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T. Mitchell Prudden, M.D.

It is commonly neither wise nor necessary for people not professionally concerned to think much about disease, or weigh anxiously the chance or mode of its acquirement. But now and then conditions arise which demand general attention and instruction regarding certain diseases in order that a great, threatening calamity may be averted. Such a condition faces the people in all lands to-day in the appalling prevalence of tuberculosis. A disease which in mild or severe form affects at least one-half of the whole human race, and which causes the death of full one-seventh of all who pass away, killing about one-third of those who perish between the ages of fifteen and forty-five—a disease which is most insidious in its onset, and often relentless in its course, and which may be largely prevented—is one about which we cannot be indifferent, and should not be longer inactive.

There has long been reason for believing that tuberculosis is a communicable disease. Its prevalence in certain families and communities, its frequent occurrence in those who have personally attended upon its victims, its onset in those who have occupied apartments vacated by consumptives—such facts observed over and over again abundantly justify the belief in its communicability. Up to the commencement of the last decade the cause of the disease was altogether unknown, and no definite data were at hand which could enable us to fix upon a feasible plan for limiting its ravages. But in these later years a great light has been thrown upon this and other kindred diseases.

Most intelligent people are aware that within the past decade a new field in the domain of life has been revealed and widely explored. It has been learned that in earth and air and water there exist countless myriads of living things so minute as to lie far beyond the limits of the unaided vision, and yet in the aggregate so potent in the maintenance of the cycle of life upon earth that without their activity all life would soon cease to be, and the elements which for a short span fall under the sway of the life forces in all higher animals and plants would lapse finally and irrevocably into their primal state. These tiny organisms are called germs, microbes, or micro-organisms. One great and important group of them belongs among the microscopic plants called bacteria. These bacteria as a class are important in their economy of nature, because they live for the most part on dead organic material—that is, such material as has once formed a portion of some living thing.

The world's store of available oxygen, hydrogen, carbon and nitrogen, out of which all living beings are largely formed, is limited, and if after these have served their temporary uses, as the medium through which that mysterious potency called life alone can find expression, they were not speedily released, new generations of living beings could neither assume nor maintain their place in the great cycle of life. And so these tiny plants, year in, year out, by day and by night, unseen and mostly unheeded, are busy always in making possible the return of each year's visible vegetation and the maintenance of an unbroken succession of generations in man and beast.

Different groups and races among the bacteria have different habitations, and vary widely in their special powers. Complex and powerful as is the aggregate result which they accomplish in the world, the performances of the individual are comparatively simple. They are most liberally endowed with the capacity for multiplication, and each germ acts as a tiny chemical laboratory, taking into itself the organic matter on which it feeds, and resolving it into new compounds. Some of the latter are used in building up and maintaining its own body, while others are given off into the surrounding media.

We are but just beginning to peer at the mysterious processes which go on under the influence of the bacteria in this underworld of life, and to realize that all the lore which unwearied toilers in the past have gathered in their studies of the visible forms of animals and plants, makes but one of the many chapters in nature's story-book of life.

But this new and stimulating point of view, toward which the studies of the past decade have led us, does not look so largely into the domain of the practical that it would greatly attract the majority of business and pleasure and ennui ridden mankind were it not for one very practical fact which these recent studies have revealed. This is, that among the myriads of altogether beneficent bacteria which people the earth, and air, and water, there are a few forms which have chosen out of all the world as their most congenial residence the bodies of men. But even this would be of only passing interest to most people were it not still further unfortunately true that in the performance of their simple life-processes these man-loving bacteria, feeding on the tissues of their host, and setting free certain subtle poisons in his blood, each after its kind, can induce those disturbances of the body's functions and those changes in its structure which we call disease.

The diseases caused by the growth of germs in the body are called infectious. The germs causing some of the infectious diseases are given off from the bodies of their victims in such form as to be readily transmitted through the air to others, in whom they may incite similar disease. Such diseases are spoken of as readily communicable, though it is not actually the disease itself, but only the germ causing it, which is transmitted. In other infectious diseases transmission but rarely occurs. Many infectious diseases are very easily communicated from the sick to the well under unsanitary and uncleanly conditions, which with proper care are very little liable to spread.

