starch, and between the strong acid and
the sawdust.

If we looked into the matter more closely, we should find that what has
happened is that the starch and the sawdust have changed into quite
different substances. Starches are _insoluble_ in water; that is,
although they can be softened and changed into a jelly-like substance,
they cannot be completely melted, or dissolved, like salt or sugar.
Sugar, on the other hand, is a perfectly _soluble_ or "meltable"
substance, and can soak or penetrate through any membrane or substance
in the body. Therefore all the starches which we eat--bread, biscuit,
potato, etc.--have to be acted upon by the ferments of our saliva and
our pancreatic juice, and turned into sugar, called glucose, which can
be easily poured into the blood and carried wherever it is needed, all
over the body. Thus we see what a close relation there is between starch
and sugar, and why the group we are studying is sometimes called the
starch-sugars.

Wheat--our Most Valuable Starch Food. The principal forms in which
starch comes upon our tables are meals and flours, and the various
breads, cakes, mushes, and puddings made out of these. Far the most
valuable and important of all is wheat flour, because this grain
contains, as we have seen, not only starch, but a considerable amount of
vegetable "meat," or gluten, which is easily digested in the stomach.
This gluten, however, carries with it one disadvantage--its stickiness,
or gumminess. The dough or paste made by mixing wheat flour with water
is heavy and wet, or, as we say, "soggy," as compared with that made by
mixing oatmeal or corn meal or rice flour with water. If it is baked in
this form, it makes a well-flavored, but rather tough, leathery sort of
crust; so those races that use no _leavening_, or rising-stuff, in their
wheat bread, roll it out into very thin sheets and bake it on griddles
or hot stones.

Most races that have wheat, however, have hit upon a plan for overcoming
this heaviness and sogginess, and that is the rather ingenious one of
mixing some substance in the dough which will give off bubbles of a gas,
_carbon dioxid_, and cause it to puff up and become spongy and light,
or, as we say, "full of air." This is what gives bread its well-known
spongy or porous texture; but the tiny cells and holes in it are filled,
not with air, but with carbon dioxid gas.

Making Bread with Yeast. There are several ways of lightening bread
with carbon dioxid gas. The oldest and commonest is by mixing in with
the flour and water a small amount of the frothy mass made by a germ, or
microbe, known as _yeast_ or the _yeast plant_. Then the dough is set
away in a warm place "to rise," which means that the busy little yeast
cells, eagerly attacking the rich supply of starchy food spread before
them, and encouraged by the heat and moisture, multiply by millions and
billions, and in the process of growing and multiplying, give off, like
all other living cells, the gas, carbon dioxid. This bubbles and spreads
all through the mass, the dough begins to rise, and finally swells right
above the pan or crock in which it was set. If it is allowed to stand
and rise too long, it becomes sour, because the yeast plant is forming,
at the same time, three other substances--alcohol, lactic acid (which
gives an acid taste to the bread), and vinegar. Usually they form in
such trifling amounts as to be quite unnoticeable. When the bread has
become light enough, it is put into the oven to be baked.

The baking serves the double purpose of cooking and thus making the
starch appetizing, and of killing the yeast germs so that they will
carry their fermentation no further. Bread that has not been thoroughly
baked, if it is kept too long, will turn sour, because some of the yeast
germs that have escaped will set to work again.

[Illustration: A THOROUGH BAKING, AND A VALUABLE CRUST

Note the cleanly way of handling the food.]

That part of the dough that lies on the surface of the loaf, and is
exposed to the direct heat of the oven has its starch changed into a
substance somewhat like sugar, known as _dextrin_, which, with the
slight burning of the carbon, gives the outside, or crust, of bread its
brownish color, its crispness, and its delicious taste. The crust is
really the most nourishing part of the loaf, as well as the part that
gives best exercise to the teeth.

Making Bread with Soda or Baking-Powders. Another method of giving
lightness to bread is by mixing an acid like sour milk and an alkali
like soda with the flour, and letting them effervesce[8] and give off
carbon dioxid. This is the mixture used in making the famous "soda
biscuit." Still another method is by the use of _baking-powders_, which
are made of a mixture of some cheap and harmless acid powder with an
alkaline powder--usually some form of soda. As long as these powders
are kept dry, they will not act upon each other; but as soon as they are
moistened in the dough, they begin to give off carbon dioxid gas.

[Illustration: AN IDEAL BAKERY WITH LIGHT, AIR, AND CLEANLINESS]

Neither sour milk and soda nor baking-powder will make as thoroughly
light and spongy and digestible bread as will yeast. If, however,
baking-powders are made of pure and harmless materials, used in proper
proportions so as just to neutralize each other, and thus leave no
excess of acid or alkali, and if the bread is baked very thoroughly,
they make a wholesome and nutritious bread, which has the advantage of
being very quickly and easily made. The chief objection to soda or
baking-powder bread is that, being often made in a hurry, the acid and
the alkali do not get thoroughly mixed all through the flour, and
consequently do not raise or lighten the dough properly, and the loaf or
biscuit is likely to be heavy and soggy in the centre. This heavy, soggy
stuff can be neither properly chewed in the mouth, nor mixed with the
digestive juices, and hence is difficult to digest. If, however, soda
biscuits are made thin and baked thoroughly so as to make them at least
half or two-thirds crust, they are perfectly digestible and wholesome,
and furnish a valuable and appetizing variety for our breakfast and
supper tables.

[Illustration: A BASEMENT BAKERY--A MENACE TO THE PUBLIC HEALTH

Disease germs multiply in the dark and damp of the basement. The
clothing hanging up in this bakery is a very probable source of
infection.]

Bran or Brown Bread. Flour made by grinding the wheat-berry without
sifting the husks, or bran, out of it is called "whole-wheat" meal; and
bread made from it is the brown "bran bread" or "Graham bread." It was
at one time supposed that because brown bread contained more nitrogen
than white bread, it was more wholesome and nutritious, but this has
been found to be a mistake, because the extra nitrogen in the brown
bread is in the form of husks and fibres, which the stomach is quite
unable to digest. Weight for weight, white bread is more nutritious than
brown. The husks and fibres, however, which will not digest, pass on
through the bowels unchanged and stir up the walls of the intestines to
contract; hence they are useful in small quantities in helping to keep
the bowels regular. But, like any other stimulus, too much of it will
irritate and disturb the digestion, and cause diarrhea; so that it is
not best to eat more than one-fifth of our total bread in the form of
brown bread. Dyspeptics who live on brown bread, or on so-called "health
foods," are simply feeding their dyspepsia.

"Breakfast Foods." The same defect exists in most of the breakfast
cereals which flood our tables and decorate our bill-boards. Some of
these are made of the waste of flouring mills, known as "middlings,"
"shorts," or bran, which were formerly used for cow-feed. The claims of
many of them are greatly exaggerated, for they contain no more
nourishment, or in no more digestible form, than the same weight of
bread; and they cost from two to five times as much. As they come on
our tables, they are nearly seven-eighths water; and the cream and sugar
taken with them are of higher food value than they are. They should
never be relied upon as the main part of a meal.

Corn Meal. Corn meal is one of the richest meals in nutritive value
for its price, as it has an abundance of starch and a small amount of
fat. It is, however, poor in nitrogen, and like the other grains, in
countries where wheat will grow, it is chiefly valuable for furnishing
cakes, fritters, and mushes to give variety to the diet, and help to
regulate the bowels.

Oatmeal. Oatmeal comes the nearest to wheat in the amount of nitrogen
or protein, but the digestible part of this is much smaller than in
wheat, and the indigestible portion is decidedly irritating to the
bowels, so that if used in excess of about one-fifth of our total
starch-food required, it is likely to upset the digestion.

Rye. Rye also contains a considerable amount of gluten, but is much
poorer in starch than wheat is; and the bread made out of its flour--the
so-called "black bread" of France and Germany--is dark, sticky, and
inclined to sour readily. Most of the "rye" bread sold in the shops, or
served on our tables, is made of wheat flour with a moderate mixture of
rye to give the sour taste.

Rice. Rice consists chiefly of starch, and makes nutritious puddings
or cakes, and may be used as a vegetable, in the place of potatoes, with
meat and fish. It is, however, lacking in flavor, and when properly
cooked, contains so much water that it has to be eaten in very large
amounts to furnish much nutrition.

Potatoes. The only important starchy food outside of the grains is
potatoes. These contain considerable amounts of starch, but mixed with a
good deal of cellulose, or vegetable fibre, and water, so that, like
rice, large amounts of them must be eaten in order to furnish a good
fuel supply. They, however, make a very necessary article of diet in
connection with meats, fish, and other vegetables.

As a rough illustration of the fuel value of the different starch foods,
it may be said that in order to get the amount of nourishment contained
in an ordinary pound loaf of wheat or white bread, it would be necessary
to eat about seven pounds of cooked rice, as it comes on the table;
about twelve pounds of boiled potatoes; or a bowl of oatmeal porridge
about the size of a wash-basin.


SUGARS

Where Sugar is Obtained. The other great member of the starch, or
carbohydrate, group of foods is sugar. This is a scarcer and more
expensive food than starch because, instead of being found in solid
masses in grains and roots like starch, it is scattered, very thinly,
through the fruits, stems, and roots of a hundred different plants,
seldom being present in greater amounts than two or three per cent. It
is, however, so valuable a food, with so high a fuel value, and is so
rapidly digested and absorbed, that man has always had a very keen
desire for it, or, as we say, a "sweet tooth," and has literally
searched the whole vegetable kingdom the world over to discover plants
from which it could be secured in larger amounts. During the last two
hundred years it has been obtained chiefly from two great sources: the
juicy stem of a tall, coarse reed, or cane, the sugar-cane, growing in
the tropics; and (within the last fifty years) the sweet juice of the
large root of a turnip-like plant, the beet. Another source of sugar, in
the earlier days of this country, was the juice or sap of the sugar
maple, which is still greatly relished as a luxury, chiefly in the form
of syrup.

Honey is nearly pure sugar together with certain ferments and flavoring
extracts, derived in part from the flowers from which it is gathered,
and in part from the stomach, or crop, of the bee.

The Food Value of Sugar. In the early days of its use, sugar, on
account of its expensiveness, was looked upon solely as a luxury, and
used sparingly--either as a flavoring for less attractive foods, or as a
special treat; and like most new foods, it was declared to be
unwholesome and dangerous. But sugar is now recognized as one of our
most useful and valuable foods. In fuel value, it is the equal, indeed
the superior, weight for weight, of starch; and as all starch has to be
changed into it before it can be used by the body, it is evident that
sugar is more easily digested and absorbed than starch, and furnishes
practically a ready-made fuel for our muscles.

How We should Use Sugar. The drawbacks of sugar are that, on account
of its exceedingly attractive taste, we may eat too much of it; and
that, because it is so satisfying, if we do eat too much of it either
between meals or at the beginning of meals, our appetites will be
"killed" before we have really eaten a sufficient supply of nourishing
food. But all we have to do to avoid these dangers is to use common
sense and a little self-control, without which any one of our appetites
may lead us into trouble.

On account of this satisfying property, sugar is best eaten at, or near,
the close of a meal; and taken at that time, there is no objection to
its use nearly pure, as in the form of sweet-meats, or good wholesome
candy. Its alleged injurious effects upon the teeth are largely
imaginary and no greater than those of the starchy foods. The teeth of
various tropical races which live almost entirely on sugar-cane during
certain seasons of the year are among the finest in the world; and any
danger may be entirely avoided by proper brushing and cleaning of the
teeth and gums after eating.

[Illustration: CANDY, LIKE OTHER FOODS, SHOULD BE CLEAN.

Candy sold on the street is always questionable. It should never be
bought from a cart or stand that is not covered with glass.]

If eaten in excess, sugar quickly gives rise to fermentation in the
stomach and bowels; but so do the starches and the fats, if
over-indulged in. Its real value as a food may be judged from the fact
that the German army has made it a part of its field ration in the shape
of cakes of chocolate, and that the United States Government buys pure
candy by the ton, for the use of its soldiers.


FOOTNOTES:

[7] On this account, they are often spoken of as carbohydrates, or
"carbon-water stuffs."

[8] See page 11.



CHAPTER VI

THE COAL FOODS (_Continued_)


ANIMAL FATS

The Digestibility of Fats. We have now come to the last group of the
real Coal foods, namely, the fats. Fats are the "hottest" and most
concentrated fuel that we possess, and might be described as the
"anthracites," or "hard coals" of our Coal foods. They are, also, as
might be expected from their "strength" or concentration, among the
slowest to digest of all our foods, so that, as a rule, we can eat them
only in very moderate amounts, seldom exceeding one-tenth to one-sixth
of our total food-fuel. It is not, however, quite correct to say that
fats are hard to digest, because, although from their solid, oily
character, they take a longer time to become digested and absorbed by
the body than most other foods, yet they are as perfectly and as
completely digested, with the healthy person, as any other kind of food.
Indeed, it is this slowness of digestion which gives them their
well-known staying-power as a food.

Their Place in our Diet. The wholesomeness of fats is well shown by
our appetite for them, which is very keen for small amounts of
them--witness, for instance, how quickly we notice and how keenly we
object to the absence of butter on our bread or potatoes. To have our
"bread well-buttered" is a well known expression for comfort and good
fortune; yet a very little excess will turn our enjoyment into disgust.
Fat, and particularly the cold fat of meat, "gags" us if we try to eat
too much of it.

Fortunately, most of these fat-foods are quite expensive, pound for
pound, and hence we are not often tempted to eat them in excess. Within
proper limits, then, fats are an exceedingly important and useful
food--a valuable member of the great family of Coal foods.

The Advantages of Fat as a Ration. The high fuel value and the small
bulk of fats give them a very great practical advantage whenever
supplies of food have to be carried for long distances, or for
considerable lengths of time, as in sea voyages and hunting and
exploring trips. So that in provisioning ships for a long voyage, or
fitting out an expedition for the Arctic regions, fats, in the shape of
bacon or pork, pemmican,[9] or the richer dried fishes, like salmon,
mackerel, and herring, will be found to play an important part. Fats
also have the great advantage, like the starches, of keeping well for
long periods, especially after they have been melted and sterilized by
boiling, or "rendering," as in the case of lard, or have had moderate
amounts of salt added to them, as in butter.

If you were obliged to pick out a ration which would keep you alive,
give you working power, and fit into the smallest possible bulk, you
would take a protein, a sugar, and a fat in about equal amounts. Indeed,
the German emergency field-ration, intended to keep soldiers in the
field for three or four days without their baggage-wagons, or
cook-trains, is made up of bacon, pea-meal, and chocolate. A small
packet of these, which weighs only a little over two pounds, and which
can be slipped into the knapsack, will, with plenty of water, keep a
soldier in fighting trim for three days.

Butter. The most useful and wholesome single fat is the one which is
in greatest demand--butter. This, as we have seen, is the churned and
concentrated fat of milk, to which a little salt has been added to keep
the milk-acid (_lactic acid_) which cannot be entirely washed out of it,
from "turning it sour" or rancid. The rancid, offensive taste of bad or
"strong" butter is due to the formation of another acid call _butyric_
("buttery") _acid_.

Butter is the best and most wholesome of our common fats because it is
most easily digested, most readily absorbed, and least likely to give
rise to this butyric acid fermentation. We should be particularly
careful, even more so almost than with other foods, to see that it is
perfectly sweet and good, because when we swallow rancid butter, we are
simply swallowing a ready-made attack of indigestion. Most people's
stomachs are strong enough to deal with small amounts of rancid butter
without discomfort; but it is a strain on them that ought to be
avoided, especially when good butter is simply a matter of strict
cleanliness and care in handling and churning the cream, and of keeping
the butter cool after it has been made.

Plenty of sweet butter is one of the most important and necessary
elements in our diet, especially in childhood. And if children are
allowed to eat pretty nearly as much as they want of it on their bread
or potatoes, and plenty of its liquid form, cream, on their berries and
puddings, it will save the necessity of many a dose of cod-liver oil, or
bitter physic. Cream is far superior to either cod-liver or castor oil
for keeping us in health.

Oleomargarine. On account of the expensiveness of butter, there are a
number of substitutes sold, which go under the name of _oleomargarine_.
These are made of the fat, or suet, of beef or mutton, mixed with a
certain amount of cream and real butter, to give them an agreeable
flavor. They are wholesome and useful fats, and for cooking purposes may
very largely be substituted for butter. Owing to the fact that their
fat is freer from the milk acids, they keep better than butter; and
sweet, sound oleomargarine is to be preferred to rank, rancid butter.
But it is not so readily digestible as butter is; is more liable to give
rise to the butyric acid fermentations in the stomach; is not nearly so
appetizing; and its sale as, and under the name of, _butter_ is a fraud
which the law rightly forbids and punishes.

[Illustration: A SMALL STORE, CLEANLY AND HONEST

The milk is well kept, the bread and candies are under glass, and
"butterine" is not sold as butter.]

Lard. The next most useful and generally used pure fat is lard--the
rendered, or boiled-down, fat of pork. It is a useful substitute for
butter in cooking, where butter is scarce. But, even in pastry or cakes,
it has neither the flavor nor the digestibility of butter, and the
latter should always be used when it can be had.

Bacon and Ham. The most useful and digestible fat meats are bacon and
ham, as the dried, salted, and usually smoked, meat of the pig is
called. Like all other fats, they can be eaten only in moderate amounts;
but thus eaten, they are both appetizing, digestible, and very
nutritious. One good slice of breakfast bacon, for instance, contains as
much fuel value as two large saucers of mush or breakfast food, or two
eggs, or two large slices of bread, or three oranges, or two small
glasses of milk, or a quart of berries.


NUTS

How Nuts should be Used. Another form of fat is the "meat" of
different nuts--walnuts, pecans, almonds, etc. These are quite rich in
fats, and also contain a fair amount of proteins, and are, in small
quantities, like other fats, appetizing and useful articles of food. But
they should not be depended upon to furnish more than a small amount of
the whole food supply, or even of its necessary fat, because nearly all
nuts contain pungent or bitter aromatic oils and ferments, which give
them their flavors, but which are likely to upset the digestion. This is
particularly true of the peanut, which is not a true nut at all, but is,
as its name indicates, a kind of pea grown underground. Peanuts, on
account of their large amount of these irritating substances, are among
the most indigestible and undesirable articles of diet in common use. A
certain amount of these irritating substances present in nuts may be
destroyed by careful roasting and salting; but this must be most
carefully done, and it shrinks them in bulk so that the finished product
is far more expensive than butter or fat meat of the same nutritive
value. Good salted almonds, for instance, cost fifty to eighty cents a
pound.

The proper place for nuts is where they usually come on our tables--at
the end of a meal. Those who attempt to cure themselves of dyspepsia by
a nut diet are simply making permanent their disease.


FOOTNOTES:

[9] Pemmican is a sort of "canned beef" made originally out of the best
parts of venison and buffalo-meat. This is boiled, and packed into skin
bags; then melted fat is poured in, so as to fill up all the chinks and
form a thick layer over the surface. It is now made of beef packed in
canvas bags, and is much used by polar expeditions and Alaskan miners.



CHAPTER VII

KINDLING AND PAPER FOODS--FRUITS AND VEGETABLES


The Special Uses of Fruits and Vegetables. We come now to the very
much larger but much less important class of foods--the Kindling foods,
which help the Coal foods to burn, and supply certain stuffs and
elements which the body needs and which the coal foods do not contain.
These are the vegetables--other than potatoes and dried peas and
beans--and fruits.

Fruits and vegetables contain certain mineral elements, which are not
present in sufficient proportions in the meats, starches, and fats.
Furthermore, the products of their digestion and burning in the body
help to neutralize, or render harmless, the waste products from meats,
starches, and fats. Thirdly, they have a very beneficial effect upon the
blood, the kidneys, and the skin. In fact, the reputation of fruits and
fresh vegetables for "purifying the blood" and "clearing the complexion"
is really well deserved. The keenness of our liking for fruit at all
times, and our special longing for greens and sour things in the spring,
after their scarcity in our diet all winter, is a true sign of their
wholesomeness.

Not the least of their advantages is that they contain a very large
proportion of water; and this, though diminishing their fuel value,
supplies the body with a naturally filtered and often distilled supply
of this necessary element of life. One of the best ways of avoiding that
burning summer thirst, which leads you to flood your unfortunate stomach
with melted icebergs, in the form of ice water, ice cold lemonade, or
soda water, is to take an abundance of fresh fruits and green
vegetables.

Many of the vegetables contain small amounts of starch, but few of them
enough to count upon as fuel, except potatoes, which we have already
classed with the Coal foods. Most fruits contain a certain amount of
sugar--how much can usually be estimated from their taste, and how
little can be gathered from the statement that even the sweetest of
fruits, like ripe pears or ripe peaches, contain only about eight per
cent of sugar. They are all chiefly useful as flavors for the less
interesting staple foods, particularly the starches. In fact, our
instinctive use of them to help down bread and butter, or rice, or
puddings of various sorts, is a natural and proper one. Like the
vegetables, they contain various salts which are useful in neutralizing
certain acid substances formed in the body. Soldiers in war, or sailors
upon long voyages, who are fed upon a diet consisting chiefly of salted
or preserved meat, with bread or hard biscuit and sugar, but without
either fruits or fresh vegetables, are likely to develop a disease
called scurvy. Little more than a century ago, hundreds of deaths
occurred every year in the British and French navies from this disease,
and the crews of many a long exploring voyage--like Captain Cook's--or
of searchers for the North Pole, have been completely disabled or even
destroyed entirely by scurvy. It was discovered that by adding to the
diet fruit, or fresh vegetables like cabbage or potatoes, scurvy could
be entirely prevented, or cured.[10]

Their Low Fuel Value. How little real fuel value fruits and
vegetables have, may be easily seen from the following table. In order
to get the nourishment contained in a pound loaf of bread, or a pound of
roast beef, you would have to eat: 12 large apples or pears (5 lbs.);
4-1/2 qts. of strawberries; a dozen bananas (3-1/2 lbs.); 7 lbs. of
onions; 2 doz. large cucumbers (18 lbs.); 10 lbs. of cabbage; 1/2 bushel
of lettuce or celery.

Apples, the most Wholesome Fruit. Head and shoulders above all the
other fruits stands that delight of our childhood days, apples. Well
ripened, or properly cooked, they are readily digested by the average
stomach; though some delicate digestions have difficulty with them. They
contain a fair amount of acids, and from five to seven per cent of
sugar. Their general wholesomeness and permanent usefulness may be
gathered from the fact that they are one of the few fruits which you can
eat almost daily the year round, or at very frequent intervals, without
getting tired of them. Food that you don't get tired of is usually food
which is good for you.

Dried apples are much inferior to the fresh fruit, because they become
toughened in drying, and because growers sometimes smoke them with fumes
of sulphur in the process, in order to bleach or whiten them; and this
turns them into a sort of vegetable leather.

Other Fruits--their Advantages and Drawbacks. Next in usefulness
probably come pears, though these have the disadvantage of containing a
woody fibre, which is rather hard to digest, and they are, of course,
poorer "keepers" than apples. Then come peaches, which have one of the
most delicious flavors of all fruits, but which tend to set up
fermentation and irritation in delicate stomachs, though in the average
stomach, when eaten in moderation, they are wholesome and good. Then
come the berries--strawberries, raspberries, blackberries,--all
excellent and wholesome, when fresh in their season, or canned or
preserved.

One warning, however, should be given about these most delicious,
fragrant berries; and as it happens to apply also to several of our most
attractive foods, it is well to mention it here. While perfectly
wholesome and good for the majority of people, strawberries, for
instance, are to a few--perhaps one in twenty--so irritating and
indigestible as to be mildly poisonous. The other foods which may play
this kind of trick with the stomachs of certain persons are oranges,
bananas, melons, clams, lobsters, oysters, cheese, sage, and parsley,
and occasionally, but very rarely, eggs and mutton. This is a matter
which each of you can readily find out by experiment. If strawberries,
melons, and other fruits agree with you, then eat freely of them, in due
moderation. But if, after three or four trials, you find that they do
not agree with you, but make your stomach burn, and perhaps give you an
attack of nettle-rash or hives, or a headache, then let them alone.

The banana is of some food value because it contains not only sugar, but
considerable quantities of starch--about the same amount as potatoes.
But, if bananas are not fully ripe, both their starch and sugar are
highly indigestible; while, if over-ripe, they have developed in them
irritating substances, which are likely to upset the digestion and cause
hives or eczema, especially in children. Bananas should therefore be
regarded rather as a luxury and an agreeable variety than as a
substantial part of the diet.

Food Values of the Different Vegetables. The vegetables depend for
their value almost solely upon the alkaline salts and the water in them,
and upon their flavor, which gives an agreeable variety to the diet.
Parsnips, beets, and carrots are among the most nutritious, as they
contain some starch and sugar; but they so quickly pall upon the taste
that they can be used only in small amounts.

Turnips and cabbages possess the merit of being cheap and very easily
grown. They contain valuable earthy salts, plenty of pure water, and a
trace of starch. But these advantages are offset by their large amount
of tough, woody vegetable fibre; this is incapable of digestion, and
though in moderate amounts it is valuable in helping to regulate the
movements of the bowels, in excess it soon becomes irritating. Both of
them, particularly cabbages, contain, also, certain flavoring extracts,
very rich in sulphur and exceedingly irritating to the stomach, which
cause them to disagree with some persons. If these are got rid of by
brisk boiling in at least two waters, then cabbage is a fairly wholesome
and digestible dish for the average stomach. And because of its
cheapness and "keeping" power, it is often the only vegetable that can
be secured at a reasonable cost at certain seasons of the year.

Onions, especially the milder and larger ones, are an excellent and
wholesome vegetable, containing small amounts of starch, although their
pungent flavor, due to an aromatic oil, makes them so irritating to some
stomachs as to be quite indigestible.

Sweet corn, whether fresh or dried, is wholesome, and has a fair degree
of nutritive value, as it contains fair amounts of both starch and
sugar. It should, however, be very thoroughly chewed and eaten
moderately, on account of the thick, firm indigestible husk which
surrounds the kernel.

Tomatoes are an exceedingly valuable, though rather recent addition to
our dietary. Their fresh, pungent acid is, like the fruit acids,
wholesome and beneficial; and they can be preserved or canned without
losing any of their flavor. They were at one time denounced as being
indigestible, and even as the cause of cancer; but these charges were
due to ignorance and distrust of anything new.

Lighter Vegetables, or Paper Foods. The lighter vegetables such as
lettuce, celery, spinach, cucumbers, and parsley have, in a previous
chapter, been classed with the paper foods. They are all agreeable
additions to the diet on account of their fresh taste and pleasant
flavor, though they contain little or no nutritive matter.

The Advantages of a Vegetable Garden. Notwithstanding their slight
fuel value, there are few more valuable and wholesome elements in the
diet than an abundant supply of fresh green vegetables. Everyone who is
so situated that he can possibly arrange for it, should have a garden,
if only the tiniest patch, and grow them for his own use, both on
account of their greater wholesomeness and freshness when so grown, and
because of the valuable exercise in the open air, and the enjoyment and
interest afforded by their care.

[Illustration: THE JOY OF HIS OWN GARDEN PATCH]


FOOTNOTES:

[10] As vegetables and fruit are bulky and likely to spoil, on the long
voyages of sailing vessels before steamships were invented bottles of
the juice of limes (a small kind of lemon) were added, instead, to the
hard-tack and "salt-horse" of the ship's stores. Because of this custom,
the long-voyage merchantmen who carried cargoes round the Horn or the
Cape were for years nicknamed "Lime-juicers."



CHAPTER VIII

COOKING


Why We Cook our Food. While some of all classes of food may be eaten
raw, yet we have gradually come to submit most of our foods to the heat
of a fire, in various ways; this process is known as _cooking_. While
cooking usually wastes a little, and sometimes a good deal, of the fuel
value of the food and, if carelessly or stupidly done, may make it less
digestible, in the main it makes it both more digestible and safer,
though much more expensive. This it does in three ways: by making it
taste better; by softening it so as to make it more easily masticated;
and by sterilizing it, or destroying any germs or animal parasites which
may be in it.

Cooking Improves the Taste of Food. It may seem almost absurd to
regard changing the taste of a food as of sufficient importance to
justify the expense and trouble of a long process like cooking. Yet this
was probably one of the main reasons why cooking came into use in the
first place; and it is still one of the most important reasons for
continuing it. No one would feel attracted by a plate of slabs of raw
meat, with a handful of flour, a raw potato or two, and some green
apples; but cook these and you immediately have an appetizing and
attractive meal. Any food, to be a thoroughly good food, must "taste
good"; otherwise, part of it will fail to be digested, and will sooner
or later upset the stomach and clog the appetite.

Cooking Makes Food Easier to Chew and Digest. The second important use
of cooking is that it makes food both easier to masticate and easier to
digest. As we have seen, it bursts the little coverings of the starchy
grains, and makes the tough fibres of grains and roots crisp and
brittle, as is well illustrated in the soft, mealy texture of a baked
potato, and in the crispness of parched wheat or corn. It _coagulates_,
or curdles, the jelly-like pulp of meat, and the gummy white of the egg,
and the sticky gluten of wheat flour, so that they can be ground into
tiny pieces between the teeth.

[Illustration: THE KITCHEN SHOULD BE CARED FOR AS ONE OF THE MOST
IMPORTANT ROOMS IN THE HOUSE]

We could hardly eat the different kinds of grains and meals and flours
in proper amounts at all, unless they were cooked; indeed they require
much longer and more thorough baking, or boiling, than meats. The amount
of cooking required should always be borne in mind when counting the
cost of a diet, as the fuel, time, and labor consumed in cooking
vegetable articles of diet often bring up their expense much more nearly
to that of meats than the cost of the raw material in the shops would
lead us to expect.

Cooking Sterilizes Food. A third, and probably on the whole, the most
valuable and important service rendered by cooking is, that it
sterilizes our food and kills any germs, or animal parasites, which may
have been in the body of the animal, or in the leaves of the plant,
from which it came; or, as is far the commoner and greater danger, may
have got on it from dirty or careless handling, or exposure to dust.
While it was undoubtedly the great improvement that cooking makes in the
taste of food that first led our ancestors--and probably chiefly induces
us--to use the process, it is hardly probable that they would have
continued to bear the expense, trouble, and numerous discomforts of
cooking, had they not noticed this significant fact: that those families
and tribes that had the habit of thoroughly cooking their food, suffered
least from diseases of the stomach and intestines, and hence lived
longer and survived in greater numbers than the "raw fooders." We are
perfectly right in spending a good deal of time, care, and thought on
cooking, preparing, and serving our food, for we thus lengthen our lives
and diminish our sicknesses. Civilized man is far healthier than any
known "noble savage," in spite of what poets and story-tellers say to
the contrary.

The Three Methods of Cooking. The three[11] chief methods
of cooking--_baking_, or roasting; _boiling_, or stewing; and
_frying_--have each their advantages as well as disadvantages. No one of
them would be suitable for all kinds of food; and no one of them is to
be condemned as unwholesome in itself, if intelligently done; although
all of them, if carelessly, or stupidly, carried out, will waste food,
and render it less digestible instead of more so. In the main, the
methods that are in common use for each particular kind of food, or
under each special condition, are reasonable and sensible--the result of
hundreds of years of experimenting. The only exceptions are that, on
account of its ease and quickness, frying is resorted to rather more
frequently than is best; while boiling is more popular than it should
be, on account of the small amount of thought and care involved in the
process.

Roasting, or Baking. Roasting, or baking, is probably the highest form
of the art of cooking, developing the finest flavors, causing less waste
of food value, and requiring the greatest skill and care. On general
principles, we may say that almost anything which can be roasted or
baked, should be roasted or baked.

On the other hand, roasting or baking has the disadvantage of taking a
great deal of fuel and of time, and of being exceedingly fatiguing and
annoying for the cook, making the labor cost high; and it cannot be used
where a meal is needed in a hurry. If the process is carelessly done and
carried too far, it may also waste a great deal of the food material,
either by burning or scorching, or by the commoner and almost equally
wasteful process of turning the whole outside of the roast--particularly
in the case of meat--into a hard, tough, leathery substance, which it is
almost impossible either to chew or to digest.

Boiling. The advantages of boiling are that it is the easiest of all
forms of cookery, and within the grasp of the lowest intelligence; that,
on account of keeping the food continually surrounded by water, it leads
to less waste and is far less likely than either baking or frying to
result in destroying part of the food if not carefully watched; and that
it can be used in cooking many cheap, coarse foods, such as the mushes,
graham meal, corn meal, hominy, potatoes, cabbages, turnips, etc., which
furnish the bulk of our food.

On the other hand, from the point of view of fuel used, it is the most
expensive of all forms of cooking; and unless a fire is being kept up
for other purposes, which allows boiling or stewing to go on on the back
of the stove as an "extra," without additional expense, careful
experiments have shown that the prolonged boiling needed by many of
these cheaper and coarser foods, especially such as are recommended by
most diet reformers, brings their total cost up to that of bread, milk,
eggs, sugar, and the cheaper cuts of meat,--all of which are more
wholesome and more appetizing foods.

[Illustration: A KNOWLEDGE OF COOKING IS A VALUABLE PART OF A GOOD
EDUCATION]

The supposed saving in boiling meat, that you get two courses, soup and
meat, out of one joint, is imaginary; for, as we have seen, the soup or
water in which meat has been boiled contains little, or nothing, of the
fuel value, or nourishing part of the meat; and all the flavor that is
saved in this is lost by the boiled meat, rendering it not only much
less appetizing, but also less digestible. You cannot have the flavor of
your food in two places at once. If you save it in the soup, you lose it
from the meat.

Frying. The chief advantages of frying are its marked saving of time,
of fuel, and of discomfort to the cook; it also develops the appetizing
flavors of the food to a very high degree. A wholesome, appetizing meal
can be prepared by frying, much more quickly than by either baking or
boiling, and with less than half the fuel expense.

[Illustration: BOYS, AS WELL AS GIRLS, SHOULD KNOW HOW TO COOK]

The drawbacks of frying come chiefly from unintelligent and careless
methods of applying it. It is somewhat wasteful of food material,
particularly of meats; although, if the fat which is fried out in the
process can be used in other cooking, or turned into a gravy, a good
deal of this waste can be avoided. As, in frying, some form of fat has
to be used to keep the food from burning, this fat is apt to form a
coating over the surface and, if used in excessive amounts, at too low a
temperature, may soak deeply into the food, thus coating over every
particle of it with a thick, water-proof film, which prevents the juices
of the stomach and the upper part of the bowel from attacking and
digesting it. This undesirable result, however, can be entirely avoided
by having both the pan and the melted fat which it contains, _very_
hot, before the steak, chop, potatoes, or buckwheat cakes are put into
the pan. When this is done, the heat of the pan and of the boiling fat
instantly sears over the whole surface of the piece of food, and forms a
coating which prevents the further penetration of the fat. Quick frying
is, as a rule, a safe and wholesome form of cooking. Slow frying, which
means stewing in melted grease for twenty or thirty minutes, is one of
the most effective ways ever invented of spoiling good food and ruining
digestion.

Why Every One should Learn how to Cook. Every boy and every girl ought
to know how to cook. Cooking is a most interesting art, and a knowledge
of it is a valuable part of a good education. Everybody would find such
a knowledge exceedingly useful at some time in his life; and most of us,
all our lives long. As a life-saving accomplishment, it is much more
valuable than knowing how to swim. Every schoolhouse of more than five
rooms should have a kitchen and a lunch room as part of its equipment,
and classes should take turns in cooking and serving lunches for the
rest of the children.[12]


FOOTNOTES:

[11] For meats a fourth method may be used--_broiling_, which for flavor
and wholesomeness is superior to any other, but requires a special and
rather expensive type of clear, hot fire and a high degree of skill.

[12] Whenever lunches are brought by children, or the school-lunch is a
problem, if possible equip a spare room with a gas or a coal stove,
sink, tables, chairs, necessary dishes, etc., and let classes under
direction of teacher take turns in purchasing food supplies for lunch;
cooking and serving lunch; planning dietaries with reference to balanced
nutrition, digestibility, and cheapness; washing pots, pans, and dishes;
cleaning kitchen; protecting and storing foods; finding risks of
spoiling, contamination, infection, fly-visiting; and practicing other
forms of kitchen hygiene.



CHAPTER IX

OUR DRINK


FILLING THE BOILER OF THE BODY-ENGINE

The Need of Water in the Body-Engine. If you have ever taken a long
railway journey, you will remember that, about every two or three hours,
you would stop longer than usual at some station, or switch, for the
engine to take in water. No matter how briskly the fire burns in the
furnace, or how much good coal you may shovel into it, if there be no
water in the boiler above it to expand and make steam, the engine will
do no work. And an abundant supply of water is just as necessary in our
own bodies, although not used in just the same way as in the engine.

The singular thing about water, both in a locomotive and in our own
bodies is that, absolutely necessary as it is, it is neither burned up
nor broken down in any way, in making the machine go; so that it gives
off no energy, as our food does, but simply changes its form slightly.
Exactly the same amount of water, to the ounce, or even the teaspoonful,
that is poured into the boiler of an engine, is given off through its
funnel and escape-pipes in the form of steam; and precisely the same
amount of water which we pour into our stomachs will reappear on the
surface of the body again in the form of the vapor from the lungs, the
perspiration from the skin, and the water from the kidneys. It goes
completely through the engine, or the body, enables the one to work and
the other to live, and yet comes out unchanged.

Just how water works in the engine we know--the heat from the furnace
changes it into steam, which means that heat expands it, or makes it
fill more space. This swelling pushes forward the cylinder that starts
the wheels of the engine. The next puff gives them another whirl, and in
a few minutes the big locomotive is puffing steadily down the track.

Water is Necessary to Life. Just how water works in the body we do not
know, as most of it is not even turned into steam or vapor. But this
much we do know, that life cannot exist in the absence of water. Odd as
it may seem to us at first sight, ninety-five, yes, ninety-nine per cent
of our body cells are water-animals, and can live and grow only when
literally swimming in water.

The scaly cells on the surface of our skin, our hair, and the tips of
our nails are the only parts of us that live in air. In fact, over
five-sixths of the weight and bulk of our bodies is made up of water.
Some one has quaintly, but truthfully, described the human body as
composed of a few pounds of charcoal, a bushel of air, half a peck of
lime, and a couple of handfuls of salt dissolved in four buckets of
water. The reason why nearly all our foods, as we have seen, contain
such large amounts of water is that they, also, are the results of
life--the tissues and products of plants or animals.

Water Frees the Body from Waste Substances. Water in the body, then,
is necessary to life itself. But another most important use is to wash
out all the waste substances from the different organs and tissues and
carry them to the liver, the kidneys, the lungs, and the skin, where
they can be burned up and got rid of. We must keep our bodies well
flushed with water, just as we should keep a free current of water
flowing through our drain-pipes and sewers.

It Keeps the Body from Getting Over-heated. In summer time, or in hot
climates the year round, an abundant supply of water is of great
importance in keeping the body from becoming overheated, by pouring
itself out on the skin in the form of perspiration, and cooling us by
evaporation, as we shall see in the chapter on the skin.

The Meaning of Thirst. None of us who has ever been a mile or more
away from a well, or brook, on a hot summer's day needs to be told how
necessary water is, for comfort as well as for health. The appetite
which we have developed for it--_thirst_, as we call it--is the most
tremendous and powerful craving that we can feel, and the results of
water starvation are as serious and as quick in coming as is the
keenness of our thirst. Men in fairly good condition, if they are at
rest, and not exposed to hardship, and have plenty of water to drink,
can survive without food for from two to four weeks; but if deprived of
water, they will perish in agony in from two to three days.

[Illustration: THE CHAINED CUP

An "Exchange" for disease germs.]

We should Drink Three Pints of Water a Day. Although all our foods,
either as we find them in the state of nature, or as they come on the
table cooked and prepared for eating, contain large quantities of water,
this is not enough for the needs of the body; to keep in good health we
must also drink in some form about three pints, or six glassfuls, of
water in the course of the day. Part of this goes, as you will remember
(p. 16), to dissolve the food so that it can be readily absorbed by our
body cells in the process of digestion.


WHERE OUR DRINKING WATER COMES FROM

Water Contained in our Food is Pure. Seeing that five-sixths of our
food is water, it is clearly of the greatest importance that that water
should be pure. That part of our water supply which we get in and with
our foods is fortunately, for the most part, almost perfectly pure,
having been specially filtered by the plants or animals which originally
drank it, or having been boiled in the process of cooking.

[Illustration: THE SPOUTING FOUNTAIN

Where no lips need touch the cup.]

Water is Always in Motion. The part of our water supply which we take
directly, in the form of drinking water, is, however, unfortunately
anything but free from danger of impurities. The greatest difficulty
with water is that it will not "stay put"--it is continually on the
move. The same perpetual circulation, with change of form, but without
loss of substance, which is taking place in the engine and in our
bodies, is taking place in the world around us. The water from the
ocean, the lakes, and the rivers is continually evaporating under the
heat of the sun and rising in the form of vapor, or invisible steam,
into the air. There it becomes cooler, and forms the clouds; and when
these are cooled a little more, the vapor changes into drops of water
and pours down as rain, or, if the droplets freeze, as snow or hail. The
rain falls upon the leaves of the trees and the spears of the grass, or
the thirsty plowed ground, soaks down into the soil and "seeps" or
drains gradually into the streams and rivers, and down these into the
lakes and oceans, to be again pumped up by the sun. All we can do is to
catch what we need of it, "on the run," somewhere in the earthy part of
its circuit.

Why our Drinking Water is Likely to be Impure. Every drop of water
that we drink or use, fell somewhere on the surface of the earth, in the
form of rain or snow; and if we wish to find out whether it is pure and
safe, we must trace its course through the soil, or the streams, from
the point where it fell. Our drinking water has literally washed "all
outdoors" before it reaches us, and what it may have picked up in that
washing makes the possibilities of its danger.

As it falls from the skies, it is perfectly pure--except in large cities
or manufacturing centres, where rain water contains small amounts of
soot, smoke-acids, and dust, but even these are in such small amounts as
to be practically harmless. But the moment it reaches the ground, it
begins to soak up something out of everything that it touches; and here
our dangers begin.

Risks from Leaf Mould. Practically the whole surface of the earth is
covered with some form of vegetation--grass, trees, or other green
plants. These dying down and decaying year after year, form a layer of
vegetable mould such as you can readily scratch up on the surface of the
ground in a forest or old meadow; this is known as leaf mould, or
_humus_. As the water soaks through this mould, it becomes loaded with
decaying vegetable matter, which it carries with it down into the soil.
Most of this, fortunately, is comparatively harmless to the human
digestion. But some of this vegetable matter, such as we find in the
water from bogs or swamps, or even heavy forests, will sometimes upset
the digestion; hence, the natural dislike that we have for water with a
marshy, or "weedy," taste.

[Illustration: NATURE'S FILTER-BED

The spring water is pure; the brook may gather infection as it goes.]

Nature's Filter-Bed. When, however, this peaty water soaks on down
through the grass, roots, and leaf mold, into the soil, it comes in
contact with Nature's great filter-bed--the second place in the circuit
where the water is again made perfectly pure. This filter-bed consists
of a layer of more or less spongy, porous soil, or earth, swarming with
millions of tiny vegetable germs known as bacteria. These eagerly pick
out all the decaying vegetable substances of the water and feed upon
them, changing them into harmless carbon dioxid water, and small amounts
of _ammonia_. Not only will this filter-bed, or spongy mat of bacteria,
burn up and remove all traces of vegetable decay, but if the rain
happens to have soaked through the decaying body of a bird or animal or
insect, the bacteria will just as eagerly feed upon these animal
substances and change them into harmless gases and salts.[13]

By the time the rain water has reached the deeper layers of the soil,
it is again perfectly pure and has also, in seeping through the soil,
picked up certain mineral salts (such as _calcium_, _sodium_, and
_magnesium_) which are of use in the body; so that in an open or thinly
settled country, the water in streams, rivers, and lakes is usually
fairly pure and quite wholesome. That is why, in ancient times, the
great majority of villages and towns and camps were situated on the bank
of some stream, where a supply of water could easily be obtained.


CAUSES AND DANGERS OF POLLUTED WATER

Wells--the Oldest Method of Supplying Water. It was long ago
discovered that, by digging pits or holes in the ground, the rain water,
in its steady flow toward the streams and lakes, could be caught or
trapped, and that if the pit were made deep enough, a sufficient amount
would accumulate during the winter or spring to last well on into the
summer, unless the season were unusually dry. These pits, or water
traps, are our familiar _wells_, from which most of our water supply,
except in the large cities, is still taken. These wells were naturally
dug, or sunk, as near as might be to the house, so as to shorten the
distance that the water had to be carried; and from this arose their
chief and greatest source of danger.

The Danger to Wells from Household Waste. Every house has, like our
bodies, a certain amount of waste, which must be got rid of. Some of
this material can, of course, be fed to pigs and chickens, and in that
way disposed of. But the simplest and easiest thing to do with the
watery parts of the household waste is to take them to the back door and
throw them out on the ground, while table-scraps and other garbage are
thrown into the long grass, or bushes--a method which is still,
unfortunately, pursued in a great many houses in the country and the
suburbs of towns. If the area over which they are thrown is large
enough, and particularly if the soil is porous and well covered with
vegetation, nature's filter-bed--the soil, the bacteria, and the roots
of the grass and other plants combined--will purify a surprising amount
of waste; but there is always the danger, particularly in the wet
weather of spring and of late fall, that the soil will become charged
with more of these waste matters than the bacteria can destroy, and that
these waste poisons will be washed down in the rain water right into the
pit, or trap, which has been dug for it--the well.

[Illustration: AN EXAMPLE OF GOOD FARM DRAINAGE

Here the farmhouse is set above the barn, pens, and cattle yard, and at
some distance from them. The drainage from these is into the lower
fields, so that a well driven into the high ground not far from the
house is presumably safe.]

The Danger from Outbuildings. This danger is further increased by the
fact that for the same reason--the vital need of plenty of water for all
living creatures--the hen coop, the pig pen, the cow stable, and the
horse barn are all likely to be built clustering around this same well.
If the fertilizer from these places is, as it should be in all
intelligent farming, protected from the rain so as not to have all its
strength washed out of it, and removed and spread on the soil at
frequent intervals, the well may even yet escape contamination; but the
chances are very strongly against it. If you will figure out that a well
drains the surface soil in every direction for a distance from ten to
thirty times its own depth, and that the average well is about
twenty-five feet deep, you can readily see what a risk of contaminating
the well is caused by every barn, outhouse, or pen within from sixty to
a hundred and fifty yards from its mouth.

Every well from which drinking water is taken should be at least fifty,
and better, a hundred and fifty, yards away from any stable, outhouse,
or barn; or set well up-hill from it, so that all drainage runs away
from its basin. This, of course, is possible only in the country, or in
villages or small towns, where houses have plenty of ground about them.
Consequently, the health laws of most cities and states forbid the use
of shallow wells for drinking purposes in cities of over 10,000
population.

Causes which Produce Pure Well Water. Occasionally a well will be
driven through a layer of rock or hard water-proof clay, before the
water-bearing layer of soil, or sand, is struck, so that its water will
be drawn, not from the rain that falls on the surface of the ground
immediately about it, but from that which has fallen somewhere at a
considerable distance and filtered down through the soil. This water, on
account of the many, many layers of soil through which it has filtered,
and the long distance it has come, is usually fairly pure, so far as
animal or vegetable impurities are concerned, though it is apt to have
become too strong in certain salty and mineral substances, which give it
a taste of salt, or iron, or sulphur. If, however, it is free from these
salty substances, it makes a very pure and wholesome drinking water; and
if the upper part of the well shaft be lined with bricks and cement, so
that the surface water cannot leak into it, it may be used with safety
for drinking purposes even in the heart of a city.

[Illustration: THE DANGER SPOT ON THE FARM

The milk inspector on visiting this dairy farm found that the well was
receiving the drainage of both house and privy. The well water was used
for drinking and for washing the milk pails (seen behind the fence).]

The Greatest Single Danger to Well Water. The greatest single danger
to the purity of well water is the privy vault. This is doubly
dangerous, first, because it is dug below the level at which the
bacteria in the soil are most abundant and active, so that they cannot
attack and break up its contents; and the impurities, therefore, are
gradually washed down by the rain water into the soil, unchanged, and
seep directly into the well. The other reason is that its contents may
contain the germs of serious diseases, particularly typhoid fever and
other bowel troubles. These germs and their poisons would usually be
destroyed by the bacteria of the soil, if not poured out in too large
quantities; but in the privy vault they escape their attack, and so are
carried on with the slow leakage of water into the well; then those who
use that water are very liable to have typhoid fever and other serious
diseases.

Early Methods of Prevention. On account of these filth-dangers, it
began, a century or so ago, to be the custom in cleanly and thoughtful
households to provide, first, ditches, and then, lines of pipes, made
out of hollow wood or baked clay, and later of iron, called drains,
through which all the watery parts of household wastes could be carried
away and poured out at some distance from the house. Then toilets, or
flush-closets, were built, and this kind of waste was carried completely
away from the house, and beyond danger of contaminating the wells.

How Streams were Contaminated. For a time this seemed to end the
danger, as the waste was soaked up by the soil, and eaten by its hungry
bacteria and drunk up again by the roots of plants. But when ten or a
dozen houses began to combine and run their drain-pipes together into a
large drain called a sewer, then this could not open upon the surface of
the ground, but had to be run into some stream, or brook, in order to be
carried away. As cities and towns, which had been obliged to give up
their wells, were beginning to collect the water from these same brooks
and streams in reservoirs and deliver it in pipes to all their houses,
it can be easily seen that we had simply exchanged one danger for
another.

The Loss of Life from Typhoid Fever. For a time, indeed, it looked as
if the new danger were the greater of the two, because, when the typhoid
germs were washed into a well, they poisoned or infected only one, or at
most two or three, families who used the water from that well. But when
they were carried into a stream which was dammed to form a reservoir to
supply a town with water, then the whole population of the town might
become infected. A great many epidemics of typhoid fever occurred in
just this way, before people realized how great this danger was. Simply
from the pouring of the wastes from one or two typhoid fever cases into
the streams leading into the water reservoir used by a town, five
hundred, a thousand, or even three or four thousand cases of typhoid
have developed within a few weeks, with from one hundred to five hundred
deaths.

[Illustration: TYPHOID EPIDEMIC IN THE MOHAWK-HUDSON VALLEY, 1891-92

In 1891-92 typhoid fever broke out in Schenectady on the Mohawk River.
Following this, Cohoes and West Troy, which drew their water supply from
the Mohawk below Schenectady, and Albany, which drew its supply from the
Hudson below the mouth of the Mohawk, suffered from typhoid epidemics;
while Waterford and Troy, which drew their supplies from the Hudson
_above_ the mouth of the Mohawk, and the river towns that, like
Lansingburgh, drew from other sources, entirely escaped the infection.]

In fact, even to-day, when these dangers are better understood, and
while most of our big cities are getting fairly clear of typhoid, so
ignorant and careless are the smaller towns, villages, and private
houses all over the United States, that over 35,000 deaths[14] from
typhoid fever occur every year in a country which prides itself upon its
cleanliness and its intelligence. This means, too, that there are at
least half a million people sick of the disease, and in bed or utterly
prevented from working, for from five to fifteen weeks each. All of
which frightful loss of human life and human labor, to say nothing of
the grief, bereavement, and anxiety of the two million or more families
and relatives of these typhoid victims, is due to eating dirt and
drinking filth. Dirt is surely the most expensive thing there is,
instead of the cheapest.


METHODS OF OBTAINING PURE WATER

Wise Planning and Spending of Money is Necessary. If our city wells
are defiled by manure heaps and vault-privies, and our streams by
sewage, where are we to turn for pure water? All that is required is
foresight and a little intelligent planning and wise spending of money.
Of course the community must take hold of the problem, through a Board
of Health, or Health Officer, appointed for the purpose; and this is why
questions of health are coming to play such an important part in
legislation, and even in politics. No matter how fast a city is growing
or how much money its inhabitants are making, if it has an impure water
supply or a bad sewage system, there will be disease and death,
suffering and unhappiness among its people, which no amount of money can
make up for. Cleanliness is not only next to godliness, but one of the
most useful forms of it; and a city can afford to spend money liberally
to secure it--in fact, it is the best investment a city can make.

Artesian and Deep Wells. The earliest, and still the most eagerly
sought-for, source of pure water supply is springs or deep wells, such
as we have referred to. Both of these are fed by rain water which has
fallen somewhere upon the surface of the earth. As the layers of earth
or rock, of which the crust of the earth is made up, do not run level,
or horizontal, but are tilted and tipped in all directions, this rain
water soaks down until it reaches one of these sloping layers that is so
hard, or tough, as to be waterproof, and then runs along over its
surface in a sort of underground stream. If anywhere in the course of
this stream a very deep well shaft is driven right down through the soil
until it strikes the surface of this sloping layer of rock, then the
water will rise in this shaft to the level of the highest point from
which it is running.

[Illustration: ARTESIAN WELL BORINGS

The sketch shows a wide section from northern Illinois to central
Wisconsin, in which the cities have rejected the water supplies afforded
by the rivers, choosing instead to bore down almost to hard rock to
insure the purity of the supply.]

If this highest point of the waterproof layer be many miles away, up in
the hills above the surface of the ground where the well is dug, then
the water will rise to the surface and sometimes even spout twenty,
thirty, or fifty feet above it. This forms what is known as a _gushing_,
or _artesian_, well (from Artois, a province in France, in which such
wells were first commonly used) and furnishes a very pure and valuable
source of water supply. If it rises only twenty, thirty, or fifty feet
in the well-shaft, but keeps flowing in at a sufficient rate, then we
get what is known as a "living," or _permanent_ well, and this also is a
very valuable and pure source of water supply.

Springs. Springs are formed on the same plan as the deep well, but
with the difference that the waterproof layer on top of which the water
is running either crops out on the surface again, lower down the
mountain, or folds upon itself and comes up again to the surface some
distance away from the mountain chain, out on the level. This is why
springs are usually found in or near mountainous or hilly regions. If
the water of a spring has gone deep enough into, or far enough through,
the layers of the earth, it may, like water of some of the artesian
wells, contain certain salts and minerals, particularly soda, sulphur,
and iron. Such springs are often highly valued as mineral water, healing
springs, or baths, partly because of these salts, partly on account of
their peculiar taste. Most of the virtues ascribed to mineral waters or
springs are due, however, to their _pure water_, and its cleansing
effects internally and externally when freely used.

Springs are among the most highly prized sources of water supply,
because they have gone underground sufficiently deep to become well
filtered and cooled to a low temperature, and usually not far enough to
become too heavily loaded with salts or minerals like the waters of the
deep wells. It must, however, be remembered that they also come from
rain-water, and that in hilly or broken regions the source of that rain
water may be the surface of the ground only a few hundred yards up the
hill or mountain, and impurities there may affect it. Much of the
delightful sparkle of spring water is due, as in the case of the popular
soda water, to the presence of carbon dioxid, only in spring water it is
produced by the decomposition of vegetable matter in it. As springs
usually break out in a hollow or at the foot of a hill, unless
carefully closed in they are quite liable to contamination from rain
water from the surrounding surface of the ground. Where springs of a
sufficient size can be reached, or a sufficiently "live" series of deep
wells can be bored, these furnish a safe source of water supply for
cities. But of course not more than one city in five or ten is so
favored.

Mountain Reservoirs. Two other methods of securing a water supply are
now generally adopted. One is to pick out some stream up in the hills or
mountains, within fifteen miles or so of the city, and put in a dam,
thus making a reservoir, or to enlarge some lake which already exists
there. At the same time, the entire valley, or slope of the mountain,
which this stream or lake drains of its surface water, is bought up by
the Government, or turned into a forest reserve, so that no houses can
be built or settlement of any kind permitted upon it. It can still be
used for lumber supply, for pastures, and, within reasonable limits, for
a great public hunting and fishing reserve and camping resort.

[Illustration: A CITY WATER SUPPLY BROUGHT FROM THE FAR HILLS]

Almost every intelligent and farsighted town, which has not springs or
deep wells, is looking toward the acquirement of some such area as this
for its source of pure water. Many great cities go from thirty to fifty
miles, and some even a hundred and fifty miles, in order to reach such a
source, carrying the water into the city in a huge water-pipe, or
_aqueduct_. These cities find that the millions of dollars saved by the
prevention of death and disease amount to many times the cost of such a
system, while the water rents gladly paid by both private houses and
manufacturing establishments give good interest on the investment. Any
town can afford to go a mile for every thousand of its population for
such a source of water supply as this; and secure, _gratis_, a valuable
forest preserve, public park, and beauty spot.[15]

Filtration. The other method, which has to be adopted by cities
situated on level plains, or at the mouths of great rivers, is to take
the water of some lake, or river, as far out in the former, or as high
up the latter, as possible, and purify it by filtration. This can be
done at a moderate expense by preparing great settling-basins and
filter-beds. The first are great pools or small lakes, into which the
water is run and held until most of the mud and coarser dirt has settled
or sunk. Then this clear water above the sediment is run on to great
beds, first of gravel, then of coarse sand, then of fine sand; and if
these beds are large enough, and frequently changed and cleaned, so that
they do not become clogged, and the process is carried out slowly, the
water, when it comes through the last bed, is pure enough to drink
safely.[16]

[Illustration: A RESERVOIR AND COSTLY DAM]

One of these sources of a safe and wholesome water-supply--the deep
flowing well, or spring; the water shut up in the mountains in its lake
or reservoir; or the slow filter-bed--should be used by every
intelligent and progressive town of more than a thousand inhabitants.

