Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1/Inaugural Address
TRANSACTIONS
OF
The Society of Tropical Medicine and Hygiene
INAUGURAL ADDRESS
BY THE PRESIDENT,
SIR PATRICK MANSON, K.C.M.G., F.R.S.
(Read at the First Ordinary Meeting of the Society, June 26th, 1907.)
I TRUST that it does not augur badly for the success of the Society of Tropical Medicine and Hygiene that its first President has to commence his Inaugural Address with an apology. Such, unfortunately, is the case. I intended to devote some time to preparation, but having been called on unexpectedly to take part in the recent International Conference on Sleeping Sickness, I have been so occupied that I have not been able to find adequate time or to give that care to preparation that the importance of this occasion demands. I apologise in advance, and trust you will be indulgent to my shortcomings.
Before proceeding further, I wish to express my appreciation of the compliment the Council has paid me in electing me the first President of the Society, a Society which, although the youngest, has some reason to expect that it will be one of the most useful and fruitful of the medical institutions of the country. During nearly the whole of ray professional life tropical disease has interested me, and as opportunity offered I have endeavoured to follow up the subject, and, if I may be allowed the expression, to forward the interests of the cause. Now that I am fast approaching the end of my career, to find that these efforts, however humble, are appreciated by my colleagues is to me most gratifying. I need hardly say that I thank you sincerely for the compliment, and that I shall do my best to discharge the duties of the office with which I am entrusted, and to forward the interests of our Society.
Our objects are various. An important one is to bring together the men who are interesting themselves in tropical medicine, with the idea that by so doing the subject itself will be advanced and we ourselves benefited. With a view to securing these objects, the Society has been placed on a basis as broad as possible. Although domiciled in the Metropolis, it is open to any member of the profession, whether domiciled in London, Great Britain and Ireland, or abroad, and also to those followers of any science or profession capable of forwarding, directly or indirectly, the interests of tropical medicine.
It is apparent to any one who has followed the discoveries of recent years that tropical medicine, more than any other branch of medicine, is dependent on several of the collateral sciences, more especially on the various branches of natural history. Our basis therefore has to be a broad one, and in drawing up the constitution of the Society this point has been kept steadily in view.
At one time the specialising of tropical medicine was looked on somewhat askance, and still more so the establishment of special schools for the teaching of tropical medicine. Doubtless the formation of this Society will be regarded by some in a similar way, but as time goes on and the general body of the profession becomes acquainted with our objects and our work, I have no doubt, as has been the case with the special teaching of tropical medicine, that we shall soon be tolerated and ultimately approved.
How important it is for the subject itself, as well as for those who are engaged in its study, that the latter should have opportunities, such as this Society is calculated to afford, of placing themselves abreast of the times will be readily understood when we think of the rapid progress that tropical medicine has made within the last few years. This progress has been as remarkable as it has been great; indeed, it is hard to keep pace with it. No sooner have we settled down to digest some new and important discovery than a fresh and perhaps more startling one is offered us; and this, too, we must digest and assimilate if we are to practise, or to teach, or to work to the best advantage.
As with the growth of a child, we hardly appreciate the recent progress of tropical medicine, living with it, so to speak, as we do from day to day; but if we come from abroad after an absence of years, or if we compare the state of knowledge, say, of twenty years ago with that of to-day, we shall find that the stripling has not only altered in feature, but has grown into a veritable giant.
I sometimes take from their shelves the text-books of my student days and compare their contents with those of the text-books of to-day—Watson's with, say. Osier's Principles arid Practice of Medicine. The contrast is remarkable. A perusal of Osier's shows how nearly all the old theories have been upset; how new diseases have been brought to light, old drugs and methods of treatment abandoned, pathology and etiology in most instances completely changed. If the contrast be great between the general medicine of to-day and that of forty or fifty years ago, it is even still greater in the case of tropical medicine. As regards the latter, it is unnecessary to go back to the days of Watson to recognise a striking contrast. It suffices to compare the tropical medicine of the early 'nineties as represented, say, by Davidson's Hygiene and Diseases of Warm Climates, published in 1893, with one of the recent text-books, say, the section on Tropical Medicine in the new edition of Allbutt's System of Medicine edited by Rolleston.
