Part 41

Vertical lines are drawn from two pairs of symmetrical points. The continuous lines refer to the higher curve, the broken lines (from the points of intersection of the two curves) refer to the lower curve. The lines will be seen to divide the curves into three parts. This division is of such a character that the sum of the two lateral areas is equal to the central area for each case. ]

FIG. 140. Curve of monthly number of deaths from Small-pox during an epidemic at Warrington, Lancashire, in 1743.

FIG. 141. Curve of weekly number of cases of Scarlet Fever registered during an epidemic at Glasgow in 1892.

Both curves are fitted to the theoretical epidemic curve, and are modified from Brownlee. The curves are in both cases explained on the assumption that the infectivity, having reached a high point at the beginning of the outbreak, decreases thenceforward in geometrical progression. ]

When we are dealing with living beings or are dealing with things that may indefinitely approximate to a mathematical rule, but never entirely fit it. Especially when the living beings are also human beings, with their infinitely complex relationships, various factors are present which interfere with the exact application of mathematical findings. Nevertheless, the theoretical form of the epidemic is an extremely useful framework into which actual epidemics may often be fitted, with greater or less exactness. In the accompanying figures (Figs. 140-141) are adduced cases of greater exactness. There are, however, many cases in which an ‘outbreak’ does not seem to fit the simple theoretical curve at all. Examination of such curves has in some cases suggested that we have not one epidemic or disease but two or more to deal with. In some cases it has been possible to analyze the outbreak on the basis of two or more theoretical curves, suggesting in fact two or more outbreaks of similar but not identical causation (Fig. 142).

FIG. 142. THE CURVES OF SOME EPIDEMICS, which do not follow the theoretical curve, may be analyzed as compounded of two or more epidemics, each of which accords individually to the mathematical rule. Thus ‘Summer Diarrhoea’ is a seasonal disease very fatal to infants in England during the hot months, July and August. The angular curve shows the average daily incidence of deaths from this disease in London during the fifty-three years 1850-1903. It can be analyzed into two of the theoretical epidemic curves.

Each reading of the curve, calculated from the actual cases of ‘Summer Diarrhoea of Infants’, can be divided into two, as indicated in the step-like readings, one dotted and the other continuous. These accord beautifully with two theoretical curves, thus indicating not one but two recurrent epidemics. It thus seems probable that two separate sources of infection are confused as ‘Summer Diarrhoea of Infants’.

What can be the causative element which constrains the incidence of a disease in a population to follow mathematical rules? An answer was provided by John Brownlee (1868-1927), the late statistician to the Medical Research Council of England. The leading fact about an Epidemic is that it rises to a maximum, falls, and then dies out, and that the curve representing the number of new cases in a series of equal and consecutive periods of time throughout the Epidemic is symmetrical. In practice the decline is usually a little slower than the rise. This is sometimes, at least, due to better observation and record of the later cases. Now why does an Epidemic die out? The possible reasons may be reduced to three. Firstly, the end of an Epidemic may be due to the exhaustion of susceptible persons in the population. That is to say, all the survivors are immune, either being so by nature or having become so by having contracted the disease and recovered. Secondly, it is conceivable that the liability to the disease should be decreased, not by rise in the proportion of immunes, but by externally acting causes, as, for instance, by rise of seasonal temperature, which would provide conditions under which the organism loses its infectivity. Expressed in older language, this is to say that the ‘Epidemic Constitution’ (p. 342) has changed. Thirdly, the infecting organisms may, of their own inner nature, lose their infectivity. The second factor may act in special cases, but may be disregarded except in those cases. We are, therefore, left with the first and third.

Now it is possible to construct curves that would correspond to the exhaustion of the supply of susceptible persons by continuous increase of the proportion of those who become immune either by taking the disease or by dying. These curves, however, have the character that their descent is more rapid (and neither as rapid nor less rapid) than their ascent. It is the merit of Brownlee to have suggested that the actual curve of the Epidemic corresponds to a known though very little understood biological phenomenon, namely change in the infectivity of the invading organisms. The simplest expression of his discovery is that the loss of infectivity of these organisms is approximately in the ratio given by a geometrical progression. That is, if the infectivity of the Epidemic be m, and at the end of a unit of time mg (when g is less than unity), at the end of a second unit of time it will be mg^2, and at the end of the third mg^3, and so on. Assuming this to be a fact, the course of Epidemics would follow the curve of normal error (Fig. 139).