Sewage and its Disposal. At the same time, while seeking a source of
water-supply far removed from any possibility of contagion, we must not
neglect the other end of the problem, the protecting of our rivers and
lakes from pollution so far as possible; for the water from these must
necessarily be used by thousands of people along their banks, either
directly, or in the form of shallow wells, sunk not far from the water's
edge. Moreover, so foul are many of our rivers and streams becoming in
thickly settled regions that fish can no longer live in them, and it is
hardly safe to bathe in them.[17] Fortunately, however, a great deal of
the worst contamination can be prevented by using modern methods of
disposing of sewage, such as filter-beds and sewage farms. All of these
methods use the bacteria of the soil, or crops growing in it, to eat up
the waste and thus purify the sewage.

[Illustration: SCRAPING THE SEDIMENT FROM THE BOTTOM OF A RESERVOIR]


HOME METHODS OF PURIFYING WATER

Boiling. Where the water that you are obliged to drink is not known to
be pure, then it can be made quite safe for drinking purposes by the
simple process of boiling it for about ten or fifteen minutes. But this,
except in travelling or in emergencies, is a lazy, slipshod substitute
for pure water, and extremely unsatisfactory as well; for the boiling
drives off all its air and other gases, and throws down most of the
salts, so that boiled water has a flat, insipid taste. These salts,
although sometimes regarded as impurities, are not such in any true
sense; for the lime and soda especially are of considerable value in the
body, so that boiled or sterilized water is neither a pleasant nor a
wholesome permanent drink. Instead of boiling the water, get to work to
protect your own well from filth of all sorts, if you drink well water;
or, if not, to help the Board of Health to agitate, and keep on
agitating, until something is done to compel your selectmen or City
Council to secure a pure supply.

[Illustration: THE DOMESTIC FILTER IN USE

Unless the sand and charcoal in the glass bulb is very frequently
cleaned, it serves merely as a "catch-all" for impurities, through which
the water must flow.]

Domestic Filters. Much the same must be said of _private_ or _domestic
filters_. These are, at best, temporary substitutes, and should not be
depended upon for permanent use. Many of them are made to sell rather
than to purify, and will remove only the larger or mechanical impurities
from the water. Others, while they work well at first, are exceedingly
likely to become clogged, when the tendency is to punch at them to make
them work faster, thus either poking a hole through them or cracking the
filter-shell, so that a stream of water flows steadily through, just as
impure as when it entered. Private filters, like boiling water, are only
temporary ways of meeting conditions _which ought not to be allowed to
exist at all_ in civilized communities, or in your own homes.

A score of court decisions in all parts of the world have now held that
the water company is legally responsible for all avoidable pollution of
public water-supplies, and nine tenths of pollutions _are_ avoidable.


FOOTNOTES:

[13] These gases and salts are eagerly sucked up by the roots of plants,
so that the soil bacteria are our best friends, changing poisonous
decaying things into harmless plant-foods. They are the chief secret of
the fertility of a soil; and the more there are of them the richer a
soil is.

[14] This makes fourteen times as many deaths from typhoid in proportion
to the population as occur in Germany.

[15] New York City, for instance, goes forty miles up into the hills to
the great Croton reservoir for its water supply; and as this is proving
insufficient, is preparing to go ninety-five miles up into the Ramapo
Hills to secure control of a whole country-side for a permanent source
of supply. Portland, Oregon, nearly twenty years ago, with then a
population of some 75,000, built an aqueduct sixty miles up into the
mountains to a lake on the side of Mt. Hood, and has reaped the
advantages of its foresight ever since, in a low death rate and a rapid
growth (200,000 in 1910), as well as a financial profit on its
investment. Los Angeles, California, is preparing to build an aqueduct a
hundred and thirty miles, and tunnel two mountain ranges in order to
reach an inexhaustible supply of water.

[16] Of late, currents of electricity are passed through the water
(setting free _oxygen_ or _ozone_) which make the purifying of it much
more rapid and complete.

It is, however, often considered safer to pass the water through still
another filter bed, consisting of layers of charcoal, which has the
power of gathering oxygen in its pores, to attack and _oxidize_, or burn
up, the remaining impurities in the water. A sort of scum forms over the
surface of the last and finest bed of sand or charcoal, and if this scum
is not too frequently removed, though it makes the filtering slower, the
water comes out purer. On examining this scum, we find it to consist of
a thick mat of our old friends, the purifying bacteria of the soil. So
that the last step of our artificial filtration is simply an imitation
of nature's great filter-bed.

[17] Several streams emptying into the Ohio River from a thickly settled
region are said to be actually pumped out into waterworks systems, used
for drinking, washing, and manufacturing, and run back into the river
again through sewers by the different cities along its banks, at such
frequent intervals that every drop of water in them passes through
waterworks systems and sewers _three times_ before it reaches the mouth
of the stream.



CHAPTER X

BEVERAGES, ALCOHOL, AND TOBACCO


The Popularity of Beverages. For some curious reason, the habit has
grown up of taking a large part of the six glasses of water that we
require daily in the form of mixtures known as beverages. These
beverages are always much more expensive than pure water; are often
quite troublesome to secure and prepare; have little, or no, food value;
are of doubtful value even in small amounts; and injurious in large
ones. Why they should ever have come into such universal use, in all
races and in all ages of the world, is one of the standing puzzles of
human nature. They practically _all consist of from ninety to
ninety-eight per cent_ of water, the food elements that may be added to
them being in such trifling amounts as to be practically of no value.
They serve no known useful purpose in the body, save as a means of
introducing the water which they contain; and yet mankind has used them
ever since the dawn of history.

We Have no Natural Appetite for Beverages. It is a most striking fact
that, although these beverages have been drunk by the race for
centuries, we _have never developed an instinct or natural appetite for
them_! No child ever yet was born with an appetite or natural liking for
beer or whiskey; and very few children really like the taste of tea or
coffee the first time, although they soon learn to drink them on account
of the sugar and cream in them. Thus, nature has clearly marked them off
from all the _real_ foods on our tables, showing that they are not
essential to either life or health; and that they are absolutely
unnecessary, and almost always harmful in childhood and during the
period of growth. If no child ever drank alcohol until he really craved
it, as he craves milk, sugar, and bread and butter, there would be no
drunkards in the world. Our other food-instincts have shown themselves
worthy to be trusted--why not trust this one, and let these beverages,
especially alcohol, absolutely alone?

Statistics from the alcoholic wards of our great hospitals show that of
those who become drunkards, nearly ninety per cent _begin to drink
before they are twenty years old_. Of that ninety per cent, over
two-thirds took their first drink, not because they felt any craving for
it, or even thought it would taste good, but because they saw others
doing it; or thought it would be a "manly" thing to do; or were afraid
that they would be laughed at if they didn't! Whatever vices and bad
habits our natural appetites, and so-called "animal instincts," may lead
us into, drunkenness is not one of them.

This striking hint on the part of nature, that alcoholic beverages are
unnecessary, is fully confirmed by the overwhelming majority of hundreds
of tests which have been made in the laboratory, showing clearly that,
while these beverages may give off trifling amounts of energy in the
body, their real effects and the sole reason for their use are their
stimulating, or their discomfort-deadening (_narcotic_) effect. And the
more carefully we study them, the heavier we find the price that has to
be paid for any temporary relief or enjoyment which they may seem to
give.

Tea, Coffee, and Cocoa. The "weakest" and most commonly used of these
beverages or amusement foods, are tea, coffee, and cocoa. These have an
agreeable taste, mildly stimulate the nervous system, and, when used in
moderation by adults, seldom do much harm. To a small percentage of
individuals, who are specially sensitive to their effects, they seem to
act as mild poison-foods, much in the same way as strawberries, cheese,
or lobsters do to others.

Tea is made from the green leaves of a shrub growing in hilly districts
in China, Japan, and Southern India. The finer and more delicately
flavored brands are from the young leaves, shoots, and flowers of the
plant; while the coarser and cheaper are from the old leaves, stalks,
and even twigs--the latter containing the most _tannin_, which, as we
shall see, is the most injurious element in tea.

Coffee is made from the seeds of a cherry-like berry growing upon a
shrub, or low tree, on tropical hillsides. The bulk of our supply comes
from South America, and is known as "Rio" coffee, from Rio Janeiro, the
port in Brazil from which most of it is shipped. That from the East
Indies is known as Java, and that from Arabia as Mocha; though these
last two are now but little more than trade-names for certain finer
varieties of coffee, no matter where grown.

Cocoa and chocolate are made from the bean-like seeds of a small tree
growing in the tropics and, in cake, or solid, form, contain
considerable amounts of fat, and usually sugar and vanilla, which have
been added to them to improve their flavor. As, however, only a
teaspoonful or so of the powdered cocoa, or chocolate, goes to make a
cupful, the actual food value of cocoa or chocolate, unless made with
milk, is not much greater than that of tea or coffee with cream and
sugar. They contain less _caffein_ than either tea or coffee, but are
liable to clog rather than to increase the appetite for other foods.

Effects of Tea, Coffee, and Cocoa. Though the flavors of tea, coffee,
and cocoa are so different, they all depend for their effect upon a
spicy-tasting substance, called caffein from its having been first
separated out of coffee. The caffein of tea is sometimes called _thein_,
and that of cocoa _theobromin_; but they are all practically the same
substance. Part of the taste of these beverages is due to the caffein,
but the special flavor of each is given by spicy oils and other
substances which it contains. Caffein acts as a mild stimulant both to
the nervous system and brain, and to the heart; as is shown by the way
in which tea or coffee will wake us up or refresh us when tired, or, if
drunk too late at night, keep us from going to sleep. If used in large
amounts, especially if taken as a substitute for food, tea and coffee
upset the nervous system and disturb the heart, and produce an
unwholesome craving for more.

[Illustration: A MILK STATION IN A CITY PARK

Many cities have established such stations, where people can buy, for a
cent or two, a drink that is far better than soda water or any other
beverage.]

Their chief value lies in the hot water they contain, which has been
sterilized by boiling, while its heat assists the process of digestion;
and in the fact that their agreeable taste sometimes gives us an
appetite and enables us to eat more of less highly flavored foods, like
bread, crackers, potatoes, or rice, than we would without them. They
are, also, usually taken with cream, or milk, or sugar, which are real
foods and bring their fuel value up to about half that of skimmed milk.
So far as they stimulate the appetite and increase the amount of food
eaten, they are beneficial; but when taken as a substitute for real
food, they are most injurious. A cup of coffee, for instance, makes a
very poor breakfast to start the day on; for although it gives you a
comforting sense of having eaten something warm and satisfying, it
contains very little real food, and soon leaves you feeling empty and
tired; just as an engine would give out if you put a handful of shavings
into its fire-box, and expected it to do four hours' work on them.

The most disturbing effects of tea and coffee upon the digestion are due
to the tannin which they contain if boiled too long, especially in the
case of tea. This tannin, fortunately, will not dissolve in water except
by prolonged boiling or steeping; so that if tea is made by pouring
boiling water over the tea leaves and pouring it off again as soon as it
has reached the desired strength and flavor, and coffee by being just
brought to a boil and then not allowed to stand more than ten or fifteen
minutes before use, no injurious amounts of tannin will be found in
them. Tea, made by prolonged stewing on the back of the stove, owes its
bitter, puckery taste to tannin, and is better suited for tanning
leather than for putting into the human stomach.

Boys and girls up to fifteen or sixteen years of age are much better off
without tea, coffee, or cocoa; for they need no artificial stimulants to
their appetites, while at the same time their nervous systems are more
liable to injury from the harmful effects of over-stimulation. If the
beverages are taken at all, they should be taken very weak, and with
plenty of milk and cream as well as sugar.


ALCOHOL

How Alcohol is Made. The most dangerous addition that man has ever
made to the water which he drinks is alcohol. It is made by the action
of the yeast plant on wet sugar or starch--a process called
_fermentation_. Usually the sugar or starch is in the form of the juice
of fruits; or is a pulp, or mash, made from crushed grains like barley,
corn, or rye. As the spores of this yeast plant are floating about
almost everywhere in the air, all that is usually necessary is to let
some fruit juice or grain pulp stand at moderate warmth, exposed to the
air, when it will begin to "sour," or ferment.

Wine. When the yeast plant is set to work in a tub or vat of grape
juice, it attacks the fruit sugar contained in the juice, and splits it
up into alcohol and carbon dioxid, so that the juice becomes bubbly and
frothy from the gas. When from seven to fifteen per cent of alcohol has
been produced, the liquid is called wine. It contains, besides alcohol,
some unchanged fruit sugar, fruit acids, and some other products of
fermentation (known as _ethers_ and _aldehydes_), which give each kind
of wine its special flavor.

Beer, Ale, and Cider. If the yeast germ be set to work in a pulp or
mash of crushed barley or wheat, the starch of which has been partly
turned into sugar by malting, it breaks up the sugar into alcohol and
carbon dioxid. When it has brewed enough of the starch to produce
somewhere from four to eight per cent of alcohol, then the liquid, which
still contains about three or four per cent of a starch-sugar called
_maltose_, is called beer, or ale. It is usually flavored with hops to
give it a bitter taste and make it keep better. If the same process be
carried out in apple juice, we get the well known hard cider with its
biting taste.

Whiskey, Brandy, and Rum. When left to itself, the process of
fermentation in most of these sugary or starchy liquids will come to a
standstill after a while, because the alcohol, when it reaches a certain
strength in the liquid, is, like all other toxins, or poisons produced
by germs, a poison also to the germ that produces it. The yeast-bacteria
probably produce alcohol as a poison to kill off other germs which
compete with them for their share of the sugar or starch. So even the
origin of this curious drug-food shows its harmful character. We should
hardly pick out the poison produced by one germ to kill another germ as
likely to make a useful and wholesome food.

[Illustration: PROPORTION OF ALCOHOL

IN LIGHT WINE    IN BEER    IN WHISKEY

The liquid shows what part of a tumblerful of each is alcohol.]

If man had been content to leave this fermentation process to nature, it
is probable that many of the worst effects of alcohol would never have
been heard of. But these lighter forms of alcoholic drinks did not
satisfy the unnatural cravings which they had themselves created. Some
people never can leave even bad-enough alone. So man, with an ingenuity
which might have been much better used, sought a way of getting a liquor
which would contain more alcohol than nature, unaided, could be made to
brew in it. A little experimenting showed that the alcohol in fermenting
juices was lighter than water; so that by gently heating the fermenting
mass, the alcohol would evaporate and pass off as vapor, with a little
of the steam from the water. Then, by catching this vapor in a closed
vessel and pouring cold water over the outside of the vessel, it could
be condensed again in the form of a clear, brownish fluid of burning
taste, containing nearly fifty per cent of alcohol, instead of the
original five or six.

This evaporated or distilled mixture of alcohol and water, if made from
a mash of corn, wheat, rye, or potatoes, is called whiskey; if from
fruit-juice, brandy. A similar liquor, made out of fermented rice, is
known as _arrack_ in India, or _saké_ in Japan; and the liquor made from
fermented molasses is called rum.

Alcohol not a True Food, but a Drug. The much disputed question as to
whether alcohol is a food or not, is really of little or no practical
importance. It is quite true, as might be expected, from its close
relation to sugar and the readiness, for instance, with which it will
burn in an alcohol lamp or stove, that alcohol, in small amounts, is
capable of being burned in the body, thus giving it energy. This may
give it a certain limited value in some forms of sickness, as, for
instance, in certain fevers and infections, when the stomach does not
seem to be able to digest food. But here it acts as a medicine rather
than as a true food and, like all other medicines, should be used only
under skilled medical advice and control. For practical purposes, any
trifling food value it may have is more than offset by its later
poisonous and disturbing effects and, secondly, by its enormous
expensiveness.

The greatest amount of alcohol that could be consumed in the body at all
safely would barely supply one-tenth of the total fuel value needed; and
if any one were to attempt to supply the body with energy by the use of
alcohol, he would be blind drunk before he had taken one-third of the
amount required. From the point of view of expense alone, to take
alcohol for food is like killing buffalos for their tongues and letting
the rest of the carcass go to waste, as the Indians and pioneer hunters
of the plains used to do. It never has more than a fraction of the food
value of the grain or fruit out of which it was made; and the amount of
nutriment that it contains costs ten times as much as it would in any of
the staple foods.

Moreover, when it is taken with an ordinary supply of food, it is found
that, for every ounce of alcohol burned in the body, a similar amount of
the other food is prevented from being consumed, and probably goes to
waste, owing to the harmful effects of alcohol upon digestion.
Therefore, to talk of alcohol as a food is really absurd.

The Effect of Alcohol on Digestion. It has been urged by some that
alcohol increases the appetite, and enables one to digest larger amounts
of food. The early experiments seemed to support this claim by showing
that alcohol, well diluted, and in moderate amounts, increased appetite
and the flow of the gastric juice. When the experiments were carried a
little further, however, it was clearly shown that its presence in the
stomach and intestines, in such amounts as would result from a glass of
beer, or one or two glasses of claret-wine with a meal, interfered with
the later stages of digestion, so that the later harmful effects
overbalanced any earlier good effects.

Its Effect on the Temperature of the Body. Another claim urged in its
favor was that it warmed the body and protected it against cold. It
ought to have been easy for any one with a sense of humor to judge the
value of this claim by the fact that it was equally highly commended by
its users as a means of keeping them cool in hot weather. Its supposed
effects in the case of both heat and cold were due to the same fact: it
deadened the nerves for a time to whatever sense of discomfort one might
then be suffering from, but made no change whatever in the condition of
the body that caused the discomfort. Any drug which has this deadening
effect on the nerves is called a narcotic; and it is in this class that
alcohol belongs, together with the stronger narcotics, _opium_,
_chloroform_, _ether_, and _chloral_.

In fact, it was quickly found in the bitter school of experience that
alcohol, though producing an apparent glow of warmth for the time,
instead of increasing our power to resist cold, rapidly and markedly
lessens it; so that those who drink heavily are much more likely to die
from cold and exposure than those who let alcohol alone. Nowadays,
Arctic explorers, explorers in the tropics, officers of armies upon
forced marches, and those who have to train themselves for the most
severe strains on their powers of endurance, all bear testimony to the
fact that the use of alcohol is harmful instead of helpful under these
conditions, and that it is not for a moment to be compared to real
foods, like meat, sugar, or fat.

Its Effects on Working Power. Then it was claimed that alcohol
increased the working power of the body; that more work and better work
would be done by men at hard labor, if a little beer, or wine, was taken
with their meals. Indeed, most of those who take alcohol believe that
they work faster and better, and with less effort with it than without
it. But the moment that this _feeling_ of increased power and strength
was submitted to careful tests in the laboratory and in the workshop, it
was found that instead of _more_ being accomplished when alcohol was
taken, even in very moderate amounts, _less_ was accomplished by from
six to twelve per cent. The false sense of increased vigor and power was
due to the narcotic power of alcohol to deaden the sensations of fatigue
and discomfort.

It was discovered long ago, almost as soon as men began to put
themselves into training for athletic feats or contests, that alcohol
was not only useless, but very injurious. Any champion who, on the eve
of a contest, "breaks training" by "taking a drink," knows that he is
endangering his record and giving his competitors an advantage over him.

Its Deadening Effect. In short, we must conclude that the so-called
stimulating effects of alcohol are really due to its power of deadening
us to sensations of discomfort or fatigue. Its boasted power of making
men more "sociable" by loosening their tongues is due to precisely the
same effect: it takes off the balance-wheels of custom, reserve, and
propriety--too often of decency, as well. This is where the greatest
and most serious danger of alcohol comes in, that even in the smallest
doses, it begins to deaden us both mentally and morally, and thus
lessens our power of control. This loss of control steadily increases
with each successive drink until finally the man, completely under the
influence of liquor, reaches a stage when he can neither think
rationally nor speak intelligently, nor even walk straight or stand
upright--making the most humiliating and disgusting spectacle which
humanity can present.

Harmful Effects on the Body. All doctors and scientists and thoughtful
men are now practically agreed: First, that alcohol in excess is
exceedingly dangerous and injurious, and one of the most serious enemies
that modern civilization has to face.

Second, that even in the smallest doses, as a deadener of the sense of
discomfort, it blinds the man who takes it to the harm it is doing and,
as soon as its temporary comforting effects begin to pass off, naturally
leads its victim to resort to it again in increasing doses. In fact,
unlike a true food which quickly satisfies, the use of alcohol too often
creates an appetite that grows by what it feeds on, and is never
satisfied. For every natural appetite or instinct, nature provides a
check; but she provides none for tastes that must be acquired. The last
man to find out that he is taking too much is the drinker himself. Taken
first to relieve discomfort, its own poisonous after-effects create a
new and permanent demand for it.

The third point on which agreement is almost unanimous among scientists
and physicians is that, as will be seen in later chapters, there are a
considerable number of diseases of the liver, of the heart and blood
vessels, of the kidneys, and of the nervous system, which are produced
by, or almost always associated with, alcohol. There are, for instance,
three different kinds of alcoholic insanity. It is true that these
disease-changes most commonly occur in the tissues of those who use
alcohol to excess; and it is also probably true that what the alcoholic
poison is doing in these cases, is picking out the weak spots in the
body and the weaker individuals in the community. Even the strongest and
best of us have our little weaknesses of digestion, of nerves, and of
disposition that we know of, as well as others that we are not
acquainted with. And what is the use of running the risk of having these
picked out and made worse in this dangerous and unpleasant manner, just
for the sake of a little temporary indulgence?

Moreover, while it is admitted that most of these harmful effects of
alcohol are produced by its use in excess, it is daily becoming a more
and more difficult matter to decide just how much is "excess." It
certainly differs widely in different individuals, and in different
organs and parts in the same body. An amount of alcohol which one man
might possibly take without harm may greatly injure another; and its
frequent use, though it does not produce the slightest sign of
intoxication, or even of discomfort, or headache, may be slowly and
fatally damaging the cells of the liver or kidney. In fact, the
conviction is growing among scientists that alcohol does the greatest
harm in this slow, insidious way without its user's realizing it in any
way until too late to break the fearful habit.

It may even be perfectly true that alcohol seriously injures not more
than ten or fifteen per cent of those who take it in small quantities;
but how can you tell whether you, or your liver, or kidney, or nerve
cells, belong in the ten per cent or the ninety per cent class? On
general principles, it would hardly seem worth while making the test
simply for the sake of finding out. You never can _quite_ tell what
alcohol has done to you, until the _post mortem_ (after death)
examination--and then the question will not interest you very much.

Its Effect upon Character. Just as alcohol deadens the body and the
senses, especially the higher ones--so it has a terrible effect upon the
mental and moral sides of our natures. The results of the use of alcohol
are so well known that it is unnecessary here to either describe or
picture them. All that is needed is to keep our eyes open upon the
street, and read the police reports. What good effects upon man's better
nature has alcohol to show as an offset for this dreadful tendency to
bring out the worst and lowest in man?

Increasing Knowledge of the Bad Effects of Alcohol is Decreasing its
Use. It is most impressive that almost everything we have found out
about alcohol in the short time that we have been studying it carefully
has been to its discredit. Fifty years ago beer and wine, all over the
civilized world, were commonly regarded as foods. Now they are not
considered true foods, but harmful beverages. Fifty years ago alcohol
was believed to improve the digestion and increase the appetite. Now we
know that it does neither. It was believed to increase working power,
and has now been clearly shown to diminish it. It was supposed to
increase the thinking power and stimulate the imagination, and now we
know that it dulls and muddles both.

Fifty years ago it was freely used as medicine for all sorts of
illnesses, both by doctor and patient; it was supposed to stimulate the
heart, to sustain the strength, to increase the power of the body to
resist disease, and to sustain and support life in emergencies. Now we
know that practically all these claims are unfounded, and that such
value as it has in medicine is chiefly as a narcotic, as a deadener of
the sense of discomfort. As a result, it is already used in medicine
only about one-fourth as much as it was fifty years ago, and its use is
still steadily decreasing.

Fifty years ago, in this country, in England, and on the continent of
Europe, farm laborers and servants living in the house, expected so many
pints or quarts of ale or beer a day, as part of their regular food
rations, just as they now would expect milk or tea or coffee. It was
only a few years ago that the great steamship companies stopped issuing
_grog_, or raw spirits, to the sailors in their employ, as part of their
daily ration, because they at last came to realize how harmful were its
effects. And a score of similar instances could be mentioned, showing
that the unthinking and general use of alcohol as a beverage at our
tables is steadily and constantly diminishing. Great temperance
societies are springing up in this and other civilized countries and are
having a powerful influence in showing the harm of the use of alcohol
and in inducing people to abstain from using it.

This movement is only fairly started, but is being hastened by such
practical and important influences as the experience of many of the
great business corporations, such as railroads, steamship companies,
insurance companies, banks, and trust companies, which support the
findings of science against alcohol in almost every respect. On account
of the manner in which alcohol unconsciously dulls the senses and blurs
the judgment, these companies began long ago weeding out from their
employ all men who were known to drink to excess; then they began to
reject those who were likely to occasionally over-indulge, or take it
too freely; and now, finally, many of them, particularly the railway and
steamship companies, will not employ--except in the lowest and poorest
paid classes of their service--and will not promote to any position
which puts men in charge of human life and limb, those who use alcohol
in any form or amount.

Nearly all the captains, for instance, of our great trans-atlantic
liners, whose duties in storm or fog keep them on the bridge on
continuous duty for forty-eight, sixty, and even seventy-two hours at a
stretch, with thousands of lives depending upon their courage and their
judgment, are total abstainers. And while twenty-five years ago they
used to think that they could not go through these long sieges of storm
duty without plenty of wine or whiskey, they now find that they are far
better off without any alcoholic drink.

Another powerful force in the same direction is our insurance companies,
practically all of whom now will refuse to insure any man known
habitually to use alcohol to excess, because where lists have been kept
of their policy-holders showing which were users of alcohol and which
total abstainers, their records show that the death rate among the users
of alcohol is some twenty per cent greater than among the total
abstainers. A similar result has also been reached in the companies that
insure against sickness, whose drinking members average nearly twice as
many weeks of sickness during the year as the abstaining ones. So both
of these two great groups of business corporations are becoming powerful
agencies for the promotion of temperance.

Within fifty years from now the habitual use of alcohol will probably
have become quite rare. It is already becoming "good form" among the
best people not to drink; and the fashion will spread, as the bad
effects of alcohol become more generally understood.


TOBACCO

Smoking, a Senseless Habit. Smoking is the curious act of drawing
smoke into the mouth and puffing it out again. Why this custom should
have become so widespread is even a greater puzzle than is the drinking
of alcohol. In civilized countries at least, it is a custom of much more
recent growth than "drinking," as it was introduced into Europe from
America by the early explorers, notably those sent out by Sir Walter
Raleigh. As tobacco-smoke is neither a solid nor a liquid, but only a
gas, no one could even pretend that it is of any value, either as food
or drink. All that can be said of smoking, even by the most inveterate
smoker, is that it is a habit, of no possible use or value to body or
mind, and of great possibilities of harm.

Another singular thing about smoking is that its effects vary so greatly
according to the individual who practices it, that scarcely any two
smokers can agree as to the exact reason why they smoke, except that in
some vague way smoking gives them pleasure. The only thing that they do
agree upon is that they miss it greatly, and crave it keenly whenever
they stop it. The only thing that stands out clearly about smoking is
that while it does no good, and does not even give one definite and
uniform kind of pleasure, it does form a powerful and over-mastering
habit, which is exceedingly difficult to break, and develops a craving
which can be satisfied only by continuing, or returning, to it.

It is Very Difficult to Break the Habit of Smoking. As a matter of
practical experience, not one smoker in fifty who tries to swear off
ever succeeds in doing so permanently. Why then should any one form a
habit, which is of no benefit whatever, which is expensive, unpleasant
to others, and which may become exceedingly injurious, simply for the
sake of saddling one's self with a craving which will probably never be
got rid of all the rest of one's life? The strongest and most positive
thing that a smoker can say about his pipe, or cigar, or cigarette, is
that he could not get along without it; and he will usually add that he
wishes he had never begun to use it. You are better off in every way by
letting tobacco strictly alone, and never teaching yourself to like it.

Tobacco is Not a Natural Taste. As might be expected, in the case of
such an utterly useless drug, we have no natural liking or instinct for
it; and the taste for it has to be acquired just as in the case of
alcohol, only as a rule with greater difficulty and with more painful
experiences of headache, nausea, and other discomforts.

[Illustration: A BOARD OF HEALTH EXAMINATION FOR WORKING PAPERS

The Board of Health of the City of New York requires that all children
between the ages of fourteen and sixteen shall have certificates of good
health before they can be employed in business. Any employer who hires a
child without such a certificate is liable to a heavy fine. This law is
to protect the health of both the worker and the public.]

Nicotine, a Powerful Poison. Tobacco contains and depends largely for
its effects upon considerable amounts of a substance called _nicotine_.
This is a powerful poison, even in very small doses, with only feeble
narcotic, or pain-deadening, powers; but fortunately, the larger part of
it is destroyed in the process of burning. Enough, however, is carried
over in the smoke, or absorbed through the butt of the cigar or
cigarette, or the mouth-piece of the pipe, to injure the nervous system,
especially in youth. As will be seen in the chapter upon the "Care of
the Heart," it especially attacks the nerves supplying the heart, and is
thus most harmful to growing boys.

On account of its injurious effects upon the nerves of the heart,
smoking has long been forbidden by trainers and coachers to all athletes
who are training for a contest or race. In addition to its poisonous
effects upon the nervous system, tobacco also does great harm to boys
and young men by providing them with an attractive means of filling up
their time and keeping themselves amused without either bodily or mental
effort. The boy who smokes habitually will find it much easier to waste
his time in day-dreams and gossip, and tends to become a loafer and an
idler.

The Advantage that Non-Smokers have over Smokers. When both of these
influences are taken together, it is little wonder that the
investigations of Dr. Seaver, the medical director of Yale, showed that
out of the 187 men in the class of 1881, those not using tobacco during
their college course had gained, over the users of tobacco, twenty-two
per cent in weight, twenty-nine per cent in height, nineteen per cent in
growth of chest, and sixty-six per cent in increase of lung capacity.

[Illustration: A TEST OF CLEAR HEAD AND STEADY NERVES

The boy who smokes cigarettes finds it increasingly difficult to obtain
a position in a bank or other large commercial house.]

In the Amherst graduating class for the same year, the non-users of
tobacco had gained twenty-four per cent more in weight, thirty-seven per
cent more in height, and forty-two per cent more in growth of chest than
had the smokers. In lung capacity, the tobacco users had lost two cubic
inches, while the abstainers had gained six cubic inches.

As a wet-blanket upon ambition, a drag upon development, and a handicap
upon success in life, the cigarette has few equals and no superiors. The
stained fingers and sallow complexion of the youthful cigarette smoker
will generally result in his being rejected when applying for a
position. The employer knows that the non-smoking boy is much more
likely to succeed in his work and win his way to a position of trust and
influence than is the "cigarette fiend." Especially in these days of
sharp competition, no boy can afford to contract a habit which will so
handicap him in making his way as will the cigarette habit.



CHAPTER XI

THE HEART-PUMP AND ITS PIPE-LINE SYSTEM


THE BLOOD VESSELS

Where the Body Does its Real Eating. When once the food has been
dissolved in the food-tube and absorbed by the cells of its walls, the
next problem is how it shall be sent all over the body to supply the
different parts that are hungry for it; for we must remember that the
real eating of the food is done by the billions upon billions of tiny
living cells of which the body is made up.

The Pipe Lines of the Body. What do we do when we want to carry water,
or oil, or sewage, quickly and surely from one place to another? We put
down a pipe line. We are wonderfully proud of our systems of water and
gas supply, and of the great pipe lines that carry oil from wells in
Ohio and Indiana clear to the Atlantic coast. But the very first man
that ever laid a pipe to carry water was simply imitating nature--only
about ten or fifteen million years behind her. No sooner has our food
passed through the cells in the wall of the food-tube, than it goes
straight into a set of tiny tubes--the blood-pipes, or _blood
vessels_--which carry it to the heart; and the heart pumps it all over
the body.

Veins and Arteries. These blood-tubes running from the walls of the
food-tube to the heart are called _veins_; and the other tubes through
which the heart pumps the blood all over the body are called _arteries_.
If you will spell this last word "air-teries," it may help you to
remember why the name was given to these tubes ages ago. When the body
was examined after death, they were found to be empty and hence were
not unnaturally supposed to carry air throughout the body, and
"air-teries" they have remained ever since. While absurd in one way, the
name is not so far amiss in another, for an important part of their work
is to carry all over the body swarms of tiny baskets, or sponges, of
oxygen taken from the air.

Why the Blood is Red. The first and main purpose of the blood-pipes
and the heart is to carry the dissolved food from the stomach and
intestines to the cells all over the body. But the cells need air as
well as food; and, to carry this, there are little basket-cells--the
_red corpuscles_. Take a drop of blood and put it under a microscope,
and you will see what they look like. The field will be simply crowded
with tiny, rounded lozenges--the red cells of the blood, which give it
its well-known color.

[Illustration: BLOOD CORPUSCLES (Greatly magnified)

_A_, red blood; _B_, white blood.]

The White Corpuscles or Scavengers of the Blood. As the blood-tubes
are not only supply-pipes but sewers and drainage canals as well, it is
a good thing to have some kind of tiny animals living and moving about
in them, which can act as scavengers and eat up some of the waste and
scraps; and hence your microscope will show you another kind of little
blood corpuscle, known, from the fact that it is not colored, as the
_white corpuscle_. These corpuscles are little cells of the body, which
in shape and behavior are almost exactly like an _ameba_--a tiny "bug,"
seen only under the microscope, that lives in ditch-water. Under the
microscope the white corpuscles look like little round disks, about
one-third larger than the red corpuscles, and with a large kernel, or
_nucleus_, in their centre. They have the same power of changing their
shape, of surrounding and swallowing scraps of food, as has the ameba,
and are a combination of scavengers and sanitary police. When disease
germs get into the blood, they attack and endeavor to eat and digest
them; and whenever inflammation, or trouble of any sort, begins in any
part of the body, they hurry to the scene in thousands, clog the
blood-tubes and squeeze their way out through the walls of the smallest
blood-tubes to attack the invaders or repair the damage. This causes the
well-known swelling and reddening which accompanies inflammation.

Blood, then, is a sticky red fluid, two-thirds of which is food-soup,
and the other third, corpuscles. How tiny the blood-corpuscles are, may
be guessed from the fact that there are about 5,000,000 red cells and
10,000 white cells in every _cubic centimetre_ (fifteen drops) of our
blood.

How the Blood Circulates through the Body. Now let us see how some
portion of the body, say the right thumb, gets its share of food and of
oxygen through the blood. We will start at the very beginning. The food,
of course, is put into the mouth, chewed by the teeth, and softened and
digested in the stomach and intestines. It is then taken up by the cells
of the mucous coat of the intestines and passed into the network of tiny
blood-pipes surrounding them, between the lining of the bowels and their
muscular coat. These tiny blood-pipes, called _capillaries_, run
together to form larger pipes--the small veins; and the small veins from
the walls of the intestine and stomach finally run together into one
large pipe, or trunk-line (called the _portal vein_), which carries them
to the liver.

[Illustration: DIAGRAM OF THE CIRCULATORY SYSTEM

All details are omitted. The connection between arteries and veins is
shown only in the brain. Both heart and blood vessels are considerably
enlarged to show clearly the course of the blood.]

In passing through the liver, the blood is purified of some irritating
substances picked up from the food-tube, and the melted food which it
contains is further prepared for the use of the cells of the body. The
portal vein of the liver breaks up into a network of veins, and these
again break up into a number of tiny capillaries, in which the blood is
acted upon by the cells of the liver. These capillaries gather together
again to form veins, and finally unite into two large veins at the back
of the liver, which run directly into the great trunk-pipe of all the
veins of the body--the _vena cava_ (or "empty vein," so called because
it is always found empty after death), about an inch from where this
opens into the right side of the heart.

In the vena cava the blood from the food-tube, rich in food, but poor in
oxygen, mixes with the impure, or used-up, blood brought back by the
veins from all over the body and, passing into the right side of the
heart, is pumped by the heart through a large blood-pipe to the lungs.
This large blood-pipe divides into two branches, one for each lung; and
these again break up into smaller branches, and finally into tiny
capillaries, which are looped about in fine meshes, or networks, around
the air-cells of the lung. Here, through the thin and delicate walls of
the capillaries the blood cells give off, or breathe out, their carbon
dioxid and other waste gases (which are passed out with our outgoing
breath), and at the same time they breathe in oxygen which our incoming
breath has drawn into the lungs.

This oxygen is picked up by, and combines with, the red coloring matter
of the millions of little oxygen sponges, or baskets--the red
corpuscles--and turns them a light red color, causing the blood to
become bright red, such as runs in the arteries and is known as
_arterial blood_.

The loops of tiny capillaries around the air cells of the lungs run
together again to form larger pipes; and these unite, at the point of
each lung nearest the heart, to form two large blood pipes--one from
each lung--which pour the rich, pure blood, loaded with both food and
oxygen into the left side of the heart. The left side of the heart pumps
this blood out into the great main delivery-pipe for pure blood, known
as the _aorta_, and this begins to give off branches to the different
parts of the body, within a few inches of where it leaves the heart.

[Illustration: SURFACE VEINS AND DEEP-LYING ARTERIES OF INNER SIDE OF
RIGHT ARM AND HAND

The deep-lying veins that run parallel to the arteries have been
omitted; so have the veins of three of the fingers.]

One of the first of these branches to be given off by the aorta is a
large blood pipe, or artery, to supply the shoulder and arm; this artery
runs across the chest, thence across the armpit, and down the arm to the
elbow. Here it divides into two branches, one to supply the right, and
the other the left, side of the forearm and hand. These branches have by
this time got down to about the size of a wheat straw; the one supplying
the right side is the artery which we feel throbbing in the wrist, and
which we use in counting the pulse. From it run off smaller branches to
supply the thumb and fingers. These branches break up again into still
smaller branches, and they into a multitude of tiny capillaries, which
run in every direction among all the muscle cells, delivering the food
and oxygen at their very doors, as it were. The muscle cells eagerly
suck out the food-stuffs, and breathe in the oxygen of the blood; at the
same time, they pour into it their waste stuffs of all sorts, including
carbon dioxid. These rob the blood of its bright red oxygen color and
turn it a dirty purplish, or bluish, tint.

The loops of capillaries again run together, as they did in the liver
and in the lung, to form tiny veins; and these run together at the base
of the thumb and in the wrist, to form larger ones through which the now
poor and dirty blood is carried back up the arm over much the same
course as it took in coming down it. Indeed, the veins usually run
parallel with, and often directly alongside of, the arteries. The blood
passes through the armpit, across the chest, into the great main pipe
for impure blood, the vena cava, and through this into the right side of
the heart, where it again meets the rich, but waste-laden blood from the
food tube and liver, and starts on its circuit through the lungs and
around the body again.

The blood reaches every portion of our body in precisely this same
manner, only taking a different branch of the great pure-blood delivery
pipe, the aorta, according to the part of the body which it is to reach,
and coming back by a different vein-pipe.

Why the Arteries are more deeply Placed than the Veins. In the limbs
and over the surface of the body generally, the arteries are more deeply
placed than the veins, so as to protect them from injury, because the
blood in the arteries is driven at much higher pressure than in the
veins and spurts out with dangerous rapidity, if they are cut. Some of
the veins, indeed, run quite a little distance away from any artery and
quite close to the surface of the body, so that you can see them as
bluish streaks showing through the skin, particularly upon the front and
inner side of the arms.

The Capillaries. Of course, the blood pipes into which the food is
sucked through the walls of the food tube, and those in the lung,
through which the oxygen is breathed, as well as those in the thumb
through which food is taken to the muscle-cells, have the tiniest and
thinnest walls imaginable. For once, the name given them by the wise
men--capillaries (from the Latin _capilla_, a little hair)--fits them
beautifully, except that the hairs in this case are hollow, and about
one-twentieth of the size of the finest hair you can see with the naked
eye. So tiny are they that they compare with the big veins near the
heart into which they finally empty much as the smallest and slenderest
twigs of an elm do with its trunk. What they lack in size, however, they
more than make up in numbers; and a network of them as fine and close as
the most delicate gauze goes completely around the food tube between its
mucous lining and muscular coat.

Though thickest and most abundant on the inner and outer surfaces of the
body, every particle of the body substance is shot through and through
with a network of these tiny tubes. So close and fine is this network in
the skin, for instance, that, as you can readily prove, it is impossible
to thrust the point of the finest needle through the skin without
piercing one of them and "drawing blood," as we say, or making it bleed.
From this network of tiny, thin-walled tubes, the body-cells draw their
food from the blood.

[Illustration: DIAGRAM OF ARTERY, CAPILLARIES, AND VEIN]

The Meaning of Good Color. It is the red blood in this spongy network
of tiny vessels that gives a pink coloring to our lips and the flush of
health to our cheeks. Whenever for any reason the blood is less richly
supplied with food or oxygen, or more loaded with "smoke" and other body
dirt than it should be, we lose this good color and become pale or
sallow. If we will remember that our hearts, our livers, our brains, and
our stomachs, are at the same time often equally "pale" and sallow--that
is, badly supplied with blood--as our complexions, we can readily
understand why it is that we are likely to have poor appetites, poor
memories, bad tastes in our mouths, and are easily tired whenever, as we
say, our "blood is out of order." The blood is the life. Starve or
poison that, and you starve or poison every bit of living stuff in the
body.


THE HEART

Structure and Action of the Heart. Now what is it that keeps the blood
whirling round and round the body in this wonderful way? It is done by a
central pump (or more correctly, a little explosive engine), with thick
muscular walls, called the _heart_, which every one knows how to find by
putting the hand upon the left side of the chest and feeling it beat.
The heart is really a bulb, or pouch, which has ballooned out from the
central feed pipe of the blood supply system, somewhat in the same way
that the stomach has ballooned out from the food tube.

The walls of this pouch, or bulb, are formed of a thick layer of very
elastic and powerful muscles almost as thick as the palm of your hand.
When the great vein trunk has poured blood into this pouch until it is
swollen full and tight, these muscles in its walls shut down sharply and
squirt or squeeze the blood in the heart-pouch into the great
artery-pipe, the aorta. In fact, you can get a very fair, but rough,
idea of the way in which the heart acts by putting your half-closed hand
down into a bowl of water and then suddenly squeezing it till it is shut
tight, driving the water out of the hollow of your hand in a jet, or
squirt.

"But," some of you will ask at once, "what is to prevent the blood in
the heart, when the muscle wall squeezes down upon it, from shooting
backward into the vena cava, instead of forward into the aorta?"

Nature thought of that long ago, and ingeniously but very simply
guarded against it by causing two little folds of the lining of the
blood pipes to stick up both where the vena cava enters the heart and
where the aorta leaves it, so as to form little flaps which act as
valves. These valves allow the blood to flow forward, but snap together
and close the opening as soon as it tries to flow backward. While
largest and best developed in the heart, these valves are found at
intervals of an inch or two all through the veins in most parts of the
body, allowing the blood to flow freely toward the heart, but preventing
it from flowing back.

As the heart has to pump all the blood in the body twice,--once around
and through the lungs, and once around and through the whole of the
body,--it has become divided into two halves, a right half, which pumps
the blood through the lungs and is slightly the smaller and the thinner
walled of the two; and a left half, which pumps the purified blood,
after it has come back from the lungs, all over the rest of the body.

[Illustration: THE EXTERIOR OF THE HEART

Showing the strands of muscle that compose it, the arteries and veins
that feed and drain the muscle coat, and fat protecting these.]

Each half, or side, of the heart has again divided itself into a
receiving cavity, or pouch, known as the _auricle_; and a pumping or
delivering pouch, known as the _ventricle_. And another set of valves
has grown up between the auricle and the ventricle on each side of the
heart. These valves have become very strong and tough, and are tied back
in a curious and ingenious manner by tough little guy ropes of tendon,
or fibrous tissues, such as you can see quite plainly in the heart of an
ox. It is important for you to remember this much about them, because,
as we shall see in the next chapter, these valves are one of the parts
of the heart most likely to wear out, or become diseased.

[Illustration: DIAGRAM OF VALVES IN THE VEINS AND HEART

In _A_ the blood flows forward naturally. In _B_ and _C_ is shown what
would happen were the blood to reverse its course, as it does when it
meets an obstruction: the pockets would fill until they met and closed
the passageway.]

Heart Beat and Pulse. The heart fills and empties itself about eighty
times a minute, varying from one hundred and twenty times for a baby,
and ninety for a child of seven, to eighty for a woman, and seventy-two
for a full-grown man.

When the walls of the ventricles squeeze down to drive out their blood
into the lungs and around the body, like all other muscles they harden
as they contract and thump the pointed lower end, or _apex_, of the
heart against the wall of the chest, thus making what is known as the
_beat_ of the heart, which you can readily feel by laying your hand upon
the left side of your chest, especially after you have been running or
going quickly upstairs. As each time the heart beats, it throws out half
a teacupful of blood into the aorta, this jet sends a wave of swelling
down the arteries all over the body, which can be felt clearly as far
away as the small arteries of the wrist and the ankle. This wave of
swelling, which, of course, occurs as often as the heart beats, is
called the _pulse_; and we "take" it, or count and feel its force and
fullness, to estimate how fast the heart is beating and how well it is
doing its work. We generally use an artery in the wrist (_radial_) for
this purpose because it is one of the largest arteries in the body which
run close to the surface and can be easily reached.

Summary of the Circulation of the Blood. We will now sum up, and put
together in their order, the different things we have learned about the
circulation of the blood through the body.

[Illustration: THE BLOOD-ROUTE THROUGH THE HEART

_R.A._, right auricle; _L.A._, left auricle; _R.V._, right ventricle;
_L.V._, left ventricle; _A_, aorta; _P.A._, pulmonary artery; _P.V._,
pulmonary veins; _V.C.s._, Vena cava superior; _V.C.i._, Vena cava
inferior. At the entrance to the pulmonary artery are shown two of the
pockets of the valve, the third pocket having been cut away with the
front side of the artery. The other blood-tubes have similar valves, not
shown in the diagram.]

Starting from the great vein trunk, the vena cava, it pours into the
receiving chamber, or auricle, of the right side of the heart, passes
between the valves of the opening into the lower chamber, the right
ventricle. When this is full, the muscles in the wall of the ventricle
contract, the valve flaps fly up, and the blood is squirted out through
the pulmonary artery to the lungs. Here it passes through the
capillaries round the air cells, loses its carbon dioxid, takes in
oxygen, and is gathered up and returned through great return pipes to
the receiving chamber, or auricle, of the left side of the heart. Here
it collects while the ventricle below is emptying itself, then pours
down between the valve flaps through the opening to the left ventricle.
When this is full, it contracts; the valves fly up and close the
orifice; and the blood is squirted out through another valve-guarded
opening, into the great main artery, the aorta. This carries it, through
its different branches, all over the body, where the tissues suck out
their food and oxygen through the walls of the capillaries, and return
it through the small veins into the large vein pipes, which again
deliver it into the vena cava, and so to the right side of the heart
from which we started to trace it.

Although the two sides of the heart are doing different work, they
contract and empty themselves, and relax and fill themselves, at the
same time, so that we feel only one beat of the whole heart.

One of the most wonderful things about the entire system of blood tubes
is the way in which each particular part and organ of the body is
supplied with exactly the amount of blood it needs. If the whole body is
put to work, so that a quicker circulation of blood, with its millions
of little baskets of oxygen, is needed to enable the tissues to breathe
faster, the heart meets the situation by beating faster and harder.
This, as you all know, you can readily cause by running, or jumping, or
wrestling.



CHAPTER XII

THE CARE OF THE HEART-PUMP AND ITS PIPE-LINES


The Effect of Work upon the Heart. Whatever else in this body of ours
may be able to take a rest at times, the heart never can. When it stops,
we stop! Naturally, with such a constant strain upon it, we should
expect it to have a tendency to give way, or break down, at certain
points. The real wonder is that it breaks down so seldom. It has great
powers of endurance and a wonderful trick of patching up break-downs and
adjusting itself to strains.

Every kind of work, of course, done in the body throws more work upon
the heart. When we run, or saw wood, our muscles contract, and need more
food-fuel to burn, and pour more waste-stuff into the blood to be thrown
off through the lungs; so the heart has to beat harder and faster to
supply these calls. When our stomach digests food, it needs a larger
supply of blood in its walls, and the heart has to pump harder to
deliver this. Even when we think hard or worry over something, our brain
cells need more blood, and the ever-willing heart again pumps it up to
them. This is the chief reason why we cannot do more than one of these
things at a time to advantage. If we try to think hard, run foot races,
and digest our dinner all at one and the same time, neither head,
stomach, nor muscles can get the proper amount of blood that it
requires; we cannot do any one of the three properly, and are likely to
develop a headache, or an attack of indigestion, or a "stitch in the
side," and sometimes all three. So the circulation has a great deal to
do with the intelligent planning and arranging of our work, our meals,
and our play. If we are going to increase our endurance, we must
increase the power of our heart and blood vessels, as well as that of
our muscles. The real thing to be trained in the gymnasium and on the
athletic field is the heart rather than the muscles.

Fortunately, however, the heart is itself a muscle, alive and growing,
and with the same power of increasing in strength and size that any
other muscle has. So that up to a proper limit, all these things which
throw strain upon the heart in moderate degree, such as running,
working, and thinking, are not only not harmful, but beneficial to it,
increasing both its strength and its size. The heart, for instance, of a
thoroughbred race-horse is nearly twice the size, in proportion to his
body weight, of the heart of a dray-horse or cart-horse; and a deer has
more than twice as large a heart as a sheep of the same weight.

[Illustration: THE SCHOOL PHYSICIAN EXAMINING HEART AND LUNGS]

The important thing to bear in mind in both work and play, in athletic
training, and in life, is that this work must be kept easily within the
powers of the heart and of the other muscles, and must be increased
gradually, and never allowed to go beyond a certain point, or it becomes
injurious, instead of beneficial; hurtful, instead of helpful. Over-work
in the shop or factory, overtraining in the gymnasium or on the
athletic field, both fall first and heaviest upon the heart.

Importance of Food, Air, and Exercise. At the same time, the system
must be kept well supplied through the stomach with the raw material
both for doing this work and for building up this new muscle. When
anyone, in training for an event, gets "stale," or overtrained, and
loses his appetite and his sleep, he had better stop at once, for that
is a sign that he is using more energy than his food is able to give him
through his stomach; and the stomach has consequently "gone on a
strike."

How to Avoid Heart Overstrain and Heart Disease. The way, then, to
avoid overstrain and diseases of the heart and blood vessels is:--

First, to take plenty of exercise, but to keep that exercise within
reasonable limits, which, in childhood, ought to be determined by a
school physician, and in workshops and factories by a state factory
physician.

Second, to take that exercise chiefly in the open air, and as much of it
as possible in the form of play, so that you can stop whenever you begin
to feel tired or your heart throbs too hard--in other words, whenever
nature warns you that you are approaching the danger line.

Third, to keep yourself well supplied with plenty of nutritious,
wholesome, digestible food, so as to give yourself, not merely power to
do the work, but something besides to grow on.

Fourth, to avoid poisonous and hurtful things like the toxins of
infectious diseases; and alcohol, tobacco, and other narcotics, which
have a harmful effect upon the muscles, valves, or nerves of your heart,
or the walls of your blood vessels.

Fortunately, the heart is so wonderfully tough and elastic, and can
repair itself so rapidly, that it usually takes at least two, and
sometimes three, causes acting together, to produce serious disease or
damage. For instance, while muscular overwork and overstrain alone may
cause serious and even permanent damage to the heart, they most
frequently do so in those who are underfed, or badly housed, or
recovering from the attack of some infectious disease. While the poisons
of rheumatism and alcohol will alone cause serious damage to the valves
of the heart and walls of the blood vessels, yet they again are much
more liable to do so in those who are overworked, or underfed, or
overcrowded.

The Disease of the Stiffening of the Arteries. The points at which our
pipe-line system is most likely to give way are the valves of the heart,
and, more likely still, the muscles of the heart wall and of the walls
of the blood vessels. These little muscles are slowly, but steadily,
changing all through life, becoming stiffer and less elastic, less
alive, in fact, until finally, in old age, they become stiff and rigid,
turning into leathery, fibrous tissue, and may even become so soaked
with lime salts as to become brittle, so that they may burst under some
sudden strain. When this occurs in one of the arteries of the brain, it
causes an attack of _apoplexy_, or a "stroke of paralysis." Overstrain,
or toxins in the blood, may bring about this stiffening of the arteries
too soon, and then, we say that the person is "old before his time." A
man is literally "as old as his arteries."

The causes which will hasten the stiffening of the arteries are, first
of all, prolonged overwork and overstrain,--due especially to long hours
of steady work in unwholesome shops or surroundings; second, the
presence in the blood of the poisons of the more chronic infectious
diseases, like tuberculosis; third, the waste products that are formed
in our own body, and are not properly got rid of through lungs, skin,
and kidneys; and fourth, the use of alcohol, tobacco, and other
narcotics.

The Bad Effects of Alcohol. Alcohol is particularly likely to damage
the walls of the blood vessels and the heart, first, because it is a
direct poison to their cells, when taken in excess, and often in what
may appear to be moderate amounts, if long continued; secondly, because
it is frequently taken, especially by the poorer, underfed class of
workers, as a substitute for food, causing them literally to "spend
their money for that which is not bread," and to leave their tissues
half-starved; and thirdly, because, by its narcotic effects, it
decreases respiration and clogs the kidneys and the skin, thus
preventing the waste products from leaving the body.

How the Heart Valves may be Injured. The valves of the heart are
likely to give way, partly because they are under such constant strain,
snapping backward and forward day and night; and partly, because, in
order to be thin enough and strong enough for this kind of work, they
have become turned, almost entirely, into stringy, half-dead, fibrous
tissue, which has neither the vitality nor the resisting power of the
live body-stuffs like muscles, gland-cells, and nerves. They are so
tough, however, that they seldom give way under ordinary wear and tear,
as the leather of a pump valve, or of your shoes, might; but the thing
which damages them, nine times out of ten, is the germs or poisons of
some infectious disease.

These poisons circulating through the blood, sometimes set up a severe
inflammation in the valves and the lining of the heart. Ulcers, or
little wart-like growths, form on the valves; and these may either eat
away and destroy entirely parts of the valves or, when they heal, leave
scars which shorten and twist the valves out of shape, so that they can
no longer close the openings. When this has happened, the heart is in
the condition of a pump which will not hold water, because the leather
valve in its bucket is broken or warped; and we say that the patient
has _valvular_ or _organic_ heart disease.

The disease which most frequently causes this serious defect is
rheumatism, or rheumatic fever; but it may also occur after pneumonia,
typhoid, blood poisoning, or even after a common cold, or an attack of
the grip. This is one of several reasons why we should endeavor, in
every way, to avoid and stop the spread of these infectious diseases;
not only are they dangerous in themselves, but although only two of
them, rheumatism and pneumonia, frequently attack the heart, all of them
do so occasionally, and together they cause nearly nine-tenths of all
cases of organic heart disease.

Should you be unfortunate enough to catch one of these diseases, the
best preventive against its attacking the heart, or causing serious
damage, if it does, is a very simple one--rest in bed until the fever is
all gone and your doctor says it is perfectly safe for you to get up;
and avoid any severe muscular strain for several months afterward.

This is a most important thing to remember _after all infections and
fevers_, no matter how mild. Even where the heart valves have been
seriously attacked, as in rheumatism, they will often recover almost
completely if you keep at rest, and your heart is not overtaxed by the
strain of heavy, muscular work, before it has entirely recovered. Ten
days' "taking it easy" after a severe cold, or a bad sore throat, may
save you a serious strain upon the heart, from which you might be months
or even years in recovering.

But even where serious damage has been done to the heart, so that one of
its valves leaks badly, nature is not at the end of her resources. She
simply sets to work to build up and strengthen and thicken the heart
muscle until it is strong enough to overcome the defect and pump blood
enough to keep the body properly supplied--just as, if you are working
with a leaky pump, you will have to pump harder and faster in order to
keep a good stream of water flowing. It is astonishing how completely
she will make good the loss of even a considerable part of a valve.

Doctors no longer forbid patients with heart disease to take exercise,
but set them at carefully planned exercise in the open air, particularly
walking and hill-climbing; at the same time feeding them well, so as to
assist nature in building up and strengthening the heart muscle until it
can overcome the defect. In this way, they may live, with reasonable
care, ten, fifteen, or twenty years--often, in fact, until they die of
something else.

Don't worry about your heart if it should happen to palpitate, or take a
"hop-skip-and-jump" occasionally. You will never get real heart disease
until you have had some fever or serious illness, which leaves you short
of breath for a long time afterward.

