RT Journal T1 TUberculin and iodid of potassium JF Journal of the American Medical Association JO Journal of the American Medical Association YR 1909 FD November 6 VO LIII IS 19 SP 1566 OP 1566 DO 10.1001/jama.1909.02550190042005 UL http://dx.doi.org/10.1001/jama.1909.02550190042005 AB Beginning with Koch's discovery of tuberculin and its use later as a diagnostic means, various attempts were made to obtain bacterial products which might be used as specific diagnostic measures. A noticeable result of these attempts was the discovery of mallein and its use in the diagnosis of glanders. More recently work has been carried out showing in several instances the diagnostic value of injections of certain dead bacteria in infections caused by those particular organisms. Of special importance in this connection seem to be the gonococcus reactions of Irons1 and the ocular typhoid reaction first described by Chantemesse and modified by Hamburger.2In 1897 Rondot demonstrated that weak doses of potassium iodid produced, in individuals with incipient tuberculosis, reactions which were similar to those produced by tuberculin and were supposed to be caused by the liberation of tuberculin from the lesions. Later its use as a diagnostic