I need not here put on parade the whole uncanny list of germ diseases, in which tuberculosis stands foremost, followed by pneumonia, diphtheria, typhoid fever, scarlatina, cholera, small-pox, and the rest. Nor need I call to mind the means by which our growing knowledge in this domain has been day by day laid under tribute for suggestions of hope and safety for the stricken. It is a record of brilliant conquest in nature, and already of far-reaching beneficence to man.

But the great fundamental advance which signalizes the past decade is the lifting of this whole class of fateful germ diseases out of the region of the intangible and mysterious, and their establishment, on the basis of positive experimental research, in the domain of the comprehensible and definite. The things which cause them are no longer for us mysterious emanations from the sick, or incorporate expressions of malign forces against which conjurations or prayers could alone promise protection, but they are particulate beings, never self-engendered, never evolved in the body, always entering from without—things which we can see and handle and kill.

Let us now glance at the germ called the tubercle bacillus, the germ which induces and which alone can induce tuberculosis. It does not exist and thrive in the body of men or animals in health. Without the entrance of this particular germ into the human body from without, tuberculosis cannot develop in it. Without the transmission of this germ in some way or other in a living condition from the sick to the well, tuberculosis cannot spread. In the life-story of this tiny germ lie both the potency for mischief which we deplore and the secret of our release from its bondage.

The tubercle bacillus is a little colourless, rod-like plant, so small that even many thousands of them piled together would make a heap far too small to be visible to the naked eye. It cannot move about, nor can it grow without moisture, nor at a temperature much above or much below that of the human body. The material on which it feeds must be very nicely adapted to its requirements, and it has no lurking and growing places in nature outside of the bodies of men and a few warm-blooded animals. It can be cultivated artificially in the laboratory, and we know more about its life and peculiarities than about almost any other germ. While it can remain alive in a dried state for many weeks, it is readily killed by heat, by sunlight, and by many of those chemical substances which we call disinfectants. It does not flourish equally well in the bodies of all human beings.

When once it gains lodgment in a body suited to its growth it multiplies slowly, each germ dividing and subdividing, taking from the tissues material for its growth, and returning to them certain subtle poisons which it sets free. The action of the tubercle bacillus is peculiar in that it stimulates the cells of the body, wherever it may lodge and grow, to the formation of little masses of new tissue, which we call tubercles. These tubercles are as a rule short-lived, and, if the disease progresses, tend to disintegrate. If the tubercles have grown in such situations as to make this possible, as in the intestinal canal or the lungs, the disintegrated and broken-down material, often containing myriads of the living germs, may be cast off from the body. In tuberculosis of the lungs, or consumption, this waste material is thrown off with the sputum [spittle]. While almost any part of the body may be affected, tuberculosis of the lungs is by far the most common form of the disease.

It follows from what has been said that the only way in which we can acquire tuberculosis is by getting into our bodies tubercle bacilli from tuberculous men or animals. The only animals liable to convey the disease to man are tuberculous cattle, and these through the use of either meat or milk. The danger from the use of uncooked meat or the unboiled milk from tuberculous cattle is real and serious, but it will not be considered here at length, because the great and prevailing danger of infection comes from another source.

Almost as soon as the significance of the tubercle bacillus was established, a series of studies was undertaken on the possibility of the spread of the disease by the breath or exhalations of the persons of consumptives. These studies at once showed that the tubercle bacillus cannot be given off into the air of the breath from the moist surfaces of the mouth and air passages, nor from any material which may come from them while this material remains moist, nor from healthy unsoiled surfaces of the body. The establishment of this fact is of far-reaching consequence, because it shows that neither the person nor the breath of the consumptive is a direct source of danger, even to the most constant and intimate attendants.

While the discharges from the bowels in persons suffering from tuberculosis of the intestinal tract may contain many living bacilli, the usual mode of disposal of these discharges protects us from any considerable danger from this source.

It is the sputum after its discharge from the body on which our attention must be fixed. While the sputum is moist it can, as a rule, do no harm, unless it should be directly transmitted to those who are well by violent coughing, sneezing, etc., by the use of uncleansed cooking or eating utensils, by soiled hands, or by such intimate personal contact as kissing or fondling. But if in any way the sputum becomes dried, on floors or walls or bedding, on handkerchiefs or towels, or on the person of the patient, it may soon become disseminated in the air as dust, and can thus be breathed into the lungs of exposed persons.