Danger to the Heart through the Nervous System. The other chief way in
which the heart may be affected is through the nervous system. Being the
great supply pump for the entire body, it is, of course, connected most
thoroughly and elaborately by nerve wires with the brain and, through
it, with every other organ in the body. So delicately is it geared,--set
on such a hair-trigger, as it were,--that it not only beats faster when
work is done anywhere in the body, but begins to hurry in anticipation
of work to be done anywhere. You all know how your heart throbs and
beats like a hammer and goes pit-a-pat when you are just expecting to do
something important,--for instance, to speak a piece or strike a fast
ball,--or even when you are greatly excited watching somebody else do
something, as in the finish of a close race.

Two-thirds of the starts and jumps and throbbings that the heart makes,
are due to excitement, or nervous overstrain, or the fact that your
dinner is not digesting properly; and they don't indicate anything
serious at all, but are simply useful danger signals to you that
something is not just right.

In work and in athletics for instance, this rapid and uncomfortably
vigorous action of the heart is one of nature's best checks and guides.
When your heart begins to throb and plunge uncomfortably, you should
slow up until it begins to quiet down again, and you will seldom get
into serious trouble. The next time you try the same feat, you will
probably find that you can go a little farther, or faster, without
making it throb. Indeed, getting into training is very largely getting
the heart built up and educated, so that you can run or play, or wrestle
hard without overtaxing it. Whatever you can do within the limits of
your heart is safe, wholesome, and invigorating; whatever goes beyond
this, is dangerous and likely to be injurious.

[Illustration: ROWING IS A SPLENDID EXERCISE FOR HEART AND LUNGS]

Occasionally, however, some of the nerves which control the heart become
disturbed or diseased so that, instead of the heart's simply beating
harder and faster whenever more blood is really needed, it either throbs
and beats a great deal harder and faster than is necessary, or goes
racing away on its own account, and beats "for dear life," when there is
no occasion for it, thus tiring itself out without doing any good, and
producing a very unpleasant feeling of nervousness and discomfort. This
may be due to overwork, whether with muscles or brain; or to worry or
loss of sleep, in which case it means that you must put on the brakes,
take plenty of rest and exercise in the open air, and get plenty of
sleep. Then these danger signals, having accomplished their warning
purpose, will disappear.

Other Causes of Heart Trouble. At other times, this palpitation is due
to the presence of poisons in the blood, either those of infectious
disease, or of certain waste products produced in the body in excess,
as, for instance, when your digestion is out of order, or your skin,
kidneys, and bowels are not working properly; or it is due to tea,
coffee, or tobacco.

Effects of Tea and Coffee. Tea and coffee, if taken in excess, will
sometimes produce very uncomfortable palpitation, or rapid over-action
of the heart, with restlessness and inability to sleep. They usually act
in this way only when taken in large amounts, or upon a small percentage
of persons who are peculiarly affected by them; and this palpitation is
seldom serious, and disappears when their excessive use is stopped.

Tobacco and its Dangers to the Heart. Tobacco has a very injurious
effect upon the nerves of the heart in the young, making them so
irritable that the heart will beat very rapidly on the least exertion;
so that gradually one becomes less and less inclined to attempt exertion
of any sort, whether bodily or mental, and falls into a stagnant, stupid
sort of condition which seriously interferes with both growth and
progress.

In other cases, tobacco dulls and deadens the nerves controlling the
heart, as it does the rest of the nervous system and the brain, so that
the smoker feels as if nothing were worth while doing very hard, and it
becomes difficult for him to fix his mind upon a subject. At the same
time, it dulls the appetite so that one takes less wholesome food; and
it checks, or clogs up, the sewer-pipes of the skin, the liver, and the
kidneys.

Of course, as you know, all trainers and coaches, even though they be
habitual smokers themselves, absolutely forbid tobacco in any form to
athletes who are training for a contest, on account of its effects upon
the nervous system and the heart.

A certain percentage of individuals are peculiarly susceptible to
tobacco, so that it has a special poisonous effect upon the nerves of
the heart, causing a rapid pulse and shortness of breath, known as
_tobacco heart_. This is not of very common occurrence; but it is
exceedingly troublesome when it does occur, and it takes a long time to
get over it, even after the use of tobacco has been stopped entirely.
Sometimes it leads to permanent damage of the nerves and of the heart.

Give your heart plenty of vigorous exercise, but don't make it beat
uncomfortably hard. Give it plenty of food, sleep, and fresh air; _avoid
poisoning it_, either with the toxins of diseases, or with your own
waste-poisons, or alcohol, or tobacco; and it will serve you faithfully
till a good old age.



CHAPTER XIII

HOW AND WHY WE BREATHE


Life is Shown by Breathing. If you wanted to find out whether a little
black bunch up in the branches of a tree were a bird or a cluster of
leaves, or a brown blur in the stubble were a rabbit or a clod, the
first thing you would probably look for would be to see whether it
moved, and secondly, if you could get close enough without its moving
away, whether it were breathing. You would know perfectly well if you
saw it breathing that it was alive, and that, if it were not breathing
at all, it would probably be dead, or very nearly so.

Why is breathing so necessary to life that it lasts practically as long
as life does, and when it stops, life stops too? Animals can stop eating
for days, or even weeks, and yet live, especially if they were fairly
fat when they began to fast. Indeed, some animals, like woodchucks,
bears, and marmots, will go to sleep in the fall, and sleep right on
through to spring without eating a mouthful. But if any animal or bird
is prevented from breathing for three minutes, it will die.

Short Storage Supply of Air. There is a difference between the kind of
things that you take in when you breathe and the kind of things you take
in when you eat or drink. Food and drink are solids and liquids; and the
body is a great sponge of one soaked full of the other, so that large
amounts of food and water can be stored up in the body. But what you
take in when you breathe is, of course, air--which is neither a solid
nor a liquid, but a gas, very light and bulky. Of gases the body can
soak up and hold only a very small amount; so its storage supply of
them will be used up completely in about three minutes, and then it dies
if it cannot get more air.

Why our Bodies Need Air-Oxidation. The body is made up of millions of
tiny living animals called cells, which eat the food that is brought to
them from the blood and pour their waste and dirt back again into the
same current. Now, what would happen if we were to throw all the garbage
from the kitchen, and the wash water from the kitchen sink, and the
dirty water from the bathroom right into the well out of which we pumped
our drinking water? We should simply be poisoned within two or three
days, if indeed we could manage to drink the disgusting mixture at all.
That is exactly what would happen to our body cells if they were not
provided with some way of getting rid of their waste and dirt.

[Illustration: THE GREAT ESSENTIAL TO LIFE--AIR

If the air, supplied to the diver through the tube, is cut off for three
minutes, or even less, the diver cannot live.]

Part of the waste that comes from our body cells is either watery, or
easily dissolved in water; and this is carried in the blood to a
special set of filter organs--the liver and the kidneys--and poured out
of the body as the _urine_. Another part of it, when circulating through
the skin, is passed off in the form of that watery vapor which we call
perspiration, or sweat. But part of the waste can be got rid of only by
burning, and what we call burning is another name for combining with
oxygen, or to use one word--_oxidation_; and this is precisely the
purpose of the carrying of oxygen by the little red blood cells from the
lungs to the deeper parts of the body--to burn up, or oxidize, these
waste materials which would otherwise poison our cells. When they are
burnt, or oxidized, they become almost harmless.

Why the Red Cells Carry only Oxygen to the Body. But why do not the
red cells carry air instead of just oxygen? This is simply a clever
little economy of space on nature's part. As a chemist will tell you the
air which we breathe is a mixture of two gases--one called nitrogen and
the other oxygen; just as syrup, for instance, is a mixture of sugar and
water. Then too, as in syrup, there are different amounts of the two
substances in the mixture: as syrup is made up of about one-quarter
sugar and three-quarters water, so air is made up of one-fifth oxygen
and four-fifths nitrogen. Now the interesting thing about this mixture,
which we call air, is that the only really "live" and vital part of it
for breathing purposes is the one-fifth of oxygen, the four-fifths of
nitrogen being of no use to our lungs. In fact, if you split up the air
with an electric current, or by some other means, and thus divide it
into a small portion of pure oxygen (one-fifth), and a very much larger
portion (four-fifths) of nitrogen, the latter would as promptly
suffocate the animal that tried to breathe it as if he were plunged
under water.[18]

It may perhaps be difficult to think of anything burning inside of your
bodies where everything is moist, especially as you do not see any
flame; but you do find there one thing which always goes with burning,
and that is warmth, or heat. This slow but steady and never-ceasing
burning, or oxidation, of the waste and dirt inside your bodies is what
keeps them warm. When you run fast, or wrestle, or work hard, your
muscle-cells work faster, and make more waste, and you breathe faster to
get in the oxygen to burn this up--in other words, you fan the body
fires, and in consequence you get a great deal hotter, and perhaps
perspire in order to get rid of your surplus heat.

The Ocean of Air. Where does the blood in the body go in order to get
this oxygen, which is so vital to it? Naturally, somewhere upon the
surface of the body, because we are surrounded by air wherever we sit,
or stand, or move, just as fishes are by water. All outdoors, as we say,
is full of air. We are walking, just as fishes swim, at the bottom of an
ocean of air some thirty miles deep; and the nearer we get up toward the
surface of that ocean, as, for instance, when we climb a high mountain,
the lighter and thinner the air becomes. Above ten thousand feet we
often have great difficulty in breathing properly, because the air is so
thin and weak in oxygen.

How the Lungs Grew Up. In the simplest forms of life, any part of the
soft and delicate surface will do for the blood to reach, in order to
throw off its load of carbon "smoke" and take on its supply of oxygen.
In fact, animals like jellyfish and worms are lungs all over. But as
bodies begin to get bigger, and the skin begins to toughen and harden,
this becomes more and more difficult, although even the highest and
biggest animals like ourselves still throw off a certain amount of this
carbon dioxid and other gases through the skin. Accordingly, certain
parts of the surface of the body are set apart specially for this
business of breathing; and as we already have an opening into the body
provided by the mouth and food tube, the simplest thing to do is to use
the mouth for taking in air, when it is not being used for taking in
food, and to set aside some part of the food tube for breathing
purposes.

[Illustration: DIAGRAM OF THE AIR TUBES AND LUNGS

The arrows show the direction of the incoming air.]

The lungs sprout out from the front of the gullet, just below the root
of the tongue, in the days when we are getting ready to be born. The
sprout divides into two, forming the beginning of the pair of lungs.
Each lung sprout again divides into two, and each of the two smaller
buds again into two, until finally we have the whole chest filled up
with a "lung-tree" whose trunk stems and leaves are hollow. The stem of
the tree or bush becomes the windpipe (_trachea_). The first two
branches into which it divides form the right and left lung tubes,
known as _bronchi_. The third, fourth, fifth, sixth, etc., divisions,
and so on, form what are known as the _bronchial tubes_. These keep on
splitting into tinier and tinier twigs, until they end, like the bush,
in little leaves, which in the lung, of course, are hollow and are
called the air cells (_alveoli_). This budding off of the lungs from the
gullet is the reason why the air we breathe and the food we swallow go
down the same passage. Every mouthful of our food slides right across
the opening of the windpipe, which has to be protected by a special
flap, or trap-door of gristle, called the _epiglottis_. If you try to
eat and talk at the same time, the epiglottis doesn't get warning of the
coming of a swallow of food in time to cover the opening of the
windpipe, and the food goes down the wrong way and you cough and choke.

Now, if you will just place your fingers upon the front of your neck and
slide them up and down, you will, at once, feel your windpipe--a hard,
rounded tube with ridges running across it,--while, no matter how
carefully you feel, or how deeply you press, you cannot feel your gullet
or esophagus at all. Just take a mouthful of water, however, put your
fingers deeply on each side of the windpipe, and swallow, and you will
feel something shoot down the esophagus, between your fingers, toward
the stomach.

Both of these tubes were made of exactly the same materials to begin
with. Why have they become so different? A moment's thought will tell
you. One, the gullet, has only to swallow solid food or drink, so that
its walls can remain soft, and indeed fall together, except when it is
actually swallowing. The other tube, the air-pipe or windpipe, has to
carry air, which neither will fall of its own weight, nor can readily be
gulped down or belched up. It is absolutely necessary that its walls
should become stiff enough to keep it open constantly and let the air
flow backward and forward. So we find growing up in the walls of this
air pipe, cells which turn themselves into rings of gristle, or
cartilage.

What the Breath Is. As you know, your "breath," as you call it,--that
is to say, the used-up air which you blow out of your lungs,--is
different in several ways from pure, or unused air. In the first place,
it is likely to have a slight musky or mousy odor about it. You never
like to breathe any one else's breath, or have any one breathe in your
face. This dislike is due to certain gases, consisting of impurities
from the blood, the cells of the lungs, the throat, the nose, and, if
the mouth is open, the teeth. These are not only offensive and
disagreeable to smell, but poisonous to breathe.

Then your breath is much warmer than the rest of the air. In fact, on a
very cold morning you may have tried to warm up your fingers by
breathing on them; and you have also noticed that if a number of people
are shut up in a room with doors and windows closed, it soon begins to
feel hot as well as stuffy. This heat, of course, is given off from the
blood in the lungs and in the walls of the throat and nose, as the air
passes in and out again.

When you stand at the window on a cold day, the glass just in front of
your mouth clouds over, so that you can no longer see through it; and if
you rub your finger across this cloud, it comes away wet. Evidently, the
air is moister than it was when you breathed it in; this moisture also
has been given off from the blood in the lungs.

But what of the principal waste gas that the blood gives off in the
lungs--the carbon "smoke," or carbon dioxid? Can you see any trace of
this in the breath? No, you cannot, for the reason that this gas is like
air, perfectly clear and transparent, and never turns to moisture at any
ordinary temperature. But it has a power of combining with certain other
things and forming substances which, because they are combinations of
carbon, are called _carbonates_. The commonest substance with which it
will do this is lime. If you take a glass or a bottle two-thirds full of
lime water, and breathe into it through a glass tube or straw, you will
see in a very few minutes that it is becoming milky or cloudy from the
formation of visible carbonate of lime, which, when you get enough of
it, makes ordinary limestone. So, although you cannot see, or smell,
this carbon "smoke" in your breath, you can readily prove that it is
present.

[Illustration: "IMPROVING THEIR WIND"]

How and Why our Breathing Varies. When you run or wrestle, you breathe
faster in order to draw more air into the lungs. At the same time, your
heart beats faster in order to drive a larger amount of blood through
the lungs. If you run too far, or wrestle too hard, your heart and your
lungs both go faster and faster, until finally they reach a point when
they cannot go any quicker, and the poisonous waste substances are
formed in your muscles faster than they can possibly be burned up, even
by the quickest breathing and the hardest pumping of your heart. Then
you begin to get "out of breath"; and if you were compelled--in order to
save your life, for instance--to keep on running, or fighting, you
would at last be suffocated by your own waste and dirt, and fall
exhausted, or unconscious.

On the other hand, by carefully training your muscles and your heart and
your lungs by exercises of various sorts in the open air, beginning with
easy ones and going on to harder and longer ones, you can "improve your
wind," so that your heart will be able to pump more blood through the
lungs per minute, and your lungs will be able to expand themselves more
fully and more rapidly without fatigue.

If you can recall having had a fever of any sort, even a slight one,
such as comes with a sore throat or a bad cold, you may remember that
you breathed faster and that your heart beat faster, and yet you were
not doing any work with your muscles. The cause, however, is the same;
namely, the amount of waste that is being produced in the body--in this
case, by the poisons (toxins) of the germs that cause the fever. The
more waste that is formed in the body, the more effort the heart and
lungs will make to try to get rid of it.

The Ribs. How does the air get in and out of the lung tubes? Evidently
you do not and cannot swallow it as you would food or drink; and as it
will not run down of its own accord when you simply open your mouth,
nature has had to devise a special bit of machinery for the purpose of
sucking it in and pressing it out again. This she has done in a rather
ingenious manner by causing certain of the muscle-rings in the wall of
the chest to turn first into gristle, or cartilage, and then later into
bone, making what are known as the _ribs_; these run round the chest
much as hoops do round a barrel, or as the whalebone rings did in the
old-fashioned hoop skirt. When the muscles of the chest pull these ribs
up, the chest is made larger,--like a bellows when you lift the
handle,--air is sucked in, and we "breathe in" as we say; when the
muscles let go, the ribs sink, the chest flattens and becomes smaller,
the air is driven out, and we "breathe out."


FOOTNOTES:

[18] This nitrogen, though of no value for breathing, is of great value
as a food, forming, as we have seen, an important part of all meats, or
proteins, which build the tissues of our bodies. It can, however, be
taken from the air only with great difficulty, by a very roundabout
route; the bacteria of the soil eat it first, then they pass it on as
food to the roots of plants; animals eat plants, and we eat the animals,
and thus get most of our nitrogen.



CHAPTER XIV

HOW TO KEEP THE LUNG-BELLOWS IN GOOD CONDITION


THE NEED OF PURE AIR

Free Air is Pure. As air, in the form of wind, actually sweeps all
outdoors, day and night, it clearly is likely to pick up a good many
different kinds of dust and dirt, which may not be wholesome when
breathed into our lungs. Fortunately, nature's great outdoor system of
purifying the air is almost perfect, so that it is only when we build
houses and shut in air from the great outdoor circulation, that "dirt"
that is really dangerous begins to get into it. Caged air is the only
air that is dangerous. Free-moving air is always perfectly safe to
breathe any hour of the day or night, or any season of the year.

Shut-in and Stagnant Air is Foul. This restless air-gas cannot be
stored outside of the body, any better than it can be inside. For one
thing, it is too bulky; and for another, it begins to become impure in
various ways, as soon as it is shut up. It is the most unmanageable food
that we "eat," for we can neither cook it nor wash it like solid food,
nor filter it nor boil it like water, except on a very limited scale. We
can do nothing to it except to foul it, which we do with every breath
that we breathe, every fire that we make, every factory that we build.
Our only chance of safety, our only hope of life, is to connect every
room and every corner of those little brick and mortar boxes, those
caged sections of out-of-doors, that we call houses, with nature's great
system of air supply, "All Outdoors." Fortunately, the only thing
needed to make the connection is to open a window--no need to send for a
plumber or put in a meter, and there is no charge for the supply after
connections have been made.

The Enormous Amount of Air. Air outdoors is everywhere, for practical
purposes, absolutely pure, just as water is when it comes down from the
clouds. And like water, its only dangerous impurities are what we put
there ourselves. The purity of outdoor air is due mainly to the fact
that there is such an enormous amount of it, not only the miles and
miles of it that stretch away on every side of us, but nearly thirty
miles of it straight up above our heads; its purity is also due to the
fact that, like water, it is always in motion. When heated by the sun,
it expands; and, in doing so, it rises because it is less dense and
therefore lighter. As soon as the pressure of the air above is lessened,
air rushes in below from all the cooler regions around. This rushing of
air we call a _wind_. If the low pressure lies to the north of us, the
air rushes northward over us to fill it, and we say the wind is from the
south; if the air is flowing to the south of us, we say the wind is from
the north.

How Air is Purified. In these winds certain small amounts of dust, or
dirt, or leaf mould are whirled up into the air, but these are promptly
washed down again whenever it rains; and the same is true of the smoke
impurities in the air of our great cities. Air is also constantly being
purified by the heat and light of the sunbeams, burned clean in streaks
by the jagged bolt of the lightning in summer, and frozen sweet and pure
by the frosts every winter. So that air in the open, or connected with
the open, and free to move as it will, is always pure and wholesome. But
to be sure of this, it must be "eaten alive"--that is, in motion.
Stagnant air is always dead and, like all dead things, has begun to
decay.

The Carbon Dioxid in the Air. Air, as you will remember (p. 132), is a
mixture of oxygen and nitrogen, and its value in the body is that it
gives off part of its oxygen to combine with the body wastes and burn
them to carbon dioxid. Oddly enough, even pure outdoor air contains tiny
traces of carbon dioxid; but the amount is so very small as to be of no
practical importance, in spite of the fact that every kind of animal
that lives and moves upon the earth is pouring it out from his lungs
every second. The rapidity with which it disappears is due in part to
the rapidity with which it rises and spreads, or is blown, in every
direction; and in part to the wonderful arrangement by which, while
animals throw off this poisonous gas as waste, plants eagerly suck it in
through the pores in their leaves and eat it, turning it into the
carbohydrates, starch and sugar, which, in turn, become valuable foods
for the animals. So perfect is this system of escape, or blowing away,
of carbon dioxid, combined with its being eaten up by plants, that even
the air over our great cities and manufacturing towns contains only the
merest trifle more of carbon dioxid than that over the open country. Its
other smoke-impurities, dirts and dusts, escape, or are blown away so
rapidly that they are seldom thick enough to be injurious to health,
except in the narrowest and darkest streets; so that it is always safe
to open your windows wide for air, wherever you may live. The principal
danger from smoke is that it cuts off the sunlight.

The Necessity for Ventilation--Impurities of Indoor Air. The worst
impurities in air are those that come from our own breaths and our own
bodies; and, unexpectedly enough, carbon dioxid is not one of them. In
spite of hundreds of experiments, we do not yet know exactly what these
impurities are, though they are doubtless given off from our lungs, our
skins, our mouths, and teeth, especially if the latter are not kept
clean and sweet, but left dirty and decaying.

We do know, however, to a certainty that air shut up in a room, or
house, with people, rapidly becomes poisonous and unwholesome. As we
breathe on an average about eighteen or twenty times to the minute when
we are grown up, and twenty-five to thirty times a minute when we are
children, you can readily see how quickly the air in an ordinary-sized
room will be used up, and how foul and unfit for further breathing it
will become from being loaded with these bad-smelling lighter gases,
with the carbon "smoke," with heat, and with moisture. The only way in
which a room can be kept fit for human beings to breathe in is to have a
draught, or current of air, pouring into it through open windows, or
open doors, or ventilating shafts, at least as rapidly as it is being
breathed by the persons who occupy that room. By hundreds of tests this
has now been found to be on an average about four bushels a minute for
each person, and any system of proper ventilation must supply this
amount of air in order to make a room fit to sit in.

If a man, for instance, accidentally gets shut into a bank-vault, or
other air-tight box or chamber, it will be only a few minutes before he
begins to feel suffocated; and in a few hours he will be dead, unless
some one opens the door. A century ago, when the voyage from Europe to
America was made in sailing vessels, whenever a violent storm came up,
in the smaller and poorer ships the hatches were closed and nailed down
to keep the great waves which swept over the decks from pouring down the
cabin-stairs and swamping the ship. If they were kept closed for more
than two days, it was no uncommon thing to find two or three children or
invalids among the unfortunate emigrants dead of slow suffocation; and
many of those who were alive would later have pneumonia and other
inflammations of the lungs. On one or two horrible occasions, when the
crew had had a hard fight to save the ship and were afraid to open the
hatches even for a moment, nearly one-third of the passengers were found
dead when the storm subsided. So it is well to remember that we are
fearfully poisonous to ourselves, unless we give nature full chance to
ventilate us.

There are also other ways in which the air in houses may be made impure
besides by our own bodies, but none of them is half so serious or
important. All the lights that we burn in a house, except electric ones,
are eating up oxygen and giving off carbon dioxid. In fact, a burning
gas jet will do almost as much toward fouling the air of a room as a
grown man or woman, and should be counted as a person when arranging for
ventilation.

If gas pipes should leak, so that the gas escapes into a room, it is
very injurious and unwholesome--indeed, in sufficient amounts, it will
suffocate. Or, if the sewer pipes in the walls of the house, or in the
ground under the cellar, are not properly trapped and guarded, _sewer
gas_ may escape into the house from them, and this also is most
unwholesome, and even dangerous.

Cellar and Kitchen Air. Houses in which fruit and vegetables are
stored in the cellar become filled with very unpleasant odors from the
decay of these. Others again, where the kitchen is not properly
ventilated, get the smoke of frying and the smell of cooking all through
them. But such sources of impurity, while injurious and always to be
strictly avoided, are neither half so dangerous when they occur, nor
one-tenth so common as the great chief cause of impure air--our breaths
and the other gases from our bodies, with the germs they contain.

Drafts not Dangerous. Now comes the practical question, How are we to
get rid of these breath-poisons? From the carelessness of builders, and
the porous materials of which buildings are made, most houses are very
far from air-tight, and a considerable amount of pure air will leak in
around window-casings, door-frames, knot-holes, and other cracks, and a
corresponding amount of foul air leak out. But this is not more than
one-fifth enough to keep the air fresh when the rooms are even partially
occupied, still less when they are crowded full of people. As each
individual, breathing quietly, requires about four bushels of air (one
and a half cubic yards) a minute, it is easy to see that, when there are
ten or more people in a room, there ought to be a steady current of air
pouring into that room; and when there are twenty or even forty people,
as in an average schoolroom, the current of air (provided there _is_
one) must move so fast to keep up the supply that the people in the room
begin to notice it and call it "a draft." It would be difficult to
ventilate a room for even four or five persons without producing, in
parts of it, a noticeable draft of air. In fact, it is pretty safe to
say that, if somebody doesn't feel a draft the room is not being
properly ventilated. At one time this was considered a very serious
drawback--drafts were supposed to be so dangerous. But now we know that
a draft is only air in motion, and that air in motion is the _only air
that is sure to be pure_. There is nothing to be afraid of in a draft
which is not too strong, if you are clean outside and in, and reasonably
vigorous. If the draft is too strong, move away from the window or the
door. Colds are very seldom caught from the cold, pure air of a draft,
but nearly always from the germs, or dirt, in the still, foul air of a
tightly closed room. This fact has swept away the chief objection to the
_direct_, or natural, method of ventilating through open windows.

Methods of Ventilation. Fortunately, as often happens, the simplest
and most natural method of ventilation is the best one. Open the
windows, and let the fresh air pour in. If there be any room which
hasn't windows enough in it to ventilate it properly, it is unfit for
human occupation, and is seldom properly lighted. Most elaborate and
ingenious systems of ventilation have been devised and put into our
larger houses, and public buildings like libraries, court-houses,
capitols, and schools. Some of them drive the air into each room by
means of a powerful steam, or electric, fan in the basement; others suck
the used-up air out of the upper part of each room, thus creating an
area of low pressure, to fill which the fresh air rushes in through
air-tubes or around doors and windows. They have elaborate methods of
warming, filtering, and washing the air they distribute. Some work
fairly well, some don't; but they all have one common defect--that what
they pump into the rooms is not _fresh_ air, though it may conform to
all the chemical tests for that article. "The proof of the pudding is in
the eating," and fresh air is air that will make those who breathe it
_feel_ fresh, which the cooked and strained product of these artificial
ventilating systems seldom does.

[Illustration: THE "DARK ROOM" DANGER OF THE TENEMENTS

The rooms "ventilate" from one to another; bedroom, dining-room, and
kitchen being practically one room, with only one window opening to the
_outer air_. Most of the old small tenements were built on this plan and
are accountable for much of the lung disease in cities to-day.]

If they could be combined with the natural, window system of
ventilation, they would be less objectionable; but the first demand of
nearly all of them is that the windows must be kept shut for fear of
breaking the circuit of their circulation. Any system of ventilation, or
anything else, that insists on all windows being kept shut is radically
wrong. It is only fair to say, however, that most of these systems of
ventilation attempt the impossible, as well as the undesirable thing of
keeping people shut up too long. No room can be, or ought to be,
ventilated so that its occupants can stay in it all day long without
discomfort. In ventilating, we ought to _ventilate the people in the
room_, as well as the room itself. This can only be done successfully by
turning the people out of doors, at least every two or three hours if
grown-ups, and every hour or so if children. That is what school
recesses are for, and they might well be longer and more frequent.

[Illustration: VENTILATING THE PUPILS, AS WELL AS THE CLASSROOM]

The first and chief thing necessary for the good ventilation of houses
and schools is plenty of windows, which are also needed to give proper
light for working purposes, and to let in the only ever-victorious enemy
of germs and disease--sunlight.

Secondly, and not less important, the windows should fit properly, and
be perfectly hung and balanced, so that the sash will come down at a
finger's touch, stay exactly where it is put, and go up again like a
feather, instead of having to be pried loose, wrested open, held in
place with a stick, and shoved up, or down again, only with a struggle.

[Illustration: A WELL-AIRED CLASSROOM

The windows to the left of the pupils cannot, of course, be shown in the
picture, but it can be seen that the lighting of the room is chiefly
from that side. Notice that the windows are both down from the top and
up from the bottom.]

There should be, if possible, windows on two sides of every room, or, if
not, a large transom opening into a hall which has plenty of windows in
it. With this equipment and a good supply of heat, any room can be
properly ventilated and kept so. But it _will not ventilate itself_.
Ventilation, like the colors of the great painter Turner, must be "mixed
with brains"; and those brains must be in the room itself, not down in
the basement. In the schoolroom, each teacher and pupil should regard
the ventilation of the room as the most important single factor in the
success of their work. The teacher has a sensitive thermometer and guide
in, first, her own feelings and, second, the looks and attention of her
pupils. There should be vacant seats or chairs in every room so that
those too near the window in winter can move out of the strong current
of cold air.

[Illustration: A HEALTHFUL ARRANGEMENT OF WINDOWS AND SHADES

The windows face in more than one direction. The shades are hung in the
middle, not only regulating the light in the room, but allowing free
passage of air at the top.]

Windows should reach well up toward the ceiling and be opened _at the
top_, because the foul air given off from the lungs at the temperature
of the body is warmer than the air of the room and consequently rises
toward the ceiling. It is just as important in ventilation to _let the
foul air out_ as to let the fresh air in. In fact, one is impossible
without the other. Air, though you can neither see it, nor grasp it, nor
weigh it, is just as solid as granite when it comes to filling or
emptying a room. Not a foot, not an inch of it can be forced into a room
anywhere, until a corresponding foot or inch is let out of it somewhere.
Therefore, never open a window at the bottom until you have opened it
at the top. If you do, the cold fresh air will pour in onto the floor,
while the hot foul air will rise and bank up against the ceiling in a
layer that gets thicker and thicker, and comes further and further down,
until you may be actually sitting with your head and shoulders in a
layer of warm foul air, and your body and feet in a pool of cool pure
air. Then you will wonder why your head is so hot, and your feet so
cold!

Currents and Circulation of Air. In fact, this tendency of hot air to
rise, and of cold air to sink, or rush in and take its place, which is
the mainspring of nature's outdoor system of ventilation, is one of our
greatest difficulties when we wall in a tiny section of the universe and
call it a room. The difficulty is, of course, greatest in winter time,
when the only pure air there is--that out of doors--is usually cold.
This is one of the few points at which our instincts seem to fail us.
For when it comes to a choice between being warm or well ventilated, we
are sadly prone to choose the former every time. Still we would much
rather be warm _and_ well ventilated than hot and stuffy, and this is
what we should aim for.

The main problem is the cost of the necessary fuel, as it naturally
takes more to heat a current of air which is kept moving through the
room, no matter how slowly, than it does a room full of air which is
boxed in, as it were, and kept from moving on after it has been warmed.
The extra fuel, however, means the difference between comfort and
stuffiness, between health and disease. Fortunately, the very same cold
which makes a room harder to heat makes it easier to ventilate. When air
is warmed, it expands and makes a "low pressure," which sucks the
surrounding cooler air into it, as in the making of winds; so that the
warmer the air inside the room, or the colder the air outside of it,
which is practically the same thing, the more eagerly and swiftly will
the outdoor air rush into it. So keen is this draft, so high this
pressure, that some loosely-built houses and rooms, with only a few
people in them, will in very cold weather be almost sufficiently
ventilated through the natural cracks and leaks without opening a window
or a door at all. And what is of great practical importance, an opening
of an inch or two at the top of a window will admit as much fresh air on
a cold day as an opening of a foot and a half in spring or summer, so
swiftly does cold air pour in.

Bearing this in mind, and also that it is always best to ventilate
through as many openings as possible, both to keep drafts of cold air
from becoming too intense, and to give as many openings for the escape
of the foul air as possible, there will be little difficulty in keeping
any room which has proper window arrangements well ventilated in winter.
An opening of an inch at the top of each of three windows is better than
a three-inch opening at the top of one. But you must use your brains
about it, watching the direction of the wind, and frequently changing
the position of the window sashes to match the changes of heat in the
room, or of cold outside.

No arrangement of windows, however perfect, is likely to remain
satisfactory for more than an hour at a time, except in warm weather.
This watchfulness and attention takes time, but it is time well spent.
"Eternal vigilance" is the price of good ventilation, as well as of
liberty; and you will get far more work done in the course of a morning
by interrupting it occasionally to go and raise or lower a window, than
you will by sitting still and slaving in a stuffy, ill-smelling room.

Plenty of Heat Needed. Any method of heating--open fireplace, stove,
hot air, furnace, hot water, or steam--which will keep a room _with the
windows open_ comfortably warm in cold weather is satisfactory and
healthful. The worst fault, from a sanitary point of view, that a
heating system can have is that it does not give enough warmth, so that
you are compelled to keep the windows shut. Too little heat is often as
dangerous as too much; for you will insist on keeping warm, no matter
what it may cost you in the future, and a cold room usually means
hermetically sealed windows. Remember that coal is cheaper than colds,
to say nothing of consumption and pneumonia.

[Illustration: A HEALTHFUL BEDROOM

Windows on two sides; shades rolling from the middle; draperies few and
washable; no carpet, but rugs by the bedside.]

Ventilating the Bedroom. The same principles that apply to ventilating
a living-room or day-room apply to ventilating a bedroom. Here you can
almost disregard drafts, except in the very coldest weather, and, by
putting on plenty of covering, sleep three hundred days out of the year
with your windows wide open and your room within ten degrees of the
temperature outdoors. You need not be afraid of catching cold. On the
contrary, by sleeping in a room like this you will escape three out of
four colds that you usually catch. Sleeping with the windows wide open
is the method we now use to cure consumption, and it is equally good to
prevent it.

No bedroom window ought to be closed at the top, except when necessary
to keep rain or snow from driving in. Close the windows for a short time
before going to bed, and again before rising in the morning, to warm up
the room to undress and dress in; or have a small inside dressing-room,
with your bed out on a screened balcony or porch. But sleep at least
three hundred nights of the year with the free air of heaven blowing
across your face. You will soon feel that you cannot sleep without it.
In winter, have a light-weight warm comforter and enough warm, but
light, blankets on your bed, and leave the heat on in the room, if
necessary--but _open the windows_.


COLDS, CONSUMPTION, AND PNEUMONIA

Disease Germs. In all foul air there are scores of different kinds of
germs--many of them comparatively harmless, like the yeasts, the moulds,
the germs that sour milk, and the bacteria that cause dead plants and
animals to decay. But among them there are a dozen or more kinds which
have gained the power of living in, and attacking, the human body. In so
doing, they usually produce disease, and hence are known as _disease
germs_.

[Illustration: DISEASE GERMS

(Greatly magnified)

(1) Bacilli of tuberculosis; (2) Bacilli of typhoid fever.]

These germs--most of which are known, according to their shape, as
_bacilli_ ("rod-shaped" organisms), or as _cocci_ (round, or
"berry-shaped" organisms)--are so tiny that a thousand of them would
have to be rolled together in a ball to make a speck visible to the
naked eye. But they have some little weight, after all, and seldom float
around in the air, so to speak, of their own accord, but only where
currents of air are kept stirred up and moving, without much opportunity
to escape, and especially where there is a good deal of dust floating,
to the tiny particles of which they seem to cling and be borne about
like thistle-down. This is one reason why dusty air has always been
regarded as so unwholesome, and why a very high death rate from
consumption, and other diseases of the lungs, is found among those who
work at trades and occupations in which a great deal of dust is
constantly driven into the air, such as knife-grinders, stone-masons,
and printers, and workers in cotton and woolen mills, shoddy mills,
carpet factories, etc.

[Illustration: A VACUUM CLEANER

Most of the dust being emptied from the bag, would, in ordinary
sweeping, have been merely blown around the room. By the vacuum process
the dust is sucked up through the tube into the storing receptacle.]

In cleaning a room and its furniture, it is always best to use a carpet
sweeper, a vacuum cleaner, or a damp cloth, as much as possible, the
broom as little as may be, and the feather duster never. The two latter
stir up disease germs resting peacefully on the floor or furniture, and
set them floating in the air, where you can suck them into your lungs.

There are three great groups of disease germs which may be found
floating in the air wherever people are crowded together without proper
ventilation--for most of these disease germs cannot live long outside of
the body, and hence come more or less directly from somebody else's
lungs, throat, or nose. The most numerous, but fortunately the mildest
group, of these are the germs of various sorts which give rise to
_colds_, _coughs_, and _sore throats_. Then there are two other
exceedingly deadly germs, which kill more people than any other disease
known to humanity--the bacillus of consumption, and the coccus of
pneumonia.

Our best protection against all these is, first, to have our rooms well
ventilated, well lighted, and well sunned; for most of these germs die
quickly when exposed to direct sunlight, and even to bright, clear
daylight. The next most important thing is to avoid, so far as we can,
coming in contact with people who have any of these diseases, whether
mild or severe; and the third is to build up our vigor and resisting
power by good food, bathing, and exercise in the open air, so that these
germs cannot get a foothold in our throats and lungs.

Colds. Two-thirds of all colds are infectious, and due, not to cold
pure air, but to foul, stuffy air, with the crop of germs that such air
is almost certain to contain. They should be called "fouls," not
"colds." They spread from one person to another; they run through
families, schools, and shops. They are accompanied by fever, with
headache, backache, and often chills; they "run their course" until the
body has manufactured enough antitoxins to stop them, and then they get
well of their own accord. This is why so many different remedies have a
great reputation for curing colds.

If you "catch cold," stay in your own room or in the open air for a few
days, if possible, and keep away from everybody else. You only waste
your time trying to work in that condition, and will get better much
more quickly by keeping quiet, and will at the same time avoid infecting
anybody else. Get your doctor to tell you what mild antiseptic to use in
your nose and throat; and then keep it in stock against future attacks.
Often it is advisable to rest quietly in bed a few days, so as not to
overtax the body in its weakened condition.

[Illustration: EXERCISE IN THE COLD IS A GOOD PREVENTIVE OF COLDS]

Keep away from foul, stuffy air as much as possible, especially in
crowded rooms; bathe or splash in cool water every morning; sleep with
your windows open; and take plenty of exercise in the open air; and you
will catch few colds and have little difficulty in throwing off those
that you do catch. Colds are comparatively trifling things in
themselves; but, like all infections however mild, they may set up
serious inflammations in some one of the deeper organs--lungs, kidneys,
heart, or nervous system, and frequently make an opening for the
entrance of the germs of tuberculosis or pneumonia. Don't neglect them;
and if you find that you take cold easily, find out what is wrong with
yourself, and reform your unhealthful habits.

[Illustration: A YEAR OF CONSUMPTION ON MANHATTAN ISLAND

Every black dot represents one case reported. The groupings show how
rapidly the disease spreads from one household to another in the same
locality.]


HOW TO CONQUER CONSUMPTION

Different Forms of Tuberculosis. The terrible disease tuberculosis is
the most serious and deadly enemy which the human body has to face. It
kills every year, in the United States, over a hundred and fifty
thousand men, women, and children--_more lives than were lost in battle
in the four years of our Civil War_. It is caused by a tiny germ--the
_tubercle bacillus_--so called because it forms little mustard-seed-like
lumps, or masses, in the lungs, called _tubercles_, or "little tubers."
For some reason it attacks most frequently and does its greatest damage
in the lungs, where it is called _consumption_; but it may penetrate and
attack any tissue or part of the body. Tuberculosis of the glands, or
"kernels," of the neck and skin, is called _scrofula_; tuberculosis of
the hip is _hip-joint disease_; and tuberculosis of the knee, _white
swelling_. "Spinal disease" and "hunch-back" are, nine times out of ten,
tuberculosis of the backbone. Tuberculosis of the bowels often causes
fatal wasting away, with diarrhea, in babies and young children; and
tuberculosis of the brain (called _tubercular meningitis_) causes fatal
convulsions in infancy.

[Illustration: CONSUMPTION IN CHICAGO

Four hundred and seventy-seven cases in one month--February, 1909.]

Tuberculosis of the Lungs--How to Keep it from Spreading. Tuberculosis
of the lungs is the most dangerous of all forms, both because the lungs
appear to have less power of resistance against the tubercle bacillus,
and also because from the lung, the bacilli can readily be coughed up
and blown into the air again, or spit onto the floor, to be breathed
into the lungs of other people, and thus give them the disease.
Two-thirds of all who die of tuberculosis die of the pulmonary, or lung,
form of the disease, popularly called consumption.

The first thing then to be done to put a stop to this frightful waste of
human life every year is to _stop the circulation of the bacillus from
one person to another_. This can be done partially and gradually by
seeing that every consumptive holds a handkerchief, or cloth, before his
mouth whenever he coughs; that he uses a paper napkin, pasteboard box,
flask, or other receptacle whenever he spits; and that these things in
which the sputum is caught are promptly burned, boiled, or otherwise
sterilized by heat. The only sure and certain way, however, of stopping
its spread is by placing the consumptive where he is in no danger of
infecting any one else. And as it fortunately so happens that such a
place--that is to say, a properly regulated sanatorium, or camp--is the
place which will give him his best chance of recovery, at least five
times as good as if he were left in his own home, this is the plan which
is almost certain to be adopted in the future. Its only real drawback is
the expense.

But when you remember that consumption destroys a hundred and fifty
thousand lives every year in this country alone, and that it is
estimated that every human life is worth at least three thousand dollars
to the community, you will see at once that consumption costs us in
deaths alone, four hundred and fifty million dollars a year! And when
you further remember that each person who dies has usually been sick
from two to three years, and that two-thirds of such persons are
workers, or heads of families, and that tens of thousands of other
persons who do not die of it, have been disabled for months and damaged
or crippled for life by it, you can readily see what an enormous sum we
could well afford to pay in order to stamp it out entirely.

One of the most important safeguards against the disease is the law
that prevents spitting in public places. Not only the germs of
consumption, but those of pneumonia, colds, catarrhs, diphtheria, and
other diseases, can be spread by spitting. The habit is not only
dangerous, but disgusting, unnecessary, and vulgar, so that most cities
and many states have now passed laws prohibiting spitting in public
places, under penalty of fine and imprisonment.

[Illustration: A REPORT-FORM FROM A HEALTH DEPARTMENT LABORATORY

In a suspected case, the physician sends a specimen of the sputum to the
Laboratory to be tested, and receives a reply according to the result of
the test. The form is filled in with the name of the patient and signed
by the Director of the Laboratory.]

The next best safeguard is plenty of fresh air and sunlight in every
room of the house. These things are doubly helpful, both because they
increase the vigor and resisting power of those who occupy the rooms and
might catch the disease, and because direct sunlight, and even bright
daylight, will rapidly kill the bacilli when it can get directly at
them.

How great is the actual risk of infection in crowded, ill-ventilated
houses is well shown by the reports of the tuberculosis dispensaries of
New York and other large cities. Whenever a patient comes in with
tuberculosis, they send a visiting nurse to his home, to show him how
best to ventilate his rooms, and to bring in all the other members of
the family to the dispensary for examination. No less than from
_one-fourth to one-half_ of the children in these families are found to
be already infected with tuberculosis. The places where we look for our
new cases of tuberculosis now are in the same rooms or houses with old
ones. A careful consumptive is no source of danger; but alas, not more
than one in three are of that character.

[Illustration: A SIGN THAT OUGHT NOT TO BE NECESSARY

But, being necessary, it should be strictly respected and obeyed.]

It has been estimated that any city or county could provide proper
camps, or sanatoria, to accommodate all its consumptives and cure
two-thirds of them in the process, support their families meanwhile, and
stop the spread of the disease, at an expense not to exceed five dollars
each per annum for five years, rapidly diminishing after that. If this
were done, within thirty years consumption would probably become as rare
as smallpox is now. Some day, when the community is ready to spend the
money, this will be done, but in the mean time, we must attack the
disease by slower and less certain methods.

[Illustration: A COMPARATIVE DEATH-RATE OF CONTAGIOUS DISEASES

Note the number of deaths from tuberculosis to one from smallpox; yet
smallpox before the days of vaccination and quarantine, was the
universal scourge. Similarly, by preventive measures, we are controlling
the other diseases. Why not also tuberculosis? (Statistics for greater
New York, 1908; total number of deaths from all causes, 73,072.)]

Why the Fear and Danger of Consumption have been Lessened. Terrible
and deadly as consumption is, we no longer go about in dread of it, as
people did twenty-five years ago, before we knew what caused it; for we
know now that it is preventable and that two-thirds of the cases can be
cured after they develop. The word consumption is no longer equivalent
to a sentence of death. The deaths from tuberculosis each year have
diminished almost one-half in the last forty years, in nearly every
civilized country in the world; and this decrease is still going on.

The methods which have brought about this splendid progress, and which
will continue it, if we have the intelligence and the determination to
stick to them, are:--First, the great improvements in food supply,
housing, ventilation, drainage, and conditions of life in general, due
to the progress of modern civilization and science, combined with a
marked increase in wages in the great working two-thirds of the
community. Second, the discovery that consumption is caused by a
bacillus, and by that alone, and is spread by the scattering of that
bacillus into the air, or upon food, drink, or clothing, to be breathed
in or eaten by other victims. Third, increase of medical skill and
improved methods of recognizing the disease at a very early stage. A
case of consumption discovered early means a case cured, eight times out
of ten.

Its Cure and Prevention. Fortunately, the same methods which will cure
the disease will also prevent it. The best preventatives are food, fresh
air, and sunshine. Eat plenty of nourishing food three times a day,
especially of milk, eggs, and meat. Sit or work in a gentle current of
air, keep away from those who have the disease, sleep with your windows
open, take plenty of exercise in the open air, and you need have little
fear of consumption.

In the camps, or sanatoria, for the cure of consumption, these methods
are simply carried a little further, to make up for previous neglect.
The patients sit or lie out of doors all day long, usually in reclining
chairs, in summer under the trees, and in winter on porches, with just
enough roof to protect them from rain or snow. They sleep in tents, or
in shacks, which are closed in only on three sides, leaving the front
open to the south. They dress and undress in a warm room, or the
curtains of the tent are dropped, or the shutters of the shack closed
night and morning until the room is warmed up. In cold climates they
dress day and night almost as if they were going on an arctic relief
expedition, and spend twenty-four hours out of the twenty-four in the
open air.

[Illustration: A TUBERCULOSIS TENT COLONY IN WINTER]

They eat three square meals a day, consisting of everything that is
appetizing, nutritious, and wholesome, with plenty of butter, or other
fats; and in addition, drink from one to three pints of new milk and
swallow from six to twelve raw eggs a day. You would think they would
burst on such a diet, but they don't; they simply gain from two to four
pounds a week, lose their fever and their cough, get rid of their night
sweats, and usually in from two to five weeks are able to be up and
about the camp, taking light exercise. When they have reached their
full, normal, or healthy weight for their height and age, their amount
of food is reduced, but still kept at what would be considered full
diet for a healthy man at hard work. If sick people can be made well by
this open air treatment, those of us that are well ought not be afraid
to have a window open all night.

Two-thirds of the treatment that would cure you of consumption will
prevent your ever having it. While tuberculosis chiefly attacks the
lungs, it is really a disease of the entire body, or system, and cannot
attack you if you will keep yourself strong, vigorous, and clean in
every sense of the word.

How to Recognize the Disease in its Early Stages. To recognize the
disease early is, of course, work for the doctor; but he must be helped
by the intelligence of the patient, or the patient's family, or he may
not see the case until it is so far advanced as to have lost its best
chance of cure. We can now recognize consumption before the lungs are
seriously diseased. Among the most useful methods with children is the
rubbing or scratching of a few drops of the toxin of the tubercle
bacillus, tailed _tuberculin_, into the skin. If the children are
healthy, this will leave no mark, or reddening, at all; but if they have
tuberculosis, in two-thirds of the cases it will make a little reddening
and swelling like a very mild vaccination. But in order to get any good
from this, cases must be brought to a doctor, early, without waiting for
a bad cough, or for night sweats.

Signs of Consumption. The signs that ought to make us suspicious of a
possible beginning of tuberculosis are first, loss of weight without
apparent cause; fever, or flushing of the cheeks, with or without
headache, every afternoon or evening; and a tendency to become easily
tired and exhausted without unusual exertion. Whenever these three signs
are present, without some clear cause, such as a cold, or unusual
overwork or strain, especially if they be accompanied by a rapid pulse
and a tendency to get out of breath readily in running upstairs, they
should make us suspect tuberculosis; and if they keep up, it is
advisable to go at once and have the lungs thoroughly examined. Nine
cases out of ten, seen at this stage, are curable--many of them in a few
months.

Even if we should not have the disease, if we have these symptoms we
need to have our health improved; and a course of life in the open air,
good feeding, and rest, which would cure us if we had tuberculosis, will
build us up and prevent us from developing it.

[Illustration: AN OUTDOOR CLASSROOM FOR TUBERCULOUS CHILDREN

The roof and the side awnings are the only obstructions to the outer
air.]


PNEUMONIA

Its Cause and Prevention. The other great disease of the lungs is
_pneumonia_, formerly known as inflammation of the lungs. This is rapid
and sudden, instead of slow and chronic like tuberculosis, but kills
almost as many people; and unfortunately, unlike tuberculosis, is not
decreasing. In fact in some of our large cities, it is rapidly
increasing. Although we know it is due to a germ, we don't yet know
exactly how that germ is conveyed from one victim to another. One thing,
however, of great practical importance we do know, and that is that
pneumonia is a disease of overcrowding and foul air, like tuberculosis;
that it occurs most frequently at that time of the year--late winter and
early spring--when people have been longest crowded together in houses
and tenements; and that it falls most severely upon those who are
weakened by overcrowding, under-feeding, or the excessive use of
alcohol. How strikingly this is true may be seen from the fact that,
while the death-rate of the disease among the rich and those in
comfortable circumstances, who are well-fed and live in good houses, is
only about five per cent,--that is, one in twenty,--among the poor,
especially in the crowded districts of our large cities, the death-rate
rises to twenty per cent, or one in five; while among the tramp and
roustabout classes, who have used alcohol freely, and among chronic
alcoholics, it reaches forty per cent. The same steps should be taken to
prevent its spread as in tuberculosis--destroying the sputum, keeping
the patient by himself, and thoroughly ventilating and airing all rooms.
As the disease runs a very rapid course, usually lasting only from one
to three weeks, this is a comparatively easy thing to do.

Though pneumonia is commonly believed to be due to exposure to cold or
wet, like colds, it has very little to do with these. You will not catch
pneumonia after breaking through the ice or getting lost in the snow,
unless you already have the germs of the disease in your mouth and
throat, and your constitution has already been run down by bad air,
under-feeding, overwork, or dissipation. Arctic explorers, for instance,
never catch pneumonia in the Frozen North.



CHAPTER XV

THE SKIN


OUR WONDERFUL COAT

What the Skin Is. The skin is the most wonderful and one of the most
important structures in the body. We are prone to think lightly of it
because it lies on the surface, and to speak of it as a mere coating, or
covering--a sort of body husk; but it is very much more than this. Not
only is it waterproof against wet, a fur overcoat against cold, and a
water jacket against heat, all in one, but it is also a very important
member of the "look-out department," being the principal organ of one of
our senses, that of touch.

The eyes in the beginning were simply little colored patches of the
skin, sunk into the head for the purpose of specializing on the
light-rays. The smelling areas of the nose also were pieces of the skin,
as were also the ears. Not only so, but--although it is a little hard
for you to understand how this could have happened--the whole brain and
nervous system is made up of folds of the skin tucked in from the
surface of the back; so that we can say that the skin, with the organs
that belong to it and have grown from it--the eyes, nose, ears, brain,
and nerves--forms the most wonderful part of the body. Everything that
we know of the world outside of us is told us by the skin and the
look-out organs that have grown out of it. The skin is not only the
surface part and coating of the body, far superior to any six different
kinds of clothing which have yet been invented, but it is related to,
and assists in, the work of nearly half the organs in the body. Not only
all that we learn by touch and pressure, but everything that we know of
heat and cold, of moisture and dryness, and most of pain, comes to us
through our skin, through the little bulbs on the ends of the nerve
twigs in it. It also helps the lungs to breathe, the kidneys to purify
the blood, and the heart to control the flow of blood through the body.

A healthy skin is of very great importance; and part of this health we
can secure directly, by washing and bathing, scrubbing and kneading and
rubbing, because the skin lies right on the surface, where we can
readily get at it. But, on the other hand, no amount of attention from
the outside alone will keep it healthy. All the organs inside the body
must be kept healthy if the skin is to be kept in good condition.
Although the external washing and cleaning are very important, the
greater part of the work of developing a healthy skin and a good
complexion must be done from the inside.

The Two Layers which Make Up the Skin. Like our "internal skin," the
mucous membrane, which lines our stomach and bowels, the skin is made up
of two layers--a deeper, or basement, sheet, woven out of tough strands
of fibrous stuff (_derma_); and a surface layer (_epidermis_) composed
of cells lying side by side like the bricks in a pavement, or the tiles
on a floor, and hence called "pavement" (_epithelial_) cells. These
pavement cells are fastened on the basement membrane much as the kernels
of corn grow on a cob; only, instead of there being but one layer, as on
a cob of corn, there are a dozen or fifteen of them, one above the
other, each one dovetailing into the row below it, as the corn kernels
do into the surface of the cob. As they grow up toward the surface from
the bottom, they become flatter and flatter, and drier, until the outer
surface layer becomes thin, fine, dry, slightly greasy scales, like
fish-scales, of about the thickness of the very finest and driest bran.

We are continually Shedding our Skin. One way in which the skin keeps
itself so wonderfully clean and fresh is by continually shedding from
its surface showers of these fine, dry, scaly cells, which drop, or are
rubbed off, as they dry. This is the reason why no mark, not even a
stain or dye, upon the skin, will stay there long; for no matter how
deeply it may have soaked into the layers of the pavement-cells, every
cell touched by it will ultimately grow up to the surface, dry up, and
fall off, carrying the stain with it.

If you want to make a mark on the skin that will be permanent, you have
to prick the colors into it so deeply that they will go through the
basement layer and reach cells which will not grow toward the surface.
This "pricking-in" operation is known as _tattooing_; and it is as
foolish as it is painful, for blood-poisoning and other diseases may be
carried into the system in the process.

[Illustration: THE LAYERS OF THE SKIN

_E_, epidermis; _C_, capillaries; _D_, dermis; _F_, fat globules and
connecting fibres.]

Perhaps you will wonder why, if you are shedding these scales from all
over your surface every day, you don't see them. This is simply because
they are so exceedingly small, thin, and delicate, that you cannot see
them unless you get a large number of them together; and when you are
changing your clothing, bathing, etc., they are rubbed off and float
away. If a part of the body has been shut in--as when a broken arm, for
instance, is in a cast, which cannot be changed for several weeks--when
finally you take off the bandage, you will find inside it spoonfuls--I
had almost said handfuls--of fine scales, which have been shed from the
skin and held in by the wrappings.


THE GLANDS IN THE SKIN

Sweat Glands. Like all the pavement (epithelial) surfaces of the body,
inside and out, the skin has the power of making glands by dipping down
little pouches or pockets into the layers below. In the skin, these
little gland-pockets are of two kinds, the _sweat glands_ and the _hair
glands_.

The sweat glands are tiny tubes which go twisting down through the
different pavement layers, through the basement layer, and right into
the coat of fat, which lies just under the skin. The tube of the sweat
gland soaks, or picks, out of the blood some of the waste-stuff--just as
the kidney tube does in the kidney,--together with a good deal of water
and a small amount of delicate oil, and pours them out on the surface of
the body in the form of the "sweat," or _perspiration_.

As you will remember, when the muscles work hard and pour more waste
into the blood, then the heart pumps larger amounts of blood out into
the skin; and this causes it to redden. The sweat glands work harder to
purify this extra blood, and they pour out the waste and oil and water
on the surface. As soon as this water gets upon our hot skin, it begins
to evaporate and cool us off, as well as to carry off some of the waste
in the form of gas. The trace of oil in the perspiration helps to
lubricate the skin and keep it soft; but when too much of it is poured
out we have that greasy feeling, which we have all felt after perspiring
freely.

From all this cooling and breathing and blood-purifying work going on
upon the surface of our skin, you can easily see why it is so important
that all our clothing should be loose and porous and that next the skin
easily washed; else it will very soon become clogged up and greasy, and
shut off the breathing and blood-purifying work of the skin and make it
dirty and unhealthy. This continual mist of water, rising and bubbling
up through our skin like springs out of a hillside, is another of
nature's wonderful ways of cleansing the skin and of preventing any kind
of dirt from permanently sticking to or lodging in it. Remember, you do
not need to dig below the surface when you wash.

Hair Glands. The other kind of skin glands, the hair glands, are also
pouches growing out from the deepest part of the stem of the hair, known
as the root, or _hair bulb_.

[Illustration: THE GLANDS IN THE SKIN

_S_, sweat gland; _H_, hair bulb; _O_, oil gland; _T_, touch bulb at tip
of nerve.]

From the root of the hairs, two or three little bundles of muscle run up
toward the surface of the skin. When these contract, they pull the root
of the hair up toward the surface, causing the hair to stand erect, or
"bristle," as we say. This is what makes the hair on a dog's or a cat's
back stand up when he is angry; but the commonest use of the movement
is, when animals are cold, to make their coats stand out so as to hold
more air and retain the body-heat better. We have lost most of our hairy
coating, but whenever we get chilly, whether from cold or from fright,
these little muscles of our hair bulbs contract and pull the hair glands
of our skin up toward the surface, so that it looks all "pimply" or
"goose-skinned."

