Infections And How To Avoid Them

Sources: A Handbook Of Health

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.

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.

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


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


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


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.

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.

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.

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.

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.

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 larvae, 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


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.

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


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.

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.

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-a-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