The wide distribution of tubercle bacilli in the air of living-rooms, and in other dusty places where people go, is due partly to the frequency of the disease and the large numbers of living bacilli which are cast off in the sputum (sometimes millions in a day), and partly to the fact that many of the victims of consumption go about among their fellows for purposes of business or pleasure for months or years. So each consumptive, if not intelligently careful, may year after year be to his fellow-men a source of active and serious and continual infection.

This, then, the dried, uncared-for sputum of those suffering from pulmonary tuberculosis, is the great source of danger; this the means so long concealed by which a large part of the human race prematurely perishes. Let but this discharged material be rendered harmless or destroyed before it dries in all cases, and the ravages of this scourge would largely cease. This is not a theoretic matter only, for again and again have the living and virulent germs been found clinging to the walls and furniture and bedding and handkerchiefs of consumptive persons, and in the dust of the rooms in which they dwell. A malady whose victims far outnumber those of all other infectious diseases put together, sparing neither rich nor poor, seizing upon life while it is as yet only a promise, but most inexorable in the fulness of its tide—this malady can be largely prevented by the universal and persistent practice of intelligent cleanliness.

We have learned in the past few years one fact about tuberculosis which is of incalculable comfort to many, and that is that the disease is not hereditary. It is very important that we should understand this, because it seems to contradict a long-prevalent tradition, and a belief still widely and sorrowfully entertained. Bacteria, and especially most disease-producing bacteria, are very sensitive in the matter of growth and reproduction to the conditions under which they are placed, and especially to the material on which they feed. So that a germ which can induce serious disease in one species of animal is harmless in the body of a different though closely allied form. More than this, different individuals of the same species, or the same individual at different times, may have the most marked differences in susceptibility in the presence of disease-producing germs. What this subtle difference is we do not know. Whether the body at one time affords a congenial soil to the invading germs and at another does not, whether its marvelous and complex powers of resisting the virulent tendencies of disease-producing bacteria at one period or in one individual are more vigorous than in another, and vary at different times, we do not certainly know. This, however, we do know, that certain individuals are more likely than others to yield to the incursions of the tubercle bacillus. This vulnerability in the presence of invading germs we call susceptibility, and susceptibility to the action of the tubercle bacillus is hereditary. It is not the disease, tuberculosis, which comes into the world with certain individuals or with successive children of the same family, but the aptitude to contract it should external conditions favour. What subtle impress on the cells which are to develop into the new individual renders him more than another an easy prey to the tubercle bacillus should it later find lodgment in his body we do not know, and we may not hope soon to be enlightened, since all the intricate mysteries of heredity seem involved in the problem. But this we do know, that how ever much the child of tuberculous parents or a member of a tuberculous family may be predisposed to the disease, he cannot acquire tuberculosis unless by some mischance the fateful germ enters his body from without. What has been all through these years regarded as the strongest proof of the hereditary transmission of tuberculosis—namely, the occurrence of the disease in several members of the same household—is, in the new light, simply the result of household infection—the breathing of air especially liable to contain the noxious germs, or their entrance in some other way into the bodies of persons especially sensitive to their presence. I do not mean to imply that under no conditions can the tubercle bacillus be transmitted from the mother to the child before its birth. In a few instances this is believed to have happened. But its occurrence is so extremely infrequent that it may be regarded as accidental, and of no serious importance from our present point of view.

But it will perhaps be said, “If the tubercle bacilli are so widely diffused, why do we not all acquire tuberculosis, and why was the world not long since depopulated?” In order to explain this matter I must ask the reader to look with me for a moment at some of the body's natural safeguards against bacterial and other invaders from the air. It has been found that a person breathing in germ and dust-laden air through the nose breathes out again air which is both dust and germ free. The air passages of the nose are tortuous, and lined with a moist membrane, against which the air impinges in its passage. On these moist surfaces most of the solid suspended particles, the germs among them, are caught and held fast, and may be thrown off again by secretion. In breathing through the mouth this safeguard is not utilized. Again, the upper passages leading to the lungs are lined with a delicate membrane of cells, whose free surfaces are thickly beset with tiny hairlike projections. These projections are constantly moving back and forth with a quick sweep, in such a way that they carry small particles which may have escaped the barriers above up into the mouth, from which they may be readily discharged. In this way much of the evil of breathing dust and germ-laden air is averted. But in spite of these natural safeguards a great deal of foreign material does, under the ordinary conditions of life indoors or in dusty places, find lodgment in the delicate recesses of the lungs. The body tolerates a good deal of the deleterious material, but its overtasked toleration fails at last, when serious disease may ensue.