Each hair pouch has sprouted out from its sides a pair of tiny pouches,
which form _oil glands_ to lubricate the hair and keep it sleek and
flexible. It is hard to beat nature at her own game, and her method of
oiling the hair is far superior to any hair oil that can be put on from
the outside. Keep your hair well brushed and washed, and nature will oil
it for you much better than any hair oil or scalp reviver ever
invented.[19]


THE NAILS

How the Nails are Made. Another "trade," which our wonderful skin has
literally "at its fingers' ends," is that of making nails. Indeed, every
kind of scale, armor, fur, feather, and leather coating possessed by
bird, beast, or fish was made by, and out of, the skin. Nail-making,
however, is one of its simplest feats, as it is carried out merely by
turning a little patch, or area, of itself into a horn-like substance.
This, the skin of insects, of fishes, of crocodiles, etc., does all over
the surface of their bodies; but in animals and birds only a number of
little patches at the tips of the toes harden up in this way, to form
the claws or nails; and in birds, the beak; and in some animals, the
horns. So it is quite correct to call the substance of our nails
"horn-like."

In some animals and birds, these little horny patches at the ends of the
toes grow out into long, curved hooks, or broad, digging chisels and
scoops; but on our own fingers, they simply make a little mould over the
finger-tip. If, however, they are protected from being broken off, they
will grow four or five inches long; in fact, they are carefully trained
to do this by some of the upper classes in China, merely for the purpose
of showing that they have never been obliged to degrade themselves, as
they foolishly regard it, by working with their hands.

You can easily prove that the nails do grow constantly from the root or
base, out toward the tip, by watching, some time when you have pounded
one of your nails, how the black or discolored patch in it will grow
steadily outward toward the tip, where it will be broken off and shed.

You cannot see the softest and youngest row, or layer, of the nail cells
at the base, because a fold of skin, the _nail fold_, has been doubled,
or folded, over them to protect them while they are young and soft. It
is not best to push this fold of skin back too much, as, by so doing,
you may uncover the young nail cells while they are soft and tender, and
expose them to injury. The reason why there is a little whitish crescent
at the base of the nail is that the cells of the nail do not grow hard
and horn-like and transparent until they have grown out a quarter of an
inch or so from under the fold, but at first look whitish, or opaque,
like the rest of the skin.

Health Shown by the Color of the Nails. Your nails and your lips are
not really any redder, or pinker, than the rest of your skin; but the
cells forming them are clear and transparent and allow the red blood to
show through. This is why we often look at the nails and lips to see
what the color of the blood is like, and how well or badly it is
circulating. If the blood is _anemic_, or thin, then both lips and nails
are pale and dull. If the blood is healthy and the circulation good,
then the nails are pink, and the lips clear red. If, on the other hand,
the circulation is bad, as in some forms of lung disease and heart
disease, so that the blood is loaded with carbonic acid until it is
blue and dark, then the lips may become purplish or dark blue, and the
finger nails nearly the same color.


THE BLOOD-MESH OF THE SKIN

The Blood Vessels under the Skin. Not merely the nails and the lips,
but the whole surface of the skin is underlaid with a thick mat, or
network, of blood vessels. These vessels are all quite small, so that a
cut has to go down completely through the skin, and generally well down
into the muscles, before it will reach any blood vessel which will bleed
at a dangerous rate. But there are so many of them, and they cover such
a wide surface throughout the body, that they are actually capable of
holding, at one time, nearly one-tenth of all the blood in the body.

This "water-jacket" coat of tiny blood vessels all over our body has
some very important uses: It allows the heart to pump large amounts of
blood out to the surface to be purified by the sweat glands, and to
breathe out a little of its carbon dioxid and other gas-poisons.

The Skin as a Heat Regulator. Heat, as well as waste, is given off by
the blood when it is poured out to the surface; so another most
important use of the skin is as a heat regulator. As we have already
seen, every movement which we make with our muscles, whether of arms and
limbs, heart, or food tube, causes heat to be given off. We very well
know, when we work hard at anything, we are likely to "get warmed up."
Although a certain amount of this heat is necessary to our bodily
health, too much of it is very dangerous.

Just as it is best for the temperature, or heat, of a room to be at
about a certain level, somewhere from 60° to 70° F., so it is best for
the interior of our bodies to be kept at about a certain heat. This, as
we can show by putting a little glass thermometer under the tongue, or
in the armpit, and holding it there for a few minutes, is a little over
98° F. (98.4° to be exact); and this we call "body heat," or "blood
heat," or "normal temperature." Our body cells are, in one way, a very
delicate and sensitive sort of hot-house plants, though tough enough in
other respects. Whenever our body heat goes down more than five or six
degrees, or up more than two or three degrees, then trouble at once
begins. If our temperature goes down, as from cold or starvation, we
begin to be drowsy and weak, and finally die. If, on the other hand, our
temperature climbs up two, three, or four degrees, then we begin to be
dizzy and suffer from headache and say we have "a fever."

A fever, or rise of temperature, that can be noted with a thermometer,
is usually due to disease germs of some sort in the body; and most of
the discomfort that we suffer is really due more to the poisons (toxins)
of the germs than to the mere increase of heat, though this alone will
finally work serious damage. However, as we well know from repeated
experience, we need only to run or work hard in the sun for a
comparatively short time to make ourselves quite hot enough to be very
uncomfortable; and if we had no way to relieve ourselves by getting rid
of some of this heat, we should either have to stop work at once, or
become seriously ill. This relief, however, is just what nature has
provided for in this thick coat of blood vessels in our skin; it enables
us to throw great quantities of blood out to the surface where it can
get rid of, or, as the scientists say, "radiate," its heat. This cooling
process is hastened by the evaporation of the perspiration poured out at
the same time, as we have seen.

One of the chief things in training for athletics is teaching our skin
and heart together to get rid of the heat made by our muscles, as fast,
or nearly as fast, as we make it, thus enabling us to keep on running,
or working, without discomfort. As soon as we stop running, or working,
the heart begins to slow down, the blood vessels in the skin contract
and diminish in size, the flush fades, and we begin to cool off. We are
not making either as much heat or as much waste as we were, and hence do
not need to get rid of so much through our skins.

When we feel cold, just the opposite kinds of change occur in the skin.
The blood vessels in the skin contract so as to keep as much of our warm
blood as possible in the deeper parts of our body, and prevent its
losing heat. As blood showing through the pavement-layer of the skin is
what gives us our color, or complexion, our skin becomes pale and
pasty-looking; and if all the blood is driven in from the surface, our
lips and finger nails will become blue with cold. Here again, by changes
in the skin, nature is simply trying to protect herself from the loss
of too much heat.

If we exercise briskly, or eat a good warm meal, and thus make more heat
inside of our body, then there is no longer any need to save its surface
loss in this way; and the blood vessels in our skin fill up, the heart
pumps harder, and the warm, rich color comes back to our faces and lips
and finger nails.

So perfectly and wonderfully does this skin mesh of ours work, by
increasing or preventing the loss of heat, that it is almost impossible
to put a healthy man under conditions that will raise or lower his
temperature more than about a degree, that is to say, about one per cent
above, or below, its healthful level. Men studying this power of the
skin have shut themselves into chambers, or little rooms, built like
ovens, with a fire in the wall or under the floor, and found that if
they had plenty of water to drink and perspired freely, they could stand
a temperature of over 150° F. without great discomfort and without
raising the temperature of their own bodies more than about one degree.
If, however, the air in the chamber was moistened with the vapor of
water, or steam, so that the perspiration could no longer evaporate
freely from the surface of their bodies, then they could not stand a
temperature much above 108° or 110° without discomfort.

Other men, who were trained athletes, have been put to work in a closed
chamber, at very vigorous muscular exercise, so as to make them perspire
freely. But while a thermometer placed in that chamber showed that the
men were giving off enormous amounts of heat to the air around them,
another thermometer placed under their tongues showed that they were
raising the temperature of their own bodies only about half a degree.
One man, however, happened to try this test one morning when he was not
feeling very well, and didn't perspire properly, and the thermometer
under his tongue went up nearly four degrees.


THE NERVES IN THE SKIN

How We Tell Things from Touch, and Feel Heat and Cold and Pain. Last
of all, the skin is the principal organ of the sense of touch, and also
of the "temperature sense"--the sense of heat and cold--and of the sense
that feels pain. All these feelings are attended to by little bulbs
lying in the deeper part of the skin and forming the tips of tiny nerve
twigs,[20] which run inward to join larger nerve branches and finally
reach the spinal cord. There are millions of these little bulbs
scattered all over the surface of the skin, but they are very much
thicker and more numerous in some parts than in others; and that is why,
as you have often noticed, certain parts of the skin are more sensitive
than others. They are thickest, for instance, on the tips of our fingers
and on our lips, and fewest over the back of the neck and shoulders,
and across the lower part of the hips.[21]

For a long time, it was supposed that all these little nerve-bulbs in
the skin did the same kind of work, because they looked, under the
microscope, exactly alike; but it was found that they divide the work up
among them, so that some of them give their entire attention to heat,
and others to cold, others to touch, and others again to pain. So
carefully has the work been mapped out among them that they report to
different centres in the brain and spinal cord, so that we now
understand why, in diseases which happen to attack one or other of these
centres, we may lose our sense of heat and cold, as in that terrible
disease, _leprosy_; or our sense of touch, as in _paralysis_; or we may
even, in some very rare cases, lose our sense of pain, and yet have all
our other senses perfect.


FOOTNOTES:

[19] Hairs are of value chiefly as protection against cold and wet,
although we have got rid of them and substituted clothing for this
purpose, except on the top of our heads; but their roots also are very
richly supplied with nerves so that they form almost a sort of feelers,
or organs of sense. Many animals that move about much in the dark, like
cats and bats, for instance, have their lips or faces studded with long,
delicate, stiff hairs called whiskers, which act in this way and prevent
their bumping into objects in the dark. And it is probable that the
bristling of the hair on a dog's back, when he is angry or frightened,
is in part for this purpose--to enable him to slip aside and dodge a
blow, even after it has touched the ends of the hairs. This great
sensitiveness of the hair roots is what makes it hurt so when any one
pulls your hair.

[20] See the diagram of the skin on page 171.

[21] You can easily test this by a very simple experiment. Take a pair
of dividers; or, if you haven't these, a couple of long pins or needles
will do. Set them with their points a quarter of an inch apart. Then
touch these points, first closing your eyes, so that you will not be
able to see them, to the tip of one of your fingers, and you will
readily feel that _two_ points touch the skin. Turn your hand over and
touch the back of it with the two points, and they will feel like one
point. Carry the test further, over other parts of the body, and you
will find that they are much less sensitive; thus you will find that at
the back of the neck, or over the shoulder-blades, you will have to put
the points nearly an inch apart before you can tell that there are two
of them. This simply means that you have to touch two separate touch
bulbs before you can get the idea of "two-ness." As these bulbs are an
inch or more apart in the skin of the back, you have to spread the
points of the dividers that distance. You can also prove that the
touching of two nerve-buds gives the idea of "two-ness" by crossing two
of your fingers and placing a pea, or small round piece of chalk,
between their crossed tips. If you close your eyes and roll the pea on
the table, or desk, you will think you have two peas between your
fingers.



CHAPTER XVI

HOW TO KEEP THE SKIN HEALTHY


CLOTHING

Clothes should be Loose and Comfortable. Man is the only animal that
has no natural suit of clothing. Birds have feathers, and animals have
fur, or hair, which they shed in summer and thicken up in winter without
even thinking about it, so that they do not have to bother with either
overcoats or flannels. The wise men say that man originally had a full
suit of hair like other animals, and that he gradually got rid of it, as
he became human. Whether this be true or not, the fact remains that he
has none now; and consequently he must invent and manufacture something
to take its place.

Originally, in the time of our savage ancestors, clothing was worn
chiefly as protection from cold at night, so that all the earlier forms
of clothing were of a more or less blanket-or cloak-like form, and
wrapped, or swathed, the whole body without fitting closely to the
limbs. It is interesting to remember this fact, because even our most
highly civilized forms of clothing still show this same tendency. The
skirt, for instance, is simply a survival of the lower end of the
blanket, which has never been cut down to fit the limbs.

The principles upon which garments should be built are two: First, they
should fit closely enough to the body and limbs to protect them from
either injury or cold, even while free activity of every sort is
allowed--you could not wrestle in a blanket or run very far in a sack.
Second, they should be thick enough to protect us from cold, and yet at
the same time porous enough not to interfere with the natural breathing
and ventilating of the skin. A garment should be as loose as possible
without interfering with our movements, and as free and as light as can
be worn with reasonable warmth and protection. The less clothing you can
wear and be comfortable, the better.

We should particularly avoid binding or cramping the chest and the hips
and waist. If clothing is too tight about the chest, it interferes both
with free movement of the arms and, what is even more important, with
the breathing movements of the chest. If too tight about the waist and
hips, it badly cripples the lower limbs and interferes with the proper
movements of the diaphragm in breathing, and with the passage of the
food and the blood through the bowels.

Your instincts are perfectly right that make you dislike to be squeezed
or pinched or cramped in any way, or at any point, by your clothing; and
if you will only follow these instincts all through your lives, you will
be far healthier and happier.

The Texture of Clothing. Just as for ages we have experimented with
different kinds of food, so we have with different kinds of material for
clothing. We have used the skins of animals; mats woven out of leaves
and grasses; the feathers of birds; the skins of fishes; cloths made of
wool and of cotton; and even the cocoon spun by certain caterpillars,
which we call _silk_. But of all these materials, practically only two
have stood the test of the ages and proved themselves the most suitable
and best all-round clothing materials--wool and cotton.

Woolen cloth, woven from the fleece of sheep or goats or camels or
llamas or alpacas, has three great advantages, which make it _the_
outside clothing of the human species. First, it is sufficiently tough
and lasting to withstand rips and tugs and ordinary wear and tear;
second, it is warm--that is, it retains well the body heat; and third,
it is porous, so that it will allow gases and perspiration from the
surface of the body to pass through it in one direction, and air for the
skin to breathe, in the other.

[Illustration: RESULTS OF TIGHT CLOTHING

(1) The normal thorax. (2) The thorax and organs cramped and lifted by
pressure of the clothing. (From an X-ray photograph.--After Dickinson.)]

No clothing, of course,--not even fur,--has any warmth in itself; it
simply has the power of retaining, or keeping in, the warmth of the body
that it covers. The best and most effective way of retaining the body
warmth is to surround the body with a layer of dead, or still, air,
which is the best non-conductor of heat known. Hence, porous garments,
like loosely-woven flannels, blankets, and other woolen cloths, are warm
because they contain or hold large amounts of air in their spongy mesh.

The reason why furs are so warm is that their soft, furry under-hairs,
or "pelt" as the furriers call it, entangle and hold an enormous amount
of air. The fur of ordinary sealskin, for instance, is about half an
inch deep; and _ninety per cent_ of this half-inch is air. If you wet
it, its fur "slicks down" to almost nothing, although the most drenching
wetting will not wash all the air out of it, but still leaves a dry
layer next to the skin. The fur of mink skin, coon skin, or wolf skin,
is an inch thick; and nearly eighty per cent of this thickness is air.

The great advantage for clothing purposes of wool over fur is that the
wool is porous through and through, while the fur is borne upon, and
backed by, a layer of leather--the skin of the animal upon which it
grew--which layer, after tanning and curing, becomes almost absolutely
air-tight.

As a matter of fact, furs are worn mostly for display and are most
unwholesome and undesirable garments. The only real excuse for their
use, save for ornament in small pieces or narrow strips, is on long,
cold rides in the winter, and among lumbermen, frontiersmen, and
explorers. They hold in every particle of perspiration and poisonous gas
thrown off by the skin, and if worn constantly, make it pale, weak, and
flabby; and the moment we take them off, we take cold.

For outer garments and general wear, nothing yet has been discovered
equal to wool, particularly at the cooler times of the year. But for
under wear, in the hotter seasons and climates, wool has certain
disadvantages. It is likely to be rough and tickling to most skins,
which makes it uncomfortable, especially in warm weather. It is also
difficult and troublesome to wash woolens without shrinking them; and,
as soon as they do shrink, not only do they become uncomfortably tight,
but the natural pores in them which make them so valuable close up, and
they become almost air-tight. Finally, when loaded with perspiration,
woolens easily become offensive, so that they must be frequently changed
and washed; and as they are also high in price, it is easily seen that
there are practical drawbacks to their use.

Cotton is much softer and pleasanter to the skin than wool, is cooler in
hot weather, is much cheaper, and is very easily washed without losing
either its shape or its porousness. It can be so woven as to be almost
as porous as wool, and to retain that porousness even when saturated
with perspiration. It does not soak up and retain the oils and odors of
perspiration in the way that wool does; and on the whole, for under
wear, and for general wear at the warm seasons of the year, it is not
only more comfortable, but far more healthful, than wool. Persons of
fair health and reasonably vigorous outdoor habits, whose skins are well
bathed and ventilated, can wear properly woven cotton or linen
undergarments the whole year round with perfect safety.

[Illustration: A COMFORTABLE DRESS FOR OUTDOOR STUDY IN COLD WEATHER

The thick bags pulled up to the shoulders keep the body surrounded by a
layer of warm air.]

Linen and silk both make admirable and healthful under wear, if woven
with a properly porous mesh. Linen has the advantage of remaining more
porous than cotton, when moist with perspiration. But for healthy people
they have no advantages over cotton that are not offset by their higher
prices.


BATHS AND BATHING

Bathing as a Means of Cleanliness. It has been said that one of the
reasons why man lost his hairy coat was that he might be able to wash
himself better and keep cleaner. However this may be, he has to wash a
great deal oftener than other animals, most of whom get along very well
with currying, licking, and other forms of dry washes, and an occasional
swim in a river or lake.

You can readily see how necessary for us washing is, when you remember
the quarts of watery perspiration, which are poured out upon our skins
every day, and the oily and other waste matters, some of them poisons,
which the perspiration leaves upon our skins. Especially is some means
of washing necessary when the free evaporation of perspiration and the
free breathing of the skin has been interfered with by clothing which is
water-tight or too thick.

Bathing as a Tonic. But bathing is of much greater value than simply
as a means of cleansing. Splashing the body with water is the most
valuable means that we have of toning up and hardening the skin, and
protecting us against the effects of cold. The huge and wonderfully
elaborate network of blood vessels that lies in and just under our skins
all over our bodies is, from the point of view of circulation, second
only in importance to our hearts, and from the point of view of taking
cold, and of resisting the attack of disease, one of the most important
structures in our entire body. If, by means of daily baths, you keep
this mesh of blood vessels in your skin toned up, vigorous, and elastic,
and full of red blood, it will do more to keep you in perfect health and
vigor than almost any other one thing, except an abundance of food, and
plenty of fresh air and exercise. A healthy skin is the best
undergarment ever invented.

Right and Wrong Bathing. The best form of bath is either the tub or
the shower bath; and the cooler the water, provided that you warm up to
it quickly and pleasantly, the greater the tonic effect, the more
exhilaration and pleasure you will get out of it, and the more it will
harden your skin against cold. But it should never under any
circumstances be any cooler than you can _readily_ and pleasantly react,
or warm up to, during the bath and afterward. The habit of plunging into
a great tub of ice-cold water all winter long, except for people of
vigorous constitutions and active habits, may often do quite as much
harm as good. Have your bath water just cool enough to give you a
slight, pleasant shock, as you plunge into it, or turn it on, so that
you will enjoy the glow and sense of exhilaration that follows; and you
will get all the good there is out of the cold bath, and none of the
harm. By beginning with moderately cool water you will find that you
come to enjoy it cooler and cooler. If a bath-room is not at hand, a
large wash-bowl of cool, or cold, water into which you can dip your
hands and splash well over the upper half of your body every morning,
and once or twice a week all over your body, will keep your skin clean
and vigorous. If you cannot warm up properly after a cool bath, there is
something wrong about your habits of life; and you had better change
them, and keep changing them, until you find you can enjoy it. For some
delicate children, a quick plunge into, or splash with, very hot water
in the morning will give somewhat the same tonic effect as stronger ones
can get from cold water.

[Illustration: AS A TONIC, SWIMMING IS THE BEST FORM OF BATHING]

Warm baths are best taken at night, just before going to bed, though
the danger of catching cold after them on account of their "opening up
the pores of the skin," has been very greatly exaggerated. They have,
however, a relaxing effect upon the skin, and take out an undue amount
of the natural oil which nature provides for its oiling and softening,
so that, except for special reasons, it is best not to take them oftener
than once, or twice, a week.

Soaps and Scrubbing Brushes. As part of the perspiration deposited
upon our skins is in the form of a delicate oil, and as this oil may
become mixed with dirt, or dust, and form a mixture not readily soluble
in water, it is at times advisable to add to the water something that
will dissolve oil. The commonest thing used for this purpose is soap,
which is a combination of an _alkali_--most commonly _soda_, though
occasionally _potash_ (lye) is used in the soft soaps--with a fat or an
oil. The combination of the two, which we call soap, has been invented
for two reasons; one, that it makes a convenient, solid form in which
the alkali, needed to dissolve the body oil, can be used in such
strength as not to burn or injure the skin; the other, that the fat in
the soap will, to some extent, take the place of the natural oil, or
fat, which it washes off.

Necessary as soap is, it should be used very moderately. You should
never lather and scrub your skin as if it were a kitchen floor, for the
reason that, with the dirt, the alkali also washes and dissolves out a
considerable amount of the natural oil of the skin, and leaves it harsh
and dry. On this account, it is best not to use soap upon the covered
portions of the body, and in the full bath, oftener than once or twice a
week; and upon the face, oftener than once or twice a day. But the hands
may be washed with soap more frequently.

It is also best to avoid the too frequent use of hot water, even upon
the hands and face, for the same reason; it takes out too much of the
natural oil of the skin, along with the dirt. Unless the dirt be of some
infectious, or offensive, character, it is often best to content
yourself with washing off just the "big dirt," and wait for the bubbling
up of the perspiration through your skin to bring the deeper dirt up to
the surface, and wash that off later, in the course of two or three
hours.

Soaps to be Avoided. Soaps that lather too quickly and easily should
always be avoided, for this shows that they contain an excessive amount
of soda or other alkali. It is also best to avoid, or at least be very
wary of, any soaps which are dark-colored or heavily perfumed, as these
disguises may indicate the presence of decaying, offensive fats, and
even of grease extracted from garbage. This is what strong perfumes in
soaps are chiefly used for. Beware of all such, and especially of tar
soaps, for the black color and the strong odor of tar can cover up any
amount of bad quality.

Medicated soaps (soaps containing medicines) are also best let alone.
They are only fit to be used on the advice of a doctor. Most of them are
out and out humbugs, and make up for their richness in drugs by their
poorness in good, pure fat and alkali. Moreover, what may suit one
particular diseased condition of the skin is quite as likely to be
injurious as helpful to another. Any drug which has the power of curing
disease is almost certain to be irritating to a healthy skin; and
nothing can be put into a soap beyond pure, sweet fat, or oil, and good
soda, which will make it any better, or more wholesome, for a healthy
skin. If your skin be red, or itchy, or scaly, or out of condition in
any way, go to a doctor and get the appropriate treatment for that
particular disease, instead of smearing on the surface of your body some
drug of which you know nothing, in the hope of its being the proper
thing for the little patch of diseased skin.

Avoid Using Skin Brushes. Scrubbing brushes and skin brushes of all
sorts should be used even more sparingly than soap or hot water, for the
same reason. Nature did not coat us over with either boards or rubber,
but with delicate, velvety, sensitive, living skin worth ten times as
much as any sort of leather, bark, rubber, or cloth, for resisting cold,
heat, and injuries. It is most important for the health of the skin that
we keep that velvety coating unscratched and unbroken. The use of
brushes and bristles of all sorts, therefore, should be chiefly
restricted to the hair and the finger nails, as for every ounce of dirt
that they take out of the skin, they do a pound of damage to it. They
scrub off the delicate epidermis, as well as the natural oil in it, and
leave it dry and irritated and ready to crack open. Then more dirt gets
into the cracks just formed, and more scrubbing with bristles and hot
water and soap is indulged in to get it out. This opens the cracks still
further, and the next layer of dirt is worked in still deeper. Wash
frequently with cold or cool water, occasionally with hot water, and
sparingly with soap; and limit the use of brushes to the nails and the
hair.


CARE OF THE NAILS

Importance of Clean Nails. On account of their constant use, your
hands are brought in contact with dusty or dirty substances in your work
and in your play; and it is very easy for some of this dirt, and such
germs as it may contain, to lodge in the little chink under the free
edge of the nail, between it and the rounded end of the finger. It is of
great importance that this nail chink should be kept clean, not only
because it looks both ugly and untidy to have the ends of your fingers
"in mourning," with black bands across them, but also because the germs
lodged under your nails may get onto your food the next time that you
eat, and set up irritation and fermentation in your stomach. They may
also cause other trouble; for instance, if your collar chafes the back
of your neck, and to relieve the itching you rub it a little too hard
with your finger, your nail may scratch the skin; and if it be blackened
with infectious dirt, this may get into the little scratch and give rise
to a boil, or a festering sore.

How to Clean the Nails. This cleaning of the nails, however, must be
done carefully and gently; for, if too harsh methods are used, the
delicate skin on the under surface of the nail will be torn, the nail
will be roughened or split, the dirt will work in just that much deeper
next time, and the germs in it may set up inflammations under the nail.
For this reason it is best not to use a sharp-pointed knife in cleaning
the nails, but a blunt-pointed nail cleaner, such as can be bought for a
few cents at any drug store, or such as many pocket-knives are now
provided with. It is also best to trim the nails with a file or with
scissors, instead of a knife, as the latter may split or tear the nail,
or cut down to the quick. Before any of these are used, the nails should
be thoroughly softened in warm water, and scrubbed with a moderately
stiff nailbrush, such as should be kept on every washstand.

It is also best not to push back the fold of skin at the base of the
nails, with instruments of any sort; or indeed, with anything harder
than the ball of the thumb or finger. This fold protects the delicate
growing part, or root, of the nail; and if it is shoved back too
vigorously, the root may become exposed, or even inflamed and infected,
and cause one of those extremely irritating little sores known as a
"hangnail."


DISEASES AND DISTURBANCES OF THE SKIN

Their Chief Causes. Skin troubles are of two main kinds according to
their cause: _internal_, due to the irritation of waste-poisons, or
toxins, in the blood; and _external_, from direct injury or irritation
of the skin from without.

The latter are often due to the wearing of too tight or too heavy
clothing, or the failure properly to wash, cleanse, and ventilate the
skin. Some of the lesser disturbances come from the chafing of collars,
wristlets, and belts, and are, of course, relieved by loosening the
clothing or substituting soft, comfortable cotton for rasping flannels.
Others come from the use of too strong soaps, or the too frequent use of
hot water, or too vigorous scrubbing of the skin, and these can be
relieved by the avoidance of their cause.

Sunburn and Freckles and how to Cure Them. Upon the hands and face,
sunburn and freckles may occur from exposure to the weather. They are
not caused necessarily by exposure to direct sunlight; as the bright
light and the cold air out of doors, also, will produce this irritating
effect upon the skin.

The best way to cure sunburn is to bathe in cool water, take a night's
rest, then go out the next day, and the day after, and take another dose
of exposure, keeping this up until your face is hardened to stand a
reasonable amount of sun. If you are in proper condition, neither your
face nor your hands will sunburn uncomfortably. If they do, except under
extreme exposure, it is a sign that you have not been living out of
doors enough.

The various face-washes and creams and dusting powders which are used
for the relief of sunburn, while they may, if mild enough, make the face
feel somewhat more comfortable for a little time, owe most of their
virtues to the fact that they are generally used at bedtime and then get
the credit for the cure which nature works while you are asleep. If you
should buy them, and keep them on your dressing-table unopened, where
you could see them before you went to bed, you would in nine cases out
of ten be just as much better in the morning as if you had used them.

The only harm done by freckles is to your vanity. They and sunburn both,
in fact, are protective actions on nature's part, filling the skin with
coloring matter, or _pigment_, so as to protect it, and the tissues
below, from the irritating effects of the strong rays of light.

A like deposit of pigment, in greater amounts, in the skins of races who
live in or near the tropics, gives rise to the characteristic coloring
of the black, brown, and yellow races. The pigment, or coloring matter,
is of exactly the same kind in all, from the negro to the white. The
brown race having a little less of it than the negro, the yellow race a
little less yet, and the white least of all, though there is some of it
in even the whitest of skins.

Real Skin Diseases. Most of the serious and lasting diseases of the
skin are caused by the attack of germs. Perfect cleanliness and
ventilation are the best protection against them all; but if you should
be unfortunate enough to catch one of these diseases, your doctor will
be able to give you the mild germicide or antiseptic that will kill the
particular germ that may have lodged upon your skin.

The commonest form of inflammation of the skin is called _eczema_, and
eight-tenths of all eczemas are due to some mild germ, and can be cured
by the appropriate poison for it.

Other diseases, particularly of the scalp, such as _ringworm_ and
_dandruff_, are due to other forms of vegetable germs, and may be cured
by their proper poisons; while others, such as the so-called "prairie
itch" (_scabies_), and lice in the hair, are due to the presence of tiny
animal _parasites_.

The Hookworm. Another disease which enters through the skin is the now
famous _hookworm_, or blood-sucking parasite, which has been found to be
so common in tropical regions and in our Southern States. This parasite
has the curious habit of attaching itself by hooks surrounding its
mouth (which gave it its name), to the lining of the human intestine,
particularly its upper third. There it swings, and lives by sucking the
blood of its victim. When the worm has once attached itself in the
intestine, it may live for from five to fifteen years. All this time it
is constantly laying eggs; and these eggs, which are so tiny that they
have to be put under a microscope to be seen, pass out in the feces; and
if they are not deposited in a proper water closet, or deep vault, but
scattered about upon the surface of the soil, the eggs quickly hatch
into tiny, little wriggling worms called _larvæ_, which are still
scarcely large enough to be seen with the naked eye.

These larvæ live in the soil; and, when it is wet and muddy, they get up
between the toes of boys and girls who are going barefoot, burrow their
way in through the skin, and produce a severe itching inflammation of
the skin of the feet, known as "ground-itch," "toe-itch" or "dew-itch."
When they have worked their way through the skin, they bore on into a
blood vessel, are carried to the heart, pumped by the heart into the
lungs, and there again work their way out of the blood vessels into the
bronchial, or air tubes, crawl up these through the windpipe and voice
organ into the throat, are swallowed into the stomach, and from there
pass on into the upper intestine to attach themselves for their
blood-sucking life. If they are sufficiently numerous, their victim
becomes thin, weak, and bloodless, with pale, puffy skin, and shortness
of breath; he is easily tired on the least exertion, and ready to fall a
victim to any disease, like tuberculosis, pneumonia, or typhoid, that
may happen to attack him.

Their spread can be absolutely prevented either by the strict use of
toilets or deep vaults, thus preventing the deposit of feces anywhere
upon the surface of the ground; or by the constant wearing of shoes or
sandals, thus preventing the larvæ from attacking the feet and working
their way through the skin and body into the intestine.

Fortunately, the disease is as curable as it is common, and two doses of
a proper germicide, with a day in bed, and a laxative, will promptly
cure it except in the worst cases.

The Rashes of Measles, Scarlet Fever, etc. Many of the infectious
fevers, such as measles, scarlet fever, chicken-pox, and smallpox, are
attended by rashes, or _eruptions_, upon the surface of the skin, due to
a special gathering or accumulation of the particular germs causing each
disease, just under the skin. When the skin sheds, or flakes off, after
the illness, the germs are shed in the scales and float, or are carried
about, and thus spread the disease to others.

These rashes or eruptions are not dangerous in themselves, though often
very uncomfortable, but help us to recognize the disease; they probably
show us the sort of thing that is going on in the deeper parts of the
body. If you imagine that your throat and bronchial tubes and lungs are
peppered as full of the disease spots as your skin is, in measles and in
scarlet fever, you will readily understand why your throat is so sore
and why you have so much tickling and coughing.

The Health of the Scalp and Hair. The scalp, being covered by hair,
does not perspire so freely as the rest of the skin of the body; but a
considerable amount of oily waste matter is poured out on it, and the
surface of its skin scales off in exactly the same way as does the rest
of the body. If this accumulation of tiny scales and grease is not
properly brushed out, it forms an excellent seed-bed for some of the
milder kinds of germs that attack the skin; and a scurfy, itchy
condition of the scalp is set up, known as dandruff.

The best way to keep the scalp clean of these accumulations of greasy
scales is by vigorous and regular brushing with a moderately stiff, but
flexible, bristle brush. Wire brushes should not be used, as the wires
scratch and irritate the delicate scalp and do more harm than good. If
you watch a groom brushing and currying the coat of a thoroughbred
horse, you will get a fair idea of hew you ought to treat your own scalp
at least twice a day, night and morning.

If this currying of the hair be thoroughly done, and the head washed
with soap and hot water about once a week for short hair and twice a
month for long hair, most of the dangers of dandruff and of other
infections of the scalp will be avoided. One thing to be remembered is,
don't brush too hard or too deep. There is an old saying and a good one,
"You can't brush the scalp too little, or the hair too much."

Wetting the hair for the purpose of "slicking" it or combing it, is
about as bad a thing as could be done; for the moisture sets up a sort
of rancid fermentation in the natural oil of the scalp, giving the
well-known sour smell to hair that is combed instead of brushed, and
furnishing a splendid soil for germs and bugs of all sorts to breed in.
There is no objection to boys' and men's wetting their hair in cold
water as often as they wish, provided that they rub it thoroughly dry
afterward and give it a brisk currying with the brush.

Hair oils and greases of all sorts are sanitary nuisances, and mere
half-civilized and lazy substitutes for proper brushing and washing.
There is no drug known to medicine which will cause hair to grow, or
make it thicker or curlier. All "hair tonics" claiming to do this are
frauds.

Corns, Calluses, and Warts. Our skin not only made our hair, teeth,
and nails, but still retains in every part a trace of its nail-making
powers, so that under pressure or irritation, it can thicken up into a
heavy leather-like substance which we call _callus_. This is naturally
and healthfully present in the soles of the feet and the palms of the
hands. Savage, or barbarous, races who wear no shoes get the skin of
their soles thickened into a regular human leather, almost half an inch
thick, and as tough as rawhide. A somewhat similar condition develops in
the palms of the hands of those who work hard with spades, axes, or
other tools.

Any good process carried to excess becomes bad, and this is true of this
power of callus formation in the skin; for parts of it which are under
constant pressure, like the surface of the toes inside the shoe, and
particularly of the outside toes, the little and the big toe, develop
under that pressure patches of thickened, horny skin, which we call
_corns_. These patches start to grow into cone-shaped projections or
buttons; but being prevented from growing outward by the pressure of the
shoe, they turn upon themselves and burrow into the skin itself, and we
get the well-known ingrowing corn.

If there is anything in the human body which we ought to be thoroughly
ashamed of, it is corns; for they are caused by our own vanity, and
nothing else, in cramping our feet into shoes one or two sizes too small
for them. There are a number of things that can be done to relieve the
discomfort of the corn, but the only sure way is to remove its cause,
namely, the tight shoe.

Under other kinds of irritation, the skin has the power of growing
curious little button-like buds, or projections, which we call _warts_.
These are commonest in childhood, and generally disappear at about
twelve or fifteen years of age, when we no longer delight in dirt, and
glory in mud pies.

They can be produced upon the hands of grown men and women by irritating
fluids and substances, such as wet sugar in the case of bakers and
confectioners, and various color-stains in dye works. They seldom last
for more than a few months, and usually narrow at their base and drop
off, when the particular irritation that caused them ceases. On this
account it is seldom worth while to try to remove them by burning with
acids or cutting them off; and it is best not to pick at, or irritate,
or scratch them too much.



CHAPTER XVII

THE PLUMBING AND SEWERING OF THE BODY


The Wastes of the Body. Almost everything that the body does in the
process of living means the breaking down, or burning, of food; and
produces, like every other kind of burning, two kinds of waste--"smoke"
and "ashes."

The carbon dioxid "smoke," as we have already learned, is carried in the
blood to the lungs, where it passes off in the breath. The solid part of
our body waste, or the "ashes," is of two kinds--that which can be
melted in water, or is, as we say, _soluble_; and that which cannot be
melted in water, or is _insoluble_. The insoluble part of our solid body
waste goes into the feces and is thus disposed of.

The soluble part of the body waste goes by a somewhat more roundabout
route. With the carbon dioxid it is poured by the body cells into the
veins, carried to the heart, and pumped through the lungs, where the
carbon dioxid is thrown off. Going back to the heart it is pumped all
over the body, part of it going through a very large artery to the
liver, part through two large arteries to the kidneys, part to the skin,
and the rest all over the remainder of the body.

The blood goes completely round the body-circuit from the heart to the
fingers and toes, and back again to the heart, in less than forty-five
seconds. Practically every drop of blood in the body will be pumped
through the liver, the kidneys, and the skin, about once every half
minute, so that they get plenty of chance to purify it thoroughly when
they are working properly.

This sounds rather complicated; but is interesting, because it shows
how much of a "mind of their own" the different organs and stuffs in our
bodies have, or what, in scientific language, we call "power of
selection." The skin glands pick out of the blood those waste substances
which they are able to get rid of. The kidneys pick out another class of
waste substances, which they are best able to deal with; while the liver
which is the most important of all, attacks almost every kind of waste
brought to it by the blood, and prepares it for disposal by the
intestines, skin, and kidneys.

The Liver. The liver has a size to match its importance. It is the
largest and heaviest gland, or organ, in the body, and weighs about
three pounds, a little more than the brain. It buds off from the food
tube just below the stomach, so that its waste tube, the _bile
duct_--about the size of a goose quill--opens into the upper part of the
intestine.

The main work of the liver is to receive the blood from all over the
body and to act upon its waste substances, burning them up so that they
can be taken up, and got rid of, by the glands of the skin and the
kidneys. In the process it very frequently changes these waste
substances from poisonous into harmless forms; and even when disease
germs get into the body and infect it, the poisons, or toxins, which
they pour into the blood are carried to the liver and there usually
burned up, or turned into harmless substances.

The liver is, therefore, to be regarded as a great _poison filter_ for
the entire body. So long as it can deal with the poisons as fast as they
are formed, either by the body itself, or in the food, or by disease
germs, the body is safe and will remain healthy. But if the poisons come
faster than the liver can deal with them, as, for instance, when we have
eaten tainted meat or spoiled fruit, or have drunk alcohol, they begin
to poison our nerves and muscles, and we become, as we say, "bilious."
Our head aches, our tongue becomes coated, we have a bad taste in the
mouth, we lose our appetite and feel stupid, dull, and feverish.

Such waste materials as the liver cannot burn down so that the kidneys
and skin can handle them, it pours out through its duct into the
intestine as the bile. The bile is a yellowish-brown fluid, which
assists the pancreatic juice in the digestion of the food, and helps to
dissolve the fats eaten, but is chiefly a waste product. It turns green
when it has been acted upon by acids, or exposed to the air. So that the
bile which you throw up when you are very sick at your stomach, is green
because it has been acted upon by your gastric juice.

As you will remember, the blood which comes from the stomach and bowels
is carried by the portal vein to the liver first and, through that, to
the heart, instead of going directly to the heart, as all the other
impure blood in the body does. This is owing, in part, to the fact that
this blood, being full of substances freshly taken or made from the
food, is very likely to contain poisons; indeed, as a matter of fact,
blood taken from these veins on its way to the liver, and injected
directly into the blood vessels of an animal, acts like a mild poison.

In part, however, this blood goes first to the liver, because the liver,
besides being a great blood purifier, is a "blood-maker" in the sense
that it changes raw food-stuffs in the blood from the intestines into
forms which are more suitable for use by the brain, the muscles, and the
other tissues of the body. Some of the sugars, for instance, the liver
turns into a kind of animal starch (_glycogen_), which it stores away in
its own cells. It also turns both sugars and proteins in the portal
blood into fat, part of which it pours into the blood, and part of which
it stores away also in its own cells. Thus the liver owes its great size
partly to the large amount of blood-purifying, filtering, and
poison-destroying work which it has to do, and partly to its acting
as a storehouse of starch and fat, which the body can readily draw upon
as it needs them.

[Illustration: OUTLINE DIAGRAM SHOWING GENERAL PLAN AND POSITION OF
BODY-MACHINERY]

As all poisons formed in, or entering, the body are brought to the liver
for destruction, it is in an extremely exposed position, and very liable
to break down under the attack of these poisons, whether of infectious
diseases, or chloroform, or alcohol, or those formed by putrefaction in
the stomach and intestines. This is why those who have lived long in the
tropics and suffered from malaria, dysentery, and other infectious
diseases, and those who drink too much alcohol, or have chronic
indigestion, or dyspepsia, are likely to have swollen and inflamed
livers.

The Gall Bladder. The liver has on its under side a little pear-shaped
pouch called the _gall bladder_, in which the bile is stored before it
is poured into the bowel. If this becomes inflamed by disease germs, or
their poisons, in the blood, little hard masses will form inside it,
usually about the size of a grain of corn, known as _gall stones_. So
long as they stay in the gall bladder, they give little trouble, but if
they start to pass out through the narrow bile duct into the intestine,
they cause severe attacks of pain, known as "gall-stone colic," and, by
blocking up the duct, may dam up the flow of the bile, force it back
into the blood again, and stain all our tissues, including our skin and
our eyes, yellow; and then we say we are _jaundiced_. Jaundice may also
be caused by colds or other mild infections which attack the liver and
bile ducts and clog the proper flow of the bile.

The Kidneys. The kidneys are another form of blood-filter, which deal
chiefly with waste stuffs in the blood left from the proteins, or Meats,
of our food--meat, fish, milk, cheese, bread, peas, beans, etc. These
waste-stuffs, called _urea_ and _urates_, are formed in the liver and
brought in the blood to the kidneys. These lie on either side of the
backbone, opposite the small of the back, their lower ends being level
with the highest point of the hip-bones, nearly six inches higher than
they are usually supposed to be. When you think you have a "pain across
the kidneys," it is usually a pain in the muscles of the back much lower
down, and has nothing to do with the kidneys at all.

A very large artery carries the blood from the aorta to each side of the
kidney, and a large vein carries the purified blood back to the vena
cava and heart. Two smaller tubes about the size of a crow quill, the
waste pipes of the kidneys (the _ureters_), carry the water containing
urea and other waste substances strained out by the kidneys and called
urine, down into a large pouch, the _bladder,_ to be stored there until
it can be got rid of.

[Illustration: THE URINARY SYSTEM

_K_, kidneys; _U_, ureters; _B_, bladder; _A_, artery; _V_, vein.]

The kidneys then are big filter-glands. They, like the lungs, are made
up of a mesh, or network, of thousands of tiny tubes of two kinds, one
set of tubes being blood vessels, and the other set the tiny branches of
the kidney tubes which finally run together to form the ureters. The
urine filters through from the spongy mesh of blood tubes (capillaries)
into the kidney tubes and is poured out through the ureters. It is very
important that the urine should be discharged as fast as it fills the
bladder, that is, about once every three hours during the day. Nothing
should be allowed to interfere with this; and whenever nature tells you
that the bladder is full, it should be emptied promptly, or the poisons
which nature is trying to get rid of in the urine may get back into the
blood and cause serious trouble.

Diseases of the Kidneys. Naturally, the kidneys, working all the time
and pouring out, as they do every day, from three to four pints of the
liquid waste called urine, are subject to numerous diseases and
disturbances. One of the common causes of these is failure to keep the
skin thoroughly clean and healthy, as perspiration is of somewhat the
same character as the urine; and if it be checked, it throws an extra
amount of work upon the kidneys.

Another most important thing to keep the kidneys working well is to
drink plenty of water, at least six or eight glasses a day, as well as
to eat plenty of fresh green vegetables and fresh fruits, which, as we
have seen, are eighty per cent water. Remember, we are a walking
aquarium, and all our cells must be kept flooded with and soaked in
water in order to be healthy. If the blood becomes overloaded with
poisons, so much work may be thrown upon the kidneys that they will
become inflamed and diseased and cannot form the urine properly; and
then poisons accumulate in the system and finally produce serious
illness and even death.

It was at one time believed that eating too much of certain kinds of
foods, particularly those that leave much nitrogenous waste in the body,
such as meat and fish, could produce a diseased condition of the
kidneys, known as Bright's Disease; but we have found that the larger
part of such cases are due to the attack of the germs of infectious
diseases, particularly scarlet and typhoid fevers, tuberculosis, and
colds. The popular impression that colds from wet feet or long drives in
winter may "settle in the kidneys" is wrong, except in so far as those
colds are caused by infectious germs.

Another cause of disturbance and permanent damage to the kidneys is the
habitual use of alcohol. Even though this may be taken in only moderate
amounts, the constant soaking of the tissues with even small amounts of
alcohol may be most harmful to the kidneys, as well as to the liver.



CHAPTER XVIII

THE MUSCLES


Importance of the Muscles. It wouldn't be of much use to smell food,
if we couldn't pick it up and bite it after we had reached it; or to see
danger, if we were not able to move away from it. Every animal that
lives, moves; and every movement, whether of the entire body from one
place to another, or of parts of the body changing their relations to
one another, or altering their shape, is carried out by an elastic,
self-moving body-stuff, which we call _muscle_.

All the work that we do, whether in earning our living, or catching our
food, or chewing it, or swallowing it and driving it through our food
tube, or pumping the blood through our arteries, or drawing air into our
lungs, is done by muscles. Hence, a very large part of the body has to
be made of muscles. In fact, our muscles, put together, weigh almost as
much as all the other stuffs in the body, making over forty per cent of
our weight.

How the Muscles Act. The commonest form of muscle that we see is the
red, lean meat of beef, mutton, or pork; and this will give us a good
idea of how our own muscles look. All muscles, whatever their size or
shape, are made up of little spindle-shaped or strap-shaped cells, or
wriggling "body-cells" arranged in bands or strings. The size of a given
muscle depends upon the number of cells that it contains.

The astonishing variety of movements which muscles can make is due to
the fact that they have the power when stirred up, or stimulated, of
changing their shape. As most of the muscle substance is arranged in
bands, this change of shape on the part of the tiny cells that make up
the band means that the band grows thicker and at the same time
shorter,--just as a stretched rubber band does when it slackens,--so
that it pulls nearer together the bones or other structures to which it
is fastened at each end by fibrous cords called _tendons_, or sinews.
This shortening of the muscle band is known as _contraction_.

When you wish, for instance, to lift your hand toward your face, you
unconsciously send a message from your brain down the nerve cables in
your spinal cord, out through the nerve-wires of your neck and shoulder,
to the big _biceps_ muscle on the front of your upper arm. This muscle
then contracts, or shortens, and pulls up the forearm and hand, by
bending the elbow joint. Just in proportion as the muscle becomes
shorter, it becomes thicker in the middle; and this you can readily
prove by grasping it lightly with your fingers when it contracts, and
feeling it bulge.[22]

The food tube is surrounded with muscles, as you will remember, for
moving the food along it, or churning it. These internal muscles,
requiring only the presence of food to cause them to act, and not
needing attention on the part of the brain or the will, are known as the
_involuntary_ ("without the will") muscles.

The great group of the _voluntary_, or bone-moving muscles, which move
"with the will" and are under our direct control, may be divided roughly
into two divisions--those that move the trunk, or body proper, and run,
for the most part, lengthwise of it; and those that move the limbs.

On the body, they may be divided into two great sheets--one running up
the front, and the other up the back. When those running up the front of
the body contract, they naturally bend the back, and pull the head and
shoulders forward and downward. Or, as when you spring up and catch the
branch of a tree or a horizontal bar with your hands, these same muscles
will pull the lower part of the body and legs upward, so that you can
climb into the tree.

The largest and thickest bands of these front body muscles are found
over the abdomen, or stomach, where you can feel them thicken and harden
when you bend your body forward and pull with your arms, as in hauling
on a rope. By their pressure upon the intestines, they give the bowels
valuable support, assist in their movements, and help the circulation of
the blood through them; so that it is of considerable importance to keep
this entire group of muscles well toned up by exercises, such as
swinging your arms back over your head, and then down between your legs;
bending the head and shoulders backward and forward; swinging the legs
up over the body, either when hanging from a bar or lying on your back.
Proper exercising and toning up of these muscles will often cure
constipation and dyspepsia, by their influence upon the bowels and
stomach, and also keep one from taking on fat around the waist too
rapidly.

On the back of the body, the muscle-sheet has grown into great, thick
ropes of muscle on each side of the backbone, which you can feel
hardening and softening in the small of the back, when you stoop down or
lift weights. These are the muscles that hold the body erect, and keep
the back straight when you stand, and are the largest and hardest
working group of muscles in the body. Every minute that you sit, or
stand, they are at work; and that is why they so often get tired out,
and ache, and you say you have "a backache." They have to work harder to
keep you erect or upright when you are standing perfectly still than
when you walk or run, so that standing perfectly still is the hardest
work you can do. Next to standing still, the hardest thing is to sit
still, as you probably have found out. If it were not for these great
muscles of the back and abdomen, we should double up like a jack-knife,
either forward or backward, when we tried to stand up. It is not our
skeleton that keeps us stiff or erect, but our muscles.

[Illustration: THE MUSCLE-SHEET

Showing how the muscles, overlapping and interlocking, give shape to the
body.]

If you want to keep straight and erect, and thus have a good carriage,
you must keep these great body muscles well trained and exercised by
swinging movements, such as bending the back forward, standing with your
feet apart and then swinging your head and shoulders down and between
your legs; or, with your heels together, swinging your hands down till
the fingers touch the ground; or by the different exercises that either
bend your back, or hold it stiff and erect. Swinging from a bar, rowing,
digging with a spade, chopping or sawing wood, dancing, rope-skipping,
ball-playing, hop-scotch, and wrestling, all develop these muscles
finely and are good for both boys and girls.

Other strands of these muscles branch out to fasten themselves to the
shoulder blades and shoulders, where they help to draw the arm back as
for a blow, pull the shoulders into position when you stand upright, or,
when you have leaned forward and grasped something with the hand, help
to pull up the arm and lift it from the ground. These muscles are quite
important in holding the shoulders back and giving a good shape to the
chest and good carriage of the upper part of the body and head. They are
called into play in all exercises like striking, batting,
tennis-playing, ball-throwing, swinging, shoveling, swimming, as well as
in pulling, in lifting weights, in swinging an axe or handling a broom.

[Illustration: USE OF MUSCLES IN BOWLING

Showing _A_ thickening of flexors on front of arm, as forearm is swung
forward, and _B_ thickening of extensors on back of arm, as forearm is
swung backward.]

The muscles of the limbs are almost as numerous as those of the trunk of
the body, and even more complex. Most of them, on both arms and legs,
are in two great groups--one known as the "benders," or _flexors,_
which, when they shorten, bend the limb; and the other, the
"straighteners," or _extensors_, which straighten or extend it.

On the front of the arm, for instance, we have the large biceps
("two-headed") muscle, which runs from the shoulder to the bone of the
forearm just below the elbow and, when it shortens, bends the elbow and
lifts the arm toward the body.

On the back of the upper arm is the _triceps_ ("three-headed") muscle,
which is fastened at its lower end to a big spur of bone, the "point" of
the elbow; when it shortens, acting lever fashion, it straightens or
_extends_ the arm. If this is done quickly, the fist is swung outward
with force enough to strike quite a sharp blow, though, as you know, if
you wish to hit really hard, you have to strike with the weight and
muscles of the full arm and the body behind it, or, as we say, "from the
shoulder."

[Illustration: USE OF MUSCLES IN FOOTBALL

Showing _A_ thickening of flexors on front of thigh and leg, as foot is
swung forward; and _B_ thickening of extensors on back of thigh and leg,
as leg is swung backward.]

[Illustration: PATELLA AND MUSCLE

_P_, patella (knee cap); _M_, muscle; _L_, ligament; _T_, tendon.]

In the lower limbs, the muscles are larger because they have heavier
work to do, supporting and moving the whole weight of the body; but they
are simpler in their arrangement since they have not such a variety of
movements to carry out. The principal muscle in the thigh is the great
muscle running down the front of the thigh, and fastening to the upper
border of the _patella_, or knee cap. This muscle, when it shortens,
straightens or extends the limb, or lifts the foot from the ground and
swings it forward as in walking, or raises the knee up toward the body
when we are sitting or lying down. You can easily tell how much it is
used in walking by remembering how stiff and sore it gets when you have
taken an unusually long tramp, particularly if there has been much
hill-climbing in it. On the back of the thigh, runs another great group
of muscles, which bend or flex the limb when they shorten. When the knee
is bent, you can feel their tendons, or sinews, stand out as hard cords
beneath the knee; hence, this group is called the _ham-string_
muscles.[23]

How the Muscles are Fed. Our muscles are not only the largest, but the
"livest" part of our bodies. Their contractions and movements are caused
by their tiny "explosions" (like the chugging of an automobile, except
that we can't hear them); and in this way they burn up the largest part
of the food-fuel which we eat--mostly in the form of sugar. When they
have burned up their surplus food-fuel, they call for more; and when
this demand has been telegraphed to the brain, we say we are hungry, and
that exercise has given us an appetite. While the muscles are at work,
they demand that large supplies of fresh fuel shall be brought to them
through the blood vessels; and this makes the heart beat harder and
faster, and improves the circulation. As they burn up this fuel, they
form smoke and ashes, or waste materials, which must be got rid of--the
fluid part by perspiration from the surface of the skin, and through the
kidneys, and the gas, or "smoke," through the lungs. This is the reason
why, during exercise, we breathe faster and deeper than at other times,
and why our skin begins first to glow and then to perspire.

If these waste-materials form in the muscles faster than the blood can
wash them out, they poison the muscle-cells and we begin to feel tired,
or fatigued. This is why our muscle-cells are often so stiff and sore
next morning after a long tramp, or a hard day's work, or a football
game. A hot bath or a good rub-down takes the soreness out of the
muscles by helping them to get these poisonous wastes out of their
cells.

Thus when we play or run or work, we are not only exercising our muscles
and making them gain strength and skill, but we are stirring up, or
stimulating, almost every part of our body to more vigorous and
healthful action.

Indeed, as our muscles alone, of all our body stuffs, are under the
control of the will, our only means of deliberately improving our
appetites, or strengthening our hearts or circulation, or invigorating
our lungs, or causing a large part of our brains and minds to grow and
develop, is through muscular exercise. This is why nature has taken care
to make us all so exceedingly fond of play, games, and sports of all
sorts, in the open air, when we are young; and, as we grow older, to
enjoy working hard and fighting and "hustling," as we say; and that is
the reason, also, why we are now making muscular exercise such an
important part of education.


FOOTNOTES:

[22] The muscle does not get any bigger when it contracts, as was at one
time supposed; if you were to plunge it into a bath of water, and then
cause it to contract, you would find that it did not raise the level of
the water, showing that it was of exactly the same size as before,
having lost as much in length as it gained in thickness.

[23] In the leg below the knee, and in the forearm, we have two groups
of "benders" or _flexors_, and "straighteners" or _extensors_, as in the
upper arm and leg, only slenderer and more numerous. They taper down
into cord-like tendons at the wrist and ankle to fasten and to pull the
hands and feet "open" and "shut," just as do the strings in the legs and
arms of a puppet or mechanical doll, or the sinews in the foot of a
chicken.



CHAPTER XIX

THE STIFFENING RODS OF THE BODY-MACHINE


What Bones Are. The bones are not the solid foundation and framework
upon which the body is built, as they are usually described. They are
simply a framework of rods and plates which "petrified," or turned into
spongy limestone after the body was built, to make it firmer and stiffen
it for movement. All the animals below the fishes, such as worms,
sea-anemones, oysters, clams, and insects, get along very well without
any bones at all; and when we are born, our bones, which haven't fully
"set" yet, are still gristly and soft. The cores of the limbs, as they
begin to stiffen, first turn into gristle, or cartilage, and later into
bone; indeed, many of our bones remain gristle in parts until we are
fifteen or sixteen years of age. This is why children's bones, being
softer and more flexible than those of grown-up people, are not so
liable to break or snap across when they fall or tumble about; and why,
too, they are more easily warped or bent out of shape through lack of
proper muscular exercise and proper food.

Bones are strips of soft body-stuff soaked with lime and hardened, like
bricklayer's mortar, or concrete.[24] When you know the shape of the
body, you know the bones; for they simply form a shell over the head and
run like cores, or piths, down the centre of the back, and down each
joint of the limbs.

In turning into spongy limestone, or animal concrete, they have become
one of the deadest tissues in the body. They are tools of the muscles,
the levers by which the muscles move the limbs and body about; they
never do anything of their own accord. On account of their lifelessness
and lack of vitality, they are rather easily attacked by disease, or
broken by a blow or fall. There are such a large number of bones (two
hundred and six, all told), and they resist decay and last so much
longer after death than any other parts of the body, that they fill our
museums and text-books of anatomy, form most of our fossils, and have
thus given us rather an exaggerated idea of their importance during
life.