Of late years it has been possible to institute artificial epidemics in a series of animals under control conditions. Such experiments must, in the nature of the case, cover a large number of years, but they bid fair to throw much light on the nature and progress of human epidemics.

These results seem to show, what was believed on other grounds, that in the case of highly infective disease, to which, in any population, there are many highly susceptible, isolation of declared cases has little or no effect on the course of the Epidemic. Such diseases are Scarlet Fever, Measles, Influenza, &c. Moreover, the experimental epidemics seem to confirm the conclusions of Brownlee that in some cases at least the course of the epidemic is determined by biological changes within the parasitic beings that cause it.

Thus in the end our health, our lives, and indeed the continuance of our civilization may well depend upon a factor which is outside ourselves. For reasons which we know not, the pullulating billions of living things which are around us, upon us, within us, take up a virulence which before they had not, and after a time they lose that virulence to become as they were before. The world is devastated by an outbreak of Plague, of Cholera, of Influenza. But how and why the organisms that carry these diseases should acquire a new and more deadly infectivity lies among the secrets yet locked within the living cell. Life--the life of the Cell, of the Bacterium, of Man himself--remains among the Arcana Naturae. These are the secret things that in their essence--which is Life--remain and will remain behind the veil. From such cells we came, through such cells we shall return. As to what is the force which starts these processes on their way, we are as ignorant as children, and must remain so, in essence, till we understand the nature of the processes of coming into being and passing away. So Medicine must end where she began, quaking before the Mystery of Life, a Mystery which could only be resolved if we could express Mind in terms simpler than itself. If this could be done the veil that is cast over all flesh would indeed be rent. But the author of this work believes that the hope of this is vain and that we are here in the presence of one of the ultimate things.

EPILOGUE

We have now traced various movements in Medicine throughout the ages and have seen how all the sciences in turn have been made to bring their tribute to the alleviation of suffering. We have seen especially how the consideration of disease as a whole, and of the health of peoples as a whole, has introduced a new view in the handling of disease. Health is a public asset, and its promotion has now been recognized as a public duty. There are undeniable disadvantages in placing officers of the State in control of the personal liberties of its citizens, but, on the whole, the advantages, in matters of health, have outweighed the disadvantages. Only a professed pessimist or a crotchety reactionary could deny the gains to humanity from the passage of preventive measures from private into public hands.

There is another side of the picture which we have need also to consider. The advances in Medicine and the advantages that have accrued therefrom have been entirely the result of the application of the rational method of observation and experiment. To control Nature we must above all things understand Nature. Neither the conception of Nature as the kind old nurse nor the conception of Nature ravening red in tooth and claw will stand. Least of all can we tolerate the picture of Nature as a bountiful mother. If we go to her asking something for nothing, she (far from bountiful) will give us little but what we have given her, and to him who but begs she gives no more than a beggar’s portion. It is thus that she has served the magician and the wizard, who think they can compel her to give them all things by their paltry charms!

The amount of human labor and ingenuity that is now being thrown into the investigation of Nature is almost incredible even to men of science. Some conception of the enormous and unreadable bulk of scientific literature may be gained by a glance at the International Catalogue of Scientific Literature. This gives the titles alone of original articles in the various departments of physical science. These titles for the year 1914 alone occupied seventeen closely printed volumes! The rate of publication has accelerated considerably since then. There are now about 25,000 periodicals devoted to scientific publications! There are very few departments of science which do not have some bearing on Medicine. It is evident that no human mind can possibly compass even a year’s output of this material.

And yet it is not the bulk of writing on Science that forms the only or even the chief deterrent to the general comprehension of its principles. The mass of scientific detail has always been beyond the power of one mind to grasp. But as we have traced Rational Medicine through its long course in Antiquity and the Middle Ages to its debouchment on to our own time, we have found not only a more difficult but also a new situation. In approaching our own age we have found ever more difficulty in discussing Rational Medicine as a single channel of thought. It spreads into a Delta, of which, though the many mouths may inosculate, yet the tendency seems to be for an ever wider divergence. This diffusion, induced by increased specialization, cannot go on for ever without defeating the very objects for which specialism was invented.

On the other hand, when we glance at the tasks now being performed by the medical man, we cannot fail to be struck by the great increase in the number of things that have come to be regarded as within his sphere. It is a commonplace that he has in large part taken the place of the parson. But he has also made encroachments on the functions of the lawyer, the legislator and the judge, of the schoolmaster, the architect and the statistician. He has assumed some of the duties of the parent and guardian, while even the soldier and the policeman are to some degree under his control. In the ordering of their lives, and even in the regulation of their vices and the reform of their shortcomings, men and women are far more willing to seek the advice and help of the medical man than once they were. The reason is, without doubt, that his advice is much more worth having than it once was.