When ordinary forms of living bacteria get into the tissues of the body, a very complex cellular mechanism, not fully understood, usually results in their destruction and ultimate removal. In the presence of the tubercle bacillus the body cells are often able to build a dense enclosing wall around the affected region, shutting it off from the rest of the body. This is one of the modes of natural cure. The body cells are sometimes able, if sustained by nourishing food and an abundance of fresh air, to carry on, year after year, a successful struggle with the invading germs, so that the usefulness and enjoyment of life are but little interfered with. Finally, a certain proportion of human beings seem to be endowed at birth with some as yet unknown quality in the cells or fluids of the body which naturally unfits them for the life uses of the tubercle bacillus, and so renders the individual for longer or shorter periods practically immune.

Others, on the contrary, are, as we have seen, from birth unusually susceptible. This inherited susceptibility to the incursions of the tubercle bacillus, should this find lodgment in the body from without, by no means always reveals itself in any apparent lack of vigour or robustness of the body. Still, any habit or mode of life which diminishes the bodily vigour, whether in those predisposed to this malady or in the apparently immune, and gives it a leaning toward disease, diminishes, as a rule, the chances of a successful contest with the bacillus. And so it is that in spite of the wide distribution of these fateful germs in frequented places, and the tendency of certain vulnerable persons to succumb to their ravages, so many people are not affected by them, and so many, although not altogether escaping their malign influence, are yet able to wrest at least a moiety of life from the hand of the great destroyer.

The degree of success which may attend our crusade against tuberculosis will largely depend upon the wide diffusion of the knowledge of its communicability by means of the sputum dried and powdered and floating in the air as dust, and the intelligent persistence with which the morbid material may be safely cared for at its sources. The resolute avoidance by consumptives of the not only filthy but dangerous practice of spitting upon floors or streets, or anywhere else except into proper receptacles; the use of receptacles which may be and are frequently and thoroughly cleansed, and, best of all, of water-proof paper cups, which with their contents may be burned; or, when circumstances require, the receiving of the dangerous material on cloths or Japanese paper napkins, which may be destroyed by fire, and not on more valuable handkerchiefs on which the sputum is allowed to dry while in use or before disinfection and washing; scrupulous care by others of the sputum of those too ill to care for it themselves—these are the comparatively simple means from which we may most confidently expect relief. The details of these precautions and their adaptation to the special circumstances of those suffering from the disease can be most wisely left to the physician, and though of paramount importance, need not further engage our attention here.

To the consumptive himself these measures are not without a vital significance. For his chances of recovery may be in no small degree diminished if he be more or less constantly liable to a fresh infection from material which he has once got rid of, and which should have been destroyed.

The great volumes of fresh, moving air which we encounter out-of-doors in properly cleansed streets usually so greatly dilutes the dust, of whatever kind, that little apprehension need be felt from its presence. When, however, in crowded cities, the streets are, as is nearly always the case, save for a few favored localities, filthy, and but fitfully cared for; when choking dust clouds must be encountered by the citizen during the haphazard and slatternly essays at cleaning made by untrained and irresponsible sweepers; we cannot ignore a danger from street dust which may well incite grave apprehension. The citizen can, if he must, run from the presence of cloud-enwrapped machines furiously whirled along half-sprinkled pavements; he may avoid a block on which the hand-sweepers, in the absence or in disregard of rules, ply their nefarious brooms over unwet surfaces, because too indolent or indifferent to sprinkle them—these things he can do if he be not willing or ready to apply the citizen's remedy for municipal misrule.

But it is in rooms either of dwelling or assembling places that the ill effects of infectious dust are most potent, because the air is here not so constantly renewed as it is out-of-doors, and is liable to be breathed over and over again. Dust which gets into houses does not readily leave them, unless special and intelligent means be directed to its removal. We do not usually realize that, though the air itself in inhabited rooms is constantly changing more or less rapidly by diffusion, by draughts, or by purposed ventilation, fine dust particles are not removed under the same influences in proportionate degree. They cling more or less tenaciously to all surfaces on which they have settled, and especially to fabrics, so that currents of abundant force and sufficient distribution to change the air may and usually do leave the lodged dust particles almost entirely undisturbed.

