During the past five years the organs of many cases in which death was due to toxic substances, were submitted to complete chemical examination in this laboratory. Practically all of these were examples of sudden death occurring in the five boroughs of Greater New York for which the chief medical examiner or the medical assistant to the district attorney or both could find no anatomical cause. There were also a number of cases which were brought to my attention from other states. In this number, most of the commoner poisons, including chloroform, were represented. I have yet to encounter a case of straightforward chloral poisoning. Nevertheless, I became greatly interested in the question as to whether some of the so-called chloroform poisonings might not have actually been examples of chloral poisoning, and therefore, I made a study of various reactions to determine this point.The several tests, namely, the isonitrile, the resorcin, the orcin the alpha and beta naphthol, the Ragsky, the cyanide, the form...