Of the 1000 pages in Allbutt's book, the first 200 are exclusively devoted to protozoa, mosquitoes, blood-sucking flies, and ticks. In Davidson's work there is hardly a sentence on these subjects. Practically, this is a new and a big and rapidly growing branch of tropical medicine.
In Davidson's work the first chapter in the section on General Diseases relates to malaria. It is a very complete, carefully-written article, embracing all the most important knowledge and views of the time; yet in that article there is not a single word on the mosquito as a carrier of malaria. In those days, although Laveran's great discovery had already been before the world for twelve years, we had got no further than the conviction that the air was the common medium of infection, and there was still a lingering belief in the hippocratic idea that the drinking of marshy water produced enlargement of the spleen. Now a large part of the tropical section of Allbutt's system is occupied with the part played by the mosquito in the malarial drama. Everyone knows that the mosquito is the sole vector of malaria, and an enormous literature has grown up around a discovery which has changed radically our views, not only as regards the etiology and prophylaxis of malaria, but has given a powerful stimulus to the study of the protozoa in gal, and also the role of insects in the transmission of disease germs.
Taking the chapters in Davidson's book in their order, we come next to Tropical Typhoid Fever. Since this chapter was written, Wright's bold and apparently successful prophylaxis has been introduced, and is being extensively practised. This, although not relating to a specially tropical disease, may in time be shown to be a great advance in the prophylaxis of one of the most serious diseases occurring in the Tropics.
When he wrote the chapter on Malta Fever, Bruce had already discovered the Micrococcus melitensis; but, just as was the case with Laveran's discovery, we had to wait a long time before the discovery bore practical fruit. Now, however, we know that the micrococcus is acquired in what, when Davidson's book was written, was an entirely unsuspected medium and manner. Both from a scientific and practical standpoint, Zammit's discovery that the germ of Malta fever is eliminated in the milk of apparently healthy goats is a discovery of a little more than a year's standing. It carries with it important practical results, as has already been proved.
Yet more important are the recent discoveries in regard to the still undiscerned germ of yellow fever, especially its dependence for propagation on the offices of the stegomyia mosquito and the efficiency of the prophylactic measures founded on that circumstance.
We cannot claim any definite or important advance in our knowledge of dengue; but in plague, the subject of the next chapter in Davidson's book, the role of the rat in its diffusion—so familiar to the ancients—has once more been rediscovered and more soundly established than ever, this time not by observation only but also by experiment. This is a discovery that promises to be of great practical value in the struggle against a terrible disease; its establishment on carefully observed facts is quite a recent occurrence.
We cannot claim that there has been much material advance in any of the subjects treated of in the next three chapters of Davidson's work, namely, those on Cholera, Leprosy, and Beri-beri; but, as regards the subject of the succeeding chapter, Negro Lethargy, or the Sleeping Sickness, it may be claimed truly that the whole subject, both as regards etiology, symptoms, diagnosis, and treatment, has been completely revolutionised and placed on a sound, and, it may be, hopeful, basis. We now know that the sleeping sickness is a terminal phase of a trypanosome infection—a type of disease hitherto unrecognised in human pathology—that the immediate cause of the sleeping symptom is an infiltration of the lymphatic spaces of the brain with certain small mononuclear cells, that the disease is conveyed by the tsetse fly, and that it is amenable to some extent to arsenic, mercury, and certain dyes—all absolutely recent discovery.
Turning to the next chapter in Davidson, we are obliged to remark that the battle is still in progress as to whether yaws is syphilis or an entirely independent disease. Castellani's recent discovery of a spirochete in yaws, though interesting, has by no means solved the question.
In connection with the subjects of the next four chapters of Davidson, much work has been done and is going on; but it is to be regretted that these strenuous efforts have not proved more fruitful. The tropical fluxes—diarrhoeas and dysenteries—in the aggregate constitute, I believe, the most important department of tropical medicine. Unfortunately they are still, both as regards etiology and treatment, in an unsatisfactory state. It is true that the amoeba is creeping into favour, and that we have got the length of recognising a bacillary dysentery; but the amoeba and the bacillus dysenteriae do not, I feel sure, cover the entire field, and, unfortunately, the knowledge of their existence, although it may have done a little for diagnosis, has not materially strengthened our powers of treatment.
