The following are some of the diseases which have been remarkably
controlled through preventive medicine:
_Small-pox._—While not a scourge of the first rank, like the plague
or cholera, at the outset of the century variola was one of the
most prevalent and dreaded of all diseases. Few reached adult life
without an attack. To-day, though outbreaks still occur, it is a
disease thoroughly controlled by vaccination. The protective power
of the inoculated cow-pox is not a fixed and constant quantity.
The protection may be for life, or it may last only for a year or
two. The all-important fact is this: That efficiently vaccinated
persons may be exposed with impunity, and among large bodies of
men (_e.g._, the German army), in which revaccination is practised,
small-pox is unknown. Of one hundred vaccinated persons exposed to
small-pox, possibly one might take the disease in a mild form; of one
hundred unvaccinated persons so exposed, one alone might escape—from
twenty-five to thirty would die. To be efficient, vaccination must be
carried out systematically, and if all the inhabitants of this country
were revaccinated at intervals small-pox would disappear (as it has
from the German army), and the necessity for vaccination would cease.
The difficulty arises from the constant presence of an unvaccinated
remnant, by which the disease is kept alive. The Montreal experience in
1885 is an object-lesson never to be forgotten.
For eight or ten years vaccination had been neglected, particularly
among the French-Canadians. On February 28, 1885, a Pullman car
conductor, who came from Chicago, where the disease had been slightly
prevalent, was admitted into the Hôtel Dieu. Isolation was not carried
out, and on the 1st of April a servant in the hospital died of
small-pox. Following her death the authorities of the hospital sent to
their homes all patients who presented no symptoms of the disease. Like
fire in dry grass the contagion spread, and within nine months there
died of small-pox three thousand one hundred and sixty-four persons.
It ruined the trade of the city for the winter, and cost millions of
dollars. There are no reasonable objections to vaccination, which is
a simple process, by which a mild and harmless disease is introduced.
The use of the animal vaccine does away with the possibility of
introduction of other disorders, such as syphilis.
_Typhus Fever._—Until the middle of the present century this disease
prevailed widely in most of the large cities, particularly in Europe,
and also in jails, ships, hospitals, and camps. It was more widely
spread than typhoid fever and much more fatal. Murchison remarks of
it that a complete history of its ravages would be the history of
Europe during the past three centuries and a half. Not one of the acute
infections seems to have been more dependent upon filth and unsanitary
conditions. With the gradual introduction of drainage and a good water
supply, and the relief of overcrowding, the disease has almost entirely
disappeared, and is rarely mentioned now in the bills of mortality,
except in a few of the larger and more unsanitary cities. The following
figures illustrate what has been done in England within sixty years:
In 1838 in England twelve hundred and twenty-eight persons died of
fever (typhus and typhoid) per million of living. Twenty years later
the figures were reduced to nine hundred and eighteen; in 1878 to three
hundred and six of typhoid and to thirty-six of typhus fever. In 1892
only one hundred and thirty-seven died of typhoid fever and only three
of typhus per million living!
_Typhoid Fever._—While preventive medicine can claim a great victory
in this disease also, it is less brilliant, since the conditions which
favor its prevalence are not those specially relating to overcrowding
as much as to imperfect water supply and the contamination of certain
essential foods, as milk. It has been repeatedly demonstrated that,
with a pure water supply and perfect drainage, typhoid fever almost
disappears from a city. In Vienna, after the introduction of good
water, the rate of mortality from typhoid fever fell from twelve per
ten thousand of the inhabitants to about one. In Munich the fall
was still more remarkable; from above twenty-nine per ten thousand
inhabitants in 1857 it fell to about one per ten thousand in 1887.
That typhoid fever in this country is still a very prevalent disease
depends mainly upon two facts: First, not only is the typhoid bacillus
very resistant, but it may remain for a long time in the body of
a person after recovery from typhoid fever, and such persons, in
apparent good health, may be a source of contamination. With many of
the conditions favoring the persistence and growth of the bacillus
outside the body we are not yet familiar. The experience in the
Spanish-American War illustrates how dangerous is the concentration
together of large numbers of individuals. But, second, the essential
factor in the widespread prevalence of typhoid fever in the United
States, particularly in country districts, is the absence of anything
like efficient rural sanitation. Many counties have yet to learn the
alphabet of sanitation. The chief danger results from the impure
water supplies of the smaller towns, the local house epidemics due to
infected wells, and the milk outbreaks due to the infection of dairy
farms.
