IODINE AND HEALTH
THE last achievement of physiology in the nineteenth century was the capital discovery of the part played by the ductless or " endocrine " glands in our bodily and mental life. Of these the thyroid gland, often too obvious in the neck, is the most important- " the leader of the endocrine orchestra " : though all, and in due balance, are necessary. Gradually we learn about disorders of the others, remote from view, such as the pituitary, at the base of the brain, and the supra-renals, hardly to be noticed as tiny caps to the kidneys ; but for thousands of years mankind has been deplorably familiar with those enlargements of the thyroid which we call goitre. The thing is ugly, and it may interfere with breathing ; but nowadays we have our physiology to warn us that the consequences are not merely local, when so marvellous and versatile a gland is disordered ; and eugenics, when it ceases to be content with the last enchantments of the Darwinian age, must concern itself with the momentous issues which here involve the health and the sanity of future generations.
The thyroid is a chemical factory, of inimitable power, whose cells construct a product -essential for the life and health of the individual and the race. The growth of the body and the powers of the mind depend upon it. When it fails, in a future mother, her child may be a cretin, painful to look at, dwarfed, unteachable. And these brief -sentences merely indicate the beginnings of our ever growing knowledge of the functions of this gland, amongst which an antitoxic action against infectious disease must now be also included. Failure on the part of this gland must evidently be a formidable fact—and now we learn that it is extremely frequent, in greater or less degree, throughout the world, and notably in, for instance, Swit- zerland and Derbyshire, and the Himalayas and the Middle West of the United States. But the more one travels and observes, the more goitre one finds, and if the suggestion be made that it is an unimportant fact in such and such a place, evidence is soon forthcoming to show that goitre is abundantly there also. Modern feminine fashion, whilst doubtless good for the thyroid, in per- mitting sunlight to reach the neck, also reveals the frequency of thyroid disorder.
The history of mankind's attempts to deal with goitre is easily narrated, and most eloquent. Before our era, the Greek physicians treated it by burning sea-sponges and administering the ashes to the patient—with frequent success. It sounds like nonsense, and it certainly was empiricism : but it worked, and now we know why. A century ago, the scientific Western medicine of the time no longer employed the ashes of a marine vegetable, but held in the highest repute the chemical element called iodine—which we can readily show to have been the most characteristic and significant constituent of those potent ashes. Before me, thanks to an observant reader of a paper written on this subject last year, is a copy, formerly belonging to the library of the London Institution, of a slender treatise* upon the use of iodine in goitre, showing how absolutely the empirical facts were known a century ago. Would that I had room here to quote from this most interesting document. Yet, until the other day, we of the present century had forgotten iodine in its most valuable uses, and thought of it as merely an excellent local antiseptic or agent for local " painting " over some local inflammation. So far as my reading goes, I can only surmise that the change in medical fashion, leading to the loss of a priceless therapeutic, must have been due partly to its abuse, including the employment of unsuitable and impure preparations, vastly different from the many elegant and innocent preparations available to-day ; and partly to the new powers conferred upon surgery by anaesthesia and antisepsis. The folly and the malign power of fashion, nowhere more evident than in the history of medicine, are signal here when we recall that thirty years have elapsed since the chemists proved that iodine is the most abundant and charac- teristic constituent of the " internal secretion " by which the thyroid does its creative and protective work for our lives. Yet not until 1917 was so obvious and hopeful a clue followed, and not even to-day have we acted upon it in this country in any adequate fashion, though the American and Swiss pioneers are already being seconded vigorously in certain of our Dominions, such as Canada and New Zealand.
What is the clue ? Surely that the failure, the ex- haustion, the futile and degenerative enlargement of the thyroid may be dependent upon lack of iodine and may be prevented by its supply. Such is the case, now demonstrated in Switzerland, where I studied it last August, on a nation-wide scale. Chemical inquiry proves that, under the ordinary conditions of our modern lives, we arc iodine-starved, largely owing to our misplaced and stupid cleverness, just as we are sun-starved by the same cause. We might obtain traces of iodine in fresh, un- cooked green leaves, and in the entire grain of wheat; and from one or two other sources, but we go to vast pains to insure that we shall not do so. And, even without such * Essay on. the Effects of Iodine on the Human Constitution. By W. Gairdner, M.D. London : 1824. special devices to ensure the development of a " deficiency disease," we must go short for the reason that nowadays we live upon the dry land, often far from the sea, which is the world-reservoir of iodine, and into which the rain and the streams are ever washing iodine salts out of the soil where once they were left by the seas of remote ages. This glorious adventure of living upon the land is the condition of our greatness ; but the chemical requirements established long ago, when our ancestors lived in the sea, remain ; and the need for iodine is amongst the foremost of them.
Should we then admit the error of those pioneers, in our less remote history, who left the sea and took to the land, substituting lungs for gills ; and should we abandon the too difficult task of making good in the new environment ? Or have we, thanks largely to this new environment, developed Intelligence, whereby we can make a new world about us, fitted to our most ancient and our newest needs alike ? Indeed we have, and it tells us to go to the sources of iodine, obtain it in suitable form, and restore it to our depleted blood, whether by adding it to our drinking water, or our table salt, or our children's sweetmeats, or in volatile form to the air we breathe. Which is the best method we must ascertain, but the worst is infinitely better than none.
The American and Swiss records show that very large numbers of existing goitres disappear, and that prac- tically no new goitres appear, when iodine is restored to the bodily intake and the thyroid can work under fair conditions again. In parts of Switzerland, where the method has had time to act, no more cretins are now being . born, thanks to the proper supply of iodine to expectant mothers. Children, perhaps especially from six to sixteen, and girls even more than boys; expectant and nursing mothers, the already goitrous— these are the persons most urgently concerned ; but new evidence is forthcoming from the Galton Laboratory in University College, thanks to Dr. Percy Stocks, which indicates a positive correlation between thyroid failure and the incidence of cancer, suggesting that the middle- aged may have their own personal reasons for concern. And there is cause to assert that, in many cases, we suffer from thyroid deficiency even when no goitre exists. Evidently the time is at hand when this new and simple discovery will rightly supersede that treatment of cretinism and other consequences of thyroid failure by administration of thyroid gland substance from sheep or ox, which was the last therapeutic triumph of the last century.
The iodine chocolate preparation now officially used in Switzerland is very good. So are the best of the iodised salts, of which so many have been put upon the market since I began to urge the importance of the foreign discoveries about a year ago, but I protest against the grossly excessive price of sonic, at least, of these. In America two cities now put the necessary iodine into the public water supply.
The foregoing is evidently but an introduction of a fascinating theme, on which volumes might and certainly will be written, and of which none of us will ever hear the last. I used the word " simple " advisedly, for it is simple to add a trace of iodine, at infinitesimal cost, to our dietary, and thus abolish widespread disease wholesale, as is now being done ; but, of course, there is no end to the complexity of the problems which arise, including, be it noted, one no less majestic than that involved in the seeming creation of intelligence by chemical means. It would be wrong to leave the im- pression that we are doing nothing in this country, though to a student who believes in the principle of solvitur ambulando the temptation is to throw up his hands and ask when we propose even to turn in our sleep. The matter is being considered in official quarters, and I hope that an authoritative Committee may be formed to define the types of goitre, to prescribe the conditions for a proper survey, to discuss the modes of restoring iodine to our lives, to define the possible risks—always a darling theme for those who worry no whit about the evident present price of inaction against any evil—and, I hope, to indicate official action which shall lift our present fragmentary and inchoate practice of iodine-hygiene out of the hands of pioneers
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