The organization of research, the systematized record of experience, the improved intercommunications of our time, have combined to increase vastly the medical man’s sources of information and to make his application of them more accurate and more scientific. Moreover, there are factors in our social life itself that have tended not only to deepen the physician’s knowledge but to widen his experience. His effective working-day has greatly lengthened. No doubt, the motor car and railway train are important elements in this extension of the doctor’s day, but a far more fundamental element is the advent of the skilled nurse. Many tasks which occupied the time of the doctor in the old days are now relegated to her. The result is that the doctor sees a far greater number of patients and has a much greater experience of actual sickness than was formerly possible.

But after we have discussed all those factors which have gone to the increase of the power of Physic we have still to consider the philosophical basis which has conditioned this increase. Men do not willingly accept that in which they do not believe. The shifting of men’s trust implies a shifting in their faith. In truth the triumph of Physic has underlying it a subtler triumph, that of Scientific Determinism. The great increase in the detailed knowledge of Nature has led to a great increase in the belief in the Reign of Law. Disease and death were once thought to be the special acts of Providence. They are now widely held to be illustrations of determined natural laws. Men of science in general, and medical men in particular, are not wont to profess themselves philosophers, but, in fact, much of their work is done in a spirit which would have us believe that these determined laws are universal and are wholly outside ourselves. Has there not arisen a school that would claim that our thinking is but a seeming, and that we do but behave as though we thought? Three centuries ago Descartes conceived that the animal might be treated as a machine. If man be but an animal, consequences are entailed from which Descartes shrank, for the watchword of his philosophy was ‘Cogito, ergo sum’, I think, therefore I am. There is a newer school whose work is intimately bound up with the progress of Medicine that would abandon this basic doctrine of the father of modern Philosophy, who is also the founder of Physiology, as a separate discipline.

The position as it stands appears as a dilemma. The triumphs of Science have been secured by disregarding Mind, and yet they cannot be appreciated or advanced without invoking Mind. Unless we accept the full conclusions of the Determinist Philosophy, we are forced to the conclusion that Mind must do something to the animal body. If Mind holds the reins, there must be a point at which Mind pulls the reins. The matter ever in dispute is where that point may be. If life and growth are bound up with an Entelechy, as seems to the author of this work to be the case, there must somewhere and somehow be a level in the organism at which the laws of physics and chemistry are transcended by some other mode of action.

It is no part of our task to provide a Philosophy which will resolve all the problems that our subject raises. Nevertheless, in the presence of this dilemma, such a work should not close on too optimistic a note, in the department either of medical thought or of its application. Even if looked at merely as an interpreter of its own terms, determinist thought, which lies at the basis of modern medical developments, has not been quite so universally successful as is often supposed, and as the preceding pages of this book may lead the reader to think. While enormously increasing the sum of our knowledge of Nature, it has also tended more and more to separate the parts of that knowledge from each other. It is clear that no such way of thinking can ever give us a survey of Nature as a whole. It can never enable us to ‘think things together’, and without such thinking together our life is and must remain a contradiction and a muddle.

For a real survey of Nature we must look to another Philosophy and another Method. We are in this matter but just entering on a new era, and may it not be that some sort of solution will be provided by a better study of the Mind itself? Only by our minds can we know that Nature presents us with any order at all. It therefore behoves us to search out most diligently all that we can learn about our minds, to see whether, on the one hand, this determined order, which has so impressed our age, is in any degree within us and part of our observing instrument, or whether, on the other hand, it is wholly without us. There is much evidence that it is not wholly without us, and that Determinism is a habit in our method of thinking on certain topics, and that the emphasis on the ‘primary qualities’ (see pages 106-8) which we inherit from Galileo is by no means justified. It may be that what we think and feel and see is not only as real as what we weigh and count and measure, but that weighing, counting, and measuring are but forms of thinking, feeling, and seeing. In this connection the reader should turn over again in his mind the implications of the ‘Law of Specific Nerve Energies’ enunciated by Johannes Müller (see pp. 212-13).