The importance of scrupulously guarding the sources of supply was never
better illustrated than in the well-known and oft-quoted epidemic in
Plymouth, Pennsylvania. The town, with a population of eight thousand,
was in part supplied with drinking-water from a reservoir fed by a
mountain-stream. During January, February, and March, in a cottage by
the side of and at a distance of from sixty to eighty feet from this
stream, a man was ill with typhoid fever. The attendants were in the
habit at night of throwing out the evacuations on the ground towards
the stream. During these months the ground was frozen and covered
with snow. In the latter part of March and early in April there was
considerable rainfall and a thaw, in which a large part of the three
months’ accumulation of discharges was washed into the brook not sixty
feet distant. At the very time of this thaw the patient had numerous
and copious discharges. About the 10th of April cases of typhoid fever
broke out in the town, appearing for a time at the rate of fifty a day.
In all about twelve hundred were attacked. An immense majority of
the cases were in the part of the town which received water from the
infected reservoir.
The use of boiled water and of ice made from distilled water, the
systematic inspection of dairies, the scrupulous supervision of the
sources from which the water is obtained, an efficient system of
sewage removal, and, above all, the most scrupulous care on the part
of physicians and of nurses in the disinfection of the discharges of
typhoid fever patients—these are the factors necessary to reduce to a
minimum the incidence of typhoid fever.
_Cholera._—One of the great scourges of the present century made
inroads into Europe and America from India, its native home. We have,
however, found out the germ, found out the conditions under which it
lives, and it is not likely that it will ever again gain a foothold
in this country or Great Britain. Since the last epidemic, 1873, the
disease, though brought to this country on several occasions, has
always been held in check at the port of entry. It is communicated
almost entirely through infected water, and the virulence of an
epidemic in any city is in direct proportion to the imperfection of
the water supply. This was shown in a remarkable way in the Hamburg
epidemic of 1892. In Altona, which had a filtration plant, there
were only five hundred and sixteen cases, many of them refugees from
Hamburg. Hamburg, where the unfiltered water of the Elbe was used, had
some eighteen thousand cases, with nearly eight thousand deaths.
_Yellow Fever._—The cause of this disease is still under discussion.
It has an interest to us in this country from its continued prevalence
in Cuba, and from the fact that at intervals it makes inroads into
the Southern States, causing serious commercial loss. The history of
the disease in the other West India islands, particularly Jamaica,
indicates the steps which must be taken for its prevention. Formerly
yellow fever was as fatal a scourge in them as it is to-day in Cuba. By
an efficient system of sanitation it has been abolished. The same can
be done (and will be done) in Cuba within a few years. General Wood has
already pointed out the way in the cleansing of Santiago.
_The Plague._—One of the most remarkable facts in connection with
modern epidemics has been the revival of the bubonic plague, the most
dreaded of all the great infections. During the present century the
disease in Europe has been confined almost exclusively to Turkey and
Southern Europe. Since 1894, when it appeared at Hong-Kong, it has
gradually spread, and there have been outbreaks of terrible severity
in India. It has extended to certain of the Mediterranean ports, and
during the past summer it reached Glasgow, where there has been a
small outbreak. On this hemisphere there have been small outbreaks in
certain of the South American ports, cases have been brought to New
York, and there have been to November 1st twenty-one cases among the
Chinese in San Francisco. Judging from the readiness with which it has
been checked and limited in Australia, and in particular the facility
with which the recent outbreak in Glasgow has been stamped out, there
is very little risk that plague will ever assume the proportions which
gave to it its terrible reputation as the “black death” of the Middle
Ages. As I have already mentioned, the germ is known, and prophylactic
inoculations have been made on a large scale in India, with a certain
measure of success.
_Tuberculosis._—In all communities the _white plague_, as Oliver
Wendell Holmes calls it, takes the first rank as a killing disease. It
has been estimated that of it one hundred and twenty thousand people
die yearly in this country. In all mortality bills tuberculosis of
the lungs, or consumption, heads the list, and when to this is added
tuberculosis of the other organs, the number swells to such an extent
that this disease equals in fatality all the other acute infective
diseases combined, if we leave out pneumonia. Less than twenty years
ago we knew little or nothing of the cause of the disease. It was
believed to be largely hereditary. Koch discovered the germ, and with
this have come the possibilities of limiting its ravages.
