signs of any sickness appeared, on general principles, the
opportunity for taking contagious diseases would be much
curtailed.

This is notably important in measles, which comes on
like a feverish cold, with running at the nose, sneezing,
fever, cough, and sore eyes. A child or adult in this condi-
tion should be isolated in an airy room, with a temperature
of 65 F., and all persons, especially children, should be
kept out, except the attendant. The patient should stay
in bed until the eruption has wholly gone, and in his room
until all peeling is over, a period of from two to four weeks.
The germs of measles live but two hours after they leave
the body, so that disinfection of the sick room is unneces-
sary. Bathing of the patient and a twelve-hour airing of
the room and its contents are sufficient protection to sus-
ceptible persons.

Second and even third attacks of measles are more com-
mon than in the case of any other contagious disease. The
great fatality of measles among the natives of islands in
which the disease is not indigenous is well known, as seen
in Fiji, where over a quarter of the population died in four
months from this disease, and in the Faroe Islands.

MUMPS

This disease is generally made light of by everybody ex-
cept the patient. It differs from the other contagious dis-
eases in having a long period of development fourteen to
twenty-four days, more usually about three weeks. Rarely
the first symptoms have not shown themselves for thirty-
six to forty-two days after exposure. Patients may give
the disease to others for a few days before they become
sick, and afterward for two to four weeks from the begin-
ning, of their sickness, so that it is safer to isolate children



102 THE PREVENTION OP DISEASE

for at least three weeks. As adult males are apt to have
painful swelling of the testicles as a complication of mumps
unless they keep quiet, they should stay in bed during the
height of mumps and remain in the house for ten days.
The pain and swelling in the region under and in front of
the ears, which constitutes mumps, usually lasts for a week
or ten days.

Disinfection of the sick room and its contents is not prac-
tised in mumps because the disease appears to be acquired
by direct contact with a patient, and not with clothing and
inanimate objects which may have been exposed to the
sick. The disease is very rarely fatal, and then through
some complication.

WHOOPING-COUGH

The public needs instruction concerning the prevention
of whooping-cough more than in any other contagious
disease. This follows, first, because less pains are taken
to isolate patients than in the case of any other of the in-
fectious disorders, and, second, because both the laity and
profession appear to think and act as though whooping-
cough were a mild and comparatively inconsequential
disease.

As a matter of fact, whooping-cough is more fatal than
either measles, scarlet fever, or diphtheria, if we include
its complications, in children under five years of age. Nine
out of every ten deaths from whooping-cough are due to
pneumonia, and the severe coughing occasionally leads to
death from bleeding into the brain (apoplexy) and starva-
tion from vomiting, while deaths from heart failure and
convulsions are not uncommon. Parents are shamefully
responsible for permitting their children, suffering from
whooping-cough, to play with other healthy young people.
The reason this lapse is more frequent and possible than in



WHOOPING-COUGH 103

the case of other contagious diseases is that patients with
whooping-cough are usually about and outdoors.

The whooping-cough germ has only recently been dis-
covered and isolated. It appears to live in the mucus in
the air-passages, where it may be found during the first
few weeks of the disease. Precisely how long it may exist
in the patient is not certain, but it apparently is not carried
by healthy persons from the sick to the well, and there are
no- "carriers," as in the case of diphtheria, meningitis, etc.
One attack protects an individual from another. Almost
every one is susceptible and has the disease at some period
of life. One-half the cases are under six years of age, but
infants under six months are not so liable to the disease.
There are about 10,000 deaths a year from whooping-
cough, on the average, in the United States, and the death-
rate is 5 to 15 in 100.

After exposure one to two weeks elapse before the
symptoms begin. If more than two weeks pass after
exposure without development of the disease there is little
danger of its occurrence. Whooping-cough starts Jike an
ordinary cold and cough, although the cough is more con-
stant than usual at night. Unless whooping-cough is
prevalent it is not possible to make a diagnosis until the
second stage begins, after one or two weeks more. Then
there are severe spells of coughing, four to twenty or more
daily.

The child in one of these gives fifteen or twenty short
coughs, grows blue, and appears to be suffocating, and then
draws a long breath with a crowing sound (the whoop),
and often ends by vomiting. The whooping stage may
last an uncertain number of weeks. While children are
best kept outdoors with the disease, they should not be
permitted to play with well children until after six weeks
and after all whooping and coughing of phlegm has ceased.



