Not long since I was informed by a Physician, of great and deserved eminence, in London, that he had prescribed it to the extent of ten grains at one dose to a young woman. Most fortunately she was saved by vomiting. About a year ago, I was consulted on account of a young lady in the last stage of tubercular pulmonary consumption. She was attended by a Surgeon, who had bled her to a most unaccountable degree. This gentleman proposed to me the use of digitalis, which being objected to, he then proposed successively the use of hemlock and iodine. It was plain that he was about as well acquainted with the virtues of one medicine as with those of the other, and not better versed in the history of the disease he was treating. When a medicine of so much power is thus in the hands of every person, I trust I shall not stand in need of apology for having made public the following little treatise. Its materials have been for some time in my possession; and I was desirous of delaying yet a little the publication of them; but certain statements have gone forth to the world, of the great benefits to be derived from the use of iodine, while the history of its dangers has been most unaccountably withheld. It is in order to fill up this hiatus, and at the same time to direct particularly the attention of Practitioners to the proper manner of using it, with a view to its good effects, that this essay is written. Particular circumstances have afforded me opportunities of seeing this medicine extensively used; and at the same time of witnessing the bad effects which resulted from the prodigal manner in which it was first employed. I have also made inquiries respecting its history in countries which I have not visited. The answers I have received have not been so detailed and satisfactory as I could have wished: they have all, however, more or less confirmed the observations I have made myself, or which have been communicated to me from different parts of Switzerland and France. Some persons may, perhaps, desire to see a daily report of the different cases to which allusion is made in the following pages; but this would not have been consistent with my plan, which is rather at the present time to present an essay than a treatise to the public. Bolton Street, Piccadilly, 4th Dec. 1823. ESSAY ON THE EFFECTS OF IODINE.