[Illustration: THE HUMAN SKELETON]

The Frame-Work of the Body. Just look at any part of the body and
imagine that it has a bony core of about the same general shape as
itself, and you can reason out all the bones of the skeleton. To begin
at the top, the _skull_ is a box of strong, plate-like bones, which have
hardened to protect the brain as it grew; and the shape of its upper, or
brain, part is exactly that of the head, as you can easily feel by
laying your hands upon it. Then come bony shells, or sockets, for the
eyes and nose; and, below these, two heavy half-circles of bone, like
the jaws of a steel trap, to carry the teeth.

The thickness of the lower jaw and the size and squareness of the angle
where it bends upward to be hinged to the skull, below the ear, are what
give the appearance of squareness and determination to the faces of
strong, vigorous men or women. If we want to imply that a person has a
feeble will, or weak character, we say he has a "weak jaw."

The skull rests upon the top of the backbone, or _spinal column_, which,
instead of being one long solid bone, is made up of a number of pieces,
or sections, known as _vertebræ_. Each one of these vertebræ has a ring,
or arch, upon its back. These, running one after the other, form a
jointed, bony tube to protect the _spinal cord_, or main nerve-cable of
the body, which runs through it.

[Illustration: THE SPINAL COLUMN

_V_, vertebra; _C_, cartilage protecting spinal cord; _A_, point of
articulation on the right side.]

Although the backbone can bend forward or backward, or twist from side
to side a little, by the little pieces of bone of which it is built up
gliding and turning upon one another, it is really very stiff and rigid,
so as to protect the spinal cord and prevent its being stretched or
pinched. Most of the movements which we call bending the spine are
really movements of other joints which connect the body or head with
it. When we bend our necks, for instance, we hardly bend the backbone at
all, as most of the movement is made in the joint at the top of it,
between it and the skull. Similarly, when we bend our backs, we really
bend our backbones very little; for most of the movement comes at the
hip joints, between the thighs and the hip bones.

Each of the limbs has a single, long, rounded bone in the upper part,
known in the arm as the _humerus_, and two bones in the lower part.
These last are known as the _radius_ and _ulna_ (the "funny bone") in
the forearm, and the _tibia_ and _fibula_ in the leg. The shoulder-joint
is made by the rounded head of the humerus fitting into the shallow cup
of the _scapula_, or shoulder-blade. It is shallower than the hip joint
to allow it freer movement; but this makes it weaker and much more
easily dislocated, or put out of joint,--the most so, in fact, of any
joint in the body.

[Illustration: A BALL-AND-SOCKET JOINT

Hip joint.]

[Illustration: A HINGE JOINT

Knee joint, with the knee cap removed]

The hip joints are deep, strong, cup-shaped sockets upon each side of
the hip bones, or _pelvis_, into which fit the heads of the _femurs_ or
thigh bones. When the hip joint does become dislocated, it is very hard
to put back again, on account of its depth and the heavy muscles
surrounding it. It is quite subject to the attack of tuberculosis, or
"hip-joint disease."

[Illustration: LENGTHWISE SECTION OF BONE]

The _joints_, or points at which the bones join one another, look rather
complicated, but they are really as simple as the bones themselves. Each
joint has practically made itself by the two bones' rubbing against each
other, until finally their ends became moulded to each other, and formed
the ball-and-socket, or the hinge, according to whichever the movements
of the "bend" required. The ends, or heads, of the bones which form a
joint are covered with a smooth, shining coating of _cartilage_, or
gristle, so that they glide easily over each other.

[Illustration: CROSS SECTION OF BONE]

Around each joint has grown up a strong sheath of tough, fibrous tissue
to hold the bones together; and, inside this, between the heads of the
bones, is a very delicate little bag, or pouch, containing a few drops
of smooth, slippery fluid (_synovial fluid_) to lubricate the movements
of the joint. This is sometimes called the "joint oil," though it is not
really oil.

Bones are covered with a tough skin, or membrane (_periosteum_). They
are hardest and most solid on their surfaces, and hollow, or spongy,
inside. The long bones of the limbs are hollow, and the cavity is filled
with a delicate fat called _marrow_--just as an elderberry stem or
willow-twig is filled with pith. This tubular shape makes them as strong
as if they were solid, and much lighter.[25]

The short, square, and flattened bones of the body, such as those of the
wrist, the skull, and the hips, instead of being hollow inside are
spongy; and the spaces in the bone-sponge are filled with a soft tissue
called the _red marrow_ in which new red and white corpuscles for the
blood are born, to take the place of those which die and go to pieces.


FOOTNOTES:

[24] You can easily prove that a bone is made up of living tissue soaked
and stiffened with lime, by putting it into a jar filled with weak acid.
This will gradually dissolve and melt out the lime salts, and then you
will find that the bone has lost three-fourths of its weight and that
what remains of it is so soft and flexible that it can be bent, or even
tied into a knot.

[25] The hollow spaces in the bones of birds, however, are filled with
air, which makes them lighter for flying.



CHAPTER XX

OUR TELEPHONE EXCHANGE AND ITS CABLES


The Brain. We are exceedingly proud of our brain and inclined to
regard it as the most important part of our body. So it is, in a sense;
for it is the part which, through its connecting wires, called the
_nerves_, ties together all the widely separated organs and regions in
our body, and helps them to work in harmony with one another. We speak
of it as the master and controller of the body; but this is only
partially true.

The brain is not so much the President of our Cell Republic as a great
central telephone exchange, where messages from all over the body are
received, sifted, and transmitted in more or less modified form, to
other parts of the body. Three-fourths of the work of the brain consists
in acting as "middle-man," or transmitter, of messages from one part of
the body to another. In fact, the brain is far more the servant of the
body than its ruler; and depends for its food supply, its protection,
its health, and its very life, upon the rest of the body. The best way
to keep the brain clear and vigorous is to keep the muscles of the
stomach, the liver, the heart, and the entire body in good health.

What the Brain Does. The brain is the very wonderful organ with which
we do what we are pleased to call our thinking, and also a number of
other more important things of which we are not conscious at all. It is
a large organ, weighing nearly three pounds when full grown. In shape it
is like an oval loaf of bread split lengthwise by a great groove down
the centre, and with a curiously wrinkled or folded surface. The two
halves of the brain, called _hemispheres_ (though more nearly the shape
of a coffee-bean), are alike; and each one, by some curious twist, or
freak, of nature, receives messages from, and controls, the opposite
half of the body--the right half controlling the left side of the body,
while the left half controls the right side of the body. Thus an injury
or a hemorrhage on the left side of the brain will produce paralysis of
the right side, which is the side on which a stroke of paralysis most
commonly occurs.

All the nerve fibres in each half or hemisphere of the upper brain run
downward and inward like the sticks of a fan, to meet in a strap-like
band, or stalk, which connects it with the base of the brain and the
spinal cord. A very small amount of damage at this central part, or
base, of the brain will produce a very large amount of paralysis. We may
have large pieces of the bones of the skull driven into the outer
surface of the brain, or considerable masses of our upper brain removed,
or destroyed by tumors or disease, without very serious injury. But any
disease or injury which falls upon the base of the brain, where these
stalks run and big nerve-knots (_ganglia_) lie, will cause very serious
damage, and often death.

The whole upper brain is a department of superintendence, which has
grown up from the lower brain to receive messages, compare them with
each other, and with the records of previous messages which it has
stored up, thus giving us the powers which we call memory, judgment, and
thought. Unfortunately, however, long and carefully as we have studied
the brain, we really know little about the way in which it carries out
these most important processes of memory, of judgment, and of thought,
or even of the particular parts of it in which each of these is carried
out.

[Illustration: THE NERVOUS SYSTEM

Diagram to show brain, spinal cord, and larger nerves.]

No part of the brain, for instance, seems to be specially devoted to, or
concerned in, memory or reason or imagination, still less to any of the
emotions, such as anger, joy, jealousy or fear; so all those systems
which pretend to tell anything about our mental powers and our
dispositions by feeling the shapes of our heads, or the bumps on them,
are pure nonsense.

The most important and highest part of the brain is its surface, a thin
layer of gray nerve-stuff, often spoken of as the _gray matter_ (the
_cortex_, or "bark"), which is thrown into curious folds, or wrinkles,
called _convolutions_. This gray matter is found in the parts of the
nervous system where the most important and delicate work is done. The
rest of the nervous system is made up of what is called white matter,
from its lighter color; and this is chiefly mere bundles of telephone
wires carrying messages from one piece of gray matter to another, or to
the muscles.

We also know that a certain rather small strip of the upper
brain-surface, or cortex, about the size of two fingers, running upward
and backward from just above the ear, controls the movements of the
different parts of the body. One little patch of it for the hand,
another for the wrist, another for the arm, another for the shoulder,
another for the foot, and so on. We can even pick out the little patch
which controls so small a part of the body as the thumb or the eyelids.
So when we have a tumor of the brain or an injury to the skull in this
region, we can tell, by noticing what groups of muscles are paralyzed,
almost exactly where that injury or tumor is. Then we can drill a hole
in the skull directly over it and remove the tumor, lift up the splinter
of bone, or tie the ruptured blood vessel.

Three other patches, or areas, running along the side of the brain, each
of them about two inches across, are known to be the centres for smell,
hearing, and sight, that for sight lying furthest back. Damage to one of
these areas will make the individual more or less completely blind, or
deaf, or deprived of the sense of smell, as the case may be.

At the lower part of the area which controls the muscles of the
different parts of the body, above and a little in front of the tip of
the ear, lies a very important centre, which controls the movements of
the tongue and lips, and is known as the _speech centre_. If this should
be injured or destroyed, the power of speech is entirely lost. This,
curiously enough, lies upon the left side of the brain, and is the only
one-sided centre in the body. Why this is so is somewhat puzzling,
except that as speech is made up both of sound and of gesture, and our
gestures are usually made with the right hand, it is not unreasonable to
suppose that the speech centre should have grown up on that side of the
brain which controls the right hand, which is, as you remember, the left
hemisphere. What makes this more probable is that in persons who are
"left-handed," the speech centre lies upon the opposite or _right_ side
of the brain. So it is waste of time and does more harm than good to try
to "break" any child of left-handedness.

The Spinal Cord. Running downward from the base of the brain, like the
stalk of a flower, is a great bundle of nerve-fibres, the central cable
of our body telephone system, the spinal cord. This, you will remember,
runs through a bony tube formed by the arches of the successive
vertebrae; and as it runs down the body, like every other cable it gives
off and receives branches connecting it with the different parts of the
body through which it passes. These branches are given off in pairs, and
run out through openings between the little sections of bone, or
vertebrae, of which the spinal column is made up. They are called the
_spinal nerves_, and each pair supplies the part of the body which lies
near the place where it comes out of the cord.

The spinal nerves contain nerve wires of two sorts--the inward, or
_sensory_, and the outward, or _motor_, nerves. The sensory, or ingoing,
nerves come from the muscles and the skin and bring messages of heat and
cold, of touch and pressure, of pain and comfort, to the spinal cord
and brain. The outward, or motor, nerves running in the same bundle go
to the muscles and end in curious little plates on the surface of the
tiny muscle fibres, and carry messages from the spinal cord and brain,
telling the muscles when and how to contract.

As the spinal cord runs down the body, it becomes gradually smaller, as
more and more branches are given off, until finally, just below the
small of the back and opposite the hip bones, it breaks up by dividing
into a number of large branches which go to supply the hips and lower
limbs.

While most of the spinal cord is made up of bundles of white fibres,
carrying messages from the body to the brain, its central portion, or
core, is made of gray matter. The reason for this is that many of the
simpler messages from the surface of the body and the movements that
they require are attended to by this gray matter, or ganglia, of the
spinal cord without troubling the brain at all.

For instance, if you were sound asleep, and somebody were to tickle the
sole of your bare foot very gently, the nerves of the skin would carry
the message to the gray matter of the spinal cord, and it would promptly
order the muscles of the leg to contract, and your foot would be drawn
away from the tickling finger, without your brain taking any part in the
matter, though, if you had been awake, you would of course have known
what was going on.

This sort of reply to a stimulus, or "stirring up," without our knowing
anything about it, is known as a _reflex_ movement. Not only are many of
these reflexes carried out without any help from the will, or brain, but
they are so prompt and powerful that the brain, or will, can hardly stop
them if it tries, as, for instance, in the case of tickling the feet.
You can, if you make up your mind to it, prevent yourself from either
wriggling, pulling your foot away, or giggling, when the sole of your
foot is tickled; but if you happen to be at all "ticklish," it will take
all the determination you have to do it, and some children are utterly
unable to resist this impulse to squirm when tickled.

This extraordinary power of your reflexes has developed because only the
promptest possible response, by jerking your hand away or jumping, will
be quick enough to save your life in some accidents or emergencies, when
it would take entirely too long to telephone up to the brain and get its
decision before jumping. When you are badly frightened, you often jump
first and discover that you are frightened afterwards; and this jump,
under certain circumstances, may save your life. On the other hand, like
all instinctive or impulsive movements, it may get you into more trouble
than if you had kept still.

As you will see by the picture, the spinal nerves, which are given off
from the cord in the lower part of the neck and between the shoulder
blades, are gathered together into a great loose bundle to form the long
nerve-wires needed to supply the shoulders and arms. Those given off
from the small of the back just above the hips also run together to
form, first a network and then a big single nerve-cord, called the
_sciatic_ nerve, which many of you have probably heard of from the
frightfully painful disease due to an inflammation of it, called
_sciatica_. It is the largest nerve-cord in the body, running down the
middle of the back of the thigh to supply the muscles of two-thirds of
the leg.[26]

The substance of both the spinal cord and the brain is made up of
millions of delicate, tiny cells, called _neurons_, most of which, with
very long branches, are arranged in chains for carrying messages,
forming the white matter; while the others lie in groups, or ganglia,
for sorting and deciding upon messages, forming the gray matter.

Just at the top of the spinal cord, where it passes into the skull and
joins with the brain, it swells out into a sort of knob, about the size
of a queen olive or the head of a gold-headed cane, which is known as
the _medulla_, or "pith." This is the most vital single part of the
entire brain and nervous system; and the smallest direct injury to it
will produce instant death, partly because all the messages which pass
between the brain and the body have to go through it, and partly because
in it are situated the centres which control breathing and the beat of
the heart, and another quite important but less vital centre,--that for
swallowing.

How Messages are Received and Sent. Now to learn how smoothly and
beautifully this nerve telephone system of ours works, and how simple it
really is, although it has such a large number of lines and so many
telephones on each line, and such a large central exchange, let us see
how it deals with a message from the outside world. Suppose you are
running barefoot and step on a thorn. Instantly the tiny nerve bulbs in
the skin of the sole of your foot are stimulated, or set in vibration,
and they send these vibrations up the sciatic nerve, into and up the
whole length of the spinal cord, through the medulla, which switches
them over to the other side of the brain up through the _brain stalk_,
and out to the part of the surface (cortex) of the brain which controls
the movements of the foot. All this takes only a fraction of a second,
but it is not until the message reaches the brain-surface that you feel
pain. If you were to cut the sciatic nerve, or even tie a string tightly
around it, you could prick or burn the sole of your foot as much as you
pleased, and you would not feel any pain at all.

As soon as the surface of the brain has recognized the pain and where it
comes from, it promptly sends a return message back down the same cable,
though by different nerve-wires, to the muscles of the foot and leg,
saying, "Jerk that foot away!" As a matter of fact, this message will
arrive too late, for the centres in the spinal cord will already have
attended to this part of the matter, often almost before you know that
you are hurt.

However, there is plenty of other work for the brain to do; and its next
step, quicker than you can think, is to wake up a dozen muscles all over
the body with the order, "Sit down!" And you promptly sit down. At the
same time, the brain "central" has ordered the muscles of your arms and
hands to reach down and pick up the foot, partly to protect it from any
further scratch, and partly to pull the thorn out of it. Next it rushes
a hurry call to the muscles controlling your lungs and throat, and says,
"Howl!" and you howl accordingly. Another jab at the switchboard, and
the eyes are called up and ordered to weep, while at the same time the
muscles of the trunk of your body are set in rhythmic movement by
another message, and you rock yourself backward and forward.

This weeping and rocking yourself backward and forward and nursing your
foot seem rather foolish,--indeed you have perhaps often been told that
they are both foolish and babyish,--but, as you say, you "can't help
it," and there is a good reason for it. The howl is a call for help; and
if the hurt were due to the bite of a wolf or a bear, or the cut had
gone deep enough to open an artery, this dreadfully unmusical noise
might be the means of saving your life; while the rocking backward and
forward and jerking yourself about would also send a message that you
needed help, supposing you were so badly hurt that you couldn't call
out, to anyone who happened to be within sight of you. So that it isn't
entirely babyish and foolish to howl and squirm about when you are
hurt--though it is manly to keep both within reasonable limits.

If the message about the thorn had been brought by your eyes,--in other
words, if you had seen it before you stepped on it,--then a similar but
much simpler and less painful reflex would have been carried out. The
image of the thorn would fall on the _retina_ of the eye and through its
_optic nerve_ the message would be flashed to the brain: "There is
something slim and sharp in the path,--looks like a thorn." When this
message reached the brain, and not till then, would you see the thorn,
just as in the case of the pain message from the foot. Then the brain
would take charge of the situation just as before, flashing a hasty
message to the muscles of the legs, saying, "Jump!" while its message to
the throat and lungs, instead of "Yell," would be merely, "Say,
'Goodness!' or 'Whew!'" and you would say it and run on.

If the thing in the grass, instead of a thorn, happened to be a snake,
and you heard it rustle, then the warning message would come through
your ears to the brain, and you would jump just the same; though, as it
is not so easy to tell by a hearing message exactly where the sound is
coming from, you might possibly jump in the wrong direction and land on
top of the danger.

This is the way in which you see, hear, and form ideas of things. Your
eye telegraphs to the brain the colors; your ear, the sounds; and your
nose, the smells of the particular object; and then your brain puts
these all together and compares them with its records of things that it
has seen before, which looked, or sounded, or smelt like that, and
decides what it is; and you say you _see_ an apple, or you _hear_ a
rooster crow, or you _smell_ pies baking. Remember that, strange as it
may seem, you don't see an orange, for instance, but only a circular
patch of yellowness, which, when you had seen it before, and felt of it
with your hand, you found to be associated with a feeling of roundness
and solidness; and when you lifted it toward your nose, with the
well-known smell of orange-peel; so you called it an orange. If the
yellow patch were hard, instead of elastic, to the touch, and didn't
have any aromatic smell when you brought it up to your nose, you would
probably say it was a gourd, or an apple, or perhaps a yellow croquet
ball. This is the way in which, we say, our senses may "deceive" us, and
is one of the reasons why three different people who have seen something
happen will often differ so much in their accounts of it.

It is not so much that our senses deceive us, but that we draw the wrong
conclusions from the sights, sounds, and smells that they report to our
brains, usually from being in too great a hurry and not looking
carefully enough, or not waiting to check up what we _see_ by touching,
hearing, or tasting the thing that we look at.

This message-and-answer system runs all through our body. For instance,
if we run fast, then the muscle cells in our legs burn up a good deal of
sugar-fuel, and throw the waste gas, or smoke, into the blood. This is
pumped by the heart all over the body, in a few seconds. When this
carbon dioxid reaches the breathing centre in the medulla, it stirs it
up to send promptly a message to the lungs to breathe faster and deeper,
while, at the same time, it calls upon the circulation centre close to
it, to stir up the heart and make it beat harder and faster, so as to
give the muscles more blood to work with. If some poisonous or very
irritating food is swallowed, as soon as it begins to hurt the cells
lining the stomach, these promptly telegraph to the vomiting centre in
the brain, we begin to feel "sick at the stomach," the brain sends the
necessary directions to the great muscles of the abdomen and the
diaphragm, they squeeze down upon the stomach, and its contents are
promptly pumped back up the gullet and out through the mouth, thus
throwing up the poisons.

And so on all over the body--every tiniest region or organ in the body,
every square inch of the skin, has its special wire connecting it with
the great telephone exchange, enabling it to report danger, and to call
for help or assistance the moment it needs it.


FOOTNOTES:

[26] To give you an idea of what real things nerve-trunks are, this
sciatic nerve is as large as a small clothes-line, or, more accurately,
as a carpenter's lead pencil, and so strong that when the surgeon cuts
down upon it and stretches it to cure a very bad case of sciatica, he
can lift the lower half of the body clear of the table by it. This
strength, of course, is not due to the nerve-fibres and cells themselves
but to the tough, fibrous sheath, or covering, with which all the nerves
that run outside of the brain and spinal cord are covered and coated.
The spinal cord, though it is between one-half and three-fourths of an
inch across, or about the size of an ordinary blackboard pointer, has
little or none of this fibrous tissue in it, and is very soft and
delicate, easily torn when its bony case is broken; hence its old name,
the _spinal marrow_, from its apparent resemblance to the marrow, or
soft fat, in the hollow of a bone.



CHAPTER XXI

THE HYGIENE OF BONES, NERVES, AND MUSCLES


HOW TO GET AND KEEP A GOOD FIGURE

Erect Position is the Result of Vigorous Health. Naturally and
properly, an erect, graceful figure and a good carriage have always been
keenly desired; and much attention has been paid to the best means of
acquiring them; as we say, we try to "get the habit" of carrying
ourselves straight and well. But it must be remembered that an erect
figure and a good carriage are the results of health and vigor, rather
than the cause of them.

Stooping, round shoulders, sitting "all hunched up," or a shuffling
gait, are owing partly to bad habits, or "slouchiness," but chiefly to
weak muscles and a badly-fed nervous system, often due to a poor
digestion and a weak circulation. If a child is not healthy and
vigorous, then no amount of drilling or reminders to "sit straight" and
"stand erect" will make him do so.

It is of great importance that the child should take an erect and
correct position for reading and writing, and while sitting at his desk;
and that the desk and the seat should fit him. But it is more important
that he should not sit at his desk in a stuffy room long enough to be
harmed by a cramped position.

There are few children who will "hump over" at their desks, if the
muscles of their backs and necks are strong and vigorous, and their
brains well ventilated. Nor will many of them bore their noses into
their books, or sprawl all over their copy books when they write, unless
the light is poor, or they have some defect of the eyes which has not
been corrected by proper glasses. A bad position or a bad carriage in a
child is a sign of ill health, and should be treated by the removal of
its cause.

Curvatures--Their Cause and Cure. There are various forms of
curvatures, or bendings, of the spine which are supposed to be owing to
faulty positions of sitting or of carrying the body. There is wide
difference of opinions as to their cause; but this all are agreed on,
that they practically never occur in sturdy, well-grown, active
children; and the way that they are now corrected is by careful systems
of balancing, muscular exercise, open-air life, and abundant feeding,
instead of using steel braces, or jackets, or schoolroom drills.

[Illustration: THE POSITION OF THE BODY IS AN INDEX TO ITS HEALTH

Note the pupil in the second row who evidently needs eye glasses.]

Much the same is true of other deformities and defects of the body, as,
for instance, round shoulders, or "flat-foot," or even such serious ones
as "club-foot" and "bow-legs." Nearly all these are caused by the
weakness or wrong action of some muscle, or groups of muscles. If this
be long continued or neglected, the bones--which, you will remember,
were made by the muscles in the first place--will be warped out of
shape. When this has occurred, it is often necessary to bring back the
limb, or foot, into a nearly straight position by mechanical or surgical
means; but we now largely depend upon muscular exercises combined with
rubbing and massage with the hand, and on building up the general vigor
of the entire body, so that the muscles will pull the limb or the
backbone back into proper position. Take care of the muscles, and the
bones will take care of themselves! Make the body strong, vigorous, and
happy, and it will "hold" and "carry" itself.


OUR FEET

The Living Arches of the Foot. One of the most important things to
look after, if we wish to have an erect carriage and a swift, graceful
gait, is the shape and vigor of the feet. Each foot consists of two
springy, living arches of bone and sinew, which are also used as levers,
one running lengthwise from the heel to the ball of the toes, and the
other crosswise at the instep. These arches are built largely of bones,
but are given that springy, elastic curve on which their health and
comfort depend, and are kept in proper shape and position, solely by the
action of muscles--those of the lower part of the leg and calf.

[Illustration: IMPRINT OF (1) ARCHED FOOT AND (2) FLAT FOOT

The absence of impression on the inner border of the normal footprint at
_A_ is due to the elevation of the foot by the longitudinal arch. The
other arch lies across the foot in front of this.--After Schmidt.]

The purpose of these arches is to "give," or spring, like carriage
springs, and thus break the shock of each step and cause the body to
"ride" easily and comfortably. In order that a spring may "give," it
must expand, or spread. Far the commonest and most serious cause of a
poor, easily tired gait and a bad carriage is tight shoes, which, by
being too short, or too narrow, or both, prevent the arches of the foot
from "giving" and expanding. Not only does this produce corns, bunions,
and lame feet, but it makes both standing and walking painful and
feeble, and destroys the balance of the entire body, causing the back to
ache, the shoulders to droop forward, and the neck muscles to tire
themselves out trying to pull the head back so as to keep the face and
eyes erect. Thus one soon tires, and never really enjoys walking. If
this disturbance of balance is increased by high heels, thrust forward
under the middle of the foot, the result is very bad.

[Illustration: THE RESULT OF WEARING A FASHIONABLE SHOE

(1) A foot that has never worn a shoe (from a photograph); (2) A foot so
cramped and bent as to prevent firmness of step and gait.]

Our Shoes, an Important Factor in Health. Few more ingenious
instruments of crippling and torture have ever been invented than
fashionable tight shoes with high heels.

Kipling never said a shrewder or truer thing than when he made Mulvaney,
the old Irish drill-sergeant, tell the new recruit, "Remimber, me son, a
soljer on the marrch is no betther than his feet!" and this applies
largely to the march of life as well.

Every shoe should be at least three-quarters of an inch longer, and from
half to three-quarters of an inch wider, than the foot at rest, to allow
proper expansion of these great "carriage-spring" arches. If children
run free in the open air, either barefoot, or with light, loose,
well-ventilated shoes, or sandals, they will have little trouble, not
only with bunions, corns, "flat-foot," or lameness, but also with their
backs, their gait, and their carriage. Easily half of our backaches, and
inability to walk far or run fast in later life, to say nothing of
over-fatness and dyspepsia, are caused by tight shoes.


SLEEP AND REST

Why We Need Rest. A most important element in a life of healthful
exercise, study, and play is rest. Even when we are hard at work, we
need frequent breathing spells and changes of occupation and amusement
to keep one part of our muscles, or our brains, from poisoning itself.
But after a time, in even the strongest and toughest of us, there comes
a period when no change of occupation, no mere sitting still, will rest
us; we begin to feel drowsy and want to go to sleep. This means partly
that the fatigue poisons, in spite of fresh air and change, have piled
up faster than we can burn them, so that we need sleep to restore the
body.

All day long we are making more carbon dioxid than the oxygen we breathe
in can take care of; while we sleep, the situation is reversed--the
oxygen is gaining on the carbon dioxid. This is why the air in our
bedrooms ought to be kept especially pure and fresh.

But the need goes deeper than this: sleeping and waking are simply parts
of the great rhythm in which all life beats--a period of work followed
by a period of rest. Continuous, never-ceasing activity for any living
thing quickly means death. While externally the body appears to be at
rest, the processes of growth and upbuilding probably go on more rapidly
when we are asleep than when we are awake. The benefits of exercise are
made permanent and built into the body during the sleep that follows it.
The more rapidly young animals are growing, the more hours out of the
twenty-four they spend in sleep. When you sleep, you are not stopping
all the useful activities of your body and mind, you are simply giving
some of the most useful and most important of them a chance to work. The
only likeness between sleep and death is that in both the body is quiet
and the eyes are closed. Really we are never more alive and growing than
when asleep.

It is of the utmost importance that young children especially have all
the sleep they need, and that is precisely all that they can be induced
to take. The best rule for you, then, to follow, is to go to bed when
you feel sleepy, and to get up when you wake rested. Every child under
twelve should have at least ten hours of sleep, and every grown person
eight, or better still, nine hours. Time spent in sound, refreshing
sleep, is time well spent. If you cannot sleep well, it is a signal that
something is wrong with your health, or your habits--a danger signal of
great importance, which should be attended to at once. The best and only
safe sleep-producer is exercise in the open air.


DISORDERS OF MUSCLES AND BONES

The Muscles and Bones Have Few Diseases. Considering how complex it
is, and the never-ceasing strain upon it, this moving apparatus of ours,
the nerve-bone-muscle-machine, is surprisingly free from disease. The
muscles, though they form nearly half our bulk, have scarcely a single
disease peculiar to them, or chiefly beginning in them, unless fatigue
and its consequences might be so regarded. They may become weakened and
wasted by either lack or excess of exercise, by under-feeding, or by
loss of sleep; but most of their disturbances are due to poisons which
have got into the blood pumped through them, or to paralysis or other
injuries to the nerves that supply them.

The muscles of an arm, for instance, which has been lashed to a splint,
or shut tightly in a cast for a long time, waste away and shrink until
the arm becomes, as we say, "just skin and bone"; and the same thing
will happen if the nerve supplying a muscle, or a limb, is cut or
paralyzed.

The bones have more diseases than the muscles, but really comparatively
few, considering their great number and size, and the constant strain to
which they are subjected in supporting the body, and driving it forward
and doing its work under the handling and leverage of the muscles. Most
of their diseases are, like those of the muscles, the after-effects of
general diseases, particularly the infections and fevers, which begin
elsewhere in the body; and the best treatment of such bone diseases is
the cure and removal of the disease that caused them.

[Illustration: CALLUS FORMED AROUND A FRACTURE

An aluminum splint holds the parts of the bone together.]

Repair of Broken Bones. If bones are broken by a fall, or blow, they
display a remarkable power of repair. The "skin" covering them
(periosteum) pours out a quantity of living lime-cement, or
animal-mortar, around the two broken ends, which solders them together,
much as a plumber will make a joint between the ends of two pipes. This
repair substance is called _callus_. The most remarkable thing about the
process is that, when it has held the two broken ends together long
enough for them to "knit" firmly--that is, to connect their blood
vessels and marrow cavities properly--this handful of lime-cement, which
has piled up around the break, gradually melts away and disappears; so
that, if the ends of the bone have been brought accurately together, you
can hardly tell where the break was, except by a slight ridge or
thickening.


TROUBLES OF THE NERVOUS SYSTEM

The Nervous System is not easily Damaged. The nervous system is
subject to a good many more diseases than are either the muscles or the
bones; but, considering how complex it is, it is not nearly so easily
damaged or thrown out of balance as we usually imagine, and has
astonishing powers of repair. Instead of being one of the first parts of
the body to be attacked by a disease, such as an infection or a fever,
it is one of the very last to feel the effects of disease, except in the
sense that it often gives early that invaluable danger signal, pain.

Headache. Next after fatigue the most valuable danger signal given us
by our nerves is that commonest of all pains, _headache_. Indeed, it is
not too much to say that headache is the most useful pain in the world.
It has little to do with the condition of the brain, but occurs in the
head chiefly because the nerves of the head and face are the most
sensitive of all those in the body, and the first ones, therefore, to
"cry out" when hurt.

Headache has been described as the cry of a poisoned or starved or
over-worked nerve, and is simply nature's signal that something is going
wrong. Toxins, or poisons, formed anywhere in the body, from any cause,
get into the blood, are carried to the sensitive nerves of the head and
face, and irritate them so that they ache. It is foolish to try to do
anything to the head itself for the relief of headache, although cold
cloths, or a hot-water bottle, may be soothing in mild cases. The thing
to do is to clear the poison out of the blood, and the only way is to
find what has caused it.

Nearly all the things that cause headache do so by poisoning the blood.
A very common cause of headache, for instance, is getting over-tired,
especially if at the same time you do not get enough sleep; and, as you
already know, tiredness, or fatigue, is a form of self-poisoning.
Another very common cause of headache is bad air--sitting or sleeping in
hot, stuffy rooms with the windows shut tight. If you do this, not only
are you not getting oxygen enough into your blood to burn up the waste
poisons that your own cells are making all the time, but also you are
breathing in the waste poisons from other people's lungs, and the germs
that are always in bad air.

Another very common cause of headache is _eye-strain_. Whenever you find
that, when you try to read, the letters begin to dance before your eyes,
and your head soon begins to ache, it is a sign that you need to have
your eyes examined and perhaps a pair of glasses fitted to enable you to
see properly.

Constipation and disturbances of digestion also very often cause
headache by poisoning the blood; and, as you know, the first sign of a
bad cold, or the beginning of a fever, or other illness, will often be a
bad headache.

In short, a headache always means that something is going wrong; and the
thing to do is to set to work at once to see if you can find out what
has caused it, and then to remove the cause. If you cannot find out the
cause, then go to a doctor and ask him to tell you what it is, and what
to do to get rid of it.

Above all things, don't swallow a dose of some kind of headache
medicine, and go on with your work, or your bad habits of eating, or
using your eyes; because, even though it may relieve the pain, it
doesn't do anything whatever to remove the cause and leaves you just as
badly off as you were before you took it. Besides, most of these
headache medicines, which for a time will relieve the pain of a
headache, are narcotics, or pain-deadeners; and in more than very
moderate doses they are poisons, and often dangerous ones. Those in
commonest use, known as the "coal tar" remedies, because the chemists
make them out of coal tar,[27] are likely to have a weakening effect
upon the heart; and, while not very dangerous in small doses, they are
very bad things to get into the habit of using.

The Exaggerated Claims of Patent Medicines. The same thing must be
said of the habit of dosing yourself every time you feel a pain or an
ache, with some sort of medicine, whether obtained at some previous time
from a doctor, or bought at a drug store. A large majority of the
medicines that are most widely advertised to cure all sorts of pains and
aches contain some form of narcotic--most commonly either alcohol or
opium. The reason for this is that no one medicine can possibly be a
cure for all sorts of diseases; and the only kind of medicine that will
make almost every one who takes it feel a little bit better for the time
being is a narcotic, because it has the power of deadening the nerves to
pain or discomfort.

Careful analyses by boards of health and government chemists of a great
number of advertised medicines have shown that three-fourths of the
so-called tonics and "bitters" and "bracers" of all sorts contain
alcohol--some of them in such large amounts as to be stronger and more
intoxicating than whiskey. The same investigations have found that a
large majority of the "colic cures," "pain relievers," nearly all the
"soothing syrups" and "teething syrups," and most of the cough mixtures,
cough cures, and consumption cures contain opium, often in quite
dangerous amounts. The widely-advertised medicines and remedies
guaranteed to cure all sorts of diseases in a very short time are almost
certain to be one of two things: either out-and-out frauds, costing
about four cents a bottle and selling for fifty cents or a dollar, or
else dangerous poisons. All patent pain relievers are safe things to let
entirely alone.

Another risk in taking medicines wholesale, especially those that are
known as patent medicines, is that you never can be quite sure what you
are taking, as their composition is usually kept a strict secret. It may
happen to be something very good for your disease, it may be entirely
useless, and it may be something very harmful. There is no one drug, or
medicine, known to the medical profession, that will cure more than one
or two diseases, or relieve more than four or five disturbed and
uncomfortable conditions. As you not only do not know what you are
taking, but are not always quite sure what is the matter with you, the
chances of your getting the right remedy for your disease are not much
more than one in a hundred. If it isn't the right thing, you are
certainly wasting your money, and may be doing yourself a serious
injury.

We should not pour drugs of which we know little into a body of which we
know less. Doctors give scarcely a fourth as much medicine now as they
did fifty years ago. The best cures are food, exercise, sleep, and fresh
air.

The Effects of Disease. In the case of nearly all infectious diseases,
the effects on the nervous system are among the last to appear, and may
not occur until weeks, months, or even years after the main fever or
attack of sickness. This is one of the reasons why, when they do occur,
they are often hard to cure; the whole system has become saturated with
the poisons before they reach the nerves at all. So it happens that the
idea has grown up that nervous diseases are very hard to cure. When,
however, we know that two-thirds of them are a late result of some of
the preventable infectious diseases and fevers, we can realize that it
is perfectly possible to prevent them, and that prevention is the best
cure.

The poisons that attack the brain and nervous system may be formed in
the body by disease germs or brought in from without, as are alcohol,
tobacco, lead, or arsenic. Even such mild infections as measles, scarlet
fever, and influenza may poison certain nerves supplying the muscles of
an arm or a leg, causing temporary paralysis, or even permanent laming;
or they may attack the nerve of sight or of hearing and produce
blindness or deafness.

A great many of the cases of paralysis and insanity are caused by
alcohol. Alcohol in excess may attack the nerves supplying the arms and
legs, producing severe pain and partial paralysis. It may also, after
long-continued use, affect the cells of the brain itself, producing the
horrible condition known as delirium tremens--a form of acute insanity
with distressing delusions, in which the patient imagines that he sees
rats, snakes, and other reptiles and vermin crawling over him, or in his
room. Even in those who never use it to such excess as this, or indeed
in those who may never become intoxicated, the long-continued use of
alcohol may produce a slow poisoning and general breaking-down of the
whole nervous system, causing in time the hand to tremble, the eye to
become bleared and dim, the gait weak and unsteady, the memory
uncertain, and the judgment poor.

Are Nervous Diseases Increasing? The direct use of the brain and
nervous system has much less to do with the production of its diseases
or even its serious disturbances than is usually believed. Most of
these, as we have seen, are due either to the poisons of disease or
alcohol, or to the fatigue-poisons, or other poisons, produced in the
stomach, the liver, the muscles, or other parts of the body. The worst
results of brain-work are due to the extent to which it deprives us of
proper exercise and fresh air. Good, vigorous mental activity,--hard
brain work, in fact,--when you are in good condition, is, if not
overdone, as healthful and almost as invigorating as physical exercise
or hearty play. We often hear it said that the rush and hurry of our
modern strenuous life is increasing the number of mental diseases and
nervous breakdowns. But there is no evidence that the strain of
civilization upon our brains and nervous systems is damaging them, or
that either nervous diseases or insanity are more frequent now than they
used to be one hundred or five hundred years ago. In fact, all the
evidence that we have points in exactly the opposite direction; for, as
we have seen, most of these brain and nerve diseases are due to
infectious diseases, bad food, and bad living conditions generally, all
of which the progress of modern civilization is rapidly lessening and
preventing.

We are collecting our insane in modern hospitals and comfortable homes,
instead of letting them wander in rags about the country, and this makes
them live longer and seem more numerous. But the poorest and least
highly civilized classes and races have much more insanity among them
than those who live under more favorable conditions.


FOOTNOTES:

[27] Some of these coal-tar remedies are _Acetanilid_, and _Antipyrin_,
and _Phenacetin_.



CHAPTER XXII

EXERCISE AND GROWTH


Fatigue as a Danger Signal. The chief use of exercise in childhood,
whether of body or mind, is to make us grow; but it can do this only by
being kept within limits. Within these limits it will increase the vigor
of the heart, expand the lungs, clear the brain, deepen sleep, and
improve the appetite. Beyond these limits it stunts the body, dulls the
brain, overstrains the heart, and spoils the appetite. How are we going
to tell when these limits are being reached? Nature has provided a
danger signal--fatigue, or "tiredness."

Fatigue is due, not to complete exhaustion, but to poisoning of the
muscle, or nerve, by its own waste substances. If the fatigue is
general, or "all over," it is from these waste substances piling up in
the blood faster than the lungs, skin, and kidneys can get rid of them.
In other words, fatigue is a form of self-poisoning.

We can see how it is that exercise, which, up to the point of fatigue,
is both healthful and improving, when carried on after we are tired,
becomes just the opposite. Fatigue is nature's signal, "Enough for this
time!" That is why all methods of training for building up strength and
skill, both of mind and muscle, forbid exercising beyond well-marked
fatigue. If you yourself stop at this point in exercising, you will
find, the next time you try that particular exercise, that you can go a
little further before fatigue is felt; the third time, a little further
yet; and so, by degrees, you can build up both your body and brain to
the fullest development of which they are capable.

In muscular training, a series of light, quick movements, none of which
are fatiguing, repeated fifteen, twenty, or a hundred times, will do
much more to build up muscle and increase strength, than three or four
violent, heaving strains that tax all your strength. Real athletes and
skilled trainers, for instance, use half-or three-quarter-pound
dumb-bells and one-or two-pound Indian clubs, instead of the five-pound
dumb-bells and ten-pound clubs with which would-be athletes delight to
decorate their rooms. A thoroughbred race-horse is trained on the same
principle: he is never allowed to gallop until tired, or to put out his
full speed before he is well grown. In fact, the best methods of all
forms of exercising and training always stop just short of fatigue.
Education and study ought to be planned on the same principle. Exercise
of either our muscles or our minds after they have begun to poison
themselves through fatigue never does them any good, even if it does not
do them serious harm; and, where the exercise is for the sake of
building us up and developing our powers, it is best to stop for a
little while, or change the task, as soon as we begin to feel distinctly
tired, and then to try it again when we are rested.

[Illustration: A TRAINED BODY

Ellery H. Clark, All-around Athletic Champion of America, 1897, 1903.]

This is one of the secrets of the healthfulness and value of play and
games for children, and for older persons as well. When you get tired,
you can stop and rest; and then start in again when you feel
rested--that is to say, when your heart has washed the poisons out of
your muscles and nerves. In fact, if you will notice, you will find
that nearly all play and games are arranged on this plan--a period of
activity followed by a period of rest. Some games have regular
"innings," with alternate activity and rest for the players; or each
player takes his turn at doing the hard work; or the players are
constantly changing from one thing to another--for instance, throwing or
striking the ball one minute; running to first base the next; and
standing on base the next. Every muscle, every sense, every part of you
is exercised at once, or in rapid succession, and no part has time to
become seriously fatigued; so that you can play hard all the afternoon
and never once be uncomfortably tired, though your muscles have done a
tremendous lot of work, measured in foot-pounds or "boy-power," in that
time.

The good school imitates nature in this respect. The recitation periods
are short, and recesses frequent; a heavy subject is followed by a
lighter one; songs, drawing, calisthenics, and marching are mixed in
with the lessons, so as to give every part of the mind and body plenty
to do, and yet not over-tire any part.

All-Round Training from Work and Play. Every game that is worth
playing, every kind of work that accomplishes anything worth while,
trains and develops not merely the muscles and the heart, but the sight,
hearing, touch, and sense of balance, and the powers of judgment,
memory, and reason, as well.

If you are healthy, you know that you don't need to be told to play, or
even how, or what, to play; for you would rather play than eat. You have
as strong and natural an appetite for play as you have for food when you
are hungry, or for water when you are thirsty, or for sleep when you are
tired. It is just as right to follow the one instinct as the others,
though any one may be carried to extremes.

Some of the most important part of your training and fitting for life
is given by plays and games. Not only do they put you in better
condition to study and enjoy your work in school, but they also teach
you many valuable lessons as well. Our favorite national game,
base-ball, for instance, not only develops the muscles of your arms and
shoulders in throwing the ball and in striking and catching it, and your
lungs and heart in rushing to catch a fly or in running the bases, but
also develops quickness of sight and hearing,--requires, as we say, "a
good eye" for distance,--makes you learn to calculate something of the
speed at which a ball is coming toward you or flying up into the air,
requires you to judge correctly how far it is to the next base and how
few seconds it will take to get there and whether you or the baseman can
get there first.

More important yet, like all team games, it teaches you to work with
others, to obey orders promptly, to give up your own way and do, not
what you like best, but what will help the team most; to keep your
temper, to bend every energy to win, but to play fair. It also teaches
you that you must begin at the beginning, take the lowest place, and
gradually work yourself up; and that only by hard work and patience and
determination can you make yourself worth anything to the team, to say
nothing of becoming a "star" player.

If you will just go at your studies the way you do at base-ball, you
will make a success of them. Make up your mind to gain a little at a
time, to learn something new every day, and you will be astonished how
your knowledge will mount up at the end of the year. When you first
start in a new study, it looks, as you say, "like Greek" to you. You
feel quite sure that you never will be able to understand those hard
words or solve those problems "clear over in the back of the book." But
remember how you started in on the diamond as a "green player," with
fumbling fingers that missed half the balls thrown to you, with soft
hands that stung every time you tried to stop a "hot" ball; how you
ducked and flinched when a fast ball came at you, and how you fumbled
half your flies and, even when you fielded them, were likely to send
them in six feet over the baseman's head. But by quietly sticking to
it--watching how the good players did it, and playing an hour or two
every day during the season--you gradually _grew_ into the game, until,
almost without knowing how it happened, you had trained your muscles,
your nerve cells, and your brain and found yourself a good batsman and a
sure catcher.

[Illustration: TUG OF WAR

Good for muscle and will.]

So it will be in your school work. Just stick quietly to it, taking your
work a lesson at a time; give yourself plenty of sleep and plenty of
fresh air, and eat plenty of good food three times a day, and your mind
will grow in strength and skill as gradually, as naturally, and as
happily as your body does.

Every season of the year has its special games suited to the weather and
the condition of the ground. If you take pride in playing all of them in
their turn, hard and thoroughly, and making as good a record in them as
you can, you will find that it will not only keep you healthy and make
you grow, but will help you in your school work as well, by keeping
your wits bright and your head clear. There is a fine group of running
games, for instance, such as Prisoner's Base, or Dare Base,
Hide-and-Seek, or I Spy, and the different kinds of tag,--Fox-and-Geese,
Duck-on-Rock,--which are not only capital exercise for leg muscles,
lungs, and heart, but fine training in quickness of sight, quickness and
accuracy of judgment, and quickness of ear in catching the slightest
rustle on either side, or behind you, so that you can rush back to the
base, or "home," first.

Then with the winter comes skating, with hockey and Prisoner's Base on
the ice, and coasting and sledding and snow-balling, to say nothing of
forts and snowmen. You should try to be out of doors as many hours a day
in the winter-time as in the summer, so far as possible. If you play and
romp hard, you will find that you don't mind the cold at all, and that,
instead of taking more colds and chills, you will have fewer of these
than you had when you cooped yourself up indoors beside the warm stove.

[Illustration: THE GIANT STRIDE

A good exercise for all the muscles.]

It is just as important for girls to play all these games as it is for
boys; and girls enjoy them just as much and can play them almost, if not
quite, as well, if they are only allowed to begin when they are small
and do just as they please. There is no reason whatever why a girl
should not be just as quick of eye and ear, and as fast on the run, and
as well able to throw or catch or bat a ball, as a boy. Up to fifteen
years of age boys and girls alike ought to be dressed in clothes that
will allow them to play easily and vigorously at any good game that
happens to be in season. Girls like base-ball as well as boys do, if
they are only shown how to play it.

In summer, of course, the whole wide world outdoors turns into one great
playground; and it is largely because we turn out into this playground
that we have so much less sickness, and so many fewer cases of the
serious diseases like tuberculosis, pneumonia, and rheumatism in summer
than in winter.

Boys and girls ought to know how to swim and how to handle a boat before
they are twelve years old; for these are not only excellent forms of
exercise and most healthful and enjoyable amusements in themselves, but
they may be the means of saving lives--one's own life or the lives of
others.

As a form of exercise and education combined, nothing is better than
walks in the country or, where this is impossible, in parks and public
gardens. An acquaintance with trees, flowers, plants, birds, and wild
animals, is one of the greatest sources of enjoyment and good health
that any one can have all his life through.

Last, but not by any means least, comes that delightful combination of
work and play known as gardening, and the lighter forms of farming.
Every child naturally delights in having a little patch of ground of his
own in which he can dig and rake and weed and plant seeds and watch the
plants grow. In our large cities, where most of the houses have not
sufficient space about them to allow children to have gardens of their
own at home, land is being bought near school-houses and laid out as
school gardens, and the work done in them is counted as part of the
school work. Indeed, so important is this work considered as a part of
school education, that some large cities are actually building their
schools out in the open country, so that they can have plenty of space
for playgrounds and gardens and shops, and carrying the children from
the central parts of the city out to them by trolley or train in the
morning and back at night.

[Illustration: SCHOOL GARDENING]

Wherever you happen to live, you should engage in healthy happy,
vigorous play in the open air at least two to four hours a day all the
year round. If you live in a town, while it will not be quite so easy to
reach the woods and the fields and the swimming holes and the skating
ponds, yet you will have a large number of playmates of your own age,
and have good opportunity to play the games calling for half a dozen or
more players; and there will be plenty of vacant lots and open spaces,
or little-traveled streets, in which to play base-ball and foot-ball and
Prisoner's Base and tag. And although you may not be within reach of the
best zoological garden ever made,--a barnyard,--yet you can make
occasional trips to the city "Zoo," or the botanical gardens, or to
parks.

Healthful Methods of Study. In the growth and training of the highest,
most valuable, and most wonderful part of the body--the brain--the same
methods followed in our outdoor games will give the best results. We do
not create intelligence by study, nor manufacture a brain for ourselves,
in school. We simply develop and strengthen and improve the brains and
the mental power that we were born with.

[Illustration: A WASTED CHANCE FOR PUBLIC HEALTH

A large area in the residence section of a city, now used as a dump,
from which dust and disease can spread. It could easily be cleared and
used for children's gardens, or a playground or athletic field.]

Our minds grow as our bodies do, by healthful exercise--little at a
time, with plenty of rest and change of occupation between the periods
of work. That is why our school studies are arranged as they are:
instead of one subject being studied all the morning, or all day, four
or five subjects are studied for twenty or thirty minutes each, and a
change is made to another before our minds become over-tired and begin
poisoning themselves with fatigue toxins. A subject that is rather hard
for us is followed by one that is easier; and the hardest subjects in
the course are usually taken up early in the morning session, or after
recess, or early in the afternoon, when we are well-rested and feeling
fresh and ready for work.

We should try to keep our bodies and our brains and our sight and
hearing in the very best possible condition for our work, so as to come
up to each task that we have to master keen and fresh and clear-headed,
rather than to take pride in spending so many hours a day studying in a
half-tired, half-hearted, listless kind of way. You will find that you
will be able to master a lesson and see through a problem in half the
time if you get plenty of sleep in a room with the windows open, play a
great deal out-of-doors, and do not hurry through your meals for either
school or play.

[Illustration: AN OBSTACLE RACE]

Study just as you play ball when you are trying to make a place on the
team. Bend every energy that you have to that one thing, and forget
everything else, until you have finished it. You can do more work in
fifteen minutes in this way than you can in forty minutes of sitting and
looking out of the window and wondering how much longer the study period
is to last, and what the next chapter is about in the story that you are
reading at home, or what you are going to wear to the party next week.

Keep yourself in good condition, and then buckle down to your work as if
that were the only thing there was in the world for the time being, and
you will be surprised to find, not only how much more easily and quickly
you will do your work, but how much better you will remember it
afterwards. Do not set out to accomplish too much at a time; but when
you undertake a task, don't let go until you have finished it. If you
will train yourself in this way, you will soon find that it will seldom
take you longer to master a lesson than it will to recite it. It is
becoming more and more the custom in the best schools to plan to do all
the school work in school hours, alternating periods of recitation and
play with periods of study, so that no school-books need be taken home
at night. This cannot always be done; but it is well to come as near to
it as possible, in order, first, to learn to do work quickly and
thoroughly and to drop it when it is finished, and, secondly, to give
time to playing and resting and forming the priceless habit of reading.
You will leave school some day, but you may still be a student in the
great University of Books; and the pleasure of widening your knowledge
and kindling your imagination will never fail you or pall on you as long
as you live. An evening spent with newspapers and magazines, with books
of travel and adventure, with good stories and poetry, with enjoyable
and sensible parlor games such as authors, checkers, chess, charades,
and with music and singing, will help you more with your lessons next
day than two hours of listless yawning over text-books.

[Illustration: THE HIGH JUMP

Like the obstacle race, the high jump cultivates determination as well
as muscle.]

If you take your school work in this spirit, you will find that you will
enjoy it quite as well as any other form of exercise--even play itself.
The harder and more intelligently you play, the better you will be able
to work in the schoolroom; and the harder and more intelligently you
study, the more you will enjoy your play.



CHAPTER XXIII

THE LOOKOUT DEPARTMENT


Why the Eyes, Ears, and Nose are Near the Mouth. If you had no eyes,
ears, or nose, you might just as well be dead; and you soon would be, if
you had no one to feed you and guide you about and take care of you.
Naturally, all three of these scouts and spies of the body, which warn
us of danger and guide us to food and shelter, are near the mouth, at
the head-end of the body. The nose by means of which we smell food, to
see whether it is sweet and good or not, is directly above the mouth;
the eyes are above and on each side, like the lamps of an automobile,
but swinging in sockets like search-lights; while the ears are a couple
of inches behind, on each side of us, for catching from the sea of air
the waves that we call sound.

You could almost guess what each of these is for, just by looking at it.
The nose and the ears are open and hollow because air must pass into
them in order to bring us odors or sounds; while the eyes are solid,
somewhat like big glass marbles, to receive light--because light can go
right through anything that is transparent. Eyes, ears, and nose all
began on the surface, and sank gradually into the head, so as to be
surrounded and protected, leaving just opening enough at the surface to
allow smells, light-rays, and sound-waves to enter; and all of them have
at their bottom, or deepest part, a sensitive patch of surface, which
catches the light, or the smells, or the sounds, and sends them by a
special nerve to the brain.

These three sets of organs have gradually and slowly grown into the
shape in which we now find them, in order to do the particular kind of
smelling, seeing, and hearing that will be most useful to us. Every kind
of animal has a slightly different shape and arrangement of eye, of ear,
and of nose to fit his particular "business"; but in all animals they
are built upon the same simple, general plan.


THE NOSE

How the Nose is Made. The nose began as a pair of little puckers, or
dimples, just above the mouth, containing cells that were particularly
good smellers, in order to test the food before it was eaten. All smells
rise, so these cells were right on the spot for their particular
"business."

The original way of breathing, before the nose-dimples or pits opened
through into the throat, was through the mouth; and that is one
reason why it is so easy to fall into the bad habit of mouth-breathing
whenever the nose gets blocked by _adenoids_ or _catarrh_. Some
creatures--fishes, for instance,--breathe through their mouths entirely;
if you watch one in an aquarium or a clear stream, you will easily see
that it is going "gulp, gulp, gulp" constantly. The saying "to drink
like a fish" is a slander upon an innocent creature; for what it is
really doing is breathing, not drinking. Even a frog, which has nostrils
opening into its throat, still has to swallow its air in gulps, as you
can see by watching its throat when it is sitting quietly. And, strange
as it may seem, if you prop its mouth open, it will suffocate, because
it can no longer gulp down air.[28]

Our noses are nine-tenths for breathing, and only about one-tenth for
smelling; so that by far the greater part of the nose is built on
breathing lines. But the smelling part of it, though small, is very
important, because it now has to decide, not merely upon the goodness or
badness of the food, but also upon the purity or foulness of the air we
breathe. The _nostrils_ lie, as you can see, side by side, separated
from each other by a thin, straight plate of gristle and bone known as
the _septum_. This should be perfectly straight and flat; but very often
when the nose does not grow properly in childhood, it becomes crumpled
upon itself, or bulged over to one side or the other, and so blocks up
one of the nostrils. This is a very common cause of catarrh, and
requires, for its cure, a slight operation, a cutting away of the
bulging or projecting part of the septum. The rims of the openings of
the nose, known as the _wings_, have little muscles fastened to them
which pull them upward and backward, thus widening the air openings or,
as we say, dilating the nostrils. If you will watch any one who has been
running fast, or a horse that has been galloping, you will see that his
nostrils enlarge with every breath; and these same movements occur in
sick people who are suffering from disease of the lungs or the heart,
which makes it difficult for them to get breath enough.

Each nostril opens into a short and rather narrow, but high, passage,
known as the _nasal passage_, through which the air pours into the back
of the throat, or _pharynx_, and so down into the windpipe and lungs.
Instead of having smooth walls, however, the passage is divided into
three almost separate tubes, by little shelves of bone that stick out
from the outer wall. These are covered with thick coils of tiny blood
vessels, through which hot blood is being constantly pumped, like steam
through the coils of a radiator, so that the air, as it is being drawn
into the lungs, is warmed and moistened. The passage is lined with a
soft, moist "skin," called mucous membrane, very much like that which
lines the stomach and bowels, except that it is covered with tiny little
microscopic hairs, called _cilia_, and that its glands pour out a thin,
sticky _mucus_, instead of a digestive juice. This thick network of
blood vessels just under the thin mucous "skin" is easily scratched into
or broken, and then we have "nose-bleed."

The purpose of this mucus is to catch and hold, just as flypaper catches
flies, all specks of dust, lint, or germs that may be floating in the
air we breathe, and to keep them from going on into the lungs. As these
are caught upon the lining of the nose, they are washed down by the flow
of mucus or wafted by the movement of the tiny hairs back into the
throat, and swallowed into the stomach, where they are digested. Or, if
they are very irritating, they are blown out of the nostrils, or sneezed
out, and in that way got rid of.

If the dust is too irritating, or the air is foul and contains disease
germs, these set up an inflammation in the nose, and we "catch cold," as
we say. If we keep on breathing bad or dusty air, the walls of the nasal
passages become permanently thickened and swollen; the mucus, instead of
being thin and clear, becomes thick and sticky and yellowish, and we
have a catarrh.

Catarrh is the result of a succession of neglected "bad colds," caused,
not by fresh, cold air, but by hot, stuffy, foul air containing dust and
germs. The best and only sure way to avoid catarrh is by breathing
nothing but fresh, pure air, day and night, keeping your skin clean and
vigorous by cool bathing every day, and taking plenty of play in the
open air.