104 THE PREVENTION OF DISEASE

They should have a separate room to sleep in, and all
material which is vomited or coughed up should be burned
at once. Paper napkins and old clean cloths may be used
for collecting secretions from the nose and mouth. While
direct contact with the sick is usually the cause of con-
tagion, yet the germs may be sprayed into the air in cough-
ing and be carried about on clothing. There is a classical
case in which clothing from a patient on a ship in St.
Helena conveyed the disease to the children of a laundress
on shore.

Quite recently a vaccine has been used made in much
the same way as described for use in typhoid fever ; that is,
consisting of the dead germs of whooping-cough and in-
jected under the skin. This appears to be of considerable
value in protecting those exposed to whooping-cough from
taking the disease. Hess (1914) reports that with the
use of vaccine protection, in an epidemic of whooping-
cough, 1 in 12 took the disease, while without it almost 3
out of 4 children became sick with the disorder.

It is without danger and should be tried. The New
York Health Department has ardently advocated vaccina-
tion against whooping-cough.

Disinfection of the room should be done after the
patient has recovered. The chief danger of pneumonia is
during early convalescence.

PLAGUE. BUBONIC PLAGUE

Plague has been known from the second century, and in
the fourteenth it destroyed one-fourth of the people of
Europe, and was known as the "black death." It ravaged
Europe again in the seventeenth century, but gradually
died down, until it appeared again in Hong Kong in 1894.

There have been enormous losses from plague in India,
some five and one-half millions dying of it in the United



PLAGUE. BUBONIC PLAGUE 105

Provinces, Bombay, and the Punjab between 1896 and
1911. Since that time the disease has occurred in the
Far East, in Persia, Turkey in Asia, Java and Sumatra,
and in Egypt and Japan.

There have been a few cases in England and the United
States within the past few years, notably in San Francisco
(121 cases in 1907-08), and a few cases in Seattle, and at
the present writing (1914) an outbreak has just started in
New Orleans. With the modern manner of handling the
disease in the most civilized communities there appears
to be little danger of a large epidemic of the disease.

Several forms of the disease occur. The most common
begins with fever, headache, pain in the back and stiffness
of the limbs, and enlarged glands (buboes), especially in
the groins, appear from the third to fifth day. Some
patients are so overwhelmed by the germs that they die
within three days before the buboes form, and in the pneu-
monic type the disease is evidenced by a rapidly fatal form
of inflammation of the lungs.

Plague is contagious in less than 3 per cent, of cases, and
the contagion is seen only in the pneumonia cases crowded
together in unsanitary conditions.

Bubonic plague is transmitted to man from rats and
ground squirrels entirely by rat- or squirrel-fleas, and from
rat to rat or squirrel to squirrel by the same insect. The
disease is carried from place to place by rat-fleas on persons
or their belongings. The rat-fleas may live a week when
starved, but on human beings they may subsist three or
four weeks. Rat-fleas do not naturally take to humans or
other animals, and it is only when they are starved that
they change their habitat, except in the case of ground
squirrels, chipmunks, and a few other animals.

A single rat-flea may harbor as many as 500 plague germs
in its body, and human epidemics usually follow severe



106 THE PREVENTION OF DISEASE

outbreaks in rats, as the terrible mortality in rats drives
their fleas to the human host.

The cat- and dog-flea are apparently not invaded by the
plague germ and so are not dangerous to man. On the
contrary, in the Punjab it has been shown that where there
are from 30 to 75 cats for every 100 houses, there is no
plague, owing to the destruction of rats, and this method
of fighting plague is prescribed by the scriptures of the
Mohammedans and Hindus.

