By following this method of analysis, I have found that one grain of iodine of potassium, which is equivalent to three-quarters of a grain of iodine, may be easily discovered in six ounces of urine,—a fluid as complicated as can well be conceived. The process adopted by Professor Orfila is so nearly the same with this, as scarcely to require being detailed. He uses nitric acid instead of chlorine for decomposing the hydriodic acid. Chlorine, however, is the most delicate reagent for the purpose, if it be used in the way described above. _Action of Iodine and Symptoms in Man._—Iodide has a twofold action, one local and irritating, the other general, and produced only when it has been administered long in frequent small doses. Orfila remarked that in doses of two drachms it excited in dogs symptoms of irritation in the stomach; that death slowly ensued in seven days, without the symptoms having ever become very violent; and that the villous coat of the stomach was here and there yellow, had also patches of yellow mucus lining it, and exhibited numerous little ulcers of a yellow colour. He could not observe much injury from iodine introduced into the cellular tissue; and more lately, Dr. Cogswell remarked that in this way it merely induces phlegmonous inflammation and the usual consequences.[331] An important circumstance in regard to the physiology and medical jurisprudence of this poison and its compounds is, that it may undoubtedly be detected in the blood, both when a single large dose has been taken, and in those persons who have used it for some time medicinally. Cantu, an Italian experimentalist, discovered iodine in such circumstances in the blood, sweat, urine, saliva and milk;[332] and Bennerscheidt, a German chemist, also found it in the blood, when it had been employed outwardly.[333] In the latter instance it could not be detected in the serum, but it was detected in the crassamentum by means of starch. Some interesting facts of the same nature have also been ascertained by Dr. O’Shaughnessey, from which it appears that even in acute poisoning with this substance, satisfactory proof of its administration may be procured several days afterwards by analysing certain secretions. In a dog poisoned with iodine, he detected the poison in forty minutes in the urine, and occasionally in the same secretion so late as the fifth day, when it died. It is singular, however, that he could not find it in the same quarter on the third day, although it existed at that time abundantly in the saliva.[334] In these experiments the iodine was always found in the form of hydriodic acid, having been converted into that compound in the alimentary canal. This change takes place with such rapidity, that on one occasion, in the vomited matter discharged by a dog fifteen minutes only after the administration of iodine, Dr. O’Shaughnessey could find no iodine, but a large quantity of hydriodic acid.[335] Orfila has found it not only in