So perfect is this heating, warming, and dust-cleansing apparatus in the
nose, that by the time quite cold air has passed through the nostrils,
and got down into the back of the throat, it has been warmed almost to
the temperature of the body, or blood-heat, and has been moistened and
purified of three-fourths of its dust or disease germs. When you go out
of doors on a cold, frosty morning, your nose is very likely to block
up, because so much hot blood is pumped into these little steam-coils of
blood vessels, in order to warm the air properly, that they swell until
they almost block up the nostrils.

The Sense of Smell. The lower three-fourths of the nasal passages have
nothing whatever to do with the sense of smell; this is found only in
the highest, or third, division of the passages, right up under the root
of the nose, where odors can readily rise to it. Here can be found a
little patch of mucous membrane of a deep yellowish color, which is very
sensitive to smells, and from which a number of tiny little nerve twigs
run up to form the nerve of smell (_olfactory nerve_), which goes
directly to the brain. The position of the smell area at the highest and
narrowest part of the nose passage explains why when you have a very bad
cold, you almost lose your sense of smell; the lining of the lower part
of the nose has become so inflamed and swollen as to block up the way to
the highest part where the smelling is done.

[Illustration: ADENOIDS

A section through the nose and mouth: _A_, adenoid growth; _P_, soft
palate; _T_, right tonsil.]

Adenoids. If colds are neglected and allowed to run on, the
inflammation spreads through the nose back into the upper part of the
throat, or pharynx. Here it attacks a spongy group of glands, like a
third tonsil, which swells up until it almost blocks up the nose and
makes you breathe through your mouth. These swollen glands are called
adenoids, and cause not only mouth-breathing, but deafness, loss of
appetite, indigestion, headache, and a stupid, tired condition; so that
children that are _mouth-breathers_ are often two or more grades behind
in school, poor students, and even stunted and undersized. You can often
tell them at sight by their open mouths and vacant, stupid look. A very
simple and harmless scraping operation will remove these adenoids
entirely, and what a wonderful improvement the mouth-breather will make!
He will often catch up two grades, and gain two inches in height and ten
pounds in weight within a year.

[Illustration: MOUTH-BREATHERS

Note how swollen the face is under the eyes and how tired and dull the
whole expression.]

Adenoids not only cause deafness by blocking up the tube (_Eustachian_)
that runs from the throat to the ear,--the tube through which the air
passes when your ear "goes pop,"--but are also the commonest cause of
ear-ache and gatherings in the ear, which may burst the drum.


THE TONGUE

The Tongue is not Used chiefly for Tasting. If you will notice the
next time that you have a bad cold, you will find that you have almost
lost your sense of taste, as well as of smell, so that everything tastes
"flat" to you. This illustrates what scientists have known for a long
time, but which seems very hard to believe, that two-thirds of what we
call taste is really smell. If you carefully block up your nostrils with
cotton or wax, so that no air can possibly reach the smell region at the
top of them, and blindfold your eyes, and have some one cut a raw
potato, an apple, and a raw onion into little pieces of the same size
and shape, and put them into your mouth one after the other, you will
find that it is difficult to tell which is which.

The only tastes that are really perceived in the mouth are bitter,
sweet, sour, and salty; and even these are perceived quite as much by
the roof and back of the mouth, especially the soft palate, as they are
by the tongue. All the delicate flavors of our food, such as those of
coffee or of roast meat or of freshly baked bread, are really smells.

The tongue, which is usually described as the organ of taste, is really
a sort of fingerless hand grown up from the floor of the mouth--to help
suck in or lap up water or milk, push the food in between the teeth for
chewing, and, when it has been chewed, roll it into a ball and push it
backward down the throat. It is not even the chief organ of speech; for
people who have had their tongues removed on account of cancer, or some
other disease, can talk fairly well, although not so clearly as with the
whole tongue.

The tongue is simply a "tongue-shaped" bundle of muscles, covered with a
thick, tough skin of mucous membrane, dotted all over with little
knob-like processes called _papillæ_, which are of various shapes, but
of no particular utility, except to roughen the surface of the tongue
and give it a good grip on the food. If the mucous "skin" covering the
tongue does not shed off properly, the dead cells on its surface become
thickened and whitish, and the germs of the mouth begin to breed and
grow in them, forming a sort of mat over the surface. Then we say that
the tongue is badly coated. This coating is in part due to unhealthy
conditions of the stomach and bowels, and in part to lack of proper
cleaning of the mouth and teeth.

The Sense of Taste can usually be Trusted. Since the nose and the
tongue have had about five million years' experience in picking out what
is good and refusing what is bad, their judgment is pretty reliable, and
their opinion entitled to the greatest respect. As a general thing,
those things that taste good are wholesome and nutritious; the finest
and most enjoyable flavors known are those of our commonest and most
wholesome foods, such as good bread, fresh butter, roast meats, apples,
cheese, sugar, fruit, etc.; while, on the other hand, those things that
taste bad or bitter or salty or sour, or that we have to learn to like,
like beer or pickles or strong cheese or tea or coffee, are more often
unwholesome or have little nutritive value. Very few real foods taste
bad when we first try them. If we used our noses to test every piece of
food that went into our mouths, and refused to eat it if it "smelt bad,"
we should avoid many an attack of indigestion and ptomaine poisoning. It
is really a great pity that it is not considered polite to "sniff" at
the table.


THE EYE

How the Eye is Made. Next in importance after the smell and the taste
of our food comes the appearance of it; hence, our need of eyes to help
us in choosing what to eat, as well as how to avoid the dangers about
us.

The eyes began as little sensitive spots on the surface of the head.
Like the nose pits, as they became more sensitive, they too sank in
beneath the surface; but with this difference, that, instead of
remaining open, the rims or edges of the eye-pit grew together and
became transparent, forming a cover, or eye-glass, which became the
clear part of the eye, called the _cornea_. At the same time, the little
sensitive spot at the bottom of the eye-pit spread out into the shape of
the bottom of a cup, called the _retina_; and then the hollow of that
cup between the retina and the cornea filled up with a clear, soft,
animal jelly called the _vitreous humor_, and we have the eye as it is
in our heads to-day.

The sensitive retina, spreading out, as it does, to form the back of the
eyeball, is the nerve-coat of the eye; and from its centre a thick round
bundle of nerve fibres, known as the _optic nerve_, runs back to the
brain.


[Illustration: THE APPARATUS OF VISION

A cross-section diagram, showing eye and optic nerve, the bones forming
the orbit or socket, and the front lobes of the brain.]

The bones of the head, grown out in a ring in order to protect the eyes,
are called the _orbit_ or _socket_.

To protect the delicate glass (cornea) of the eye, there are two folds
of skin, one above and one below, known as the eyelids. The eyelids
carry a row of extra long hairs at their edges, called the eyelashes,
and a number of little glands, somewhat like those of the stomach, to
pour out a fluid, which makes the lids glide smoothly over the eyeball
and keeps them from sticking together. Underneath the upper lid a number
of these glands become gathered together and "grow in," after the
fashion of the salivary glands, to form a larger gland about the size
of a small almond, which pours out large amounts of this fluid as tears.
It is called the tear gland (_lachrymal_ gland).

Whenever a cinder or a grain of sand or a tiny insect or any other
irritating thing gets into the eye, this gland pours out a flood of
tears, which washes the intruder down into the inner corner of the eye
where it can be wiped out; or, if it be small enough, carries it down
through a little tube in the edge of each eyelid, through a little
passage known as the _nasal_, or _tear, duct_, into the nose. So, if you
get anything into your eye, much the best and safest thing to do is to
hold the lids half shut, but as loose, or relaxed, as possible, and
allow the tears to wash the speck of dust down into the inner corner of
the eye. If you squeeze down too hard with the lids, and particularly if
you rub the eye, you will be very likely to scratch the cornea with the
speck of dust or sand, or, if the speck be sharp-edged, to drive it
right into the cornea and give yourself a great deal of unnecessary pain
and trouble, or even seriously damage the eye. If the cinder or dust
doesn't wash down quickly, pull the upper lid gently away from the
eyeball by the lashes and hold it there a minute or so, when often the
cinder will drop or wash out.

As the light rays cannot be bent, or drawn into the eyes as smells can
into the nostrils, it is necessary that the eyes should be able to roll
about so as to turn in different directions; and so nature has made them
round, or globular, attaching to their outer coat or shell (the
_sclerotic_ coat) little bands of muscle, each of which pulls the
eyeball in its particular direction. There are four straight bands--one
for each point of the compass: one fastened to the upper surface of the
eye to roll it upward; another to the lower to roll it downward; another
to the outer to roll it outward; and another to the inner side to roll
it inward for near vision.[29]

There is another reason for the rounded shape of the eye--that it may
act as a lens in condensing the rays of light. In order that we may see
things clearly, the rays of light must be brought to a focus upon or
close to the retina, at the back of the eye; and our eyes are so shaped
that they form a lens of proper thickness, or strength, to do this.

You can see how this is done with an ordinary magnifying glass, or
burning-glass. The little sharply lighted and heated point to which the
light-rays can be brought is the focus of the lens, and the distance it
lies behind the lens is called the focal distance. The thicker the lens,
or burning-glass, is in the middle, the shorter its focal distance, and
the more strongly it will magnify.

A healthy, or normal, eye is of just such shape and "bulge" that rays of
light entering the eye are brought to a focus on, or close to, the
retina at the back of the eyeball. Some people, however, are
unfortunately born with eyes that are too small and flat, or do not
"bulge" enough; and then the rays of light are focused behind the retina
instead of upon it, and the image is blurred. This is known as "long
sight" (_hyperopia_), and can be corrected by putting in front of the
eyes lenses of glass, called spectacles, which bulge sufficiently to
bring the rays to focus on the retina.

An eye that is too large and round and bulging brings the rays to a
focus in front of the retina, and this also blurs the image. This form
of poor sight is called "short sight" (_myopia_), and can be relieved by
putting in front of the eye a glass that is concave, or thinnest in the
middle and thickest at the edges, in the right proportions to focus the
image where it belongs, right on the retina. This kind of glass is
sometimes called a "minifying" glass, from the fact that it makes
objects seen through it look smaller. It is also called a "minus" glass,
while the magnifying glass is called a "plus" glass. The shape of the
glasses or spectacles prescribed for an eye is just the opposite of that
of the eye. If the eye is too flat (_long-sighted_), you put on a
bulging, or convex, glass; and if the eye is too bulging
(_short-sighted_), a hollow, or concave, glass. Other eyes are
irregularly shaped in front and bulge more in one direction than
another, like an orange. This defect is called _astigmatism_ and is very
troublesome, making it hard to fit the eye with glasses, as the glasses
have to be ground irregular in shape.

[Illustration: A SCHOOL EYE-TEST

A normal eye should be able to read the smaller type easily at a
distance of twenty feet.]

We have just seen how the eye deals with rays of light coming from a
distance, which are practically parallel. When, however, books or other
objects are brought near the eye, the rays of light coming from them do
not remain parallel, but begin to spread apart, or diverge; and a
stronger lens is required to bring them to a focus upon the retina. To
provide for this, there is in the middle of the eyeball a firm, elastic,
little globular body about the size and shape of a lemon-drop, called
the _crystalline lens_. Around this is a ring of muscle, which is so
arranged that when it contracts it causes the lens to change its shape
and become more bulging, or thicker in the middle. This makes the
eyeball a "stronger" lens so that the rays of light can be brought to a
focus upon the retina.

This action is known as _accommodation_, or adjustment; and you can
sometimes feel it going on in your own eye, as when you pick up a book
or a piece of sewing and bring it up quickly, close to the eye, in order
to see clearly.

If this little muscle is worked too hard, as when we try to read in a
bad light, it becomes tired and we get what is called "eye-strain"; and
if the strain be kept up too long, it will give us headache and may even
make us sick at the stomach. The commonest cases of eye-strain are in
eyes that are too flat (_hyperopic_) where this little muscle has to
"bulge" the lens enough to make good the defect and bring the rays to a
focus. This, however, of course keeps it on a constant strain; and the
eye is continually giving out, and its owner suffering from headache,
neuralgia, dyspepsia, sleeplessness, and other forms of nervous trouble,
until the proper lens or spectacle is fitted.[30]

A surface as delicate and sensitive to light as the retina, would, of
course, be damaged by too bright a glare; so in the front of the eye,
just behind the cornea, a curtain has grown up, with an opening or
"peep-hole" in its centre, which can be enlarged or made smaller by
little muscles. This opening is the _pupil_; the curtain, which is
colored so as to shut out the rays of light, is known as the _iris_, for
the quaint, but rather picturesque, reason that _Iris_ in Greek means
"rainbow," and this part of the eye may be any one of its colors.

[Illustration: DISINFECTING A BABY'S EYES AT BIRTH]

It is the iris which, according to the amount of coloring matter
(pigment) in it, makes the eye, as we say, blue, gray, green, brown, or
black. Blue eyes have the least; black, the most.[31]

The Care of the Eyes. The most dangerous diseases of the eye are
caused by infectious germs, which get into them either from the outside,
as in dust, or by touching them with dirty fingers; or through the
blood, as in measles, smallpox, tuberculosis, and rheumatism. The more
completely we can prevent these diseases, the less blindness we shall
have in the nation. About one-sixth of all cases of blindness in our
asylums is caused by a germ that gets into babies' eyes at birth, but
can be done away with by proper washing and cleansing of the eyes.


THE EAR

Structure of the Ear. Next after sight, hearing is our most important
sense; without it, speaking, and consequently reading and writing, would
be impossible. Man learned to speak by hearing the sounds made by other
people and things, and then by listening to his own voice and practicing
until he could imitate them. Children who are unfortunate enough to be
born _deaf_ also become _dumb_, not because there is anything the matter
with their voice organs, but simply because, as they cannot hear the
sounds they make, they do not form them by practice into words and
sentences. By proper training, deaf mutes can now be taught to speak,
though their voices sound flat and "tinny," like a phonograph.

As in the nose and the eye, the important part of the ear is the nerve
spot that can "feel" the air waves that we call sound, just as the
retina "feels" light. It is from this sensitive spot that the _auditory
nerve_ carries the sound to the brain. This spot has grown into quite an
elaborate structure, buried, for safety, deeply in the bones of the
skull, close to the base of the brain. It is made up of a long row of
tiny little nerve rods, laid side by side like the keys of a piano, only
there are about three thousand of them. Each one of these is supposed to
respond, or vibrate, to a particular tone, or sound. This keyboard,
from the fact that, to save space, it is coiled upon itself like a
sea-shell, instead of running straight, is called the _cochlea_ (Greek
for "snail-shell"); it is also called, because it is the deepest, or
innermost, part of the hearing apparatus, the _internal ear_.

Just as the retina has a lens and a vitreous humor in front of it to act
upon the light, so the internal ear has an apparatus in front of it to
act upon the sound waves. This is called the _drum_ (_tympanum_). It
consists of a fold of thin, delicate skin stretched tightly across the
bottom of the outer ear canal, as parchment is stretched across the head
of a drum. If you should take a hand-mirror--best a hollow, or concave,
one--and throw a bright ray of light deep into some one's ear, you would
be able, after a little trying, to see this drum-skin stretched across
the bottom of it and about an inch and a quarter in from the surface of
the head.

[Illustration: THE APPARATUS OF HEARING

A cross-section diagram from the outer ear to the lobes of the brain.]

When the sound waves go into the ear canal and strike upon this tiny
drum, which is about two-thirds the size of a silver dime and really
more like a tambourine or the disk of a telephone or phonograph than a
drum, they start it thrilling, or vibrating, just as a guitar string
vibrates when you thrum it. These little vibrations are carried across
the hollow behind the drum by a chain of tiny bones, known as the
_ear-bones_ (called from their shapes, the _hammer_, the _anvil_, and
the _stirrup_), and passed on to the keyboard of the cochlea.

Here comes in one of the most curious things about this ingenious
hearing-apparatus. This little hollow behind the drum-skin has to be
kept full of air in order to let the drum vibrate properly, and this is
arranged for by a little tube (the Eustachian tube) which runs down from
the bottom of it and opens into the back of the throat just behind the
nasal passages, and above the soft palate. When you blow your nose very
hard, you will sometimes feel one of your ears go "pop"; and that means
that you have blown a bubble of air out through this tube into your drum
cavity.

If your nose and throat become inflamed, then the mouth of this little
tube may become blocked up; the drum can no longer thrill, or vibrate,
properly; and, for the time being, you are deaf. This tube is of great
importance, because nearly all the diseases that attack the ear start in
at the throat and travel up the tube until they reach the drum cavity.
This is why one so often has earache after an attack of the grip or
after a bad cold. The drum cavity, with its chain of bones and its tube
down to the throat, is called, from its position, the _middle ear_.

The _outer_, or _external, ear_, though far the largest of the three
parts, and quite imposing in appearance, is really of little use or
importance. It is simply a sort of receiving trumpet for catching
sounds, with a very wide and curiously curved and crumpled mouth, or
bell. The large, expanded mouth of the trumpet, called the _concha_
("conch shell"), was at one time capable of being "pricked up" and
turned in the direction of sounds, just as horses' or dogs' ears are
now; and in our own ears there are still for this purpose three pairs of
tiny unused muscles running from them to the side of the head. But the
concha is now motionless and almost useless, except for its beauty; and
it is very troublesome to wash.

The Care of the Ear. The tube of the trumpet leading down from the
surface of the ear to the drum is lined with skin; and this skin is
supplied with glands, which pour out a sticky, yellowish fluid called
_ear wax_, which catches the bits of dust or insects that get into the
ear and, flowing slowly outward, carries them with it. If it is let
alone, it will keep the ear canal clean and healthy; but some people
imagine that, because it looks yellowish, it must be dirt; and
consequently, from mistaken ideas of cleanliness, they work at it with
the end of the finger, the corner of a towel, or even with a hairpin, an
ear-spoon, or an ear-pick, and in this way stop the proper flow of the
wax and make it dry and block up the ear.

Remember, you should not wash too deeply into your ears; (as the old
German proverb puts it, "Never pick your ear with anything smaller than
your elbow"). And if you don't, you will seldom have trouble with wax in
the ear. Scarcely one case of deafness in a hundred is caused by wax.
When your ear does become blocked up with wax, it is best to go to a
doctor and let him syringe it out. Picking at it, or even syringing too
hard, may do serious damage to the ear.

If an earache is neglected, the inflammation may spread into some
air-cells in the bony lump behind the ear (the _mastoid_) and thus cause
_mastoid disease_, which may spread to, and attack, the brain if not
cured by a surgical operation.


OUR SPIRIT-LEVELS

The Sixth Sense. Though we usually speak of having five
senses,--sight, smell, hearing, touch, and taste,--we really have also a
sixth--the sense of direction, or of balance. The "machine" of this
sense is comparatively simple, being made up of three tiny curved tubes,
which, from their shape, are called the _semi-circular canals_. These
are buried in the same bone of the skull as the internal ear, and
so close to it that they were at one time described as part of it.
These little canals are three in number, one for each of the
dimensions--length, breadth, and thickness,--so that whichever way the
head or body is moved,--backward and forward, up and down, or from side
to side,--the fluid with which they are filled will change its level in
one of them, just as the "bead" does in the carpenter's spirit-level
that you can find in any tool shop. The delicate nerve twigs that run
out into the fluid in these tiny canals are gathered together into a
bundle, or nerve-cable, which runs back to the part of the brain known
as the _cerebellum_ or hind-brain, which has most to do with controlling
the balance and movements of our bodies.

It is the disturbance set up in these spirit-level canals by the
pitching and rolling of a ship, which makes us seasick. Neither the
stomach, nor anything that we may have eaten, has anything to do with
it. In the same way we sometimes become sick and dizzy from swinging too
long or too high, or from riding on the cars.


FOOTNOTES:

[28] To show in how many different ways nature may carry out the same
purpose, the smelling organs in insects, lobsters, and crabs are on the
ends and sides of tiny feelers, which they wave about; and the eyes in
lobsters, crawfish, and snails, are on the ends of stalks, which they
thrust about in all directions as a burglar handles a bull's-eye
lantern. Snakes "hear," or catch the sound-waves, with their flickering,
forked tongues; and grasshoppers and locusts have "ear-drums" on the
sides of their chests.

[29] These are called the _recti_ or "straight" muscles, upper, lower,
inner, and outer, according to their position. Then, to roll the eye
round and round, there are two little muscles, one above and one below,
which run "crosswise" of the orbit, called the upper and lower _oblique_
muscles.

[30] The retina is chiefly made up of a great number of fine little
nerve cells called, from their shape, the _rods_ and _cones_. These are
kept soaked in a colored fluid called the _retinal purple_, which
changes under the influence of light, somewhat in the same way that the
film on a photographic plate does, thus forming pictures, which are
translated by the rods and cones and telegraphed along the fibres of the
optic nerve to the brain. Naturally, all parts of the retina are not
equally sensitive to light; its centre, which is directly opposite the
pupil of the eye, is far the most so, while those around the rim of the
cup are dull. This is why, when you are looking, say at some one's face
across the room, only the face and a few inches around it are seen
perfectly clear and sharp, while the rest of the room is seen only
vaguely.

[31] As the inside of the eye is dark, or comparatively so, the pupil,
or little opening in the centre of the iris, looks black, and was at one
time supposed to be a solid body instead of a hole. You can easily watch
the pupil changing in size, according to the brightness of the light,
from a mere pin-point in very bright sunlight or gaslight, up to the
size of the butt-end of a lead pencil in the dark or in a dim light.

This change in size is very simply but ingeniously carried out by two
sets of tiny muscles. One set of these muscles runs in a ring right
around the pupil; and when they shorten, the opening is contracted or
narrowed. The other set runs outward through the iris like the spokes of
a wheel; and when they shorten, they pull the pupil open. If anyone has
had "drops" (_atropin_) put into his eyes in order to have them fitted
with glasses, he will know what a disagreeably dazzling thing it is to
have the pupil permanently enlarged, so that it cannot _contract_ in a
bright light.



CHAPTER XXIV

THE SPEECH ORGANS


The Voice, a Waste Product. It is one of the most curious things in
this body of ours that what we regard as its most wonderful power and
gift, the voice, is, in one sense, a waste product. So ingenious is
nature that she has actually made that marvelous musical instrument--the
human voice--with its range, its flexibility, and its powers of
expression, out of spent breath, or used-up air, which has done its work
in the lungs and is being driven off to get rid of it. It is like using
the waste from a kitchen sink to turn a mill.

The organs that make the human voice were never built for that purpose
in the first place. Unlike the eye and the ear, nature built no special
organ for the voice alone, but simply utilized the windpipe and
lung-bellows, the swallowing parts of the food passage (tongue, lips,
and palate) and the nose, for that purpose, long after they had taken
their own particular shapes for their own special ends.

The important point about this is that a good voice requires not merely
a large and well-developed "music box" in the windpipe, but good lungs,
a well-shaped healthy throat, properly arched jaws,--which mean good,
sound teeth,--clear and healthy nasal passages, and a flexible elastic
tongue. Of course, the blood and the nerves supplying all these
structures must be in good condition, as well. So practically, a good
voice requires that the whole body should be healthy; and whatever we do
to improve the condition of our nose, our teeth, our throat, our lungs,
our digestion, and our circulation will help to improve the
possibilities of our voice. There are, of course, many exceptions; but
you will generally find that great singers have not only splendid lungs
and large vocal cords, but good hearts, vigorous constitutions, and
bodies above the average in both stature and strength.

How the Voice is Produced. The chief parts of the breathing machine
that nature has made over for talking purposes are the windpipe, or air
tube, and the muscles in its walls. In the neck, about three inches
above the collar bone, four or five of the rings of cartilage, or
gristle,--which, you remember, give stiffening to the windpipe,--have
grown together and enlarged to form a voice box, or _larynx_.

[Illustration: THE VOCAL CORDS

Looked at from above: position _A_, in quiet inspiration; _B_, in
singing a low tone; _C_, in singing a high tone.]

The upper edge of this voice box forms the projection in the front of
the throat known by the rather absurd name of the "Adam's apple." This
grows larger in proportion to the heaviness of the sounds to be made,
and hence is larger in men than in women and boys. When the boy's voice
box begins to grow to the man's in shape and size, his voice is likely
to "break"; for it is changing from the high, clear boy's voice to the
heavy, deep voice of the man.

Inside of this voice box, one of the rings of muscle that run around the
windpipe has stretched into a pair of straight, elastic bands, or
strings, one on each side of the air pipe, known as the _vocal cords_,
or voice bands. These are so arranged that they can be stretched and
relaxed by little muscles; and, when thrown into vibration by the air
rushing through the voice box, they produce the sounds that we call
talking or singing. The more tightly they are stretched, the higher and
shriller are the tones they produce; and the more they are slackened, or
relaxed, the deeper and more rumbling are the tones.

This is why, when you try to sing a high note, you can feel something
tightening and straining in your throat, until finally you can stretch
it no tighter, and your voice "breaks," as you say, into a scream or
cry.

All musical instruments that have strings, are played, or produce their
sounds, upon this same principle. The thinner and shorter the string, or
the more tightly it is stretched, the higher the note; the heavier and
longer the string, the lower the note. But no musical instrument ever
yet invented can equal the human voice in the music of its tones, in its
range, in the different variety and quality of tones it can produce, and
in its wonderful power of expression. The human voice is a combination
of reed organ, pipe organ, trumpet, and violin; and can produce in its
tiny music box--only about two inches long by one inch wide--all the
tones and qualities of tones that can be produced on all these
instruments, except that it cannot go quite so high or so low.

All the musical instruments in the world, from the penny whistle to the
grand piano, are but poor imitations of the human music box. The
bellows, of course, of the human pipe organ are the lungs; while the
tongue furnishes the stops; and the throat, mouth, and nose, the
resonance, or sounding, chambers.

Just as a violin, or guitar, has two main parts,--a string, which
vibrates and makes the sound; and a box, or hollow body, which catches
that sound and enlarges it and gives it sweetness and vibration and
quality,--so the human voice has two similar parts--the vocal bands,
which make the sound; and a sound box, or rather series of three
resonance boxes,--the throat, the mouth, and the nasal passages,--which
enlarge and soften it and improve its quality.

You would naturally think that the strings, or cords, were the most
important part both of the voice and of a musical instrument; and in one
sense they are, as it could make no noise at all without them. But in
another sense, far more important are the sounding boxes, or resonance
chambers. The whole quality and value, for instance, of a
Stradivarius[32] violin, which will make it readily bring ten thousand
dollars in the open market, are due to the skill with which the body, or
sound box, was made; the quality of the wood used; and, odd as it may
seem, even the varnish used on it--the strings are the same as on any
five-dollar fiddle. This is almost equally true of the human voice.
While its size, or volume, is determined by the voice box and vocal
bands, and its power largely by the lungs and chest, its musical
quality, its color, and its expression are given almost entirely by the
throat, mouth (including the lips), and nose. The proper management of
these parts is two-thirds of voice training, and all these are largely
under our control.

How a Good Voice may be Developed. If the nasal passages, for
instance, are blocked by a bad cold or a catarrh or adenoids, then
nearly half the body of your violin is blocked up and deadened; half
your resonance chamber is destroyed, and the voice sounds flat and dead
and nasal. If, on the other hand, your throat be swollen, or blocked, as
by enlarged tonsils or chronic sore throat, then this part of the
resonance chamber is muffled and spoiled, and your voice will be either
entirely gone or hoarse; though perhaps by driving it very hard you may
be able to make a clear tone.

If you have an attack of inflammation or cold further down, and the
vocal bands swell, or the mucous membrane lining the voice box becomes
inflamed and thickened, then the voice is lost entirely, just as the
tone of a violin would be if a wet cloth were thrown across the strings.
But disturbances in the voice box, or larynx, cause only a very small
percentage of husky, poor, or unmusical voices.

A far commoner cause, indeed probably the commonest single cause of a
poor, squeaky, or drawling, unmusical voice is careless and improper
management of the mouth and lips. In the first place, you can easily
show that such marked differences in sound as those of the different
vowels are all produced by the mouth and lips. If you will prepare to
say the vowels--_a, e, i, o, u_--aloud, and begin with _a_, and then
hold your mouth and lips firmly in the same position, you will find that
all the other vowels also come out as _a_. If, on the other hand, you
begin with your mouth and lips in the rounded and somewhat thrust-out
position necessary to say _o_, and try to repeat the rest of the vowels,
you will find that you cannot say them at all, but only different forms
of _o_. When you have convinced yourself of this, repeat the vowels
loudly and clearly without stopping to think about the position of the
mouth, and notice how your lips, the tip and base of your tongue, and
your soft palate and throat all change their positions for each
successive vowel.

If you will try to sing the scale, beginning with a comfortable note
about the middle of your voice range, and letting your mouth take the
shape for that note unconsciously, you will find that, as you sing up
the scale, you change the shape of your mouth, lips, and tongue at every
note, thrusting the lips and mouth further forward as if to whistle,
narrowing the opening and closing up the back of your throat for the
high notes.

On the other hand, as you sing down, you tend to open the mouth and
lips more widely, to drop the bottom of your mouth--that is, the base of
your tongue--toward your throat, and your chin down toward your chest.
Again you will find, just as in the case of the different vowels, that
you can sing any tone clearly and musically after putting the mouth in
precisely the shape that best fits that tone; and learning how to do
this is a most important part of vocal training.

What we call words are simply breath sounds and voice-box sounds chopped
into convenient lengths by the movements of the tongue and lips and
throat. So when we come to the question of clear and pleasant speaking,
or, as we term it, _articulation_, the lips and tongue have almost
everything to do with making the difference between a clear, musical,
and refined enunciation, which is so easy to understand that it is a
pleasure to listen to it, and a slurred, drawling, squeaky, nasal kind
of speech, which is as hard to understand as it is unpleasant to listen
to.

Few of us can ever hope to develop a really great singing voice; but
anyone who will take the pains can acquire a clear, distinct, and
pleasing speaking voice; and perhaps half of us can learn to sing fairly
well. But to do this, we must first have good, healthy, well-developed
lungs and elastic chest walls, which can come only from plenty of
vigorous exercise in the open air, combined with good food and
well-ventilated rooms. We must have a healthy stomach, which will not
fill up with gas and keep our diaphragms from going down and enlarging
our chests properly; we must have clear nasal passages, good teeth,
well-shaped mouths and flexible lips, which we are willing to use
vigorously in articulating, or cutting up our voice sounds; and we must
have good hearing and a well-trained ear. In short, the best way to get
a clear, strong, pleasant voice is to have a vigorous, well-grown,
healthy body.


FOOTNOTES:

[32] A famous violin-maker who lived about 200 years ago in Cremona,
Italy. Fifty thousand dollars has been asked for an unusually choice
"Strad."



CHAPTER XXV

THE TEETH, THE IVORY KEEPERS OF THE GATE


Why the Teeth are Important. The teeth are a very important part of
our body and deserve far more attention and better care than they
usually get. They are the first and most active part of our digestive
system, cutting up and grinding foods that the stomach would be unable
to melt without their help. In all animals except those that have horns
or fists, the teeth are their most important weapons of attack and
defense. So important are they in all animals, including ourselves, and
so closely do they fit their different methods of food-getting and of
attack and defense, that when scientists wish to decide what class, or
group, a particular animal belongs to, they look first and longest at
its teeth.

The shape and position of the teeth literally make the lower half of the
face and give it half its expression. A properly grown and developed set
of teeth not only is necessary to health and comfort, but helps greatly
to make the face and expression attractive or unattractive. Few faces
with bright eyes, clear skin, and white, regular, well-kept teeth are
unpleasing to look at. Beauty and health are closely related, and we
ought to try to have both. In fact, nine times out of ten, what we call
beauty is the outward and visible sign of inward health. The healthier
you are, the handsomer you'll be.

It is particularly important to understand the natural growth and proper
care of the teeth because there are few organs in the body for which we
are able to do so much by direct personal attention. Our stomachs, our
livers, and our kidneys, for instance, are entirely out of sight, and
more or less out of reach; but our teeth are both easily got at and in
full view; and, to a large degree, upon the care that we give them while
they are young, will depend not only their regularity and whiteness, but
also the length of their life and the vigor and comfort of our digestion
all our lives.

[Illustration: TEETH--A QUESTION OF CARE]

The first thing to be remembered about the teeth is that, hard and shiny
and different from almost everything else in the body as they look, they
are simply a part of the skin lining the mouth, hardened and shaped for
their special work of biting and chewing. Much of the care needed to
prevent decay should be given, not to the teeth themselves directly, but
to the gums and the mucous membrane of the whole mouth. The gums and the
mouth literally _grew_ the teeth in the first place; and when they
become diseased, they secrete acids which slowly eat away the crowns and
roots of the teeth. Their diseases come chiefly from irritation by
decaying scraps of food, or from the blocking of the nose so that air is
breathed in through the mouth, drying and cracking the soft mucous
membrane. After the acids from the diseased gums have attacked the
teeth, the poisons of the germs that breed in the warmth and moisture of
the mouth cause the teeth to decay. Eight times out of ten, if you take
care of the gums the teeth will take care of themselves.

Structure of the Teeth. The upper half of the tooth, which pushes
through and stands up above the jaw and the gum, we call the _crown_;
and this is the portion that is covered with _enamel_, or "living
glass." The body of the tooth under the enamel is formed of a hard kind
of bone called _dentine_. The lower half of the tooth, which still is
buried in the jaw, we call the _root_. Wrenching the lower or root part
of the tooth loose from its socket in the jaw is what hurts so when a
tooth is pulled. The crown of the tooth is hollow, and this hollow is
filled with a soft, sensitive pulp, in which we feel toothache. Tiny
blood vessels and nerve-twigs run up from the jaw to supply this pulp
through canals in the roots of the tooth.

[Illustration: A TOOTH

(Lengthwise section.)

_E_, enamel; _D_, dentine; _P_, pulp cavity; _C_, cement; _B_, blood
vessels; _N_, nerve.]

Kinds of Teeth. If you look at your own teeth in a mirror, the first
thing that strikes you is your broad, white, shiny front teeth, four
above and four below, shaped like the blade of a rather blunt chisel.
Their shape tells what they are used for. Like chisels, they cut, or
bite, the food into appropriate sizes and lengths for chewing between
the back teeth; and from this use they are called the _incisors_, or
"cutters." From having been used for so many generations upon the kind
of food we live on, they have grown broader than the _canines_, the
teeth next to them, and almost as long.

The canines are of a cone-like shape, although it is a pretty blunt
cone, or peg. Those in the upper jaw lie almost directly under the
centre of each eye, and are called the "eye-teeth"; though their proper
name, from the fact that they are the most prominent teeth in the dog,
is the canine teeth. These are our oldest and least changed teeth; and
as you might guess from their shape, like a heavy, blunt spear-head,
were originally the fighting and tearing teeth, and still have the
longest and heaviest roots of any teeth in our jaws. If you slip your
finger up under your upper lip, you can feel the great ridge of this
root, standing out from the surface of the gum.

Lastly, looking farther back into our mouths, we see behind our canines
a long row of broad, flat-topped, square-looking teeth, which fill up
the largest part of our jaws. Again their shape tells what they are used
for. They are not sharp enough to cut with, or pointed enough to tear
with, but are just suited for crushing and grinding into a pulp, between
their broad, flat tops, any food that may be placed between them; and
from this grinding they are called the _molars_, or "mill" teeth. If you
will look closely at the back ones, you will see that each of them has
four corners, or _cusps_, with a cross-shaped, sunken furrow in the
centre, where they come together. After they have been used in grinding
food for some years and rubbing against each other, these little corner
projections become worn away, and their tops become almost flat. Those
in the upper jaw have three roots, and those in the lower jaw have two,
so that they are solidly anchored for their heavy, grinding work. The
first two molars in each jaw, behind the canines, are smaller than the
others and made up of only two pieces instead of four, and hence are
called the _bicuspids_, or "two-cusped" teeth.

As we are what the scientists call an omnivorous, or "all-devouring,"
animal, able to eat and live upon practically every kind of food that
any animal on earth can deal with,--animal and vegetable, soft and hard,
wet and dry; fruits, nuts, crabs, roots, seaweeds, insects, anything
that we can get our teeth into,--we have kept in working condition some
of every kind of teeth possessed by any living animal; and the most
important rule for keeping our teeth in health is to give all these
kinds something to do.

Just as in other animals the teeth appear when needed, and grow into the
shape required, so they grow in our own mouths when they are wanted, and
of the size and shape required at the time. We are born without any
teeth at all; and it is only when we begin to need a little solid food
added to our milk diet,--when we are about seven months old,--that our
first teeth appear; and these are incisors, first of all in the lower
jaw. Then, at average intervals of about three months, the other
incisors and the canines appear and, last of all, the molars, so that at
about two years of age we have a complete set of twenty teeth. These are
called the _milk teeth_.

Most animals (_mammals_) have formed the habit of growing two sets of
teeth--a smaller, slighter set for use during the first few months or
years of life, and a larger, heavier set to come in and take their place
after the jaws have grown to somewhat more nearly their permanent size.
In our mouths, at about seven years of age, a larger, heavier tooth
pushes up behind the last milk tooth,--called the "seventh year
molar,"--the milk teeth begin to loosen and fall out, and their places
are taken by other new teeth budding up out of the jaw just as the first
set did. These take a still longer time to grow, so that the last four
of the full set of thirty-two do not come through the gums until
somewhere between our eighteenth and twentieth years. These last four
teeth, for the rather absurd reason that they do not appear until we are
old enough to be wise, are known as the "wisdom teeth." Instead of
being, as one might expect, the hardest and longest-lived of all our
teeth, they are the smallest and worst built of our molars and among the
first of our permanent teeth to break down and disappear. Not only so,
but our jaws are so much shorter than they were in the days when man
fought with his teeth and knew nothing about cooking and had no tools or
utensils with which to grind and prepare his food, that there is
scarcely room in them for these last teeth to come through. They often
cause a great deal of pain in the process, and may even break through at
the side of the jaw and cause abscesses and other troubles.

[Illustration: THE REPLACING OF THE MILK TEETH

The "second teeth" are shown fully formed in the gums, ready to push out
the milk teeth. The wisdom teeth, which appear later, cannot be shown at
this stage.--After Gray.]

Care of the Teeth. The most important thing for the health of any
organ in the body is to give it plenty of exercise, and this is
especially true of our teeth. This exercise can be secured by thoroughly
chewing, or _masticating_, all our food, of whatever sort, especially
breads, biscuits, and cereals. Thorough chewing not only gives valuable
exercise to the teeth, but, by grinding up these foods thoroughly, makes
them easier for the stomach to digest; and, by mixing them well with the
saliva, enables it to change the starch into sugar. Meats, fish, eggs,
cheese, etc., do not need to be mixed with the saliva, nor to be ground
so fine for easy digestion in the stomach, and hence do not require such
thorough chewing, though it is better to make a rule of chewing all
food well. We can exercise our teeth also by eating plenty of foods that
require a good deal of chewing, especially the crusts of bread, and
vegetables such as corn, celery, lettuce, nuts, parched grains, and
popcorn.

It is most important to keep the nasal passages clear and free, and the
teeth sound and regular by proper dental attention, so that the jaws
will grow properly, and each tooth will strike squarely against its
fellow in the opposite jaw, and both jaws fit snugly and closely to each
other, making the bite firm and clean, and the grinding close and
vigorous. If we are mouth-breathers, our jaws will grow out of shape, so
that our teeth are crowded and irregular and do not meet each other
properly in chewing. Pressure upon the roots of the teeth, from meeting
their fellows of the opposite jaw in firm, vigorous mastication, is one
of the most important means of keeping them sound and healthy. Whenever
a tooth becomes idle and useless, from failing to meet its fellow tooth
in the jaw above or below properly, or from having no fellow tooth to
meet, it is very likely to begin to decay.

The next important thing in keeping the teeth healthy is to keep them
thoroughly clean. The greatest enemies of our teeth are the acids that
form in the scraps of food that are left between them after eating.
Meats are not so dangerous in this regard as starches and sugars,
because the fluids resulting from their decay are alkaline instead of
acid; but it is best to keep the teeth clear of scraps of all kinds.
This can best be done by the moderate and gentle use of a quill, or
_rolled_ wooden tooth-pick, followed by a thorough brushing after each
meal with a rather stiff, firm brush. Then use floss-silk, or linen or
rubber threads to "saw" out such pieces as have lodged between the
teeth.

This brushing should be given, not merely to the teeth, but to the
entire surface of the gums as well; for, as we have seen, it is the gums
that make or spoil the health of the teeth, and they, like all other
parts of the body, require plenty of exercise and pressure in order to
keep them healthy. In the early days of man, when he had no knives and
gnawed his meat directly off the bones, and when he cracked nuts and
ground all his grain with his teeth, the gums got an abundance of
pressure and friction and were kept firm and healthy and red; but now
that we take out the bones of the meat and stew or hash it, have all our
grain ground, and strip off all the husks of our vegetables and skins of
our fruits, though we have made our food much more digestible, we have
robbed our gums of a great deal of valuable friction and exercise. The
most practical way to make up for this is by vigorous massage and
scrubbing with a tooth-brush for five minutes at least three times a
day. It will hurt and even make the gums bleed at first; but you will
be surprised how quickly they will get used to it, so that it will
become positively enjoyable.

[Illustration: A TOOTH-BRUSH DRILL

A school in which the children are taught the importance of using the
tooth brush, are supplied with brushes at cost, and required to report
both on their care of their teeth and on the condition of the brushes.]

It is good to use some cleansing alkaline powder upon the brush. The
old-fashioned precipitated chalk, which makes the bulk of most tooth
powders, is very good; but an equally good and much cheaper and simpler
one is ordinary baking soda, or saleratus, though this will make the
gums smart a little at first. Any powder that contains pumice-stone,
cuttle-fish bone, charcoal, or gritty substances of any sort, as many
unfortunately do, is injurious, because these scratch the enamel of the
teeth and give the acids in the mouth a chink through which they may
begin to attack the softer dentine underneath the "glaze" of enamel.

Antiseptic powders and washes, while widely advertised, are not of much
practical value, except for temporary use when you have an abscess in
your gums, or your teeth are in very bad condition. It is almost
impossible to get them strong enough to have any real effect in checking
putrefaction of the food or diseases of the gums, without making them
too irritating or poisonous. If you keep the gums and teeth well brushed
and healthy, you will need no antiseptics.

Not only should the teeth be kept thoroughly clean and sweet for their
own sake, but also for the sake of the stomach and the health of the
blood and the whole body. The mouth, being continually moist and warm
and full of chinks and pockets, furnishes an ideal breeding ground for
all kinds of germs; and the average, uncleansed human mouth will be
found to contain regularly more than thirty different species of germs,
each numbering its millions! Among them may sometimes be found the germs
of serious diseases such as pneumonia, diphtheria, and blood-poisoning,
just waiting, as it were, their opportunity to attack the body. In fact,
a dirty, neglected mouth is one of the commonest causes of disease.



CHAPTER XXVI

INFECTIONS, AND HOW TO AVOID THEM


What Causes Disease. The commonest and most dangerous accident that is
likely to happen to you is to catch some disease. Fortunately, however,
this is an accident that is as preventable as it is common. Indeed, if
everybody would help the Board of Health in its fight against the spread
of the common "catchable" diseases, these diseases could soon be wiped
out of existence. Every one of them is due to dirt of some sort; and
absolute cleanness would do away with them altogether.

Diseases that are "catching," or will spread from one person to another,
are called _infections_; and all of them, as might be supposed from
their power of spreading, are due to tiny living particles, called
_germs_--so tiny that they cannot be seen except under a powerful
microscope. Nine-tenths of these disease germs are little plants of the
same class as the moulds that grow upon cheese or stale bread, and are
called bacteria, or bacilli. The different kinds of bacteria, or
bacilli, are usually named after the diseases they produce, or else
after the scientists who discovered them. For instance, the germ that
causes typhoid fever is called the _bacillus typhosus_; that which
causes tuberculosis is called the bacillus tuberculosis; while the germ
of diphtheria known as the _Klebs-Loeffler bacillus_, after the two men
who discovered it.

A few kinds of disease germs belong to the animal kingdom, though all
germs are so tiny that you would have to have a very powerful microscope
to tell the difference between the animal germs and the bacilli, or
little plants. Most of these animal germs are called _protozoa_ and
cause diseases found in, or near, the tropics, like malaria and the
terrible "sleeping sickness" of Africa. Smallpox, yellow fever, and
hydrophobia--the disease that results from the bite of a mad dog--are
also probably due to animal germs.

So far as prevention is concerned, however, it makes practically little
difference whether infectious diseases are due to an animal or a
vegetable germ, or to one bacillus or another. They all have two things
in common: they can be spread only by the touch of an infected person,
and "touch" includes breath,--indeed "by touch" is the meaning of both
infectious and contagious; and they can all be prevented by the
strictest cleanness, or killed by various poisons known as germicides
("germ-killers"), or disinfectants. Most of these germicides are,
unfortunately, poisonous to us as well; for, as you will remember, our
bodies are made up of masses of tiny animal cells, not unlike the animal
germs. Most of the germicides, therefore, have to be used against germs
while they are outside of our bodies.

Scripture says that "a man's foes shall be they of his own household,"
and this is true of disease germs. They grow and flourish--and, so far
as history tells us, the diseases they cause seem to have started--only
where people are crowded together in huts or houses, breathing one
another's breaths and one another's perspiration, and drinking one
another's waste substances in the well water. This fact has, however,
its encouraging side; for, since this habit of crowding together, which
we call civilization, or "citification," has caused and keeps causing
these diseases, it can also cure them and prevent their spread if all
the people will fight them in dead earnest. No amount of money, or of
time, that a town or a county can spend in stamping out these infectious
diseases would be wasted. Indeed, every penny of it would be a good
investment; for, taken together, they cause at least half, and probably
nearly two-thirds, of all deaths. Not only so, but most of the so-called
chronic diseases of the heart, kidneys, lungs, bones, and brain are due
to the after-effects of their toxins, or poisons.

How Disease Germs Grow and Spread. But perhaps you will ask, "If these
bacteria and protozoa are so tiny that we have to use a microscope, and
one of the most powerful made, in order even to see them, how is it that
they can overrun our whole body and produce such dangerous fevers and so
many deaths?" The answer is simply, "Because there are so many millions
of them; and because they breed, or multiply, at such a tremendously
rapid rate." When one of these little bacilli breeds, it doesn't take
time to form buds and flowers and seeds, like other plants, or even the
trouble to lay eggs like an insect or a bird, but simply stretches
itself out a little longer, pinches itself in two, and makes of each
half a new bacillus.

This is known as _fission_ or "splitting," and is of interest because
this is the way in which the little cells that make up our own bodies
increase in number; as, for instance, when a muscle is growing and
enlarging under exercise, or when more of the white blood cells are
needed to fight some disease. Remember that we and the disease germs are
both cells; and that, if they are numbered by millions, we are by
billions; and that we are made up of far the older and the tougher cells
of the two. Except in a few of the most virulent and deadly of fevers,
like the famous "Black Death," or _bubonic plague_, and lock-jaw, or
_tetanus_, ninety-five times out of a hundred when disease germs get
into our bodies, it is our bodies that eat up the germs instead of the
germs our bodies. Keep away from disease germs all that you reasonably
and possibly can; but don't forget that the best protection against
infectious diseases, in the long run, is a strong, vigorous, healthy
body that can literally "eat them alive."

Grow that kind of body, keep it perfectly clean inside and out, and you
have little need to fear fevers, or indeed any other kind of disease;
for you will live until you are old enough to die--and then you'll want
to, just as you want to go to sleep when you are tired. Remember that
this fight against the fevers is a winning fight, this study of disease
germs a cheering and encouraging one, because it will end in our
conquering them, not merely nine times out of ten, but ninety-nine times
out of a hundred.

We are not making this fight just to escape death; what we are fighting
for is to live out a full, useful, and happy life. And we already have
five chances to one of gaining this, and the chances are improving every
year; for science has already raised the average length of life from
barely twenty years to over forty. Broadly speaking, if you will keep
away from every one whom you know to have an infectious disease; wash
your hands always before you eat, or put anything into your mouth; keep
your fingers, pencils, pennies, and pins out of your mouth,--where they
_don't_ belong; live and play in the open air as much as possible and
keep your windows well open day and night, you will avoid nine-tenths of
the risks from germs and the dangers that they bring in their wake.

Children's Diseases. We have already studied two of the greatest and
most dangerous diseases, and the way to conquer them--tuberculosis, or
consumption, in the chapter on the lungs; and typhoid fever, in the
chapter on our drink. One of the next most important groups of
"catching" diseases--important because, though very mild, they are so
exceedingly common,--is that known as the "diseases of childhood," or
"diseases of infancy" because they are most likely to occur in
childhood. So common are they that you know their names almost as well
as you know your own--measles, mumps, whooping cough, scarlet fever, and
chicken-pox. Though they are in no way related to one another, so far as
we know (indeed, the precise germs that cause two of them--measles and
scarlet fever--have not yet positively been determined), yet they can be
practically taken together, because they are all spread in much the same
way, they all begin with much the same sort of sneezing and inflammation
of the nose and throat, they can all be prevented by the same means,
and, if properly taken care of, they result in complete recovery
ninety-five times out of a hundred.

[Illustration: THE WINNING FIGHT

Statistics for the population of the old City of New York. The chart
shows a decrease from 95 out of every 1,000 in 1891-92 to 48 out of
every 1,000 in 1909. This is due very largely to the careful methods of
prevention enforced by the Board of Health, especially the inspection of
milk.]

Any child who has sneezing, running at the nose or eyes, sore throat, or
cough, especially with headache or backache, a flushed face and
feverishness, ought to be kept at home from school and placed in a
well-ventilated, well-lighted room by himself for a day or two, until it
can be seen whether he has one of these children's diseases, or only a
common cold. If it turns out to be measles, scarlet fever, or whooping
cough, he should then be kept entirely away from other children in a
separate room, or, where that is impossible, in a special hospital or
ward for the purpose; he should be kept in bed and given such remedies
as the doctor may advise. Then no one else will catch the disease from
him; and within from two to five weeks, he will be well again. The most
important thing is not to let him get up and begin to run about, or
expose himself, too soon; five times as many deaths are caused by taking
cold, or becoming over-tired, or by injudicious eating, during recovery
after measles, scarlet fever, and whooping cough, as by the disease
itself. This one caution will serve two purposes; for, as a sick child's
breath, and the scales from his skin, and what he coughs out from his
mouth and nose are full of germs, and will give the disease to other
children from two to four weeks after the fever has left him, he ought
to be kept by himself--"in quarantine," as we say--for this length of
time, which is just about the period needed to protect him from the
dangers of relapse or taking cold. Boards of Health fix this period of
quarantine by law and put a colored placard on the house to warn others
of the danger of infection.

[Illustration: DEATH-RATE FROM MEASLES

Note that, after the quarantining of measles in 1896, the death-rate
dropped at once. Statistics for the old City of New York.]

Colds and Sore Throats. A milder and even more common kind of
infection is that known as common colds. These, as shown by their name,
were once supposed to be due to exposure to cold air, or drafts, or to
becoming wet or chilled. But, while a few of them are so caused, at
least eight, and probably nine, out of ten are due to germs caught from
somebody else. They are never caught in the open air and very seldom in
cold, pure fresh air of any sort, but almost always in the hot, foul,
stuffy, twice-breathed air of bedrooms, schoolrooms, churches, theatres,
halls, sleeping cars, etc. The colds, for instance, that you catch when
traveling, are usually due not to drafts or damp sheets, but to the crop
of cold germs left behind by the last victim.

You have probably known of colds that have run through a family or a
school or a shop. It is well worth trying to keep away from the
infection of colds, because not only is their coughing and sore throat
and hoarseness and running at the nose very disagreeable and
uncomfortable, but they may cause almost as many different kinds of
serious troubles in heart, kidneys, and nervous system as any of the
other infections. In fact, they probably cause more than any other,
because they are at least ten times as common and frequent. For
instance, many cases of rheumatism, or rheumatic fever, come after
attacks in the nose and throat, which cannot be distinguished from a
common cold or ordinary tonsilitis. Indeed, it is more than probable
that one of the ten or a dozen different germs that may get into your
nose or throat and give you a cold, is the germ that causes rheumatism.
At all events, it would be fairly safe to say, "No colds, no
rheumatism."

Whenever you have a cold, keep away from everybody that you possibly can
and stay at home from school or business for a day or two. You will do
no good to yourself or others, working in that condition; and you may
infect a dozen others. If you find anyone in your class or room or shop,
sneezing or coughing or running at the nose, report him to your teacher
or foreman; and if he won't send him home, keep away from him as much as
possible.

Diphtheria. Another common and serious disease, until quite recently
very fatal, is diphtheria. This is caused by getting into your mouth or
nose the germs from another case of the disease. This disease also is
most likely to occur in childhood, though it may attack a person of any
age, and is always serious. It may be prevented from spreading by
keeping children who have it shut up in rooms, or wards, by themselves
and keeping all other children away from them, or from their nurses or
those who have anything to do with them. Up to about thirty years ago,
it was one of the deadliest and most terrible diseases that we had
anything to do with. We knew absolutely nothing that would cure it, or
even check its course; and nearly half of the children attacked by it
died.

About that time, however, two scientists, Klebs and Loeffler, discovered
that, by taking some of the membrane, or tough growth that forms in the
throat in this disease, and by rubbing it over a plate of gelatin jelly,
they could grow on that gelatin a particular kind of germ. This germ, or
bacillus, they then put into the throats of guinea pigs, and found that
it would give them diphtheria.

This is the way disease germs are discovered, or, as we say, identified;
but of course this did not give at once any remedy for the disease.
Scientists soon found, however, that, if a very small number of these
bacilli were put into a guinea pig's throat, it would have diphtheria,
but in a very mild form. If, when it had recovered, it was again
infected, it would stand a much larger dose of the bacilli without harm.
This made them suspect that some substance had been formed in the
guinea-pig's blood that killed the bacillus or worked against its toxin,
or poison; and soon, to their delight, they succeeded in finding this
substance, which they called _antitoxin_ (meaning "against poison").
Then came the idea that if they could only get enough of this antitoxin,
and inject it into the blood of a child who had diphtheria, it might
cure the disease. A guinea pig is such a tiny animal that the amount of
antitoxin which it could form would be far too small to cure a man, or
even a child. So larger animals were taken; and it was finally found
that the largest and strongest of our domestic animals, the horse,
would, if the diphtheria germs were injected into its blood, make such
large amounts of antitoxin that merely by drawing a quart or two of the
blood--and closing up the vein again--enough antitoxin could be got to
cure fifty or a hundred children of diphtheria. This treatment has not
the slightest harmful effect upon the horse. The pain of injecting is
only like sticking a pin through the skin, while the pain of bleeding is
no greater than cutting your finger. There are now at our great
manufacturing laboratories whole stables full of horses, for the
production of this wonderful remedy.

[Illustration: DEATH-RATE FROM DIPHTHERIA AND CROUP

Statistics from the City of New York. Antitoxin was used largely from
1893-95, during which time there was a steady decrease (from 60% to 30%)
in the death-rate. After the Board of Health took up the matter,
furnishing antitoxin without cost, the death-rate continued to decrease
to less than 10% of the total number of cases, in 1909.]

With this remedy, our entire feeling toward diphtheria is changed.
Instead of dreading it above all things, we know now, from hundreds of
thousands of cures, that, if a case is seen on the first day of the
disease, and this antitoxin injected with a hypodermic needle, it is
almost certain that the patient will recover; not more than two or three
cases out of a hundred will fail. If the case is seen and treated on the
second day, all but four or five out of a hundred will recover; and if
on the third day, all but ten. In fact, the average death rate of
diphtheria has been cut down now from forty-five per cent to about six
per cent.

We now have antitoxins, or _vaccines_, for blood-poisoning; for typhoid
fever; for one of the forms of rheumatism; for boils; for the terrible
_cerebro-spinal meningitis_, or "spotted fever"; and for tetanus, or
lock-jaw. And every year there are one or two other diseases added to
the list of those that have been conquered in this way.

None of these vaccines is so powerful, or so certain in its effects, as
the diphtheria antitoxin. But they are very helpful already; and some of
them, particularly the typhoid vaccine, are of great value in preventing
the attack of the disease, as small doses of it given to persons who
have been exposed to the infection, or are obliged to drink infected
water, as in traveling or in war, very greatly lessen their chances of
catching the disease.

Vaccination, the Great Cure for Smallpox. Another valuable means of
preventing disease by means of its germs is by putting very small doses
of the germs into a patient's body, so that they will give him a very
mild attack of the disease, and cause the production in his blood of
such large amounts of antitoxin that he will no longer be liable to an
attack of the violent, or dangerous, form of the disease. Vaccines, for
this purpose, usually consist either of a very small number of the
disease germs, or of a group of them, which have been made to grow upon
a very poor soil or have been chilled or heated so as to destroy their
vitality or kill them outright. When these dead, or half-dead, bacilli
are injected into the system, they stir up the body to produce promptly
large amounts of its antitoxin. In some cases the reaction is so prompt
and so vigorous that the antitoxin is produced almost without any
discomfort, or disturbance, and the patient scarcely knows anything
about it. In others there will be a slight degree of feverishness, with
perhaps a little headache, and a few days, or hours, of discomfort. When
this has passed, then the individual is protected against that disease
for a period varying from a few months to as long as seven or eight
years, or even for life.