The modern way of fighting plague consists in poisoning
and trapping rats and examining dead rats for plague
germs, in disposal of food and garbage in rat-tight vessels,
general cleansing and destruction of shacks, out-houses,
and stables affording nests for rats, but particularly en-
forcement of rat-proof buildings, to make life impossible to
rats through starvation. These measures have been splen-
didly carried out in the United States through the agency
of the Public Health Service, often hampered as much as
possible by the state and municipal lay authorities who
were most concerned, as in California and Seattle. The
appearance of dead rats in a seaport should immediately
excite suspicion, and cultures from their bodies will decide
the existence of plague germs, together with inoculation
of guinea-pigs. Segregation of the sick, fumigation with
sulphur of ihe premises and ships to destroy rats and fleas,
and shields on the hawsers to prevent rats from boarding
ships are essential. To protect individuals against plague
there is Haffkine's vaccine, consisting of the dead bodies of
the plague germs and harmless in itself. One injection
of this reduces the chances of getting the disease four-fifths,
while those who have had the injection and acquire the
disease have two and one-half times the expectation of
recovery as compared to the uninoculated (Martin).



CHAPTER V

GERM DISEASES ONLY COMMUNICATED BY THE
BITES OF MOSQUITOES

Malaria, Yellow Fever, Dengue
MALARIA

MALARIA is now known to be due to animal parasites
(plasmodia) which are only transmitted to man by a par-
ticular kind of mosquito, the genus Anopheles, eight species
of which act as hosts to plasmodia. The mosquitoes, in






6 c

Fig. 1. Various mosquitoes in attitudes of repose: a, Culex pip-
iens or common mosquito; b, Myzorrhynchus pseudopictus; c,
Anopheles maculipennis or malarial mosquito (Manson).

their turn, get the malarial parasite into their bodies by
biting a person who has the malarial parasites in his
blood. Therefore the prevention of malaria may be
summed up, first, in destroying mosquitoes; second, in

107



108 THE PREVENTION OF DISEASE

avoiding mosquito bites; third, in taking quinin to kill
the parasites in the body. In the avoidance of mosquito
bites the individual is protected against malaria and the
community also, because only in this way do the mosqui-
toes become dangerous. Thus, malaria was practically
unknown about Boston some years ago, but the advent
of Italians, who were employed in large numbers in the
Metropolitan Sewage System, introduced malaria to the
region by infecting mosquitoes which had previously been
harmless. The disease thus became indigenous in the
neighborhood.

The female mosquito lays about 100 eggs on the surface
of fresh water, and preferably in the presence of grass and
scum of algae. After eight days the insect becomes full-
grown, does not fly great distances, and avoids wind, but
seeks protection in grass, undergrowth, and brush.

The greatest danger threatens from mosquitoes bred
within 300 feet of a house, although they may fly much
greater distances. Within this area, at any rate, all
agencies favoring the breeding of mosquitoes should be
abolished. Tall weeds, shrubs, grass, and undergrowth
of all kinds should be gotten rid of, and trees near the
house are also inadvisable in a malarial region. Collec-
tions of stagnant water are particularly dangerous. Thus,
disused wells, springs, empty cans, bottles, watering
troughs for animals, roof-gutters, rain-water barrels, or
depressions in the soil, or even in the hollow of leaves,
where water may stand a week, are prolific breeding places.

The water should be changed in these places daily, or
the receptacles should be screened, or kerosene may be
kept on the surface of standing water, or the collections of
water should be gotten rid of. One ounce of kerosene will
cover 15 square feet of water. A constant drip from a
partly opened stop-cock of a can is the best method of



MALARIA 109

application. Brooks should be kept clear of weeds, so
that there may be no standing water, and ponds should be
covered with petroleum, drained away, or stocked with
various kinds of minnows. The filling in or drainage of
marshes are essential.

Mosquito bites may be avoided by staying in a screened
house except during the hours between sunrise and sun-
set. In case this is not practicable the head should be
protected by a head net, the hands and wrists by gauntlets,
and the ankles by leggings, especially in the tropics.

The house should be absolutely screened with wire
netting of No. 16 mesh. In the tropics the bed should
also be protected by a special netting, as described under
Yellow Fever. In sitting after dark, women should cover
their ankles with high shoes and their necks with scarfs.
A bedroom well off the ground is safer from mosquitoes.

Where there are many mosquitoes in a room they may be
killed by burning broken pieces of roll sulphur in a deep
pan placed on bricks on sand, or inside a larger pan, to
avoid setting fire to the premises.

Cracks about doors and windows should be made tight
by pasting strips of paper over them.