The following points with reference to it may be stated: In a few very
rare instances the disease is transmitted from parent to child. In a
large proportion of all cases the disease is “caught.” The germs are
widely distributed through the sputum, which, when dry, becomes dust,
and is blown about in all directions. Tubercle bacilli have been found
in the dust of streets, houses, hospital wards, and much-frequented
places. A single individual may discharge from the lungs countless
myriads of germs in the twenty-four hours. Dr. Nuttall estimated from a
patient in the Johns Hopkins Hospital, who had only moderately advanced
consumption, that from one and a half to four and a third billions of
germs were thrown off in the twenty-four hours. The consumptive, as has
been well stated, is almost harmless, and only becomes harmful through
bad habits. The germs are contained in the sputum, which, when dry,
is widely scattered in the form of dust, and constitutes the great
medium for the transmission of the disease. If expectorated into a
handkerchief, the sputum dries quickly, particularly if it is put into
the pocket or under the pillow. The beard or mustache of a consumptive
is smeared with the germs. Even in the most careful the hands are apt
to be soiled with the germs, and in those who are dirty and careless
the furniture and materials which they handle readily become infected.
Where the dirty habit prevails of spitting on the floor, a room, or the
entire house, may contain numbers of germs. In the majority of all
cases the infection in tuberculosis is by inhalation. This is shown
by the frequency with which the disease is met in the lungs, and the
great prevalence of tuberculosis in institutions in which the residents
are restricted in the matter of fresh air and a free, open life. The
disease prevails specially in cloisters, in jails, and in asylums.
Infection through milk is also possible; it is doubtful whether the
disease is transmitted through meat. So widespread are the germs that
post-mortem examination has shown that a very large number of persons
show slight signs of the disease who have never during life presented
any symptoms; in fact, some recent investigations would indicate that a
very large proportion of all persons at the age of forty have somewhere
in their bodies slight tuberculous lesions. This shows the importance
of the individual predisposition, upon which the older writers laid so
much stress, and the importance of maintaining the nutrition at its
maximum.
One of the most remarkable features of modern protective medicine is
the widespread interest that has been aroused in the crusade against
tuberculosis. What has already been accomplished warrants the belief
that the hopes of even the most enthusiastic may be realized. A
positive decline in the prevalence of the disease has been shown in
many of the larger cities during the past ten years. In Massachusetts,
which has been a hot-bed of tuberculosis for many years, the death-rate
has fallen from forty-two per ten thousand inhabitants in 1853 to
twenty-one and eight-tenths per ten thousand inhabitants in 1895. In
the city of Glasgow, in which the records have been very carefully
kept, there has been an extraordinary fall in the death-rate from
tuberculosis, and the recent statistics of New York City show, too, a
similar remarkable diminution.
In fighting the disease our chief weapons are: First, education of the
public, particularly of the poorer classes, who do not fully appreciate
the chief danger in the disease. Secondly, the compulsory notification
and registration of all cases of tuberculosis. The importance of this
relates chiefly to the very poor and improvident, from whom, after
all, comes the greatest danger, and who should be under constant
surveillance in order that these dangers may be reduced to a minimum.
Thirdly, the foundation in suitable localities by the city and by the
State of sanatoria for the treatment of early cases of the disease.
Fourthly, provision for the chronic, incurable cases in special
hospitals.
_Diphtheria._—Since the discovery of the germ of this disease
and our knowledge of the conditions of its transmission, and the
discovery of the antitoxin, there has been a great reduction in its
prevalence and an equally remarkable reduction in the mortality. The
more careful isolation of the sick, the thorough disinfection of the
clothing, the rigid scrutiny of the milder cases of throat disorder,
a more stringent surveillance in the period of convalescence, and the
routine examination of the throats of school-children—these are the
essential measures by which the prevalence of the disease has been very
markedly diminished. The great danger is in the mild cases, in which
the disease has perhaps not been suspected, and in which the child may
be walking about and even going to school. Such patients are often a
source of widespread infection. The careful attention given by mothers
to the teeth and mouth of children is also an important factor. In
children with recurring attacks of tonsillitis, in whom the tonsils
are enlarged, the organs should be removed. Through these measures the
incidence of the disease has been very greatly reduced.
_Pneumonia._—While there has been a remarkable diminution in the
prevalence of a large number of all the acute infections, one disease
not only holds its own, but seems even to have increased in its
virulence. In the mortality bills, pneumonia is an easy second to
tuberculosis. It attacks particularly the intemperate, the feeble,
and the old, though every year a large number of robust, healthy
individuals succumb. So frequent is pneumonia at advanced periods of
life that to die of it has been said to be the natural end of old men
in this country. In many ways, too, it is a satisfactory disease, if
one may use such an expression. It is not associated with much pain,
except at the onset, the battle is brief and short, and a great many
old persons succumb to it easily and peacefully.
