It is a much more difficult task to discover a probable explanation of the manner in which iodine disturbs the actions of the nervous system. The rationale of diseases, even when we are best acquainted with their history, is obscure and unsatisfactory. Here it is better at once to stop short, and confess our ignorance, than, by adventurous speculation and daring theory, lay a foundation for mistakes in practice. This subject certainly presents a fine field for hypothesis, and a tempting one to a theorist. But we leave our readers in possession of the facts, and trust they will not use them with less caution than ourselves. One thing only seems probable, that is by its operation on the brain, either immediately, or through the agency of the nerves, that the effects we are considering are produced. The similarity of this effect of iodine to the mercurial erethismus, so well described by Mr. Pearson, will be evident to all, and is an analogy deserving of attention and study. I have seen many instances of gilders in Paris and Geneva affected with mercurial erethismus, closely resembling the erethismus from the use of iodine. * * * * * Our most important consideration is the cure of these painful affections. In the choleric disease the first remedy of all, and that without which we can have little hope of subduing the disease, is opium. If called early to the patient, before the bowels have yet thrown off their acrid contents, I have generally waited a little before exhibiting opium. I have done this for two reasons: First, that I might be certain of all acrid matters having been removed from the alimentary canal before the prescription of a medicine to quiet its irritation; and, secondly, because it is with great difficulty that the opium is retained while the extreme irritation of the disease is going forward. Emollient and diluting injections will in these cases be found most useful auxiliaries, both by washing out the inferior portion of the gut, and by quieting the violent action of the stomach. Hemlock and hyoscyamus sometimes succeed when opium fails. The case related at page 7 was much relieved, indeed I may say that the young lady’s life was saved, by a quarter of a grain of acetate of morphium given every half-hour. Every other form of opium was tried without effect; they were not even retained an instant on the stomach. The acetate of morphium alone could be taken, and it effectually restrained the disease, which must otherwise have very soon terminated the life of the patient. This medicine has not, however, answered my expectation in other cases. I have tried various bitter and astringent medicines in union with opium, but have found them uniformly injurious during the first stage of excitement and exacerbation. Afterwards, when the disease has in some degree abated, this class of medicine will be found useful. I cannot too strongly caution my readers against the use of purgatives in such cases.