In a reasonably well-built house this is unnecessary.
Three pounds of sulphur are suitable for a room 10 by 10
by 10 feet. Eight ounces of wood alcohol are poured
on the sulphur and ignited, and the door of the room is
closed at once and not opened for twelve hours.

A word may be said about screening houses. Where the
inmates sit outside after sunset the veranda must be
wholly screened. Mosquitoes are only active during the
night, and will enter a house through the smallest crevices,
such as keyholes and chimneys. These must be stopped by
wads of paper placed in the throats of chimneys, in fire-
places, and in keyholes. If the smallest holes are not



110 THE PREVENTION OF DISEASE

stopped a house will act as a trap for mosquitoes, who may
enter but not find their way out. Wire screens should
cover every door and window in the house which may be
opened.

Window screens should not be movable, but the frames
should fit tightly against the lower part of the upper sash
and be fastened by screws. The upper sash must not be
opened. The netting should not be larger than a No. 18
for the yellow-fever mosquito nor larger than a No. 16 for
the malarial mosquito. The number means the number of
meshes to the inch, A coat of thin paint will convert No.
14 into No. 16 mesh.

The taking of quinin to kill parasites in the body is the
most practical measure of all, although not so useful as
thorough screening, together with the taking of quinin.
Thus, in Italy, where quinin is supplied free of cost to the
poorer part of the population, the inroads of malaria have
been tremendously reduced by daily consumption of
quinin. Celli reports that the mortality from malaria has
there been lowered 75 per cent., and in the malarial region
about Rome the number of annual cases has been reduced
from 11,653 to 2974 by this means.

In our farming population, where elaborate methods of
screening and draining are not practicable, the daily use of
quinin is the most satisfactory method of preventing ma-
laria. Quinin does not, however, always kill all the
malarial parasites in the blood, because in some persons
the parasites may still exist, but the quinin keeps down
their numbers sufficiently to prevent an attack, and the
individual may feel perfectly well, the disease remaining
latent in his system. No harm is done by taking the neces-
sary preventive amount of quinin daily the year round, as
was shown by the higher officials at Panama, who took
2 grains three times daily at each meal. In some persons



MALARIA 111

this dose may cause buzzing in the ears and discomfort,
but this usually wears off within a week.

Quinin might only be taken during the mosquito season,
but in case of persons who have had malaria the parasites
may remain in sufficient numbers in the blood to produce
an attack of fever before they are again bitten by mosqui-
toes the following summer. Such persons should begin to
take quinin in March, and other persons should start to
take it in June and continue it daily to November in this
country. In the tropics it is necessary to take quinin the
year round. The dose for adults should be 2 grains of
quinin sulphate in capsules with each meal three times
daily. For children under ten, 5 grains of the tannate of
quinin in chocolate tablets are given thrice daily. This
form of quinin does not contain half as much of the drug
as the sulphate, and hence the larger dose. In children
under five, 2-grain tablets three times daily will suffice.
While capsules of quinin are the most soluble containers
and preferable, yet, where the cost is important, quinin
sulphate may be bought much more cheaply by the
hundred in tablets. If these are properly made, they
should begin to crumble in a glass of water within ten
minutes. In this case they are suitable for use. The
only objection to pills or tablets of quinin is that they are
frequently so insoluble that they pass through and out of
the intestines just as they were swallowed. In tropical
countries, where malaria is severe, it is advisable to take
more than 6 grains daily if it can be done without much
discomfort. Thus, 3 grains should be taken three times
daily, or even 10 grains daily is safer.

A patient suffering from malarial fever should be es-
pecially well protected by mosquito screening to prevent
infection of mosquitoes which might bite him and thus
transmit the disease to others. For this reason white



112 . THE PREVENTION OF DISEASE

persons avoid the neighborhood of the native quarters in
the tropics, as the mosquitoes are more apt to be infected
there.

Of course, the precautions against malaria are only
required in regions in which the disease exists; that is, in
which the mosquitoes are infected with it. The disease is
prevalent in many parts of the South and in the central
Atlantic states, especially in the fall. In the northwestern
states and on the northern Pacific coast it is unknown.

Malaria occurs in some places throughout New England,
but is much less common about New York City and
Philadelphia than formerly. The disease is only found in
the Great Lake region about Lake Erie and St. Clair.