We know the cause of the disease; we know only too well its symptoms,
but the enormous fatality (from twenty to twenty-five per cent.) speaks
only too plainly of the futility of our means of cure, and yet in no
disease has there been so great a revolution in treatment. The patient
is no longer drenched to death with drugs, or bled to a point where
the resisting powers of nature are exhausted. We are not without hope,
too, that in the future an antidote may be found to the toxins of the
disease, and of late there have been introduced several measures of
great value in supporting the weakness of the heart, a special danger
in the old and debilitated.
_Hydrophobia._—Rabies, a remarkable, and in certain countries a
widespread, disease of animals, when transmitted to a man by the bite
of rabid dogs, wolves, etc., is known as hydrophobia. The specific
germ is unknown, but by a series of brilliant observations Pasteur
showed (1) that the poison has certain fixed and peculiar properties in
connection with the nervous system; (2) that susceptible animals could
be rendered refractory to the disease, or incapable of taking it, by a
certain method of inoculation; and (3) that an animal unprotected and
inoculated with a dose of the virus sufficient to cause the disease
may, by the injection of proper anti-rabic treatment, escape. Supported
by these facts, Pasteur began a system of treatment of hydrophobia in
man, and a special institute was founded in Paris for the purpose. When
carried out promptly the treatment is successful in an immense majority
of all cases, and the mortality in persons bitten by animals proved to
be rabid, who have subsequently had the anti-rabic treatment, has been
reduced to less than one-half per cent. The disease may be stamped out
in dogs by careful quarantine of suspected animals, and by a thoroughly
carried out muzzling order.
_Malaria._—Among the most remarkable of modern discoveries is the
cause of malarial fever, one of the great maladies of the world, and
a prime obstacle to the settlement of Europeans in tropical regions.
Until 1880 the cause was quite obscure. It was known that the disease
prevailed chiefly in marshy districts, in the autumn, and that the
danger of infection was greatest in the evening and at night, and
that it was not directly contagious. In 1880 a French army surgeon,
Laveran, discovered in the red blood-corpuscles small bodies which have
proved to be the specific germ of the disease. They are not bacteria,
but little animal bodies resembling the amœba—tiny little portions
of protoplasm. The parasite in its earliest form is a small, clear,
ring-shaped body inside the red blood-corpuscle, upon which it feeds,
gradually increasing in size and forming within itself blackish grains
out of the coloring matter of the corpuscle. When the little parasite
reaches a certain size it begins to divide or multiply, and an enormous
number of these breaking up at the same time give off poison in the
blood, which causes the paroxysms of fever. During what is known as
the chill, in the intermittent fever, for example, one can always find
these dividing parasites. Several different forms of the parasites
have been found, corresponding to different varieties of malaria.
Parasites of a very similar nature exist abundantly in birds. Ross,
an army surgeon in India, found that the spread of this parasite from
bird to bird was effected through the intervention of the mosquito. The
parasites reach maturity in certain cells of the coats of the stomach
of these insects, and develop into peculiar thread-like bodies, many of
which ultimately reach the salivary glands, from which, as the insect
bites, they pass with the secretion of the glands into the wound. From
this as a basis, numerous observers have worked out the relation of the
mosquito to malaria in the human subject.
Briefly stated, the disease is transmitted chiefly by certain varieties
of the mosquito, particularly the _Anopheles_. The ordinary _Culex_,
which is present chiefly in the Northern States, does not convey
the disease. The _Anopheles_ sucks the blood from a person infected
with malaria, takes in a certain number of parasites, which undergo
development in the body of the insect, the final outcome of which is
numerous small, thread-like structures, which are found in numbers in
the salivary glands. From this point, when the mosquito bites another
individual, they pass into his blood, infect the system, and in this
way the disease is transmitted. Two very striking experiments may be
mentioned. The Italian observers have repeatedly shown that _Anopheles_
which have sucked blood from patients suffering from malaria, when sent
to a non-malarial region, and there allowed to bite perfectly healthy
persons, have transmitted the disease. But a very crucial experiment
was made a short time ago. Mosquitoes which had bitten malarial
patients in Italy were sent to London and there allowed to bite Mr.