One of the most threatening tendencies of modern times in matters of health is that of overcrowding in cities, and the great element of danger from this overcrowding is not only and not chiefly the insufficiency of air in living-rooms and the lack of ready means for its renewal, but the accumulation in this air of infectious germs floating with the dust. Abundant water supply and good sewerage have rendered possible and measurably safe, so far as the ordinary waste of life is concerned, the building of vast tenements which swarm with people. But the means of getting pure air, and especially of disposing of infectious material often floating in it when it is confined, have not at all kept pace with the demands of health and cleanliness.

But when we return to larger and more liberally furnished dwellings of the well-to-do classes, we are not reassured, for in some respects the rich are sadly handicapped by the “tyranny of things.” Of course, long and thick piled carpets afford persistent lurking-places for infectious as well as other dust. Certainly heavy hangings in a measure hinder the detergent action of the sunlight, shut the used air in and the fresh air out, and shelter floating matter which might otherwise escape. Without doubt, complex upholstery with roughened fabrics increases the difficulties in the maintenance of cleanliness. But the usage of the householder in these matters will, after all, depend upon whether his practical devotion be most at Fashion's or Hygeia's shrine. We may hope for the coming of a time when clean, clear, airy, simply furnished living-rooms shall replace the stuffy, fabric strewn apartments in which the fashionable citizen so much delights to-day.

In one particular, however, the devotion to cleanliness may be unreservedly insistent, and that is that in the cleaning of living-rooms, whether occupied by the sick or the well, the distinct and recognized purpose of the operation shall be to remove, and not simply to stir up, the ever-gathering dust. The past few years, so beneficently signalized by the exploitation of the new germ lore, have seen marked departures from the traditional sweepings and dustings of a past era; and the emancipation of the housekeeper, and incidentally of the household, from the thrall of the pestiferous feather duster seems fairly under way. Still, some of the old barbarous travesties upon cleaning widely persist. The dry broom still seeks out in the deep recesses of the carpets not the coarser particles of dirt alone, but the hordes of living germs which were for the time safely ensconced, and among these such malignant forms as the chances of the day have gathered. These all are set awhirl in the air; some collect upon salient points of the fittings and furnishings; many stay with the operator, to vex for hours the delicate breathing passages or the deeper recesses of the lungs. Then in the lull which follows, gravity reasserts its sway, and the myriad particles, both the living and the dead, slowly settle to the horizontal surfaces, especially to the carpets. Then the feather duster comes upon the scene, and another cyclone befalls. The result of it all is that the dust has finally been forced to more or less completely abandon the smooth and shining surfaces where it would be visible, and is largely caught in the surface roughness of the carpets or upholstery or hangings, ready at the lightest footfall or the chariest touch to dance into the air again, and be taken into the lungs of the victims of the prevailing delusion—the delusion that the way to care for always obnoxious and offensive and often dangerous dust is not to get it out of the house, but to keep it stirring in the air until at last it has settled where it does not vex the eye.

By the use of moist tea leaves in the sweeping of carpets, by the use of soft-textured fabrics, frequently shaken out-of-doors, or by moist cloths or chamois in dusting, much useless dust-scattering may be avoided. But no matter what the means employed, the final purpose of every household cleaning should be to get the dust, not afloat, but away.

Probably the most serious source of infection which one is liable to encounter in the usual ways of life is the occupancy at hotels of bed-rooms vacated by consumptives without subsequent efficient cleansing, and travel in sleeping cars. I need not enter here into the harrowing details of desperate uncleanness which the ordinary railway travel brings to light. It is to be hoped that popular demand for reform in the routine of hotel-keepers and railroad managers in the matter of ordinary sweeping and dusting, and in the precautions against the spread of tuberculosis, may soon usher in among them a day of reasonable sanitary intelligence.

A belief in the communicability of tuberculosis is becoming widely diffused, and it would seem to be desirable, on the ground of policy alone, for the managers of summer, and especially of winter resorts frequented by consumptives, to let it be known in no uncertain way that their precautions against the spread of infectious diseases are effectually in line with the demands of modern sanitary science.

