It is not to be wondered at that in many cases of deeply-rooted blood-disease, complicated perhaps with anæmia, structural change of organs, disordered assimilation, and various nervous symptoms, all remedies alike should prove useless. So that the experience of many practitioners, thus frequently disappointed in their hopes of a cure, has led them to question altogether the efficacy of Iodine in Scrofulous disorders. But it is generally allowed that it is more beneficial in such cases than any other medicine, and is the only remedy which is universally applicable in Scrofula. If this be true, it follows that it must have a special power over this blood-disease. Burnt sponge, and the ashes of a seaweed, the Fucus vesiculosus, both of which contain Iodine, have been used in Scrofula from very early times. But it was not until the present century that Iodine was discovered, and its efficacy in Scrofula, particularly in the cure of Goitre, pointed out by Dr. Coindet of Geneva. After this it came to be generally applied in all Scrofulous cases, and was especially recommended by M. Lugol in France, as a specific for such maladies. When given for some time, Iodine has the effect of impoverishing the blood, like Mercury and many other Catalytics, diminishing in it the amount of Fibrine. All remedies which do this favour absorption. This effect is obviously connected with the alteration in the blood, and there is no reason to suppose that any special stimulant action is exerted on the absorbent vessels. Those Catalytics which favour absorption are not all useful in the same cases, but some are most useful in one disorder, some in another. Thus they must exert a special action over morbid poisons; an action which is altogether distinct from the influence over absorption, although by this latter they may be able to cause the disappearance of effused products, and of tumours produced in various ways. In some rare cases Iodine has even been known to cause the absorption of healthy glands, as the mammæ and testicles. Iodine and Iodide of Potassium, when successful, do not merely cause the disappearance of scrofulous tumours, but further meet and neutralize the poison which is working in the system, and effect a more or less permanent cure. This could hardly be done by a remedy which had only the power of promoting absorption. It seems that some systems are able to bear with impunity very large doses of Iodide of Potassium. I once met with a medical man who denied its power altogether, because he himself had frequently taken a scruple, and sometimes a drachm at a time, without any effect. Other men are readily affected by very small quantities, and quickly experience the symptoms of Iodism. It is probable that in the former case the medicine is very quickly eliminated by the kidneys; but that in the latter it remains in the system for some time.