Manson, son of Dr. Manson, who really suggested the mosquito theory of
malaria. This gentleman had not lived out of England, and there is no
acute malaria in London. He had been a perfectly healthy, strong man.
In a few days following the bites of the infected mosquitoes he had a
typical attack of malarial fever.
The other experiment, though of a different character, is quite as
convincing. In certain regions about Rome, in the Campania, malaria is
so prevalent that in the autumn almost every one in the district is
attacked, particularly if he is a new-comer. Dr. Sambron and a friend
lived in this district from the 1st of June to the 1st of September,
1900. The test was whether they could live in this exceedingly
dangerous climate for the three months without catching malaria, if
they used stringent precautions against the bites of mosquitoes. For
this purpose the hut in which they lived was thoroughly wired, and they
slept with the greatest care under netting. Both of these gentlemen at
the end of the period had escaped the disease.
The importance of these studies cannot be overestimated. They explain
the relation of malaria to marshy districts, the seasonal incidence of
the disease, the nocturnal infection, and many other hitherto obscure
problems. More important still, they point out clearly the way by which
malaria may be prevented: First, the recognition that any individual
with malaria is a source of danger in a community, so that he must
be thoroughly treated with quinine; secondly, the importance of the
draining of marshy districts and ponds in which mosquitoes breed; and,
thirdly, that even in the most infected regions persons may escape the
disease by living in thoroughly protected houses, in this way escaping
the bites of mosquitoes.
_Venereal Diseases._—These continue to embarrass the social economist
and to perplex and distress the profession. The misery and ill-health
which they cause are incalculable, and the pity of it is that the cross
is not always borne by the offender, but innocent women and children
share the penalties. The gonorrhœal infection, so common, and often so
little heeded, is a cause of much disease in parts other than those
first affected. Syphilis claims its victims in every rank of life, at
every age, and in all countries. We now treat it more thoroughly, but
all attempts to check its ravages have been fruitless. Physicians have
two important duties: the incessant preaching of continence to young
men, and scrupulous care, in every case, that the disease may not be
a source of infection to others, and that by thorough treatment the
patient may be saved from the serious late nervous manifestations.
We can also urge that in the interests of public health venereal
diseases, like other infections, shall be subject to supervision by
the State. The opposition to measures tending to the restriction of
these diseases is most natural: on the one hand, from women, who feel
that it is an aggravation of a shocking injustice and wrong to their
sex; on the other, from those who feel the moral guilt in a legal
recognition of the evil. It is appalling to contemplate the frightful
train of miseries which a single diseased woman may entail, not alone
on her associates, but on scores of the innocent—whose bitter cry
should make the opponents of legislation feel that any measures of
restriction, any measures of registration, would be preferable to the
present disgraceful condition, which makes of some Christian cities
open brothels and allows the purest homes to be invaded by the most
loathsome of all diseases.
_Leprosy._—Since the discovery of the germ of this terrible disease
systematic efforts have been made to improve the state of its victims
and to promote the study of the conditions under which the disease
prevails. The English Leprosy Commission has done good work in calling
attention to the widespread prevalence of the disease in India and
in the East. In this country leprosy has been introduced into San
Francisco by the Chinese, and into the Northwestern States by the
Norwegians, and there are foci of the disease in the Southern States,
particularly Louisiana, and in the province of New Brunswick. The
problem has an additional interest since the annexation of Hawaii
and the Philippine Islands, in both of which places leprosy prevails
extensively. By systematic measures of inspection and the segregation
of affected individuals the disease can readily be held in check. It is
not likely ever to increase among native Americans, or again gain such
a foothold as it had in the Middle Ages.
_Puerperal Fever._—Perhaps one of the most striking of all victories
of preventive medicine has been the almost total abolition of so-called
child-bed fever from the maternity hospitals and from private practice.
In many institutions the mortality after child-birth was five or six
per cent., indeed sometimes as high as ten per cent., whereas to-day,
owing entirely to proper antiseptic precautions, the mortality has
fallen to three-tenths to four-tenths per cent. The recognition of the
contagiousness of puerperal fever was the most valuable contribution to
medical science made by Oliver Wendell Holmes. There had been previous
suggestions by several writers, but his essay on the “Contagiousness
of Puerperal Fever,” published in 1843, was the first strong, clear,
logical statement of the case. Semmelweis, a few years later, added
the weight of a large practical experience to the side of the
contagiousness, but the full recognition of the causes of the disease
was not reached until the recent antiseptic views had been put into
practical effect.