The members of families bearing a hereditary susceptibility to the acquirement of this disease should strive to foster those conditions which favour a healthy, vigorous life in occupation, food, exercise and amusement and remember that for them more than for others it is important to avoid such occupations and places as favour the distribution, in the air or otherwise, of the tubercle bacillus.

But when the individual has done what he can in making his surroundings clean, and in thus limiting the spread of the tubercle bacillus, there still remains work for municipal and State and national authorities in diffusing the necessary knowledge of the disease and its modes of prevention; in directly caring for those unable to care for themselves; in securing for all such freedom from contact with sources of the disease as the dictates of science and humanity may require.

To health boards, either national or local, must be largely entrusted the primary protection of the people against the danger from tuberculous cattle.

A national bureau of health might be of incalculable service in stimulating and harmonizing measures for the suppression of tuberculosis in various parts of the land, and in fostering research in lines which promise large practical return in the saving of life.

Tuberculosis has in this country been officially almost entirely ignored in those practical measures which health boards universally recognize as efficient in the suppression of this class of maladies. Physicians are not now generally required to report it to the local health boards. Systematic official measures of disinfection are not widely practised. But such official measures have been found extremely useful in the limitation of other communicable diseases. While consumption must logically be classed with diphtheria and scarlatina and small-pox as a communicable germ disease, it is, in fact, in the light of our present knowledge, when intelligently cared for, so little liable to spread that it is properly exempt from some of those summary measures which health authorities are justified in adopting with the more readily and less avoidably communicable maladies. Moreover, consumption is apt to involve such prolonged illness, and so often permits affected persons for months and years to go about their usual avocations, that general isolation would be both impracticable and inhumane. Moreover, for reasons which it is hoped are evident to the reader, isolation among those capable of caring for themselves is at present entirely unnecessary.

But while extreme measures are not called for, local health boards must soon act in the prevention of tuberculosis. For the present the wisest and most humane course would seem to be to attempt to secure the desired ends rather by instruction and counsel and help than by direct and summary procedures. There is no more pitiable spectacle in this land to-day than that of hundreds of victims of advanced tuberculosis in every large town who cannot be comfortably or safely cared for in the dwellings of the poor, and yet who are always unwelcome applicants at most of our hospitals and at many are denied admission altogether. They are victims of ignorance and of vicious social and hygienic conditions for which they are not largely responsible, and States and municipalities, which are most to blame, owe them at least a shelter and a place to die. Unquestionably one of the urgent duties immediately before us in all parts of the land where tuberculosis prevails is the establishment of special hospitals in which this disease can be treated and its victims safely cared for.

And now at last remains to be spoken what word of cheer and hope our new outlooks may have given us for those who are already under the shadow of this sorrowful affliction. The dreams and aspirations and strenuous labours of the students of this disease have looked steadily toward the discovery of some definite and positive means of cure, but as yet full success lingers beyond their grasp. The methods for the early detection of tuberculosis which science has pointed out make it possible for affected persons to plan such modes of life and early seek such salubrious climates as promise a hope of recovery. We have studied closely the ways in which the cells of the body often successfully resist the incursions of the already seated germs, and learned how in many ways the natural forces of cure may be sustained and strengthened. We have learned much about certain complicating occurrences which often form the most serious features in the progress of tuberculosis of the lungs, and how they may be best avoided. And so to-day the outlook for those in the earlier stages of this disease is in a considerable proportion of cases extremely encouraging. It is no longer for us the hopeless malady which it was earlier believed to be. It is not necessarily a bitter losing fight upon which one enters who becomes aware that the finger of this disease is upon him. A long and happy and useful life may still be his if the conditions which favour his cure be early and intelligently fixed upon, and patiently and faithfully persisted in. The wise physician is here the best adviser in climate and regimen, as well as in the proper selection of remedial measures, and the earlier his counsel is sought and acted on, the brighter will usually be the outlook for recovery.

Research in tuberculosis and the ministration of the physician should, and generally do, go hand in hand, and no time should be lost in bringing to the aid of the stricken what light and promise the studies of the laboratory day by day may yield. The great and beneficent work which has been accomplished by Trudeau in the Adirondack woods, in at once widening the bounds of knowledge of tuberculosis and in carrying to a successful issue in so many the varied and delicate processes of cure, is a cheering example of what may be accomplished with persistent devotion, by the light of our new knowledge, in mastering a malady so long considered hopeless.