YELLOW FEVER

The prevention of yellow fever is the most interesting of
any similar attempt in the history of medicine, on account
of the heroism involved, the ingenuity practised, and the
wonderful success attained. Yellow fever has been shown
not to be contagious through contact with a patient, his
surroundings, or discharges, but to be only transmitted
through the medium of a certain species of mosquito, the
Stegomyia fasciata. The great discovery was made in
Cuba by United States Army surgeons in 1900 following the
American occupation. As early as 1881 Dr. Carlos Finlay
of Havana had suggested that yellow fever was due to
mosquito bites, and the work of Dr. Ross in India had
proved that malaria was only caused by the bites of mos-
quitoes, and these facts and theories stimulated the
American Commission to experiment in regard to yellow
fever. This body was made up of the following United
States Army surgeons Drs. Walter Reed, Carroll,
Lazear, and Agramonte. The experiments were done at
Camp Lazear in Cuba, in a frame house with a screened



YELLOW FEVER 113

vestibule, and so constructed as to shut out sunlight and
fresh air. Previous to this time, in September, Dr. Lazear
had permitted himself to be bitten by a mosquito in a
yellow-fever ward and he sickened in five days and died a
week later of the disease. Two months later fifteen
mosquitoes which had bitten yellow fever patients were
allowed to bite one of the volunteers at camp Lazear, and
he became ill with the disease five days later, while two
other susceptible persons slept in the same room for eight-
een nights separated only by a mosquito screened partition
from the patient. These latter remained perfectly well.
Many other volunteers knowingly permitted themselves
to be bitten by mosquitoes (which had bitten yellow fever
patients a sufficient time previously) and they all took the
disease. To prove that there was no danger of contagion
from the clothes or discharges of yellow fever patients, two
soldiers and a surgeon slept for twenty-one consecutive
nights in a mosquito-screened house in which were boxes
containing clothing of yellow fever patients soiled with
their blood, urine, and bowel discharges. Each night the
men handled these by unpacking them and hanging them
on a line in the room, and each morning they packed them
up again in the box. Moreover, two other soldiers slept
twenty-one days in the night-clothes and sheets just as
they had been taken from patients recently dying from
yellow fever, and one of these men actually slept on a towel
soiled with the blood of a yellow-fever patient. None of
these volunteers took the disease. The outcome of all
these experiments proved: (1) That yellow fever was only
transmitted by the bites of a certain species of mosquito.
(2) That the mosquito is harmless for a period of twelve
days or longer after biting a yellow fever patient, but that
then the mosquito is dangerous to man as long as it lives,
in one case fifty-seven days following the biting of a patient.



114 THE PREVENTION OP DISEASE

(3) That a period of three to five days after a person is
bitten by a mosquito, which has previously bitten a yel-
low fever patient, must elapse before the patient begins to
sicken. (4) That the injection into a susceptible person
of even 8 drops of blood taken from a yellow fever
patient in the first or second days of his sickness will pro-
duce the disease in one who has not previously had it. (5)
That the mosquito to be dangerous must bite a patient
during the first three days of his sickness. (6) That there
is no danger from contact with a patient, his clothing or
discharges, but only from mosquitoes which have bitten
patients.

Owing to this knowledge that hotbed of infection,
Havana, which had been a pest-hole of yellow fever for
130 years was cleared of the disease by Col. Gorgas in 1901
by interfering with the breeding of mosquitoes, by destroy-
ing mosquitoes which had bitten yellow fever patients, and
by preventing mosquitoes from biting patients. So, again,
in Panama Col. Gorgas stamped out the disease absolutely
within sixteen months of the American occupation in 1904,
with no return since, and upon this result has the success
of the canal construction largely depended.

Yellow fever is indigenous in Vera Cruz, Rio, and
Spanish- American ports; it appears periodically in tropical
Atlantic ports of America and Africa, and occasionally
between the 15th and 35th parallels of north latitude.
Where it is prevalent the taking of the temperature on the
slightest feeling of illness will arouse the first suspicion of
the disease if there is fever. The disease begins in a person
who has been bitten three to five days before by a particu-
lar kind of mosquito, which has itself bitten a yellow