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 nineteenth century variola was one of the most prevalent and dreaded of all diseases. Few reached adult life without an attack. Today, 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 escapefrom 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 Hotel 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 nineteenth 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 over-crowding, 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 favour 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 favouring 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, secondly, 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 countries have yet to learn the alphabet of sanitation. The chief danger results from the impure water supplies of the smaller towns, while the local house epidemics are 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 nineteenth 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 today 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 connexion with modern epidemics has been the revival of the bubonic plague, the most dreaded of all the great infections. During the nineteenth 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 1 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 Wendel 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 moustache 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-childrenthese 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 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; indeed, in many cities the death-rate is now higher and it has become, to use the phrase of Bunyan, “the Captain of the men of death.” 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 with-out 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, yet. 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 connexion 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 amoebatiny 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 colouring 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. Sambon and a friend lived in this district from June 1 to September 1, 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 gonorrhoeal 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 innocentwhose 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 Fransisco by the Chinese, and into the North-western 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-tied 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.