I was called in the month of February, 1822, to visit a boy five years old, affected in the following manner. Since the period of his birth, he had always been weakly, but, for the last two years, had gradually been falling off in his flesh and strength. He complained of frequent pains in his bowels, which were alternately confined and purged; the motions were discoloured and scybalous; he frequently vomited his food; his abdomen was much swelled; the rest of his body considerably emaciated; pulse natural; appetite variable, but never great. It was impossible to doubt, from the appearance of the child, that the mesenteric glands were enlarged, and I determined to make a very cautious trial of iodine. It was the first case in which I had used it for an internal disease, and I therefore watched it with unremitting care. I began by giving my little patient twelve drops in the day, which I gradually augmented to twenty, and I had the pleasure of seeing the abdomen gradually diminish in size, the bowels become more regular, the evacuations restored to their natural colour, the pain diminish and vanish, the appetite increase, and at the end of five weeks the child return to comparative health, without the occurrence of a single untoward symptom. The only medicine I employed during this treatment, besides iodine, was occasionally a few grains of rhubarb. At the end of the five weeks the bowels acted without medicine. I am sorry to say that I lost sight of this child from this time. The parents were poor, were probably satisfied with the benefit they had received, and not willing to incur any farther expense for medicine. I have since prescribed this medicine in two other cases of disease of the mesenteric glands. The result was not so satisfactory as in the case I have just related, but both of them were considerably relieved, and had they been more attentive to the directions given them, I have little doubt that they also would have obtained a complete cure. But they were in the poorest class of society, were irregular in their habits, and paid very imperfect attention to the orders of their physician. In one of them, a young woman, fifteen years old, after she had taken fifteen drops of the solution of hydriodate of potass, twice a-day during three weeks, considerable tenderness of the whole abdomen came on, for which I judged it necessary to order the application of a dozen leeches. The relief was immediate. From the whole appearance of the case, I judged this feverish attack to be an affection of the mesenteric glands, similar to what I have described at p. 39.