MORE ABOUT IODINE
IN two articles published here last year I discussed the new theory and practice of the prevention of disease by the restoration of small quantities of iodine to our unnatural dietary. The subject is of increasing interest, not least because of its recent wide and successful extension to the nurture of domestic animals ; and I have lately been examining it further in Switzerland, which is a pioneer in this field and whence the present article is Written.
We must briefly remind ourselves of the argument. It is as follows. Thirty-one years ago iodine was found to be a constant and comparatively abundant constituent of the thyroid gland in the neck, and of its characteristic secretion. It follows, of course, that no creature pos- sessing and needing a thyroid gland can do without an adequate supply of iodine in its food. Here was a key, but it was not used. We were content to say that a complete dietary must include as a semi-negligible addendum "mineral salts," and we did not condescend to particularize further. Many years later, indeed as recently as 1917, some workers in America, headed by Dr. David Marine, then of Akron, Ohio, and now of New York, began to inquire whether the use of small quantities of iodine, not as a drug but as a food, might affect the incidence of goitre, an exceedingly common disease in the Middle West. The assumption was that the morbid enlargement of the gland, which we call goitre, and which has been known since the earliest classical times, might be due to a lack of the element which, beyond question, is essential to the work that the gland must do for the welfare of body and mind. The results in Ohio were very satisfactory. The matter was taken up in Switzerland, the most goitrous of European countries, and similar results were obtained. A Goitre Commission was formed in Switzerland to study and control the whole matter, under the direction of the Federal Bureau of Hygiene. Two years ago, in his Presidential Address to the British Association in Toronto, Sir David Bruce cited the pre- vention of goitre by iodine as the latest achievement in the prevention of disease. Already, before that date, I had drawn attention to the matter in England, and now I return to it, with some notes in continuance of my previous articles.
First, as to the geography of goitre. The accepted teaching is that the disease is commonest furthest from the sea, which is the natural reservoir of iodine. Hence we quote Switzerland, Derbyshire, and the Middle West or "goitre belt" in the United States. But inquiry shows that proximity to the sea is very far from being a guarantee against this disease. Unfortunately, it is quite common in Cornwall, for instance : and it is so widely prevalent in New Zealand that the health authorities of that Dominion have already taken official action for iodine prophylaxis. Two points may here be noted. The first is that, unless the prevailing winds be from the sea, bringing spray with them, mere proximity to it will not serve ; and the second is that, wherever lime is abundant, far more iodine than otherwise is needed. There is a "lime-iodine ratio," as it is called by Colonel McCarrison, our leading authority on the subject. We certainly have much to learn yet about the geography and, if you like, the geology of goitre ; • but, in any case, no immunity whatever can be claimed even for small sea-girt islands like those of our own country or New Zealand.
Second, there is the question of the existence of a re- -markable type of goitre in which the gland is obviously over-active, the eyeballs are prominent and the pulse is fast. This is the opposite picture, in body and mind, to that of ordinary or endemic goitre. We call it exophthal. mic goitre, or Graves' disease in England, or Basedow's disease on the Continent. Ought we to take steps to guard such patients against too much—or any—iodine Must we fear the production of large numbers of such cases if we adopt universal iodization To these questions there are two answers. The first is derived from ,the splendid work of certain physiologists and physicians in our own country, amongst whom should be named Pro- fessor Edmund Mellanby, F.R.S., of Sheffield, his colleague Dr. S. J. Cowell, and Professor Francis R. Fraser, of St. Thomas's Hospital. These workers have proved that over-action of the thyroid in animals can be cured by the use of iodine, and that this wonderful element is a specific agent of therapy in human cases of exophthalmic goitre. The very last thing here suggested is that readers who suffer from exophthalmic goitre should now begin to dose themselves with iodine. The size of the dose is all-important ; and the constant rule for all cases of illness, including all kinds of goitre, is that the patient should see and be examined and personally treated by a doctor. But the discovery that iodine is a specific even in exophthalmic goitre is a new and a most heartening one. As for the risk of producing this disease by the wide use of iodine, statistical inquiry is afoot. No proof of such a result exists ; and the foregoing record of recent discovery shows how improbable any such result must be.
In a previous article I referred to the wide variations in the strength and in the price of iodized salt, which is probably the most convenient vehicle for the general use of iodine ; and I asked for the formation of an official committee to study the subject and to "take it out of the hands of pioneers and profiteers alike." Such a coni. mittee has been formed and -is doing invaluable work. Meanwhile I return to the question of price. The lint fact is that the quantities of iodine required are minute, and that their cost is simply negligible. But in England the cost of most of the iodized salts which have been put upon the market since I began my campaign is absurdly high ; so that their general use is out of the question. On this matter I have recent information from Dr. H. Corriere, the Secretary of the Swiss Goitre Commission. The practice varies in different Cantons. In some—as, for instance, Vaud—nothing but iodized salt is now allowed to be sold at all, a rule which now obtains also in some of the States of the American Union. In other Cantons the law fixes the price of the iodized salt at the same level as the iodine-destitute salt. Until some such equality of price obtains in our own country no real progress can be made : and I cite the methods now spreading in Switzer. land and the United States for the consideration of our own authorities.
My space is gone, but the interested reader may be referred to the splendid results obtained in Cumberland by Dr. Kenneth Fraser and discussed by him in the latest official report of the Medical Officer of Health for that county : and to Farm Feeding for September, where some indication will be found of what iodine will achieve for pigs and many other thyroid-possessing animals of high
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