THE CLINICAL IMPORTANCE OF HYPERSUSCEPTIBILITY

The phenomena which we now describe under the term hypersusceptibility or anaphylaxis were noted by Arloing in 1888, and described by Koch as early as 1890, but their significance was not appreciated at that time. During the course of the experiments which led to the introduction of tuberculin, Koch noted that guinea-pigs which had once been inoculated with living tubercle bacilli acted differently from normal guineapigs when a suspension of dead tubercle bacilli was injected beneath the skin. Whereas the normal guineapigs often developed a local suppuration, the tuberculous animals often died in the course of a few hours, or if they did not die, developed extensive necrosis at the point of inoculation. This hypersusceptibility was the basis of the diagnostic use of tuberculin as proposed by Koch, and is the basis of the other more recent methods of tuberculin diagnosis. Similar observations have since been made in diseases other