Nor must we end on too optimistic a note as to the actual achievements of Science. Advances in our knowledge have certainly been very great, but they may be and often are exaggerated. We must always guard ourselves against considering mere accumulation of detail as an advance. The collection of data is but a means to an end, and if that end is not reached they are a very weariness and vexation of the philosophic spirit. Real advance in knowledge can only be tested by effective advances in theory, and thus judged the cost of progress--the cost in the brute accumulation of facts--has increased far more rapidly than progress itself. What is wanted is not so much new data as correlation in their accumulation. The increase in medical specialism is not so much evidence of advance as it is of the heaping up of uncoordinated observations.

Works on Medicine intended for popular consumption are often couched in the jubilant terms of victory. Yet there are whole departments in which no progress whatever has been made. We pride ourselves on the advance in knowledge of infectious disease which the germ theory has brought us, and yet we are utterly and completely ignorant of the two things about infectious disease which are the two things most worth knowing on that topic. Firstly, no man has conceived the way in which the parasites of disease first fastened themselves on the animal body, a specific parasite to a specific animal. In other words, we have not the least idea how diseases first begin. Secondly, no man has conceived a reason why diseases, distributed over a wide area and in many bodies, should vary in virulence from time to time, why, for instance a relatively mild condition, such as influenza, should suddenly devastate the world. It is easy to say that human resistance varies, but that is only to restate the problem in terms of which we know nothing. On these high topics of Medicine we know as much and as little as Hippocrates.

Moreover, if we turn to definite diseases, there are many conditions, and those among the most important, of which our ignorance is almost complete. Thus of the very common and painful diseases, muscular rheumatism and rheumatoid arthritis, we know hardly more than Hippocrates and our remedies are but little more effective than his. The common cold--economically the most important of all diseases, not excluding Cancer and Tuberculosis--has a vast literature, but the physician is almost helpless in its presence and can but let it run its course. Measles, Whooping-cough, and Influenza have become more deadly of late years. We have still no clear line of treatment for them. Nor have we any real insight into the nature of Cancer. Those who reach advanced age have no better chance of life than they had two hundred years ago (p. 177). Above all, it must be remembered that the great majority of deaths are caused by diseases theoretically preventable. There is a natural term to life which it is desirable that all should attain. Yet most of us will surely die a violent death as truly as though struck down by a felon’s hand. Death from disease is an unnatural and a violent death.

Faced by facts of this order there are those who constantly urge increased activity in medical ‘research’. But research can only be prosecuted by those whose talents specially fit them for the work. With reason it may be and is doubted whether there are many in Western Europe or America who could profitably be employed on medical research who are not already so employed. It is easy to make investigations on a certain level, but those best qualified to judge are of opinion that the general level of medical research has fallen, not risen, of late years. The number of publications has multiplied manyfold, but there are those who doubt if there is much increase in investigation of the first order. The increase in specialism and the extremely narrow outlook of some workers has stultified much investigation, since with his decreased range the researcher is often less able to perceive the bearings of his own work. Thus he may labor for years elaborating a technique by means of which he may collect facts without that guiding wisdom or judgment that is the mark of genius. It must ever be borne in mind that the object of fact-collecting is the deduction of law. Not all facts can be collected, for facts are infinite in number, and it is therefore necessary to select. Selection involves judgment, the final and indefinable property of Mind; for, if from the facts no laws emerge, the facts themselves become an obstacle, not an aid, to scientific advance.

All who have to read systematically large masses of modern scientific literature have been unfavorably impressed by its absence of form. It is evident that a large proportion of scientific workers lack adequate literary training and never acquire a proper sense of literary form. The growing interest in Science has had an unfavorable effect on Education in the direction of early and intensive specialization. The result is that many scientific publications are but semi-literate, they are often incoherent in presentation and even more frequently unnecessarily diffuse. Nor is it merely a matter of form. Language is but the outward and visible sign of which Thought is the inward and spiritual reality. Confused writing usually indicates and always leads to confused thinking. Thus the unliterary character of scientific writing bids fair to pass from being a mere nuisance to become a great scientific evil. Good and effective writing implies a broad and solid literary background, just as good and effective scientific research implies a broad and solid scientific background. The fact is that the Humanities and the Sciences are far from being as independent of each other as many suppose. If literary studies lead to clear and effective expression and clear and effective thinking in the domain of Science, scientific studies ventilate and inform and vitalize Literature. The separation of the two disciplines, especially in the adolescent stage of mental development, does an injury to both. The concentration of the endowments of Learning on the scientific departments and especially on the departments of applied science has given rise to a very widespread evil which is none the less evil because it is subtle.