Sprue remains a mystery. It is a specific disease undoubtedly, but the specific element has not been detected. On the other hand, the specific relation of the amoeba to a certain type of dysentery and to liver abscess may now be regarded as thoroughly established. This at least is a gain. Its complete recognition is of recent years.
There are still spurs to be won in this field of the tropical fluxes.
Almost equally important in their own line are the numerous additions to tropical helminth ology. They are far too numerous to mention on the present occasion. I might allude to one or two of them, as they are of special interest. Chief among these is Looss's discovery that the larval ankylostome obtains access to the intestinal canal by penetrating the skin on the surface of the body—a discovery suggesting possibilities which have to be reckoned with in regard to other nematodes, or even parasites in general, when we study the route by which they obtain access to the human host. The intact epidermis can no longer be regarded as the impenetrable coat of mail it was supposed to be. Leiper's experimental demonstration that the guinea-worm may be acquired through swallowing its cyclops intermediary, and also the discovery of two new and probably important parasites, Schistosomum japonicum and Amphistomum watsoni, are important additions to this department of tropical medicine. The linking up of the larval Filaria diurna with its parental form F. loa, as well as the recognition of this parasite as the cause of Calabar swellings, is a modern event.
As regards the chapter on Skin Diseases, similar advances could be credited to recent years.
The text-book of to-day has therefore to be in many respects a very different work from that of Davidson's. Besides amplification and alteration there have to be many absolutely new additions. Kala-azar, for instance, is an entirely new chapter, dealing with a subject absolutely unknown when Davidson wrote, and it is one which will soon be found to be of far-reaching importance, both practically and theoretically. The modern text-book must have chapters on spirillosis, seeing that the term "relapsing fever" which Murchison and others used, and which Carter also used in his studies in India, covers not one but a number of infections, spread probably by a corresponding number of previously unsuspected ticks or other blood-suckers.
Then the tropical pathologist must take cognisance of a number of diseases of the lower animals, important in themselves, but more important in their bearing as illustrating principles applicable to human pathology especially tropical pathology. The study of the arthropod blood-suckers and the correlated diseases has grown to be so vast a subject that for its proper appreciation special studies have to be made and its teaching relegated to special men. In Davidson's day a single culex was all that we had to bother ourselves about; but nowadays we have to know something about some 600 species of mosquitoes; and so in a less degree with ticks, tsetse flies, and several other though less important blood-suckers. Truly the burden of the student of tropical medicine has become a heavy one.
I might enumerate many other discoveries and changes in our special branch. Those I have alluded to suffice to show that within the last thirteen or fourteen years the progress in tropical medicine has been phenomenal. If we are justified in looking upon the recent past as an earnest of what will take place in the near future, my successor thirteen or fourteen years hence, when he sums up the additions that will have been made to our subject by that time, will have, perhaps not a more difficult task, but certainly a longer one.
Not only has recent discovery widened our horizon, but many additional workers are now in the field, and hitherto untrodden departments of natural science having a bearing on tropical pathology have been opened by the tropical pathologist. The multiplication of workers is extraordinary, and doubtless is accounted for by the establishment of the several tropical schools in Great Britain and else-where; not least by the sympathy and active encouragement that research in tropical pathology has received at the hands of the British Government. Time was when with justice we could reproach our rulers for indifference in this matter. Nowadays quite a different feeling obtains in official circles, and instead of being repressed and cold-shouldered the investigator in tropical pathology is encouraged in every possible way by the British Government and its officers. Other Governments, too, have ceased to be indifferent; some are actively sympathetic.
The interest which the British Government has shown in sleeping sickness promises well for our object. The fact that His Majesty's Government has called a Conference of the Foreign Powers to discuss this subject from an international point of view shows that we are entering on a new era as regards the Governmental element in the study of tropical disease. It may be that this Sleeping Sickness Conference is but the prelude to similar discussions and international agreements on other important tropical diseases, a matter of more importance than at the first glance it might appear to be.
All over our own tropical possessions laboratories are being established for the special investigation of tropical disease, and for the assistance of the tropical practitioner. These laboratories have just begun to bear fruit, and I have not the slightest doubt that ten years hence we will have important discoveries as well as an enormous accumulation of important data as a result of this enlightened policy.
