The rapidity of elimination varies with the quantity taken, a large dose giving evidence of its passage very quickly. Ranke found traces in the urine three and a half minutes after administration, and even sooner in the saliva. Nothnagel also found it early - in ten minutes in the latter secretion. Richardson found it in the urine within one minute of injecting tincture of iodine into an enlarged bursa, and, three minutes after breathing iodide of ethyl, iodine could be detected in the urine. It is an important practical point that elimination of this drug is complete sooner than that of many others. Dr. Balfour noted that even if large doses of iodide of potassium had been taken for many weeks, their elimination was complete within three or four days after ceasing to take them (Edinburgh Medical Journal, 1868). Dr. Duckworth, after a dose of 4 gr., found iodine in the saliva in five minutes, in the urine in twenty-five minutes; after twelve hours' interval it was still to be detected in both secretions, but after thirty-six hours in neither ("Bartholomew Hospital Reports," vol. iii.). Rabuteau, after 15 gr., found traces in the urine for three days; after 150 gr., for ten days; not afterward. The greater part was eliminated during the first day, little passed on the second, and scarcely a trace on the third; in the dog, elimination was somewhat slower. Claude Bernard, giving iodide of potassium, ceased to find it in the urine twenty-four hours afterward; that he detected it in the saliva for three weeks must be considered exceptional. Speck has stated that in Bright's disease the kidneys do not eliminate iodine, and Dr. Duckworth could not detect it in one case after giving 10 min. of the compound tincture; but 3 gr. of the iodide of potassium gave evidence of its presence, only much later than usual, namely, one, two, or three hours after administration.1 Baehrach, giving moderate doses of iodate of potash by the mouth to healthy subjects and to fever patients, traced the drug in the urine of both within fifteen minutes; but, on injecting it under the skin, elimination in the former occurred in five minutes, but in the latter forty minutes later (loc. cit.).
As will be noticed again under therapeutical action, iodides have a remarkable power of eliminating with themselves various metals and possibly organic poisons previously circulating in the blood or deposited in the tissues.