The best-known and oldest illustration of the use of these vaccines is
that of _smallpox_. A little more than a hundred years ago, an English
country doctor by the name of Jenner discovered that the cows in his
district suffered from a disease accompanied by irritation upon their
skins and udders, which was known as "cowpox." The dairymaids who milked
these cows caught this disease, which was exceedingly mild and was all
over within four or five days; but after that the maids would not take
smallpox, or, as we say, were immune against it. Smallpox at that time
was as common as measles is now. Nearly one-fourth of the whole
population of Europe was pock-marked, and over half the inmates in the
blind asylums had been made blind by smallpox. So common was it that it
was quite customary to take the infectious matter from the pocks upon
the skin of a mild case and inoculate children with it, so as to give
them the disease in mild form and thus protect them against a severe, or
fatal, attack; just as in country districts, a few years ago, some
parents would expose their children to measles when it happened to be a
mild form, so as to "have it over with."

It occurred to Dr. Jenner that if this inoculation with cowpox would
protect these milkmaids, it would be an infinitely safer thing to use to
protect children than even the mildest known form of inoculation. So he
tried it upon two or three of his child patients, after explaining the
situation to their parents, and was perfectly delighted when, a few
months afterward, these children happened to be exposed to a severe case
of smallpox and entirely escaped catching the disease. This was the
beginning of what we now call _vaccination_.

The germ of cowpox, which is believed to be either the cow or horse
variety of human smallpox, is cultivated upon healthy calves. The matter
formed upon their skin is collected with the greatest care; and this is
rubbed, or scraped, into the arm of the child. It is a perfectly safe
and harmless cure; and although it has been done millions of times,
never has there been more than one death from it in 10,000 cases. In a
little over a hundred years it has reduced smallpox from the commonest
and most fatal of all diseases to one of the rarest. But in every
country in the world into which vaccination has not been introduced,
smallpox rages as commonly and as fatally as ever. For instance, between
1893 and 1898 in Russia, where a large share of the people are
unvaccinated, 275,000 deaths occurred from smallpox; in Spain, where the
same condition exists, 24,000. In Germany, on the other hand, where
vaccination is practically universal, there were in the same period only
287 deaths--1/1000 as many as in Russia; and in England, only a slightly
greater number.

Another illustration, which comes closer home, is that of the Philippine
Islands. Before they were annexed by the United States, vaccination was
rare, and thousands of deaths from smallpox occurred every year. In
1897, after the people had been thoroughly vaccinated, there was not a
single death from this cause in the whole of the Islands.

[Illustration: BILL OF HEALTH

No outgoing ship may "clear the port" without a Bill of Health, signed
by the Collector of Customs and the naval officer of the Port.]

This discovery of Jenner's was most fortunate; for vaccination remains
until this day absolutely the only remedy of any value whatever that we
possess against smallpox.

Quarantine, inoculation, improvement of living and sanitary conditions,
the use of drugs and medicines of all sorts other than vaccination, have
no effect whatever upon either the spread or the fatality of the
disease. The author, when State Health Officer of Oregon, saw the
disease break out in a highly-civilized, well-fed, well-housed
community, and kill eleven out of thirty-three people attacked, just as
it would have done in the "Dark Ages." Not one of the cases that died
had been vaccinated; and, with but one exception (and in this the proof
of vaccination was imperfect), every vaccinated case recovered.
Vaccination will usually protect for from five to ten years; then it is
advisable to be re-vaccinated, and in six to eight years more, another
vaccination should be attempted. This third vaccination will usually not
"take," for the reason that two successful vaccinations will usually
protect for life.

Unexpected as it may seem, vaccination is not only a preventive of
smallpox, but a cure for it. The reason being that _vaccinia_, the
disease resulting from successful vaccination, being far milder than
smallpox, runs its course more quickly,--taking only two days to
develop,--while smallpox requires anywhere from seven to twenty days to
develop after the patient has been infected, or exposed. So, if anyone
who has been exposed to smallpox is vaccinated any time within a week
after exposure, the vaccine will take hold first, and the patient will
have either simple vaccinia, with its trifling headache and fever, or
else a very mild form of smallpox.

Some persons object to having children deliberately infected with even
the mildest sort of disease; but this is infinitely better than to
allow, as was the case before vaccination, from one-fourth to one-fifth
of them to be killed, twenty-five per cent of them to be pock-marked,
and ten per cent of them to be blinded by this terrible disease. So far
as any after-effects of vaccination are concerned, careful investigation
of hundreds of thousands of cases has clearly shown that it is not so
dangerous as a common cold in the head.

Infantile Paralysis. Another disease that has been unpleasantly
famous of late is also caused and spread by a germ. This is a form of
laming or crippling of certain muscles in childhood known as _infantile
paralysis_. It is not a common disease, though during the last two years
there has been an epidemic of it in the United States, especially in New
York and Massachusetts. The only things of importance for you to know
about it are that it begins, like the other infections, with headache,
fever, and usually with "snuffles" or slight sore throat, or an attack
of indigestion; and that its germ is probably spread by being sneezed or
coughed into the air from the noses and throats of the children who have
it, and breathed in by well children. The best known preventive of
serious results from this disease is the same as in the rest of
infectious diseases, namely, rest in bed, away from all other children,
which at the same time stops the spread of it. It furnishes one more
reason why all children having the "snuffles" and sore throat with fever
and headache should be kept away from school and promptly put to bed and
kept there until they are better.

The reason why the disease produces paralysis is that its germs
specially attack the spinal cord, so as to destroy the roots of the
nerves going to the muscles. Unless the harm done to the spinal cord is
very severe, other muscles of the arm or the leg can very often be
trained to take the place and to do the work of the paralyzed muscles,
so that while the limb will not be so strong as before, it will still be
quite useful.

Malaria. Practically the only disease due to animal germs, which is
sufficiently common in temperate or even subtropical regions to be of
interest to us, is _malaria_, better known perhaps as _ague_, or
"chills-and-fever." This disease has always been associated with swamps
and damp marshy places and the fogs and mists that rise from them;
indeed its name, _mal-aria_, is simply the Italian words for "bad air."
It is commonest in country districts as compared with towns, in the
South as compared with the North, and on the frontier, and usually
almost disappears when all the ponds and swamps in a district are
drained and turned into cultivated land or meadows.

About four hundred years ago, the Spanish conquerors of America were
fortunate enough to discover that the natives of Peru had a bitter,
reddish bark, which, when powdered or made into a strong tea, would cure
ague. This, known first as "Peruvian bark," was introduced into Europe
by the intelligent and far-sighted Spanish Countess of Chincon; and, as
she richly deserved, her name became attached to it--first softened to
"cinchona" and later hardened to the now famous "quinine." But for this
drug, the settlement of much of America would have been impossible. The
climate of the whole of the Mississippi Valley and of the South would
have been fatal to white men without its aid.

[Illustration: GERMS OF MALARIA

(Greatly magnified)

These germs are animal germs and are in the red blood corpuscles,
feeding on them.]

But although we knew that we could both break up and prevent malaria by
doses of quinine large enough to make the head ring, we knew nothing
about the cause--save that it was always associated with swamps and
marshy places--until about forty years ago a French army surgeon,
Laveran, discovered in the red corpuscles of the blood of malaria
patients, a little animal germ, which has since borne his name. This,
being an animal germ, naturally would not grow or live like a plant-germ
and must have been carried into the human body by the bite of some other
animal. The only animals that bite us often enough to transmit such a
disease are insects of different sorts; and, as biting insects are
commonly found flying around swamps, suspicion very quickly settled
upon the mosquito.

[Illustration: CULEX

Position on the wall.--After Berkeley.]

By a brilliant series of investigations by French, Italian, English, and
American scientists, the malaria germ was discovered in the body of the
mosquito, and was transmitted by its bite to birds and animals. Then a
score or more of eager students and doctors in different parts of the
world offered themselves for experiment--allowed themselves to be bitten
by infected mosquitoes, and within ten days developed malaria. At first
sight, this discovery was not very encouraging; for to exterminate
mosquitoes appeared to be as hopeful a task as to sweep back the
Atlantic tides with a broom. But luckily it was soon found that the
common piping, or singing, mosquito (called from his voice _Culex
pipiens_) could not carry the disease, but only one rather rare kind of
mosquito (the _Anopheles_), which is found only one-fiftieth as commonly
as the ordinary mosquito. It was further found that these
malaria-bearing mosquitoes could breed only in small puddles, or pools,
that were either permanent or present six months out of the year, and
that did not communicate with, or drain into, any stream through which
fish could enter them. Fish are a deadly enemy of the mosquito and
devour him in the stage between the egg and the growth of his wings,
when he lives in water as a little whitish worm, such as you may have
seen wriggling in a rain-barrel.

[Illustration: ANOPHELES

Position on the wall.--After Berkeley.]

It was found that by hunting out a dozen or twenty little pools of this
sort in the neighborhood of a town full of malaria, and filling them up,
or draining them, or pouring kerosene over the surface of the water, the
spread of the malaria in the town could be stopped and wiped out
absolutely. This has been accomplished even in such frightfully malarial
districts as the Panama Canal Zone, and the west coast of Africa, whose
famous "jungle fever" has prevented white men from getting a foothold
upon it for fifteen hundred years. Since the young mosquitoes, in the
form of wrigglers, or _larvæ_, cannot grow except in still water,
draining the pools kills them; and, as they must come to the surface of
the water to breathe, pouring crude petroleum over the water--the oil
floating on the surface and making a film--chokes them.

The common garden mosquito, while not dangerous, is decidedly a nuisance
and can be exterminated in the same way--by draining the swamps and
pools, or by flooding them with crude petroleum,--or by draining swamps
or pools into fresh-water ponds and then putting minnows or other fish
into these ponds. There is no reason why any community calling itself
civilized should submit to be tormented by mosquitoes if it will spend
the few hundred, or the thousand, dollars necessary to wipe them out. It
is prophesied that the use of quinine will soon become as rare as it is
now common, because malaria will be wiped out by the prevention of the
mosquito.

Disinfectants. So far we have been considering how to attack the germs
after they have got into our bodies, or to prevent them from spreading
from one patient to another; but there is still another way in which
they may be attacked, and that is by killing, or poisoning them, outside
the body. This process is generally known as _disinfection_, and is
carried out either by baking, boiling, or steaming, or by the use of
strongly poisonous fluids or gases, known as _disinfectants_.

While fortunately none of these disease germs can breed, or reproduce
their kind, outside the human body, and while comparatively few of them
live very long outside the human body, they may, if mixed with food or
caught upon clothing, hangings, walls, or floors, remain in a sort of
torpid, but still infectious, condition for weeks or even months.
Consequently, it has become the custom to take all the bedding,
clothing, carpets, curtains, etc., that have touched a patient suffering
from a contagious disease, or have been in the room with him, and also
any books that he may have handled, any pens or pencils that he may have
used, and either destroy them, or bake, boil, or fumigate them with some
strong germicidal, or disinfectant, vapor.

[Illustration: OILING A BREEDING GROUND OF MOSQUITOES

The photograph shows work done in the Panama Canal Zone. The swamp has
already been drained by ditches, and the work of destroying the larvæ is
being completed by the use of oil.]

This is usually done by closing up tightly the sick-room, putting into
it all clothing, bedding, pictures, books, hangings, and other articles
used during the illness (except wash-goods, which, of course, can be
sterilized by thorough boiling; and dishes and table utensils, which
also can be scalded and boiled); draping the carpet over chairs so as
to expose it on all sides, opening closets and drawers, and then filling
the room full of some strong germ-destroying fumes.

One of the best disinfectants, and the one now most commonly used by
boards of health for this purpose, is _formaldehyde_--a pungent,
irritating gas, which is an exceedingly powerful germ-destroyer. This,
for convenience in handling is usually dissolved, or forced into water,
which takes up about half its bulk; and the solution is then known as
_formalin_.

When formalin is poured into an open dish, it rapidly evaporates, or
gives up its gas; and, if it be gently heated, this will be thrown off
in such quantities as to completely fill the room and penetrate every
crevice of it, and every fold of the clothing or hangings. One pound, or
pint, of formalin will furnish vapor enough to disinfect a room eight
feet square and eight feet high, so the amount for a given room can thus
be calculated. The formalin vapor will attack germs much more vigorously
and certainly if it be mixed with water vapor, or steam; so it is
usually best either to boil a large kettle of water in the room for half
an hour or more, so as to fill the air with steam, before putting in the
formalin, or to use a combination evaporator with a lamp underneath it,
which will give off both formalin and steam. This, if lighted and placed
on a dish in the centre of a wash-tub or a large dishpan, with two or
three inches of water in the bottom of it, can be put into the room and
left burning until it goes out of its own accord.

Another very good method is to take a pan, or basin, with the required
amount of formalin (not more than an inch or two inches deep) in the
bottom of it, get everything ready with doors and windows fastened tight
and strips of paper pasted across the cracks, pour quickly over the
formalin some permanganate of potash (about a quarter of a pound to each
pound of formalin), and then bolt for the door as quickly as possible
to avoid suffocation. The resulting boiling up, or effervescence, will
throw off quantities of formaldehyde gas so quickly as to drive it into
every cranny and completely through clothing, bedding, etc. The room
should be left closed up tightly for from twelve to thirty-six hours,
when it can be opened--only be careful how you go into it, first
sniffing two or three times to be sure that all the gas has leaked out,
or holding your breath till you can get the windows open; and in a few
hours the room will be ready for use again.

Another older and much less expensive disinfectant for this purpose is
common _sulphur_. From one to three pounds of this, according to the
size of the room, is burned by a specially prepared lamp in a pan placed
in the centre of a dishpan of water, and the vapor thus made is a very
powerful disinfectant. This, however, is a very poisonous and
suffocating gas (as you will remember if you have ever strangled on the
fumes of an old-fashioned sulphur match) and, compared with formalin, is
nearly five times as poisonous to human beings, or animals, and not half
so much so to the germs. Where formalin cannot be secured, sulphur is
very effective; but its only merit compared with formalin is that it is
cheaper, and more destructive to animal parasites and vermin such as
bugs, cockroaches, mice, rats, etc., when these happen to be present.
Formalin has the additional advantage of not tarnishing metal surfaces,
as sulphur does.

It is a good thing for every household and every schoolroom to have a
bottle of formalin on hand, so that you may sniff the vapor of it into
your nostrils and throat if you think you have been exposed to a cold,
or other infectious disease, or make a solution with which to wash your
hands, handkerchiefs, pencils, etc., after touching any dirt likely to
contain infection. Half a teaspoonful in a bowl of water is enough for
this. A saucerful of it placed in an air-tight box, or cabinet, will
make a disinfecting chamber in which pencils, books, etc., can be placed
over night; and a teaspoonful of it in a quart of water will make an
actively germ-destroying solution, which can be used to soak clothing,
clean out bedroom utensils, or pour down sinks, toilets, or drains. It
is a good thing also to pour a few teaspoonfuls occasionally on the
floor of the closets in which your shoes, trousers, dresses, and other
outdoor clothing are kept, as these are quite likely to be contaminated
by germs from the dust and dirt of the streets.

Formalin is one of the best and safest general disinfectants to use. Its
advantages are, that it is nearly ten times as powerful a germicide as
carbolic acid, or even corrosive sublimate, so that it may be used in a
solution so weak as to be practically non-poisonous to human beings. It
is so violently irritating to lips, tongue, and nostrils as to make it
almost impossible for even a child to swallow it, while the amount that
would be absorbed if taken into the mouth and spit out again would be
practically harmless, so far as danger to life is concerned, though it
would blister the lips and tongue.

Bacteria, our Best Friends. While, naturally, the bacteria that do us
harm by producing disease are the ones that have attracted our keenest
attention and that we talk about most, it must never be forgotten that
they form only a very, very small part of the total number of bacteria,
or germs. These tiny little germs swarm everywhere; and the mere fact
that we find bacteria in any place, or in any substance, is no proof
whatever that we are in danger of catching some disease there.

All our farm and garden soil, for instance, is full of bacteria that not
only are harmless, but give that soil all its richness, or fertility. If
you were to take a shovelful of rich garden earth and bake it in an
oven, so as to destroy absolutely all bacteria in it, you would have
spoiled it so that seeds would scarcely grow in it, and it would not
produce a good crop of anything. These little bacteria, sometimes called
the soil-bacteria, or bacteria of decay, swarm in all kinds of dead
vegetable and animal matter, such as leaves, roots, fruits, bodies of
animals, fishes, and insects, and cause them to decay or break down and
melt away. In doing this they produce waste substances, particularly
those that contain ammonia, or nitrates, or some other form of nitrogen,
which are necessary for the growth of plants or crops.

This is why soil can be made richer by scattering over it and plowing
into it manure, waste from slaughter houses, or any other kind of
decaying animal or vegetable matter. This is promptly attacked by the
bacteria of the soil and turned into these easily soluble plant foods.
The roots of the plants grown in the soil could no more take this food
directly from dead leaves or manure than you could live on sawdust or
cocoanut matting.

So, if it were not for these bacteria, or lower plants, there could be
no higher, or green, plants. As animals live either upon these green
plants, such as grass and grains, or upon the flesh of other animals
that live upon plants, we can see that without the bacteria there would
be no animal life, not even man. No bacteria, no higher life. It would
be safe to say that, out of every million bacteria in existence, at
least 999,999 are not only not harmful but helpful to us.

One large group of bacteria produces the well-known souring of milk; and
while this in itself is not especially desirable, yet the milk is still
wholesome and practically harmless, and its sourness prevents the growth
of a large number of other bacteria whose growth would quickly make it
dangerous and poisonous. Many races living in hot countries deliberately
sour all the milk directly after milking, by putting sour milk into it,
because, when soured, it will keep fairly wholesome for several days,
while if not soured it would entirely spoil and become unusable within
twenty-four hours.

Another group of bacteria, which float about in the air almost
everywhere, are the yeasts, which we harness to our use for the very
wholesome and healthful process of bread-making. Millions upon millions
of bacteria of different sorts live and grow naturally in our stomachs
and intestines; and while they are probably of no special advantage to
us, yet at the same time the majority of them are practically, within
reasonable limits--not to exceed a few billions or so--harmless.

Insect Pests. One kind of "dirt" that should be avoided with special
care is insects of all sorts. No one needs to be told to try to keep a
house, or a room, clear of fleas, bed-bugs, or lice; indeed to have
these creatures about is considered a mortal disgrace. Not only is their
bite very unpleasant, but they may convey a variety of diseases,
including plague and blood poisonings of various sorts. But there is
another insect pest far commoner and far more dangerous than either
fleas or bed-bugs, whose presence we should feel equally ashamed of; and
that is the common house fly. This filthy little insect breeds in, and
feeds upon, filth, manure, garbage, and dirt of all sorts, and then
comes and crawls over our food, falls into our milk, wipes his feet on
our sugar and cake, crawls over the baby's face, and makes a general
nuisance of himself. Take almost any fly that you can catch, let him
crawl over a culture plate of gelatin, put that gelatin away in a warm
place, and you will find a perfect flower-garden of germs growing up all
over it, following the pattern made by the tracks of his dirty feet. In
this garden will be found not "silver bells and cockle shells and pretty
maids all in a row," but a choice mixture of typhoid bacilli, pus germs,
the germs of putrefaction, tubercle bacilli, and the little seeds which,
if planted in our own bodies, would blossom as pneumonia or diphtheria.

[Illustration: AN EDUCATIONAL FLY POSTER]

The fly is an unmitigated nuisance and should be wiped out. No half-way
measures should be considered. Fortunately, this is perfectly possible;
for his presence is our own fault and nothing else, as he can lay his
eggs and hatch only in piles of dirt and filth found about our own
houses, barns, and outbuildings. He is not a wild insect but a domestic
one and is practically never found more than a few hundred yards away
from some house or barnyard. His favorite place for breeding is in piles
of stable manure, especially horse manure; but neglected garbage cans,
refuse heaps, piles of dirt and sweepings, decaying matter of all sorts,
which are allowed to remain for more than ten days or two weeks at a
time, will give him the breeding grounds that he needs.

[Illustration: A BREEDING PLACE OF FLIES AND FILTH]

It takes him about two weeks to hatch and get away from these breeding
places; so that if everything of this sort is cleaned up carefully once
a week, or if, where manure heaps and garbage dumps have to remain for
longer periods, they are sprinkled with arsenic, kerosene, corrosive
sublimate, chloride of lime, or carbolic acid, he will perish and
disappear as surely as grass will if you wash away the soil in which it
grows. The presence of a fly means a dirty house or a dirty yard
somewhere, and to discover a fly in your house should be considered a
disgrace. Until people are aroused to the need of such cleanliness as
will make flies disappear entirely, in most places it will be necessary,
as warm weather approaches, to screen all doors and windows, and
particularly all boxes, pantries, or refrigerators in which food is
kept. If you cannot afford screens, use fly paper. These are all,
however, only half-way measures and will give only partial relief. The
best prevention of flies is absolute cleanliness. No dirt, no flies.

Dust, a Source of Danger. Dust is an easily recognized form of dirt.
It is dangerous in itself and nearly always contains germs of one sort
or another mixed in with it. Shops and factories whose processes make
much dust are usually very unhealthy for the workers, who are likely to
show a high death-rate from consumption.

Dust should be fought and avoided in every possible way. City streets
should have good modern pavements,--preferably asphalt or some crude
petroleum, or sawmill-waste, "crust," or coating,--which will not make
any dust, and which can be washed down every night with a hose. In
smaller towns where there is no pavement, dust may be prevented by
regular sprinklings during the summer, preferably with some form of
crude oil. Two or three full sprinklings of this will keep down the dust
for the greater part of the summer.

If these measures are properly carried out, they will prevent most of
the dust that accumulates in houses, as nearly all of this blows in
through the windows or is carried in on shoes or skirts. When this has
once floated in and settled down upon the walls, furniture, or carpets,
be very careful how you disturb it; for, as long as it lies there, it
will do you no harm, however untidy it may look. The broom and the
feather duster and the dry cloth do almost as much harm as they do good;
for while they may remove two-thirds of the dust from a room, they drive
the other third right into your nose and throat, where the germs it
contains can do the most possible harm. Dusting should always be done
with a damp cloth; sweeping, with a damp cloth tied over a broom; and,
wherever possible, a carpet sweeper, or, better still, a vacuum cleaner,
should be used instead of a broom.

Carpets, window curtains, and any hangings that catch dust should be
abolished--rugs that can be rolled up and taken out of doors to be
shaken and beaten should be used instead; and too many pieces of
bric-à-brac and ornaments should be avoided. All surfaces of walls,
ceilings, and floors should be made as smooth and hard and free from
angles, ledges, and projecting lines as possible. The colds usually
caught by members of the family during "spring cleaning" are usually due
to the swarms of germs stirred up from their peaceful resting places.
Let those sleeping germs lie, until you can devise some means of
removing them without brushing, or whisking, them straight into your
nostrils.



CHAPTER XXVII

ACCIDENTS AND EMERGENCIES


Ordinarily, Accidents are not Serious. Accidents will happen--even in
the best regulated families! While taking all reasonable care to avoid
them, it is not best to worry too anxiously about the possibility of
accidents; for a nervous, fearful state of mind is almost as likely to
give rise to them as is a reckless and indifferent one. Fortunately,
most accidents, especially with growing boys and girls, are
comparatively trifling in their results, and to a considerable extent
must simply be reckoned as part of the price that has to be paid for
experience, self-control, and skill. To have keen senses, vigorous and
elastic muscles, and a clear head, is better protection against
accidents than too much caution; it is also the best kind of insurance
that can be taken out against their proving serious. The real problem is
not so much to avoid accidents as to be ready to meet them promptly,
skillfully, and with good judgment when they occur, as they inevitably
will. As the old masters of swordsmanship used to teach, "Attack is the
best defense."

Luckily, healthy children are as quick as a cat and as tough as
sole-leather--if they weren't, the race would have been wiped out
centuries ago. Children in their play, on errands, going to and from
school, and in excursions through the woods and the fields, run, of
course, a great many risks. But in spite of all these dangers, the
number of children killed, or even seriously injured, in these "natural"
accidents, is not half of one per cent of those who die from disease or
bad air or poor food or overwork.

Another cheering thing about accidents is that ninety-nine out of every
hundred of them are not serious; and if you are only wise enough to know
what to do--and still more what not to do--in taking care of them, you
can recover from them safely and quickly. The bodies of healthy children
have an astonishing power of repairing themselves. Their bones are not
so brittle as those of "grown-ups"; and even when one of them is broken,
if properly splinted and dressed, it will heal up in a little more than
half the time required by the adult. And wounds and scratches and
bruises, _if kept perfectly clean_, will heal very rapidly.

Probably the commonest of all accidents are cuts and scratches. So
common is it for us to "bark" our knuckles, or our shins, or scratch
ourselves on nails and splinters and drive pins into ourselves, or let
our pocket knives slip and cut our fingers, that, if the human skin had
not the most wonderful power of repairing itself,--not merely closing up
the cut or the scratch, but making the place "as good as new,"--we
should be seamed and lined all over our hands, arms, faces, and limbs
like a city map, or scarred and pitted like a tattooed man, before we
were fifteen years old. But of course, as you know, the vast majority of
cuts and scratches and tears heal perfectly. They hurt when they happen;
and they burn, or smart, for a few hours, or hurt, if bumped, for a few
days afterward; but they heal soon and are forgotten.

On the other hand, some cuts and scratches will fester and throb and
turn to "matter" (_pus_) and even give you fever and headache and blood
poisoning. What makes the difference? It is never the size, or depth, of
the scratch or cut itself, but simply _the dirt that gets into it
afterward_. If a cut, or scratch, no matter how deep or ragged, be made
with a clean knife-blade or sliver and kept clean afterward, it will
never "matter" (_suppurate_) or cause blood poisoning. So if you know
how to keep dirt out of cuts and scratches, you know how to prevent
ninety-nine per cent of all the dangers and damage that may come from
this sort of accident.

Not more than one cut or scratch in a thousand is deep enough to go down
to an artery, so as to cause dangerous bleeding, or to injure an
important nerve trunk. So, though no one would by any means advise you
to be reckless about getting cut and scratched, yet it is better and
safer to run some risk of cuts and scratches in healthy play when young,
and learn how to keep them clean, than to grow up pale and
flabby-muscled and cowardly.

How to Prevent Infection in Wounds. It is not just dirt that is
dangerous,--although dirt of any sort is a bad thing to get into wounds
and should be kept out in every possible way,--but dirt that contains
those little vegetable bacteria that we call germs. The dirt most likely
to contain these germs--called pus germs, because they cause pus, or
"matter" in a wound--is dirt containing decaying animal or vegetable
substances (particularly horse manure, which may contain the tetanus, or
lock-jaw germ) and the discharges from wounds, or anything that has come
near decayed meat or unhealthy gums or noses or teeth. This is why a cut
or scratch made by a knife that has been used for cutting meat, or by a
dirty finger-nail, or by the claw of a cat, or by the tooth of a rat, is
often likely to fester and "run." Animals like rats and dogs and cats
often feed upon badly decayed meat; and hence their teeth, or claws, are
quite likely to be smeared with the germs that cause decay, and these
will make trouble if they get into a wound.

Fortunately, the care of a cut or scratch is very simple and practically
the same in all cases. Just make the wound thoroughly clean and keep it
so until it is healed. For a slight clean cut or scratch, a good
cleanser is pure water. Hold the hand or foot under the faucet or pump,
and let the cool water wash it out thoroughly. If you are sure that the
thing you cut it with was clean, let the blood dry on the cut and form a
scab over it. If the wound is large, or there is any danger of the water
of the well, or tap, having sewage in it (see chapter IX), it is better
to boil the water before using it. Unless the blood is spurting in jerks
from a cut artery, or bleeding very freely indeed, it is better to let
the wound bleed, as this helps to wash out any dirt or germs that have
got into it. When the bleeding has stopped, do not put on sticking
plaster, because this keeps out the air and keeps in the sweat of the
skin surrounding the wound, which is not healthful for the wound, and
may also contain some weak pus germs.

If the wound is small, the old-fashioned clean white rag that has been
boiled and washed is as good as anything that can be used for a
dressing. Tear off a narrow strip from one to two inches wide and as
many feet long, according to the position of the wound, roll it round
the finger or limb three or four times, and then take a turn round the
wrist or nearest joint, to keep the bandage from slipping off. If the
wound be likely to keep on oozing blood, put on first a thickness of
surgeon's cotton, or prepared cotton-batting, an ounce of which can be
purchased for ten cents at any drugstore. This is an excellent dressing,
because it not only sucks up, or absorbs any oozing from the wound, but
is a perfect filter-protection against germs of all sorts from the
outside. Ninety-nine simple wounds out of a hundred dressed in this way
will heal promptly and safely without danger of pus, or "matter."

If the wound happens to have been made with a knife or tool that you are
not absolutely sure was perfectly clean, or if the wound gets manure or
road-dirt or other filth rubbed into it, then it is best to go at once
to a doctor and let him give it a thorough _antiseptic_ dressing, which
consists of cleaning it out thoroughly with strong remedies, called
antiseptics,--which kill the germs, but do not injure living
tissues,--and then putting on a germ-proof dressing as before. This is
one of the "stitches in time" which will save not only nine, but
ninety-nine.

If you have a wound with dirt in it, and cannot reach a doctor, one of
the best and safest antiseptics to use is _peroxide of hydrogen_. This
is non-poisonous, and can be poured right into the wound. It will smart
and foam, but will clean out and kill most of the germs that are there.
Another safe antiseptic is pure alcohol. It is a good thing to have a
bottle of one of these in the medicine-closet, or in your "war-bag" when
camping out. A package of surgeon's cotton and two or three rolled
bandages of old cotton, linen, or gauze also should be on hand.

Dog-bites, rat-bites, or cat-bites should always be dressed by a doctor,
or made thoroughly antiseptic, mainly on account of the germs that swarm
round the roots of the teeth of these animals, and also because
treatment of this sort will prevent _hydrophobia_--although this danger
is a rare and remote one, not more than a few score of deaths from
mad-dog bites occurring in the whole United States in a year.

The wonderful progress made by surgery within the last twenty or thirty
years has been almost entirely due to two things: first, the discovery
of chloroform and ether, which will put patients to sleep, so that they
do not feel the pain of even the severest and longest operation; and,
second, but even more important, keeping germs of all kinds out of the
wound before, during, and after the operation. That sounds simple, but
it really takes an immense amount of trouble and pains in the way of
baking the dressings; boiling the instruments, and scrubbing with soap,
alcohol, hot water, and two or three kinds of antiseptics, or
germ-killers, the hands of the surgeon and of the nurse and the body of
the patient. How enormous a difference this keeping of the germs out of
the wound has made may be gathered from the fact that, while in earlier
days, before Lister showed us how to avoid this danger, surgeons used to
lose seventy-five per cent of their amputations of the thigh, from pus
infection, or blood poisoning, now they can perform a hundred operations
of this sort and not lose a single case. We can open into the skull and
remove tumors from the brain; open into the chest and remove bullets
from the lungs, and even from the heart itself; operate in fact upon any
part, or any organ, of the body with almost perfect safety and wonderful
success. Whereas, before, two-thirds of the patients so operated upon
would die, probably of blood poisoning.

How to Treat Bruises. Bruises are best treated either by holding the
injured part under the faucet, or pump, if convenient, or by plunging it
into very hot water and holding it there for ten or twelve minutes. Then
if the bruise still continues to throb or ache, wrap it up lightly with
a bandage of soft, loose cotton or linen cloth, and pour over it a
lotion of water containing about one-fourth alcohol until the bandage is
soaked, moistening it again as fast as it dries. This is also a useful
treatment for wounds that have been made by a fall, or by something
blunt and heavy, so that there is bruising as well as cutting. Most of
the household applications for wounds or bruises, such as arnica,
camphor, witch-hazel, etc., owe their virtues to the five or ten per
cent of alcohol they contain, which, by evaporating, cools the wound and
relieves inflammation, kills germs and so acts as an antiseptic, and
cleans the wound and the skin around it very thoroughly and effectively.

Bruises of all sorts, however, unless very severe, are much safer than
cuts or scratches, because they do not break the skin, and consequently
no germs can get into the tissues of the blood. Our skin, as you
remember, is one of the most wonderful water-proof, germ-proof,
hot-and-cold-proof coatings in the world; and as long as it remains
unbroken, none but a few of the most virulent disease-germs can get
through it into the body.

Boils and Carbuncles, their Cause and their Cure. Boils and carbuncles
are almost the only instances in which pus germs can get into the body
without some actual cut, tear, or breaking of the skin. They come always
from other boils or ulcers or discharging wounds and are caused by the
pus germs in these either being rubbed into the skin until it is almost
chafed through, or else being driven down into the mouth of one of the
hair follicles, or "pores." Here they proceed to grow and form a little
gathering, which soon turns to pus; and this stretches the skin and
presses upon the sensitive nerves in it so as to cause much pain. The
best way to treat them in the beginning is to give a thorough scrubbing
with hot water and soap, and then to drop right over the point, or
"head," of the gathering two or three drops of a strong antiseptic, like
formalin or peroxide or carbolic acid. If this does not check them, then
they had better be opened up freely with a sharp knife that has been
held in boiling water, or a needle that has been held in a flame until
it is red hot and allowed to cool. Then pour peroxide into the opening,
put on a light dressing, and keep soaked with alcohol and water, as for
a bruise. This evaporating dressing is far superior to the dirty,
sticky, germ-breeding poultice. If this does not clear it up within
twenty-four hours, go to a doctor and have him treat it antiseptically.

How to Stop Bleeding. If a cut should go deep enough to reach an
artery the size of a knitting needle, or larger, then the blood will
spurt out in jets. There is then some danger of so much blood being lost
as to weaken one. Our blood, however, has a wonderful power of clotting,
or clogging, round the mouth of the cut artery, so that the risk of
bleeding to death, except from quite a large artery, like that of the
thigh, or the armpit, is not very great.

For a wound in the hand or foot, that spurts in this way, it will
usually be sufficient to grasp the arm firmly above the wrist or the
elbow, or the ankle, as the case may be, with the thumb over the artery,
or even to press directly over the wound, until the bleeding stops and
the blood is thus given a chance to clot. If the wound is small and
deep, like that made by the stab of a knife, or the slip of a chisel,
then firm pressure directly over the wound itself with a thumb, or both
thumbs, will usually be sufficient to stop the bleeding.

[Illustration: A TOURNIQUET

A stone laid above the cut under the bandage will help to increase the
pressure at this point.]

Should, however, the spurting be from an artery like that of the pulse,
or from that at the bend of the elbow or the knee, then the best thing
to do is to tie quickly a handkerchief or strip of tough cloth loosely
around the limb above the wound and, slipping a short stick or bar into
the loop, twist upon it, as shown in the picture, until the blood ceases
to flow from the wound. It is much better to use a handkerchief or piece
of cloth than a cord, because the latter may cut into and damage the
tissues, when drawn as tight as is needed to stop the circulation. It is
not best to allow a bandage twisted tight enough to stop the
circulation--called a _tourniquet_--to remain tight for more than half
an hour at a time, as this may give rise to very dangerous congestion,
or serious "blood starvation" of the tissues below it. It should be
gently untwisted every half hour until the arm, or limb, below it
reddens up again, and then, if the spurting begins, should be tightened
as before. There is, however, a good chance that if the cut artery is
not too large, the blood will have clotted firmly enough in this time
to stop the bleeding; though the tourniquet had better be left on the
arm, ready to be tightened at a moment's notice, until the doctor comes.

The Treatment of Burns. Burns require more careful treatment on
account of the wide surface of the skin usually destroyed. The layer of
the skin that is most alive and most active in the process of repair is
the outer layer (the epithelial, or epidermis). A burn, or scald, if at
all severe, is likely to destroy almost the entire thickness of this,
over its whole extent. This gives both a wide surface for the absorption
of pus germs and a long delay in "skinning over," or healing. As the
same heat that made the burn has usually destroyed any germs that may be
present, it is not necessary to wash or clean a burn, like a wound,
unless dirt has been rubbed or sprinkled into it after it has been made.
The first thing to be done is to coat it over so as to shut out the air;
and this, for a slight burn, can be very well done by dusting it over
with baking soda or clean flour or with one of the many dusting, or
talc, powders on the market, containing boracic acid, or by laying over
the burn a clean cloth soaked in perfectly clean olive oil or vaseline.
If the oil or vaseline is not perfectly clean, put it on the top of a
stove and heat it thoroughly before using. Dress with soft, clean cotton
rag or lint as before, keeping wet with the alcohol lotion (one part of
alcohol to eight of water) if there be much pain, or throbbing.

If the burn is deep or the pain at all severe, it is best to call in a
doctor, as bad burns are not only agonizingly painful, but also very
dangerous on account of the wide, raw surface that they leave open to
entrance of pus germs for days and even weeks. Until a doctor can be
secured, coat it over with some non-irritating powder or oil, as for
lighter burns, or hold it in warm water to exclude the air. Do not try
to clean a burn. You only increase the pain of it and probably add to
the risk of infection.

If your clothing ever catches fire, wrap yourself up at once in a
blanket or rug to smother the flame. Remember that running will supply
more air to the flame and cause it to do more damage. If you have
nothing at hand in which to wrap yourself, lie down on the floor, or
ground, and roll over and over until you have smothered the flame.

What should be Done in the Case of Broken Bones, or Fractures. Broken
bones, or fractures, as they are called, are more serious, but
fortunately not very common. They should, of course, always be treated
by a doctor, to prevent shortening of the limb, or to prevent the bones
from growing together at an angle, or in a bad position, so as to
interfere with the use of it. Where a doctor cannot readily be had, or
the patient has to be taken to him,--as, for instance, where the
accident occurs out in the woods,--take two light pieces of board, or
two bundles of straight twigs, or two pieces of heavy paper folded
fifteen or twenty times--two folded newspapers, for instance--and,
wrapping them in cloth or paper, place one on each side of the broken
limb, at the same time gently pulling it straight. Then take strips of
cloth, or bandage, and bind these splints gently, but firmly and snugly,
the length of the limb, so that it cannot be bent in such a way as to
make the ends of the bone grate against each other. The patient can then
be lifted, or carried, with comparative comfort. Most fractures, or
broken bones, in children or young boys or girls, heal very rapidly; and
if the limb be properly straightened and splinted by competent hands, it
will be practically as good and as strong as before the accident.

Sprains. Sprains are twists or wrenches, of a joint, not severe enough
to "put it out," or dislocate it, or to break a bone. A mild sprain is a
very trifling affair, but a severe one is exceedingly painful and very
slow in healing. The best home treatment for sprains is to hold the
injured joint under a stream of cold water for ten or fifteen minutes
and then to bandage it firmly and thoroughly, but gently, with a long
"figure-of-eight" bandage, wound many times, and to keep this moist with
an alcohol lotion. Then keep the limb at rest. If the cold water does
not relieve the pain, plunge the joint into water as hot as you can
comfortably bear it and keep it there for ten or fifteen minutes, adding
fresh hot water to keep up the temperature; then bandage as before.

If the pain should not go down under either of these treatments within
six or eight, certainly within ten or twelve, hours, it is far wisest to
call a doctor, because severe sprains very often mean the tearing of
some important tendon or ligament, and the partial fracture of one of
the bones of the joint. Unless these conditions are promptly corrected,
you may be laid up for weeks, and even months, and left with a
permanently damaged--that is, stiffened--joint. You will often hear it
said that a sprain is harder to heal than a fracture; but that kind of
sprain usually includes a fracture of some small portion of a bone,
which has escaped notice and proper treatment. If the sprain is mild, so
that it does not pain you when at rest, then the bandage should be
removed every day, and the joint gently rubbed and massaged, and the
bandage replaced again. Should there be any one in reach who understands
massage, a thorough massaging right after the accident is quite helpful;
but no amateur had better attempt it, as unskilled rubbing and
stretching are likely to do more harm than good.

What to Do in Case of Poisoning. Poisoning is, fortunately, a rare
accident; and the best thing to be done first is practically the same,
no matter what poison--whether arsenic, corrosive sublimate, or carbolic
acid--has been swallowed. This is to dilute the poison by filling the
stomach with warm water and then to bring about vomiting as quickly as
possible. This can usually be done by adding a tablespoonful of mustard
to each glass of warm water drunk. If this cannot be had, or does not
act within a few minutes, then thrusting the finger as far down the
throat as it will go, and moving it about so as to tickle the throat,
will usually start gagging; or a long feather may be dipped in oil and
used in the same way. It is also a good thing to add milk or white of
egg or soap to the water, or to mix a little oil or plaster scraped off
the wall with it, as these tend to combine with the poison and prevent
its being absorbed. If the poison happens to be an acid, like vitriol,
then add a tablespoonful or more of baking soda to the hot water; if an
alkali, like lye or ammonia, give half a glass of weak vinegar. The main
thing, however, is to set up vomiting as quickly as possible.

[Illustration: POISON IVY

It may be distinguished from woodbine by its _leaves in groups of three_
(not five), _glossy_ and _smooth-edged_ (not dull and saw-toothed); its
_berries greenish-white_ (not blue).]

Another rather frequent and most disagreeable accident, which may happen
to you when out in the woods, is poisoning by poison ivy. This is due to
the leaves or twigs of a plant, which many of you probably know by
sight, touching your hands or face. If you do not happen to know what
poison ivy looks like, you had better get some one who knows to point
out the shrub to you the next time you go into the woods, and then you
should try to keep as far away from it as possible. It is sometimes
called poison oak, but both these names are incorrect, as the shrub is
really a kind of sumac. It takes its different names because it has the
curious habit of either climbing like a vine, when it is called "ivy,"
or growing erect like a bush, or shrub, when it is called "oak."

All sorts of absurd stories are told about the leaves of the shrub being
so poisonous that it is not safe to go within ten feet of it, when the
dew is on it, or to walk past it when the wind is blowing from it toward
you. But these are pretty nearly pure superstitions, because it has been
found that the substance in the leaves or bark of the shrub which
poisons the skin is an oil, which is _non-volatile_, that is to say,
will not give off any vapors to the air and, of course, cannot be
dissolved in dew or other watery moisture. You must actually touch the
leaves in order to be poisoned; but, unfortunately, this is only too
easy to do without knowing it when you are scrambling through the woods
or hunting for flowers or picking berries.

The remedy for poison ivy is a very simple one, and within the reach of
anybody, and is as effective as it is simple. This is a thorough
scrubbing of the part poisoned, just as soon as it begins to itch, with
a nail-brush and soap and hot water. This makes the skin glow for a
little while, but it washes out all the burning and irritating oil and,
if used promptly, will usually stop the trouble then and there. It is a
good idea if you know that you have touched poison ivy, or even if you
have been scrambling about actively in woods or patches of brush where
you know that the ivy is common, to give your hands a good washing and
scrubbing with sand or mud, if there is no soap at hand, in the first
stream or pool that you come to. This will usually wash off the oil
before it has had time to get through the natural protective coating of
the skin.

Snake-bite is one of the rarest of all accidents and not one-fiftieth as
dangerous as usually believed. Not more than one person in twenty bitten
by a large rattlesnake will die, and only about two in a hundred bitten
by small rattlers or by copperheads. The average poisonous snake of
North America cannot kill anything larger than a rabbit, and any
medium-sized dog can kill a rattlesnake with perfect safety. Our
horror-stricken dread of snakes is chiefly superstition. Of those who
die after being bitten by North American snakes, at least half die of
acute alcoholic poisoning from the whiskey poured down their throats in
pints; and another fourth, from gangrene due to too tight bandaging of
the limb to prevent the poison from getting into the circulation, or
from pus infections of the wound from cutting it with a dirty knife.
Alcohol is as great a delusion and fraud in snake-bite as in everything
else; instead of being an antidote, it increases the poisoning by its
depressing effect on the heart. If you should be bitten, throw a bandage
round the limb, above the bite, and tighten as for a cut artery. Then
make with a clean knife two free cuts, about half or three-quarters of
an inch deep, through the puncture, one lengthwise and the other
crosswise of the limb, and let it bleed freely. Then throw one or, if
there be room, two or three other bandages round the limb, three or four
inches apart, and tighten gently so as to close the surface veins by the
pressure, without shutting off the flow in the arteries. After thirty or
forty minutes loosen the first bandage to the same tightness and leave
it so unless the heart weakens or faintness is felt, in which case
tighten again. If this be done, there isn't one chance in a hundred of
any serious result.

How to Avoid Drowning. In case of falling into the water, the chief
thing to do is to try to keep calm and to _keep your hands below your
chin_. If you do this and keep paddling, you will swim naturally, just
as a puppy or a kitten would, even if you have never learned to swim. It
is, however, pretty hard to remember this when you go splash! into the
water. Everyone should learn to swim before he is twelve years old; and
then in at least nine times out of ten, he will be safe if he fall
overboard. Remember that, if you keep your mouth shut and your hands
going below your chin, you can keep floating after a fashion, for some
time; and in that time the chances are that help will reach you. If you
can reach a log or apiece of board or the side of a boat, just cling
quietly to that with one hand, and keep paddling with the other. Even if
you can get hold of only quite a small limb or pole or piece of a box,
by holding one hand on that and paddling with the other and kicking your
feet, you will be able to keep floating a long time unless the water be
ice cold. If you can manage to keep both your feet splashing on top of
the water and both hands going, you can swim several hundred yards.

[Illustration: Pressing out the air in the lungs.

Allowing the lungs to fill themselves.

THE NEW METHOD OF ARTIFICIAL BREATHING

Devised by a celebrated physiologist, Professor Schaefer of Edinburgh,
and now being adopted by life-saving stations and crews everywhere.]

You may sometime be called upon to save another person from drowning. In
such a case, as in every emergency, a cool head is the chief thing. Make
up your mind just what you are going to do before you do
_anything_,--then do it _quickly_! If no one is near enough to hear your
shouts for help, and no boat is at hand, if possible throw, or push, to
the one in the water a plank or board or something that will float, and
he will instinctively grasp it. If you are thrown into the water with a
person that can't swim, grasp his collar or hair, and hold him at arm's
length, to prevent his dragging you under, until help arrives, or until
you can tow him to safety.

Boys and girls, after they have learned to swim, may well practice
rescuing each other, so as to be prepared for such accidents.

Artificial Breathing. The best way to revive a person who has been
under water and is apparently drowned, is to turn him right over upon
his chest on the ground, or other level surface, turning the face to one
side so that the nose and mouth will be clear of the ground. Then,
kneeling astride of the legs, as shown in the picture, place both hands
on the small of the back and throw your weight forward, so as to press
out the air in the lungs. Count three, then swing backward, lifting the
hands, and allow the lungs to fill themselves with air for three
seconds, then again plunge forward and force the air out of the lungs
and again lift your weight and allow the air to flow in for three
seconds. Keep up this swinging backward and forward about ten or twelve
times a minute. This is the newest and by far the most effective way--in
fact the only real way--of keeping up artificial breathing. It is very,
very seldom that any one can be revived after he has been under water
for more than five minutes,--indeed, after three minutes,--but this
method will save all who can possibly be saved.

So perfect a substitute for breathing is it that if any one of you will
lie down in this position upon his face, and allow some one else to
press up and down on the small of his back after this fashion, ten or
twelve times a minute, he will find that, without making any effort of
his own to breathe, this pumping will draw enough air into his lungs to
keep him quite comfortable for half an hour.

Don't waste any time trying to pour the water out of the lungs. As a
matter of fact there is very little there, in drowned people. Don't
waste any time in undressing, or warming or rubbing the hands or feet to
start the circulation. Get this pendulum pump going and the air blowing
in and out of the lungs, and if there is any chance of saving life this
will do it; then you can warm and dry and rub the patient at your
leisure after he has begun to breathe.



QUESTIONS AND EXERCISES


CHAPTERS I AND II

1. Look up in a dictionary the words physiology and hygiene. What does
each mean? If you can, find the derivation of each. 2. Why should
everyone learn about the human body? 3. How is the "man-motor" like an
"auto"? Compare the fuel of each. 4. From what source do all the fuels
get their force or energy? 5. How do plants get their fuel, or food?
6. What is meant in saying that man takes his food at second, or third,
hand? 7. Why do we need a mouth? 8. Does a plant have a mouth? Where?
9. Draw a diagram showing how the food is carried into and throughout the
body. 10. Describe the parts of the food tube through which it goes.
11. Tell how the body-motor uses bread as a fuel. How is its form changed
before it can be used? 12. What are the salivary glands for? What work
is done by their juice? 13. What other juices help to melt the bread?
14. Which foods need the most chewing? 15. How is the food carried down
the food tube? 16. What is the appendix? Explain how it sometimes causes
trouble. 17. How can you tell the difference between colic and
appendicitis? 18. On which side is the appendix located? 19. In what
parts of the food tube are (_a_) starch, (_b_) meats, (_c_) fat
digested? 20. What causes constipation? How may it be avoided? 21. Is
drinking water at meals hurtful? If so, how?


CHAPTER III

1. If we call the body an engine, what is the fuel? what is the smoke?
what are the ashes? 2. Why and how far can we rely upon our natural
desires and appetites for food? 3. How should we choose our foods?
4. Name two serious faults that foods may have. 5. Why do we need a
variety of foods? 6. What is meant by the term "fuel value of food"?
7. How can we roughly tell to which class a food belongs or what its
fuel value is? 8. Why should animal and vegetable foods be used together?


CHAPTER IV

1. Name and describe our most common meats. 2. When is pork a valuable
food? 3. Why do we digest it slowly? 4. Why should we eat fish only
once or twice a week? 5. What food-stuffs are found in milk? 6. Name
some vegetables which contain protein food. 7. In planning a week's
diet, how often would you use these vegetables, and why? 8. What is our
greatest danger in eating meat? 9. Why is it dangerous to eat highly
seasoned stews or hashes? 10. Should cheese be eaten in large amounts at
a time? Why? 11. Describe the care taken at a good dairy. 12. Why is
this necessary? 13. Why is dirty milk less nourishing than clean milk?


CHAPTER V

1. Explain the name "starch-sugars." To which class of fuel-food might
we say that they belong? 2. Why are they cheaper than meat? 3. Why must
these foods be ground and cooked? 4. Which is the better food, white or
brown bread? Why? 5. Could we live on starch-foods alone? What is the
reason of this? 6. In what foods do we find nitrogen? In what, carbon?
7. What is a "complete food"? Name some. 8. Why must the starchy foods
be changed in the body into sugar, or glucose? 9. Name three ways by
which bread is made "light." 10. What is yeast? 11. How is bread made?
12. Why should it be thoroughly baked? 13. What causes bread to become
sour? 14. Name other important starchy foods. 15. Is sugar a valuable
food? Why? 16. In what plants do we find it?


CHAPTER VI

1. Why are fats slow of digestion? 2. If they are so valuable as "coal
foods," why do we not eat more of them at a meal? 3. Give some reasons
for carrying fats as food supply on long voyages and expeditions. 4. In
what forms are they best carried? 5. What makes up the emergency
field-ration of the German army, and why? 6. What is the most valuable
single fat, and why? 7. Name other fats in common use and describe their
effects on digestion. 8. State the food values of bacon. 9. Why should
nuts be eaten in moderate quantity only? 10. How do nuts compare in cost
(_a_) with other proteins? (_b_) with other fats? 11. What is the
peanut? 12. Why is it hard to digest? 13. What digestive juices "melt"
fats? 14. What is oleomargarine and how does it compare with butter?


CHAPTER VII

1. What is the necessity of fruits and vegetables in our dietary? Why
especially in summer? 2. Give some idea of the food value of fruits as
compared with bread and meat. 3. Name the most wholesome and useful
fruits. 4. What is the food value of bananas? Why is it very important
that they be eaten in moderation only? 5. What does (_a_) boiling and
(_b_) drying do to fruits? 6. Why seal the jars of preserved fruits?
7. Why can you not eat as much jam, at one time, as raw fruit? 8. What
disease is caused by scarcity of fresh vegetables or fruits? 9. Name
some of the common vegetables and give their fuel values. 10. Why do we
need with our meals the lighter green vegetables, although they have
little nutritive value? 11. What vegetables contain starch, what sugar,
and what digestible protein? 12. In what form is most of the nitrogen of
vegetables?


CHAPTER VIII

1. What changes occur in food when it is cooked? Describe some of the
changes. 2. What are the advantages of cooking meats and vegetables?
3. Why is it necessary that food should taste good? 4. What has cooking to
do with the cost of food? 5. Why is time well spent in cooking food?
6. Describe the different methods of cooking food and tell advantages of
each. 7. In what ways can you help make the table attractive and
preserve health? 8. In what ways may food be made less digestible and
wholesome by cooking? 9. In what way can fried food be made digestible?
10. What is the supposed economy of boiling? 11. Write out a good menu
for each meal of the day.


CHAPTER IX

1. Why is water necessary in the body? 2. How does the body take in
water other than by drinking it? 3. Why is this water sure to be pure?
4. Why is drinking water likely to be impure? 5. Where and when is water
perfectly pure? 6. What are our chief sources of water-supply? 7. What
is a well? a spring? a reservoir? 8. Which source of water-supply is
safest? 9. What are the dangers of well water? 10. How can they be
avoided? 11. What are the dangers of river water? 12. What is a filter
and how does it work? 13. What makes water rise in a spring or an
artesian well? 14. How may water suspected of being unhealthful be made
safe to drink? 15. How is sewage disposed of? 16. How can it be kept out
of the drinking water? 17. Why does it pay cities to spend large sums to
secure pure water? 18. How can a reservoir be protected? 19. What are
the risks of house filters? 20. How do bacteria help us in keeping our
water-supply pure? 21. Does your city or town have a central source of
water-supply? Where is it? 22. Visit the waterworks of your city or
town and describe to the class how the water is obtained, how prepared
for use, and how distributed to buildings.


CHAPTER X

1. How can you prove that beverages are not real foods? 2. What is tea?
What is coffee? What are chocolate and cocoa? 3. Why are tea and coffee,
if stewed, bad for the digestion? 4. Why is it better for you to let
these drinks alone? 5. How is alcohol made? 6. How is wine made? beer?
cider? whiskey? 7. When does fermentation stop, and for what reason?
8. What is the difference between whiskey and brandy? Why are these the
most harmful of these drinks? 9. Explain the effect of alcohol on the
digestion. 10. Does it increase the warmth of the body? 11. Does it
increase our working power? 12. How is it that at first people thought
that alcohol was helpful, when really it was not? 13. What is the effect
of alcohol on the nervous system? 14. Can the man who drinks alcohol
tell how, or to what extent, it is injuring him? 15. Is alcohol a food
or a medicine? 16. How does alcohol usually affect the mind and
character? 17. Why is smoking a foolish habit? 18. Why is it harmful for
boys? 19. What is nicotine? 20. What proof have we that smoking stunts
growth? 21. How is it likely to hinder a boy's career?


CHAPTER XI

1. Where does the real "eating" take place in the body? 2. How is the
food carried to these parts? 3. What does the name "artery" mean?
4. What are veins? 5. If you examine blood under a microscope, what will
you find in it? 6. What are the uses of these two kinds of little bodies
(corpuscles)? 7. Explain the process of inflammation. 8. Draw a diagram
or rough picture showing the route of the blood through the heart and
body. Mark the vena cava and the portal vein. 9. What are the
capillaries, and what does the name mean? 10. Why do the veins have
valves? 11. Explain how the different parts of the heart act, while they
are pumping and receiving the blood. 12. How many strokes of the
heart-pump are there per minute in a man? a woman? a child? 13. Which
part of the heart has the thickest muscle and why? 14. Where are the
strongest valves? 15. What blood vessels carry the blood to and from the
lungs? 16. What blood vessel carries the blood from the heart over the
body? 17. When you press your hand to the left side of your chest, what
movement do you feel? 18. Where is the best place to feel the pulse?
Why? 19. Which are generally nearer the surface, arteries or veins? Are
they near each other? 20. Why does the heart beat faster when you run?


CHAPTER XII

1. Why is it bad for you to study or exercise while you are eating, or
right after eating? 2. How does overwork, or over-training, affect the
heart? 3. What kind of play or exercise strengthens it? 4. How does good
food help it? 5. What is the best way to avoid heart diseases,
rheumatism, consumption, and pneumonia? 6. How does outdoor air help
heart-action? 7. How do alcohol and tobacco injure the blood system and
heart? 8. Why is alcohol particularly bad for underfed and overworked
people? 9. At what two points is the blood system most likely to give
way? 10. What may cause this breakage, or leakage? 11. What "catching"
diseases often cause organic disease of the heart? 12. Why should heavy
muscular work or strain be avoided after an attack of one of these
diseases? 13. How may valvular heart trouble be remedied? 14. In what
way are the nerve and blood systems connected? 15. What signal have we
that we are beginning to over-exercise the heart? 16. What do we mean by
"tobacco heart"? 17. Tell how to take care of the heart.