Our role as a Society in this respect is to try and bring ourselves and our fellow-practitioners abreast of what is being done by this army of workers; so that those of us who have to teach in this country, and those of us who go abroad to practise or to investigate, shall be thoroughly abreast of what has been done and of what is being done, and be in the best position to do full justice to tropical patients and to tropical communities, and to lend a hand at advancing our subject.
That the Society will work, and work successfully, in this direction, I have no doubt. It has, however, other functions to fulfil. As regards one or two of these, I would say a few words. Their consideration influenced me, as I have no doubt it did others, in co-operating with my colleagues in the formation of the Society. Thirty odd years ago and after eight years of experience of medical work in the Tropics, during which 1 succeeded in learning this much, namely, that I knew nothing about tropical disease, I came home on furlough. After a month or two with my people, I came to London principally with the view to rub myself up in recent medicine and surgery, more especially in their bearing on tropical subjects. But it was like fishing in a big lake for the two or three fish the big lake might or might not hold. I did not know where the particular fish I wanted lay, and I found no one to tell me where they lay or how to set about hooking them. I finally landed at the Reading Room of the British Museum. Dreary enough and profitless enough was the fishing there, as you may imagine.
Nowadays things have improved vastly in this respect. There are post-graduate classes of all sorts; but I am not quite sure that a visitor from abroad with only a few months—it may be only a few days—to spare could put his hand at once on the special information he might be in search of, or on the person or persons who could or would guide him to that information. Nor—and this is an important consideration from the standpoint of a bashful man—would he feel quite certain that he was heartily welcomed by those who might be able to supply his wants* Had such a Society as ours existed thirty-three years ago, I would not have had to go to the British Museum for my tropical pathology; I would have been put in touch at once with those who could have taught me, or been put in the way of being taught. Notwithstanding the greatly-increased facilities of recent times, there is still, in my opinion, room in London in the way I indicate, and especially in our particular branch of practice. The stranger might still have to search, perhaps in vain, for the hand that would welcome and assist him. I trust that our Society will supply this welcome and this assistance.
Again reverting to my personal experience, I once more came to London on furlough in the year 1882-3 with the same object in view—to learn the latest in medicine and surgery, especially in their application to tropical medicine. I heard plenty about the tubercle bacillus, but although I visited the Societies and became acquainted with many medical men of standing, I did not once hear of Laveran's important discovery of the malaria parasite. Indeed, it was not until I returned to China that I heard about it. I read Laveran's first book with great interest, and as I had abundant material at my command, I set to work to find the organism he described. Although repeated and prolonged attempts were made, I completely failed in my search, and almost became a sceptic about the existence of the Plasmodium, and it was not until I returned to England in 1889, and not until I had renewed opportunities of working on the subject at the Seamen's Hospital, that I saw for the first time the malaria parasite. But by that time my chances of fruitful work had gone. I had no longer abundance of material at my command. My failure to find the parasite when in China was entirely attributable to faulty technique, not from want of opportunity. Had there been a Tropical Society in 1883, doubtless Laveran's discovery would have been a prominent subject for discussion, the technique for its demonstration would have been familiar to the Fellows, and I should have gone back to China in a satisfactory position to pursue its study under favourable circumstances. I lost ten years by this.
Now, what happened to me in this matter of the malaria parasite, has, I know, happened to others equally interested in tropical medicine, equally keen to study it, and, if possible to advance it. And not only in this matter of the malaria parasite, but in other and similar organisms. They have had no opportunity of seeing these things, in their Hying visits to this country, or of learning how to recognise them. They go abroad, and, although anxious to work, they are not in a position to work in a fruitful way. The tropical schools do much, but they do not adequately supply the wants of the flying visitor. I take it that our Society has a distinct role in this direction. It will be powerfully educative, and no one wishing to get abreast of the actual position of tropical medicine at the time of his visit to London need go away ignorant on any particular point, no matter how recently it may have cropped up.
Dr. C. W. Daniels, Director London School of Tropical Medicine, gave an Epidiascope Demonstration of various microscopic and other objects of interest in Tropical Medicine.