CHAPTER XIII

1. How long can an animal live without eating? 2. How long can an animal
live without breathing? 3. Why is your body like a sponge? 4. What are
cells? 5. How do they get their food? 6. How many kinds of waste come
from the body cells? 7. How is each kind carried away from the body?
8. What does the blood carry from the lungs to the body cells? 9. Why does
it not carry air? 10. What process keeps your body warm? 11. What
happens if the body cannot get oxygen? 12. How are the human lungs
formed? 13. What is the windpipe? What are the bronchi? 14. Draw a
picture of the lung-tree showing how the tubes branch. 15. What is at
the end of each tiny branch? 16. How do the windpipe and the esophagus
differ in form? 17. Why is the windpipe stiff? 18. In what four ways is
the air you breathe out different from that which you took in? 19. Why
does lime-water become milky when you breathe into it? 20. When you run,
why do you breathe more quickly? Why does your heart beat faster?
21. How can you improve your "wind"? 22. In fever, why do you breathe more
rapidly? 23. How do the ribs and muscles help in breathing?


CHAPTER XIV

1. Why is "caged air" dangerous? 2. How is outdoor air kept clean and
pure? 3. What is air made of? 4. In what ways do people poison the air?
5. How do plants help to clean the air? 6. What is the best way to
ventilate a room? Why? 7. Why do you have recess? 8. How does impure air
make children look and feel? 9. Why is an open fire not the best means
of heating and ventilating? 10. See if the room you are now in is
properly ventilated. Why, or why not? 11. What are disease germs?
12. Why is dusty air unwholesome? 13. What is the safest way to clean a
room? 14. Name three groups of disease germs that float in the air.
15. Name three ways in which you can protect yourself against these germs.
16. What is a cold? 17. What is the best way to cure a cold? 18. How can
you prevent colds? 19. What causes consumption (tuberculosis of the
lungs)? 20. Does the tubercle bacillus attack other parts of the body?
21. Why should a consumptive hold a cloth before his face when coughing?
22. Why should his sputum be burned? 23. Why should he go to a camp or
sanatorium? Give two reasons. 24. About how much money could this
country afford to spend in fighting consumption? Why? 25. Why need we no
longer dread it as people did twenty-five years ago? 26. What methods
are used in curing the disease? 27. What methods are used for preventing
it? 28. Give two reasons why spitting should be prohibited. 29. What
will fresh-air and sunlight do to the disease germs in the dust?
30. What do we know about the germs of pneumonia? 31. Do those who use
alcohol stand a good chance in fighting pneumonia? 32. How may pneumonia
be prevented?


CHAPTER XV

1. Why is the skin so important? 2. Name some of the things that it
does. 3. How many layers has it? Describe each. 4. What glands are found
in the skin? 5. What is sweat, or perspiration, and from what does it
come? 6. Why should clothing be porous? 7. Why should clothing be
frequently washed? 8. Describe a hair gland and its muscles. 9. Describe
the process of "nail-making." 10. Is there any process like this among
the lower animals? 11. Why do we need nails? 12. What causes the white
crescent on the nail? 13. Explain how the skin is a heat regulator.
14. What is the "normal temperature" of the body? 15. How does perspiring
affect the heat of the body? 16. What are the "nerve buds" or "bulbs"?
17. Name four things that they do.


CHAPTER XVI

1. What are the uses of the skin to the rest of the body? 2. In what two
ways does the skin clean itself? 3. What should we specially avoid in
washing or scrubbing the skin? 4. What are the characteristics of a
good soap? 5. What are the dangers of a poor soap? 6. What are the
advantages of cold water in bathing? 7. How often should hot baths be
taken and why? 8. On what parts of the body should soap be most freely
used? 9. What is the best way of keeping the hair and scalp healthy?
10. Why is this important? 11. Why should hair tonics be let alone?
12. What causes dandruff? 13. How should the nails be trimmed and cleaned?
14. What should be done to the nail-fold? 15. Why is dirt under the nails
sodangerous? 16. What qualities should a good garment possess as to shape,
fit, and texture? 17. What are the advantages and disadvantages of wool?
18. What are the advantages and disadvantages of cotton? 19. Why are
furs unwholesome? 20. What is the best possible material for an
undergarment? 21. What are some of the causes of diseases of the skin?
22. What is the cause of sunburn and freckles? 23. What makes a good
complexion? 24. What is a corn? What causes it?


CHAPTER XVII

1. Name four processes that take place in the living body. 2. What two
kinds of waste do these processes cause? 3. What is the name of the
"body smoke"? 4. How is the body smoke carried away? 5. What do the
terms "soluble" and "insoluble" waste mean? 6. How does the insoluble
waste leave the body? 7. By what path does the soluble waste leave the
body? 8. How many times in an hour is all the blood in the body pumped
through the liver, kidneys, and skin? 9, Why is this done? 10. Why is
the blood from the food tube sent to the liver directly, instead of by
way of the heart? 11. Why is the liver such a large organ? 12. What does
the liver do to the blood? 13. What is the bile duct? 14. What is the
bile? 15. What is the gall bladder? 16. What do the terms "bilious" and
"jaundiced" mean? 17. What effect does alcohol have upon the liver?


CHAPTER XVIII

1. What is muscle? How much of your body weight is made up of the
muscles? 2. What two kinds of muscles are there? 3. How do muscles
change in shape? 4. What do we mean by voluntary and involuntary
muscles, and how do they differ in form and location? 5. Describe the
way in which the body muscles are arranged. What kind of actions do they
perform? 6. What exercise is good for the muscles over the abdomen? for
the muscles of the back? 7. What muscles are we using when we "bat" or
"serve" in ball and tennis? 8. How do the muscles of the limbs act for
you? 9. Where are the biceps and triceps muscles? Explain their use.
10. What are tendons? What is their use (function)? 11. How is your arm
fastened to your body? 12. Describe the arrangement of the muscles in
the lower limb. Why are they larger than the arm-muscles? 13. How does
exercising the muscles give you an appetite? What else does it do?
14. Why do you naturally love to play? 15. Why is muscular exercise in the
open air important in education?


CHAPTER XIX

1. What are the bones? 2. Make a rough sketch of the human skeleton.
3. In what sense are the bones the tools of the muscles? 4. How are the
bones of the skull arranged? 5. Give two functions (uses) of the spinal
column (back bone). 6. What bones and tendons do you use when you stand
on tip-toe? 7. How are the limbs fastened to the body and back bone?
8. Why is the collar-bone more likely to be broken than some of the other
bones? 9. How are the joints formed? 10. What is cartilage? 11. How does
it help in making the two kinds of joints we find in the body? 12. Is
there any arrangement for oiling the joints? If so, what is it? 13. When
you soak a bone in weak acid, what happens? What does this prove?
14. What causes disease or deformity of the bones?


CHAPTER XX

1. Why do we need a system of nerves? 2. What do we mean by motor
nerves? by sensory nerves? 3. How is the central system like a telephone
office? 4. What does the word ganglion mean to you? 5. What are the
ganglions (ganglia) for? 6. Is the brain a ganglion? 7. Give a rough
idea of the structure of the brain, and name its parts or divisions.
8. What does each one of these divisions do? 9. What is the result of
injury to any one of these parts? Give an instance. 10. Where do we find
the gray matter in the nervous system? 11. What is the white matter and
what does it do? 12. When the thumb is paralyzed, what do we know about
the brain? 13. Where in the body do we really smell, hear, and see?
14. What do we know about the speech centre? 15. Draw a picture of the
spinal cord and its branches. 16. Of what use are the ganglia (gray
matter) in the spinal cord? Give an example. 17. Why is it that some
children can't help wriggling when tickled? 18. Why is the medulla such
an important part of the nervous system? 19. When you touch a hot lamp
chimney, what happens in your nervous system? 20. Suppose you had seen
some tempting fruit, what would have happened in your nervous system
and in your digestive system? 21. What does the brain do with the
messages from the eyes, ears, and nose? 22. How does the
message-and-answer system protect the body? 23. How does it help us to
gain knowledge? 24. Why is it that when two people look at the same
thing at the same time they may have very different ideas of what it is?


CHAPTER XXI

1. Describe the arches of the feet and tell what they are for.
2. Describe the kind of shoe you ought to wear. 3. Do you grow while
asleep? 4. How much sleep do you need? 5. Are there many diseases of the
muscles and bones? 6. How does nature repair a broken bone? 7. What
causes most of the diseases of bones? 8. What is a slouching gait due
to? 9. What is the cause of headache? 10. How should headache be
regarded and treated? 11. What are the dangers of taking patent or
unknown medicines? 12. What do most patent medicines contain? 13. Are
the nerves resistant to disease, or specially subject to its attack?
14. What causes many of the diseases of the nerves? 15. Name some poisons
that injure the nerves. 16. How may diphtheria affect the nerves?
17. What does alcohol do to the nervous system? 18. Does our modern method
of life tend to cause or to cure nervous diseases and insanity? Why?


CHAPTER XXII

1. How much of the body will muscular exercise develop? 2. Why should
exercise and play be in the open air? 3. What is fatigue and what does
it mean? 4. Name some games that are good exercise for the body and tell
why they are so. 5. Why do marching and singing and drawing alternating
with your other lessons, help you to grow? 6. Is playing a waste of
time? Why? 7. How much exercise a day does a grown man or woman need?
8. How should this exercise be taken? 9. What senses and powers does
base-ball develop? 10. In what respects is your progress in school work
like your progress in learning to play games well? 11. What are good
games for girls? 12. Why have we less sickness in summer than in winter?
13. Why is gardening a valuable occupation? 14. When should we do our
hardest studying? 15. What is the best and most successful way to study?
16. How can you make school work as enjoyable as play? 17. What are your
duties to-day? Plan the best way to do them so that you can also take
exercise and rest and time for meals. Write this plan in the form of a
day's programme.


CHAPTER XXIII

1. What is the "Lookout Department" of the body, and how is the work of
this department distributed among the members? 2. Describe the inside
structure of the nose. 3. In what sense is the nose like a radiator?
4. What are the cilia for? 5. How does the nose dispose of dust and lint?
6. What causes catarrh and colds? 7. Where is the sense of smell
located? 8. When you have a cold, why do you often lose your sense of
smell? of taste? 9. How do you tell the difference in flavor between an
apple and an onion? 10. What does the tongue do? 11. What are the only
tastes perceived in the mouth? 12. What does a coated tongue mean?
13. Is the sense of taste a safe guide in choosing foods? Why? 14. What are
adenoids? What trouble do they cause? How can they be cured? 15. How
does the eye help to choose food? 16. Name and describe the parts of the
face around the eye. 17. Of what use is each? 18. How does the tear
gland act? 19. What is the retina? the pupil? the iris? What is each
for? 20. What do we mean by bringing the rays of light to a focus? How
can you illustrate this by a burning glass? 21. When do eyes need
glasses? 22. How can the eye change the form of its lens for near and
for far sight? What is this action called? 23. Why do children born deaf
become dumb? 24. Where do we find the key-board of hearing? Why do we
call it the cochlea? 25. Draw a picture showing the position of the
drum, "hammer," "anvil," "stirrup," and cochlea. 26. What has happened
in your inner ear when something in your ear goes "pop"? 27. Why does a
cold sometimes make you deaf? 28. Why do we have wax in the outer ear?
What is the German proverb about cleaning the ear? 29. What is our
"sixth sense"? Where do we find its organ located? What is it like?


CHAPTER XXIV

1. How is the voice a waste product? 2. What are the conditions required
to make a good voice? 3. Are great singers usually strong? Why? 4. How
was the windpipe made into the voice box? 5. Describe the vocal bands or
cords. 6. How do they act in making voice sounds? when we breathe?
7. How do catarrh and adenoids affect the voice? 8. How is the voice box
like a violin? 9. What part of the violin has most to do with the
quality of the sound? How does this apply to the human voice? 10. What
do the throat, the mouth, and the nose have to do with voice training?
11. What is one of the commonest causes of a poor voice? 12. How can you
prove this? 13. What are spoken words? 14. How is a good, clear,
distinct voice of value? 15. How can you build up a strong, clear,
useful voice?


CHAPTER XXV

1. Give four reasons why the teeth are important. 2. To take proper care
of the teeth, what other parts of the mouth need attention? 3. Draw a
picture of a tooth and label the crown, the enamel, the root, the pulp.
4. Name the different teeth, making diagrams of the upper and lower jaws
and tell how each kind of tooth is used. 5. Compare your own teeth with
those of a dog, a sheep, and a squirrel and explain the difference in
use. 6. In what order did your teeth appear in your mouth? 7. What are
the milk-teeth? 8. How many teeth have you? Have any been pulled?
9. Will you have any more later? 10. Name three things to be remembered in
exercising the teeth. 11. What is the best method to keep the teeth and
gums clean? 12. Why are "gritty" tooth-powders bad for the teeth?
13. Are antiseptics good for them? 14. Why are dirty teeth a very common
cause of disease in the body? 15. (Exercise) Write a letter to your
teacher telling how you have been taking care of your teeth in the past,
and how you purpose to do it in the future.


CHAPTER XXVI

1. How may "catching" diseases be prevented? 2. What are disease germs,
and how are they named? 3. How do disease germs grow? 4. Why should
patients with the "diseases of childhood" be placed in quarantine.
5. What causes a cold? How should you take care of one? Why keep away from
other people? 6. When and how did we find that diphtheria was due to
germs? 7. Explain how "antitoxin" prevents it. 8. How much has the death
rate in diphtheria been lowered? 9. Name the diseases for which we now
have vaccines and antitoxins. How do we grow them? 10. Tell the story
about Dr. Jenner and the milkmaids. 11. What good has his discovery
done? 12. Explain why vaccination will cure as well as prevent smallpox.
13. What is quinine, and where does it get its name? 14. Who discovered
the germ of malaria? Is it a plant or an animal? 15. What do we know
about the connection between mosquitoes and malaria? 16. What is a quick
way of killing the mosquito? 17. How does draining fields prevent
malaria? Why is malaria not so common now as in pioneer days? 18. Why do
we need disinfectants? Name some, and describe how they are used.
19. What is the best one in most cases? Why? In what ways may it be used?
20. How do the bacteria of the soil "feed" the green plants? 21. Explain
why a crop of clover will enrich the soil. What other plants also do the
same thing? 22. Name some other harmless bacteria. 23. Why ought one to
wash the hands before eating? 24. Is it possible to kill all house
flies? Why ought we to try to? How can it be done? 25. What do we find
in dust? 26. What good does it do to sprinkle streets? 27. What is the
best way to clean house?


CHAPTER XXVII

1. What is the best insurance against accidents? 2. Why do most cuts and
scratches heal quickly, while some others do not? 3. What kind of dirt
is dangerous to wounds? 4. If your knife should slip and cut you, how
ought you to take care of the cut? 5. If you know the knife is dirty,
what is the proper treatment? 6. Is "sticking-plaster" good for a wound?
Why not? 7. Why does absorbent cotton make a good dressing? 8. Give two
reasons why doctors can perform surgical operations now much more safely
than some years ago. 9. Why must surgeons and nurses keep themselves and
their patients perfectly clean? 10. What difference has this cleanliness
made in the saving of life? 11. What is the treatment for bruises? Why
are they not so dangerous as cuts? 12. What are boils and carbuncles?
13. How do we clean and heal them? 14. Where blood comes in spurts from
a cut, what does this mean? 15. How does the blood itself protect us
against infection in wounds? 16. If the wound is very deep, how can you
check the bleeding? 17. Why should the tight bandage be slightly
loosened in half an hour after it has been applied? 18. Why is it that
we do not need to clean a burn? 19. Why is it wise to keep the air from
a burn? How may it be done? 20. Why must the dressings be perfectly
clean? 21. Why do we need a doctor in the case of a broken bone? 22. If
you can't get a doctor, what is to be done? 23. What is a sprain? Tell
how to bathe and bandage it. 24. In the case of swallowing poison, why
should one drink warm water? 25. What else should be done? 26. What
should be given when lye has been swallowed? 27. What is the important
thing to remember in any such case? 28. If you fall into deep water,
what four things should you remember? 29. Explain carefully just how to
revive a person who has been under water. 30. What is the main purpose
of this method?



GLOSSARY

OF IMPORTANT TERMS USED IN THE BOOK

[Transcriber's note: In the following section vowels are transcribed as:
[)vowel] with breve
[=vowel] with macron
[.vowel] with dot above]


I. RELATING TO THE BODY AS A WHOLE

Ab'do men (or [)a]b d[=o]'m[)e]n). The cavity of the trunk immediately
below the diaphragm.

Car'ti lage. Tough, elastic tissue, generally more or less fibrous;
called also gristle (gr[)i]s'l).

Cell. The simplest form of living matter, with power to grow, develop,
reproduce itself, and, with others of its kind, build up a living
fabric.

Di'a phragm (d[=i]'[.a] fr[)a]m). The muscular membrane that separates
the thorax from the abdomen.

Duct. A tube through which fluid from a gland is conveyed.

Fa tigue' (f[.a] t[=e]g'). A condition in which the body cells are
worn out faster than they are built up, so that waste matter accumulates
in the body and poisons it.

Germ. The simplest form of life, from which a living organism
develops.

Gland. A part, or organ, that has the power of making a secretion,
peculiar to itself. A gland may be a simple pocket, or follicle, as is
an oil gland of the skin, or it may be an aggregate of such glands, as
is the liver.

Or'gan. Any part, or member, that has some specific function, or duty,
by which some one of the body's activities is carried on; for example,
the eye is the organ of vision, the liver is one of the organs of
digestion.

Tho'rax. The cavity of the trunk immediately above the diaphragm.

Tis'sue (t[)i]sh'[=u]). A fabric, or texture, composed of cells and
cell-products of one kind; as, for example, nervous tissue, muscular
tissue, fatty tissue.

Se cre'tion. A substance made from the blood, the special character of
which depends upon the kind of gland that makes, or secretes, it.


II. RELATING TO THE DIGESTIVE SYSTEM

Al i men'ta ry ca nal'. The food tube, or digestive tube, extending
from lips and nose to the end of the rectum, with its various branches
and attachments.

Bile. A yellow, bitter, alkaline liquid secreted by the liver, and
especially valuable in the digestion of fats; sometimes called gall.

Co'lon. The large intestine.

Di ges'tion. The process in the body by which food is changed to the
form in which it can pass from the alimentary canal to the blood vessels
and lymphatics.

Di ges'tive sys'tem. The alimentary canal with all its branches and
appendages; that is, all the organs that directly take part in the
process of digestion.

E soph'a gus. The tube through which food and drink pass from the
pharynx to the stomach; called also the gul'let.

Gall blad'der. The bile bladder; the sac, or reservoir, lying on the
under side of the liver, in which the bile is received from the liver,
and in which it is retained until discharged through the gall duct into
the small intestine.

Gas'tric juice. The digestive liquid secreted by the glands of the
stomach (pep'tic glands); it contains pepsin, acid, and ferments;
called also peptic juice.

In tes'tine. The last part of the alimentary canal, extending from the
pylorus. Its length is five or six times that of the body. The greater
part of its length is called the small intestine in distinction from
the remaining part, which, though much shorter, is larger in diameter,
and is called the large intestine or co'lon. The intestine as a
whole is sometimes called the bow'el.

Liv'er. The large gland that secretes bile and is active in changing
or killing harmful substances; located in the upper part of the
abdominal cavity, on the right side, and folds over on the pyloric end
of the stomach.

Lym phat'ics. Small transparent tubes running through the various
tissues, and containing a colorless fluid somewhat thinner than blood,
called lymph. This fluid is composed of the leakage from the arteries
and of wastes from the tissues, which are being carried to a larger
lymph duct to be emptied into one of the larger veins. The lymphatics in
the wall of the intestine take up some of the digested food from the
cells and pass it on through the lymph glands of the abdomen to the
lymph duct which empties into a vein near the heart.

Mas ti ca'tion. The process of grinding, or chewing, food in the
mouth.

Mes'en ter y. The tissue (part of the peritoneum) which is attached to
the intestine and, for a few inches, to the spinal column, to hold the
coils of the intestine in place.

Mu'cous mem'brane. The lining membrane, or tissue, of the entire
alimentary canal. It is very complex in structure, has different
characteristics in different areas, and contains nerves, blood vessels,
lymphatics, and in various parts special structures such as glands. It
secretes mucous. It is continuous with the outside skin of the body, as
may be seen at the lips.

Pan'cre as. The gland that secretes the pancreatic juice; located in
the abdominal cavity near the stomach.

Pan cre at'ic juice. An alkaline digestive juice poured by the
pancreas into the small intestine; especially valuable in the digestion
of starches, fats, and proteins.

Per i to ne'um. The membrane lining the abdominal cavity and enfolding
its organs.

Phar'ynx. The passage between the nasal passages and the esophagus:
the throat.

Py lor'us. (1) The opening from the stomach into the small intestine.
(2) The fold of mucous membrane, containing muscle fibres, that helps to
regulate the passage of food through the pyloric opening.

Sa li'va. The digestive secretion in the mouth, consisting of the
secretion of the salivary glands and the secretion of the mucous
membrane of the mouth.

Stom'ach. The pouch-like enlargement of the alimentary canal, lying in
the upper part of the abdominal cavity, and slightly to the left,
between the esophagus and the small intestine.


III. RELATING TO FOOD AND DRINK

Ac'id ([)a]s'[)i]d). A substance (usually sour tasting) that has,
among other properties, the power of combining with an alkali in such a
way that both substances lose their peculiar characteristics and form a
salt.

Al'co hol. A colorless liquid formed by the fermentation of
starch-sugars or certain other substances, which is highly inflammable
and burns without smoke or waste; it is a stimulant and an antiseptic.

Al'ka li. A substance that has, among other properties, the power of
neutralizing acids and forming salts with them. (See Acid.)

Car'bo hy'drates. Plant or animal substances composed of carbon,
hydrogen, and oxygen. (Called also starch-sugars.)

Chlo'ro phyll. The green coloring matter of plants, formed by the
action of sunlight on the plant cells. It is a necessary part of the
plant's digestive system, since without it the plant could not break up
the carbon dioxid of the air into the carbon which it uses in preparing
its starch food, and the oxygen which it gives off as waste.

Fer men ta'tion. A chemical change in plant or animal substance,
produced usually by the action of bacteria, in the process of which the
substance is broken up (decomposed), and new substances are formed.

Nar cot'ic. Any substance that blunts the senses, or the body's
sensibility to pain or discomfort.

Ni'tro gen. A tasteless, odorless, colorless gas, forming nearly
four-fifths of the earth's atmosphere; and constituting a necessary part
of every plant and animal tissue.

Pro'te ins. Foods containing a large amount of nitrogen; such as meat,
fish, milk, egg, peas, beans.


IV. RELATING TO THE BLOOD AND THE CIRCULATORY SYSTEM

A or'ta. The main artery of the body; it leads out from the left
ventricle of the heart, carrying arterialized blood (blood that has
been acted upon by oxygen) to all parts of the body except the lungs.

Ar'te ries. The blood vessels and their branches that carry blood from
the heart to all parts of the body. The pul'mon a ry artery carries
impure (ve'nous) blood to the lungs.

Au'ri cles (ô'r[)i] klz). The two chambers of the heart that receive
blood from the veins.

Cap'il la ries. The minute blood vessels which form a network between
the ends of the arteries and the beginnings of the veins.

Cir cu la'tion. The passage of the blood from the heart into the
arteries, and from them through the capillaries into the veins, and
through the veins back into the heart.

Cor'pus cles (cor'p[)u]s'lz). Minute jelly-like disks or cells. These
are of two kinds, red and white, the red (the oxygen carriers) being
about 350 times as many as the white, and giving the blood its color.

Heart. A muscle-sac located in the thorax between the lungs, its lower
point, or a'pex, being tilted somewhat to the left; the centre and
force-pump of the circulatory system.

Ox i da'tion. Combining with oxygen.

Ox'y gen. A colorless, odorless, tasteless gas, which forms about
one-fifth of the earth's atmosphere. It is found in all animal and
vegetable tissues. When it combines with other substances, a certain
amount of heat is produced; and if the process is sufficiently rapid, a
flame is seen.

Pulse. The regularly recurring enlargement of an artery, caused by the
increased blood flow following each contraction of the ventricle of the
heart.

Veins. The blood vessels and their branches through which blood flows
from all parts of the body back to the heart. All the veins except the
pulmonary veins carry impure (venous) blood; the pulmonary veins carry
arterialized (oxidated) blood from the lungs. Ve'na ca'va. Either of
the two large veins discharging into the right auricle of the heart.
Por'tal vein. The large, short vein that drains the liver and adjacent
parts.

Ven'tri cles. The two chambers of the heart that receive blood from
the auricles and force it into the arteries.


V. RELATING TO THE RESPIRATORY SYSTEM AND ORGANS OF EXCRETION

Al ve'o li ([)a]l v[=e]'o l[=i]). (Plural of _alveolus_). Air cells.
The cells, or cavities, that line the air passages and air sacs at the
ends of the bronchial tubes.

Breath. Air taken in or sent out in respiration; that breathed out
containing carbon dioxid, watery vapor, and various impurities.

Bron'chi (br[)o]n'k[=i]). (Plural of _bronchus_). The two main
branches of the trachea. These branch into numerous smaller branches,
called the bron'chi al tubes.

Car'bon di ox'id. A gas formed of carbon and oxygen; colorless and
odorless; has a somewhat acid taste, and is used for aerating soda water
and other beverages; is present naturally in mineral and spring waters.
It is present largely in the fissures of the earth and makes the
choke-damp of mines. Called also car bon'ic acid.

Ep i glot'tis. The valve-like cover that prevents food and drink from
entering the larynx.

Ex cre'tion. A waste substance thrown out, or rejected, from the
system; for example, carbon dioxid, sweat, ur'ine, the fe'ces.

Lar'ynx. The enlargement of the windpipe, near its upper end, across
which are stretched the vocal cords.

Lungs. Two spongy organs in the thorax, entered by the bronchi with
their bronchial tubes; they contain in the walls of their air cells the
capillaries through which the blood passes from the branches of the
pulmonary artery to the branches of the pulmonary veins.

Rec'tum. The lowest and last section of the alimentary canal, being
the discharge pipe of the large intestine, and excreting the solid
wastes in the form of the feces.

Res pi ra'tion. Breathing; the action of the body by which carbon
dioxid is given off from the blood and a corresponding amount of oxygen
is absorbed into the blood.

Skin. The continuous outer covering of the body, in the deeper layer
(der'ma) of which are located the sweat glands, which secrete
sweat (a watery, oily substance containing impurities from the blood)
and excrete it through the sweat ducts and their openings (pores) in
the surface of the skin.

Tra'che a (or tr[=a] ch[=e]' [.a]). The windpipe between the larynx
and the bronchi.

U'ri na ry system. The organs concerned in the secretion and discharge
of urine: the kid'neys (two glands in the abdominal cavity, back of
the peritoneum, which receive wastes from the blood, and excrete them as
urine), the u re'ters (ducts through which the urine flows from the
kidneys to the bladder), the blad'der (an elastic muscle-sac in which
the urine is retained until discharged from the body).


VI. RELATING TO THE NERVOUS AND MOTOR SYSTEMS

Brain. The soft mass of nerve tissue filling the upper cavity of the
skull. Its cellular tissue is gray, and its fibrous tissue white. With
the spinal cord it controls all the sensory and motor activities of the
body.

Cer e bel'lum. The part of the brain lying below the hind part of the
cerebrum.

Cer'e brum. The upper or fore part of the brain; it is divided by a
deep fissure into two hemispheres, its cor'tex (surface) lies in many
con vo lu'tions (folds), and its fibres run down into the spinal cord.
In this part of the brain are the centres, or controlling nerve cells,
of the senses and most of our conscious activities.

Gang'li a (g[)a]ng'l[)i] [.a]). (Plural of _ganglion_). Nerve knots,
or groupings of nerve cells, forming an enlargement in the course of a
nerve.

Me dul'la. A portion of the brain forming an enlargement at the top of
the spinal cord and being continuous with it; the channel between the
brain and the other parts of the nervous system.

Muscle (mus'l). A kind of animal tissue that consists of fibres that
have the power of contracting when properly stimulated. A bundle of
muscle fibres, called a muscle, is usually attached to the part to be
moved by a ten'don, or sinew. Muscles causing bones to bend are termed
flex'ors; those causing them to straighten, ex ten'sors. The
movements of muscles may be voluntary (controlled by the will), or
involuntary (made without conscious exercise of the will).

Nerve. A fibre of nerve tissue, or a bundle of such fibres, connecting
nerve ganglia with each other or with some terminal nerve organ. Nerves
running inward toward the spinal cord and the brain are called sen'so ry
nerves; those from the brain and spinal cord outward, mo'tor
nerves.

Nerv'ous system. The nerve centres with the sensory and motor nerves
and the organs of sense.

Neu'rons. The cells of the spinal cord and the brain.

Re'flex. A simple action of the nervous system, in which a stimulus is
carried along sensory nerves to a nerve centre, and from which an
answering stimulus is sent along motor nerves to call into play the
activity of some organ, without consciousness, or without direct effort
of the will.

Spi'nal cord. The soft nerve tissue that extends from the medulla
almost to the end of the spinal column, being encased by it. It controls
most of the reflex actions of the body.

Stim'u lus. Anything that starts an activity in the tissues on which
it acts; for example, light is a stimulus to the nerve tissues of the
eye.



INDEX


    Abdomen, 204.

    Accommodation, 264.

    Acetanilid, 237 _note_.

    Acid,
      as an antidote, 325;
      butyric, 53;
      carbonic, 11;
      explained, 11;
      in changing starch, 41;
      in leavening, 44, 45;
      in fruits, 57, 58, 59;
      in starch-sugars, 283;
      in digestive juices, 11 _note_;
      in mouth, 283, 285;
      lactic, 43.

    "Adam's apple," 272.

    Adenoids, 253, 256, 257, 274.

    Ague. _See_ Malaria.

    Air,
      circulation of free, 140, 149;
      composition of, 132;
      indoor currents of, 148-150;
      per person, 142;
      pure and impure, 139-146.

    Alcohol,
      a medicine, 96, 100;
      an antiseptic, 318, 319, 324;
      a narcotic, 90, 98, 99;
      a toxin, 94;
      decreasing use of, 101-103;
      effect of, on character, 101;
      in beverages, 94, 95;
      in patent medicines, 237;
      not a food, 90, 96;
      physical effects of, 97-100, 122-124, 166, 197, 199, 201, 239;
      source of, 93, 95.

    Aldehydes, 94.

    Ale, 94.

    Alimentary canal, 8, 9;
      digestion in, 9-19.
      _See also_ Gullet, Intestine.

    Alkali,
      as an antidote, 325;
      as medicine, 14, 15;
      explained, 11;
      digestive juices, 11 _note_;
      in leavening, 44, 45;
      in meat, 283;
      in soap, 186.

    Alveoli, 135.

    Ameba, white corpuscles compared to, 109, 110.

    Amherst, experiments with smokers at, 107.

    Ammonia from decay, 74, 308.

    Animals and plants contrasted, 5-7.

    Anopheles, 302.

    Antidotes. _See_ Poisoning.

    Antipyrin, 237 _note_.

    Antiseptics, use of, 317-320.

    Antitoxins, 293-296.

    Anvil, 267.

    Aorta, 112, 113, 115, 118, 119, 200.

    Apex of heart, 117.

    Apoplexy, 123.

    Appendicitis, 20.

    Appendix vermiformis, 20.

    Appetite,
      from exercise, 208;
      juice, 9.

    Appetites, explained, 21.

    Apples,
      fermented, 94;
      food value of, 58;
      fuel value of, 26.

    Aqueduct, 85.

    Arrack, 96.

    Arteries,
      bleeding from, 320-322;
      defined, 108, 109;
      function of, 17;
      position of, 113;
      red blood in, 111;
      stiffening of, 123;
      _also_, 112, 196, 200.

    Artery,
      pulmonary, 118;
      radial, 118.

    Articulation,
      of bones, 212;
      of sounds, 276.

    Artois, wells of, 82.

    Astigmatism, 263.

    Athletics, 175, 176, 242.

    Atropin, 265 _note_.

    Auricle, 116, 117, 118.


    Bacilli,
      cultivation of, 293;
      explained, 152-154, 286;
      method of naming, 286;
      multiplication of, 288.
      _See also_ Bacteria _and_ Germs.

    Backache, 204.

    Backbone. _See_ Spinal column.

    Bacon, fuel value of, 52, 54, 55.

    Bacteria,
      explained, 17;
      harmless, 152;
      in feces, 19;
      in food, 22;
      in milk, 33-38;
      in small intestine, 17;
      of disease, 152, 286;
      of soil, 74, 76, 78, 79, 83, 86, 308;
      of yeast, 43.
      _See also_ Bacilli _and_ Germs.

    Bakeries, 45, 46.

    Baking-powders, 44, 45.

    Banana, 58, 59.

    Barley, in making beer and ale, 94.

    Bathing,
      need of, 184;
      preventive of colds, 155;
      right and wrong, 184-186.

    Beans, 32.

    Beef-tea, 26, 31.

    Beer, 89.
      _See also_ Alcohol.

    Beets, 26, 59.

    Berries, 58, 59.

    Beverages, 89-93.
      _See also_ Alcohol.

    Biceps, 203, 206.

    Bile, 11 _note_, 16, 17, 198, 199;
      duct, 197, 199.

    Biliousness, 23, 197.

    "Black bread," 48.

    "Black Death," 288.

    Bladder, 200.
      _See also_ Gall bladder.

    Bleeding. _See_ Wounds.

    Blood,
      alkaline quality of, 11 _note_;
      anemic, 173, 192;
      arterial, 111;
      circulation of, 110-113, 118, 119;
      color of, 109, 111, 112, 173, 174;
      composition of, 109, 110;
      heat, 175;
      impure, 198;
      poisoning, 295, 315, 319;
      purifying of, 196;
      result of food, 18.

    Blood vessels, 108, 109.
      _See also_ Arteries, Capillaries, Veins.

    Board of Health,
      and infections, 286, 291;
      control of water supply, 77, 81, 88;
      examination, 105;
      milk inspection, 34, 38, 39, 78.

    Boils, 295, 320.

    Bolus, 9.

    Bones,
      composition and growth of; 210, 211;
      disorders of, 229, 230, 234, 235;
      fractures of, 323;
      kinds of, 212-214;
      number of, 211;
      structure of, 215;
      tuberculosis of, 157.

    Bowel. _See_ Intestine.

    Brain, 216-220;
      development of, 167.

    Brandy, 94, 95.

    Bread,
      baking, 43, 44;
      crust of, 44;
      fuel value of, 58;
      kinds and values of, 42, 46, 48;
      leavening, 42-46;
      souring of, 43, 44.

    Breakfast foods, 47.

    Breathing,
      control of, 226;
      need of continuous,130;
      operation of, 138;
      rate of, 142;
      variations in, 137, 138.

    Bright's Disease, 201.

    Bronchi, 135.

    Bronchial tubes, 135.

    Bruises, 319.

    Brushes,
      hair, 193-194;
      nail, 189;
      skin, 188.

    Bubonic plague, 288.

    Burns, 322, 323.

    Butter, 51, 52-54.


    Cabbage, 26, 58, 60.

    Caffein, 91.

    Callus, 194, 195, 234.

    Candy, 50, 52.

    Capillaries, 110, 111, 112, 113, 114, 118, 119, 200.

    Carbohydrates, 27, 41, 48, 141.
      _See also_ Starch-Sugars.

    Carbon, 42.

    Carbonates, 136.

    Carbon dioxid,
      in air, 140, 141;
      in blood, 174;
      in body cells, 112;
      in breath, 137;
      in lungs, 111, 196;
      in spring water, 74, 83;
      in yeast, 43.

    Carbuncles, 320.

    Carrots, 59.

    Cartilage, 136, 210, 214.

    Casein, 30, 36, 39.

    Catarrh, 253, 256, 274.

    Cathartic, 19.

    Cecum, 20.

    Celery, 58, 61.

    Cells, 9, 14, 15, 17, 18, 201, 287;
      eating done by, 108, 110, 112, 131;
      of liver, 111;
      of lungs, 135;
      of muscles, 202, 203, 209;
      of skin, 169, 170;
      waste from, 131, 132;
      water 111, 70.

    Cereals, 42.
      _See also_ Breakfast Foods _and_ Oatmeal.

    Cerebellum, 270.

    Cheese, 39.

    Chemical change, 42.

    Chickenpox, 290.

    Children's diseases, 289-291;
      from dirty milk, 37.

    China, wearing nails long in, 173.

    Chincon, Countess of, 301.

    Chloral, 97.

    Chloroform, 97, 199.

    Chlorophyll, 5.

    Choking, cause of, 135.

    Cider, 94.

    Cigarette habit, 104, 107.

    Cinchona. _See_ Quinine.

    Circulation,
      blood vessels of skin and, 184;
      color an index to, 174;
      control of, 226;
      rate of, 196.

    Clothing, 179-183.
      _Also_ 190, 247.

    Coal-tar remedies, 237 _note_.

    Cocci, 153;
      of pneumonia, 154, 166.

    Cochlea, 267.

    Cocoa, 90, 91-93.

    Coffee, 26, 89, 90, 91-93.

    Colds, 125, 154-156, 199, 201, 291-293.

    Colic, 23.

    Colon, 8, 18.

    Complexion, 114, 115, 176.

    Concha, 268.

    Cones, 264 _note_.

    Constipation, 19, 20, 204.

    Consumption, 152, 153, 157-166.
      _See also_ Tuberculosis.

    Contraction, 203.

    Convolutions, 219.

    Cooking, 62-68.

    Corn, 47, 60.

    Cornea, 259, 260, 261.

    Corns, 194, 195.

    Corpuscles,
      malaria germs in red, 301;
      red, 109, 111, 132;
      renewal of, 215;
      white, 109, 110.

    Cortex, 219, 223.

    Cowpox, 296, 297.

    Crystalline lens, 263.

    Cucumbers, 26, 58, 61.

    Culex pipiens, 302.


    Dandruff, 191.

    Dentine, 279.

    Derma, 168.

    Dextrin, 44.

    Diaphragm, 8, 13, 276.

    Diarrhea, 23, 47, 157.
      _See also_ Children's diseases.

    Digestion,
      by body cells, 17, 18;
      by liver, 198;
      food route in, 8;
      in intestines, 16-20;
      in mouth, 10-12;
      in stomach, 13-15;
      juices aiding, 9-12, 14-17;
      preparatory, 9.

    Digestive system, 7-9.

    Diphtheria, 293-295;
      germs of, 286, 310.

    Disease,
      causes of, 286-288;
      effects of, 238;
      germs of, 17 _note_, 152-154, 286, 301;
      growth and spread of, 288-290;
      hip-joint, 157.

    Diseases, children's, 289-291;
      nervous, 239, 240;
      occupation, 153, 195.

    Disinfectants, 193, 287, 303-307, 318.

    Disinfection, 303;
      methods of, 304-307;
      of wounds, 316-319.

    Dispensaries, tuberculosis, 160.

    Drafts, 143, 144.

    Drainage,
      extent of wells, 77;
      of sewage, 75-79;
      of swamps, 302, 303.

    Drink, 69-103.
      _See also_ Alcohol, Beverages, Water, etc.

    Drowning, treatment for partial, 327-330.

    Duct of a gland, development of, 10 _note_.

    Dust, 22, 153, 154, 312, 313.

    Dysentery, 199.
      _See also_ Diarrhea.

    Dyspepsia, 47, 199, 204, 264.


    Ear,
      care of, 268, 269;
      development of, 167, 252, 253;
      structure of, 266-270.

    Eczema, 59, 191.

    Effervescence, 11, 43, 44.

    Egg, digestion of, 14, 17.

    Enamel, 279.

    Energy in food and fuel, 4, 5.

    England, smallpox in, 296, 297.

    Epidermis, 168.

    Epiglottis, 135.

    Epithelial cells, 168, 169.

    Eruptions, 193.

    Esophagus, 7.
      _See also_ Gullet.

    Ether, 97.

    Ethers, 94.

    Eustachian tube, 257.

    Exercise, 241-251;
      appetite and, 208;
      heart and, 120-122, 126, 127, 128;
      muscles and, 204, 205, 208, 209.
      _Also_ 154, 162, 163, 176, 238.

    Extensors, 206.

    Eyes,
      care of, 266;
      development of, 167, 252, 253;
      structure of, 259-265.

    Eye-strain, 236.


    Fat, 51-55;
      fuel value of, 27, 51, 52;
      in digestion, 16, 17, 51;
      in liver, 198, 199;
      in milk, 30, 39.

    Fatigue, 241-243.

    Feces, 9, 18, 19, 192.

    Femur, 214.

    Fermentation, 94.

    Fever, 175-177;
      effect of, on heart, 125;
      in consumption, 124.

    Fibula, 213.

    Filters,
      domestic, 88;
      nature's, 74, 75, 83, 85, 86;
      of waterworks, 85, 86.

    Fish,
      fuel value of, 29;
      wastes from, 201.

    Fission of a bacillus, 288.

    Flexors, 206.

    Flies, 309-312.

    Food,
      absorption of, 17-19;
      appetizing, 9-10;
      as fuel, 4-7, 21, 25, 26;
      changed into blood, 18;
      cleanliness of, 22;
      "coal," 25, 26, 27-55;
      digestion of, 9-18;
      in blood, 110-113;
      irritating, 55, 59, 60;
      "kindling," 25, 26, 56-61;
      "paper," 25, 26, 31, 56-61;
      preservation of, 22, 23;
      sunlight in, 5-7;
      variety in, 23-25;
      water in, 73.

    Food tube. _See_ Alimentary canal.

    Foot, 230-232.

    Formaldehyde, 305-307.

    Formalin, 305-307.

    Fractures, 323, 324.

    Freckles, 190.

    Fruits,
      composition of, 24, 57, 58;
      fuel value of, 26, 58;
      in diet, 23-25;
      tainted, 22.

    Furs, as clothing, 182.


    Gall bladder, 199.

    Gall stones, 199.

    Games, 242-251.

    Ganglia, 217, 221, 223.

    Gardening, 61, 247, 248.

    Gas, illuminating, 143;
      sewer, 143.
      _See also_ Carbon dioxid, Carbonic acid.

    Gastric juice, 198.

    Gelatin,
      in veal, 29;
      for bacteria culture, 293, 309.

    German proverb, 269.

    Germany,
      smallpox in, 197;
      typhoid in, 80 _note_.

    Germicides. _See_ Disinfectants.

    Germs, 17 _note_, 301.
      _See also_ Bacilli, Bacteria, Cocci, Disinfection, Disease.

    Glands,
      development of, 10, 11 _note_;
      hair, 171, 172;
      lachrymal, 261;
      lymph, 17;
      of ear, 269;
      of intestine, 17-19;
      of stomach, 15,16;
      of throat, 256;
      oil, 171;
      parotid, 10;
      salivary, 10, 11;
      sublingual, 10 _note_;
      submaxillary, 10 _note_;
      sweat, 170, 171.

    Glucose, 41.

    Gluten, 28, 42, 48, 63.

    Glycogen, 198.

    "Goose-skin," 171.

    Gout, 32.

    Gray matter, 219, 221.

    Gristle. _See_ Cartilage.

    Gullet, 7, 9, 12, 13, 15, 134, 135.


    Habit, regularity of physical, 19.

    Hair, 70, 171, 172 _and note_;
      care of, 172, 193, 194;
      diseases of, and scalp, 191, 193.

    Ham, 54, 55.

    Hammer, 267.

    "Ham-string" muscle, 208.

    Hang nail, 189.

    Headache, 235-237, 264.

    Heart,
      alcohol and, 99, 123, 124;
      beat, 9, 13, 117, 118, 119, 126-129;
      blood vessels connecting with, 111, 112;
      care of, 122;
      disease of, 123-128;
      exercise and, 120-122, 241, 243;
      function of, 108;
      nerves and, 126-128;
      repairing power of, 122, 123;
      structure and action of, 115-117, 118, 119;
      tea and coffee and, 128.

    Heart-burn, 13.

    Heat of body,
      normal, 175;
      radiation of, 175-177.

    Heating, 149, 151.

    Hemispheres, 216.

    Hives, 59.

    Hookworm, 191-193.

    Humerus, 213.

    Humus, risks to water from, 73, 74.

    Hydrophobia, 287, 318.

    Hygiene, 1-3.

    Hyperopia, 262, 264.


    Influenza. 239.
      _See also_ Colds.

    Insanity, 239, 240.

    Insect pests, 309-312.

    Instincts, 3, 21.

    Intestine,
      absorption in, 14, 16-19;
      digestion in, 9, 15-18, 20;
      effect of fibrous foods on, 47, 60;
      hookworm in, 192;
      muscles supporting, 204.

    Iris, 265.


    Jaundice, 199.

    Jenner, Dr., 296-298.

    "Joint oil." _See_ Synovial fluid.

    Joints, 213, 214;
      injury to, 323, 324.


    Kidneys, 196, 197, 199-201.
      _See also_ Wastes.

    Kipling quoted, 231.

    Klebs-Loeffler bacillus, 286, 293.

    Knee cap. _See_ Patella.


    Lactose, 30.

    Lard, 52, 54.

    Larynx, 272-276.

    Laveran, 301.

    Leavening, 43-45.

    Legumin, 32.

    Leprosy, 178.

    Lettuce, 26, 61.

    Lime,
      carbon dioxid and, 137;
      in body, 70, 210, 211;
      in water, 88.

    "Lime-juicers," 57 _note_.

    Liver, 197-199;
      development of, 11 _note_;
      function of, 110, 111;
      juice of, 16, 17;
      position of, 13;
      vein entering, 110;
      weight of, 16.
      _See also_ Wastes.

    Lungs, 133-136;
      capillaries in, 111;
      function of, 111;
      diseases of, 153, 157-166.
      _See also_ Wastes.

    Lymphatics, 17.


    Malaria, 199, 300-303.

    Maltose, 94.

    Marrow, 215;
      "spinal," 223 _note_.

    Mastication, 11, 12.

    Mastoid, 269.

    Measles, 193, 239, 290, 291.

    Meat,
      digestion of, 14, 17;
      fuel value of, 27-29, 58;
      tainted, 22, 32, 335.
      wastes from, 201.

    Medulla, 223, 226.

    Meningitis,
      cerebro-spinal, 295;
      tubercular, 157.

    Mesentery, 16.

    Microbes. _See_ Bacteria.

    Milk,
      bacteria in, 22, 33-39, 308, 309;
      digestion of, 14, 17;
      fuel value of, 28-31;
      inspection of, 34, 38, 39, 78;
      stations, 30, 92.

    Mosquitoes, 302, 303.

    Mouth, 7, 8, 9;
      in speaking and singing, 274-276;
      infection from, 285;
      breathing, 253, 256, 257, 283.

    Mucous membrane, 14, 110, 118, 255, 256, 275.

    Mucus, 255.

    Mumps, 290.

    Muscles, 202-209;
      and nerves, 220-227;
      controlling hair, 171;
      disorders of, 229, 230, 233, 234;
      exercise of, 241-248;
      in breathing, 138.
      _See also_ 7, 12, 13, 15, 214, 261, 262.

    Myopia, 262.

    Myosin, 28.


    Nails, 172-174.
      _See also_ 70, 188, 189.

    Narcotics, 90, 97, 237, 238.

    Nerves,
      and heart, 126-128;
      and muscles, 203, 220-227;
      auditory, 266;
      optic, 260;
      sciatic, 222, 223, 224;
      sensory and motor, 220;
      spinal, 220, 221.

    Nervous system, 216-227;
      alcohol and, 97-103, 239;
      development of, 167;
      disorders of, 235-240;
      effects of disease on, 238;
      eyes and, 264;
      fatigue and, 241-243;
      tobacco and, 105, 106.

    Nettle-rash. _See_ Hives.

    Neurons, 223.

    Nicotine, 105.

    Nitrogen,
      as food, 27, 46, 47, 132, 201, 133 _note_;
      in air, 132;
      in soil, 308.

    Nose, 167, 252-255, 274-276.

    Nuts, 32, 55.


    Oatmeal, 42, 47, 48.

    Ohio River, pollution of, 87 _note_.

    Oil, in killing larvæ, 302, 303, 311.

    Oleomargarine, 53, 54.

    Onions, 58, 60.

    Opium, 97, 238.
      _See also_ Narcotics.

    Orbit, 260.

    Oxidation, 131-133.

    Oxygen,
      gas jets and, 143;
      in blood, 109, 110-113, 132;
      in water, 86.

    Ozone. _See_ Oxygen.


    Palate, 8.

    Panama, malaria in, 303.

    Pancreas, 11 _note_, 16.

    Pancreatic juice, 11 _note_, 12, 16, 17.

    Papillae, 258.

    Paralysis, 178, 239;
      infantile, 300.

    Parasites, animal, in the skin, 191-193.

    Parsnips, 59.

    Patella, 207.

    Patent medicines, 237, 238.

    Peaches, 58.

    Peanuts, 55.

    Pears, 58.

    Peas, 32.

    Pelvis, 214.

    Pemmican, 52.

    Pepsin, 14, 16.

    Peptic juice, 11 _note_, 14, 15.

    Periosteum, 215, 234.

    Peritoneum, 20.

    Peroxide of hydrogen, 318.

    Perspiration. _See_ Sweat.

    Pharynx, 8, 254, 256.

    Phenacetin, 237 _note_.

    Philippine Islands, smallpox in, 297.

    Physiology, 1-3.

    Pigment, 191.

    Pneumonia, 165, 166;
      coccus of, 154;
      effects of, on heart, 125.

    Poisoning, treatments for, 324-327.

    Poison ivy, 325, 326.

    Portal vein, 110, 198.

    Post mortem, 101.

    Potatoes, 26, 27, 40, 41, 42, 48, 56, 57.

    Privy vault, dangers from, 78, 79, 81, 192.

    Proteins, 27, 28;
      changed by liver, 198;
      in food, 28, 30, 31, 32, 47;
      wastes from, 199.

    Protozoa, 287, 288.

    Ptomaines, 22.

    Ptyalin, 11.

    Pulse, 112, 117, 118.

    Pupil, 265.

    Pylorus, 8.


    Quarantine, 291, 298.

    Quinine, 301.


    Radius, 213.

    Reading, position in, 228.

    Recti, 261.

    Rectum, 9, 18.

    Reflex, 221, 222.

    Reservoirs, 84-86;
      _also_, 79, 80, 85 _note_.

    Respiration, artificial, 329, 330.

    Retina, 260, 262, 263, 264.

    Rheumatism, 123, 125, 292, 295.

    Ribs, 138.

    Rice,
      fermented, 96;
      fuel value of, 48.

    Ringworm, 191.

    Rods, 264 _note_.

    Russia, smallpox in, 297.

    Rye, 48.


    Saké, 96.

    Saliva, 9-11, 12, 16.

    Salts, 6;
      from deep soil, 75;
      in vegetables, 57, 59, 60;
      in water, 77, 83, 88;
      laxative, 6 _note_, 19.

    Scabies, 191.

    Scapula, 213.

    Scarlet fever, 193, 201, 239, 290, 291.

    School,
      gardens, 247, 248;
      luncheons, 68;
      physician, 121, 122;
      recesses, 146.

    Sclerotic coat, 261.

    Scrofula, 157.

    Scurvy, 57.

    Seaver, Dr., experiments with smokers, 106.

    Selection, power of, 197.

    Semi-circular canals, 269, 270.

    Sense,
      of hearing, 266;
      of pain, 177, 224;
      of sight, 260;
      of smell, 256;
      of taste, 257-259;
      of temperature, 177;
      of touch, 177, 178 _and note_;
      sixth--of direction or balance, 269, 270.

    Senses and ideas, 225, 226.

    Septum, 254.

    Shoes, 195, 231, 232.

    Skeleton, 211, 212.

    Skin, 167-178;
      accidents to, 315-320, 322;
      brushes, 188;
      diseases of, 157, 178, 187, 189, 190, 191, 193.
      _See also_ Wastes.

    Skull, 212.

    Sleep, 232, 233.

    Smallpox, 287, 295-299.

    Smoking. _See_ Tobacco.

    Snake-bite, 327.

    Soaps, 11, 186, 187, 190.

    Socket. _See_ Orbit.

    Soda water, 11, 57.

    Soup, 26, 31.

    Spinal column, 212, 213;
      curvatures of, 229;
      tuberculosis of, 157.

    Spinal cord, 212, 220-223, 300.

    Spitting, 159, 160.

    Sprains, 323, 324.

    Sputum, infection from, 158, 159, 166.

    Starch,
      as fuel, 24, 27, 41;
      compared with sugar, 49;
      digestion of, 11, 12, 16, 17, 41, 42;
      in foods, 24, 31, 40, 41, 42-44, 48, 57, 59, 60;
      teeth and, 283.

    Starch-Sugars, 27, 31, 42.

    State control of health, 122.

    Sterilizing, 304.

    Stirrup, 267.

    Stomach, 7, 13-15;
      and nervous system, 227.
      _See also_ 4-6, 8, 10 _note_, 12, 204.

    Stradivarius, 274.

    Strawberries, 26, 58, 59.

    Study, how to, 248, 249.

    Sugar,
      digested starch, 11, 12, 16, 17, 41, 42;
      fuel value of, 27, 49, 50, 52, 208;
      in digestion, 198;
      in foods, 30, 36, 48, 49, 57-60;
      teeth and, 283.

    Sulphur,
      as a disinfectant, 306;
      in cabbage, 60;
      in water, 77.

    Sulphuric acid, 11.

    Sunburn, 190.

    Sweat, 11 _note_, 132, 133, 170, 181-184, 208.

    Synovial fluid, 214.


    Tannin, 91, 93.

    Tattooing, 169.

    Tea, 26, 89, 90-93.

    Teeth, 7, 277-282;
      care of, 282-285;
      infection from, 141, 285.

    Temperance, 101-103.
      _See also_ Alcohol.

    Tendons, 117, 203, 207, 208.

    Tetanus, 288, 295.

    Thein, 91.

    Theobromin, 91.

    Thigh, 207, 208.

    Thirst, 71.

    Tibia, 213.

    Tissues, 18.
      _See also_ Cells.

    Tobacco, 103-107;
      and heart, 128, 129;
      and nervous system, 239.

    Tomatoes, 60, 61.

    Tongue, 7, 9, 10, 257, 259.

    Tonsil, 256.

    Tourniquet, 321.

    Toxins, 22.

    Trachea, 134.
      _See also_ Windpipe.

    Triceps, 206.

    Trypsin, 16.

    Tubercle bacillus, 157, 158;
      toxin of, 164.

    Tuberculin test, 164.

    Tuberculosis,
      deaths from, 156;
      effects of, 123, 201;
      expense of, 158, 161;
      kinds of, 152-154, 157;
      prevention and cure of, 157-164, 309;
      symptoms of, 164, 165.

    Turner, 147.

    Turnips, 60.

    Tympanum, 257, 267, 268.

    Typhoid,
      bacillus of, 286, 295;
      effect of, on heart, 125;
      from milk, 37, 38;
      from water, 79-81;
      in Germany, 80.
      _See also_ 201, 309.


    Ulna, 213.

    Urates, 199.

    Urea, 199, 200.

    Ureters, 200.

    Urinary system, 200.

    Urine, 11 _note_, 132, 200, 201.


    Vaccination, 295-299.

    Vaccine. _See_ Antitoxin.

    Vaccinia, 299.

    Vacuum,
      process, of cleaning, 153, 154;
      of milking, 36.

    Valves,
      of heart and veins, 116-118;
      disease of heart, 123, 124-126.

    Vegetables,
      fuel value of, 26, 31, 32, 40, 56, 57, 58;
      in diet, 23-25, 59, 201;
      salts in, 57, 59;
      water in, 56, 72.

    Veins,
      denned, 108;
      function of, 110-113;
      position of, 113.
      _See also_ 9, 17.

    Vena cava, in, 113, 115, 116, 118, 119, 200.

    Ventilation,
      diseases from poor, 154;
      methods of, 144-149;
      need of, 141-143.

    Ventricle, 115, 116, 117, 118.

    Vertebrae, 212.

    Vitreous humor, 260.

    Vitriol. _See_ Sulphuric acid.

    Vocal cords, 272-275.

    Voice, 271-276.


    Warts, 195.

    Wastes,
      disposal of, 75-77, 78, 79;
      in the body, 70, 71, 196, 208.

    Water,
      body's need of, 69-71, 201;
      boiled, 87, 88;
      carbon dioxid in, 74, 83;
      filtration of, 74, 75, 83, 85, 86, 88;
      in food, 71, 72;
      marsh, 74;
      minerals in, 75, 77, 83;
      natural purifiers of, 72, 74-79, 86, 87;
      rain, 73;
      sources of impurities in, 72-80;
      supply 75, 79-86;
      when and how to drink, 15, 57.

    Water-brash, 13.

    Wells,
      artesian, 81-83, 86;
      dangers to, 75-77, 78, 79;
      permanent, 83.

    Wheat, 27, 31;
      fermented, 94;
      food value of, 42;
      whole, 46.

    Whiskey, 94, 95.
      _See also_ Alcohol, Beverages.

    White matter, 219, 221.

    White swelling, 157.

    Whooping cough, 290, 291.

    Windpipe, 134-136, 271, 272.

    Wine, 94.
      _See also_ Alcohol.

    Wings, 254.

    Wounds, treatment of, 315-319.


    Yale. _See_ Seaver.

    Yeast,
      as leavening, 43-45;
      in making alcohol, 93, 94, 309.

    Yellow fever, 287.





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