Reference has previously been made to the phenomenon of hypersusceptibility as pointed out by Rosenau and Anderson of the United States Public Health and Marine-Hospital Service.1
They showed by a series of brilliant experiments2 that, while horse serum is apparently a bland and harmless substance when injected into guinea-pigs, it renders the animal susceptible to a subsequent injection, and that if the latter is given after an interval of ten days the hypersusceptibility invariably manifests itself by severe symptoms which often result in the death of the animal. They believe that this phenomenon has a deep significance in relation to the problem of immunity, and expressed the opinion that resistance to disease may be gained largely through a process of hypersusceptibility.
These observations have attracted much attention, and, in the main, have been confirmed by a number of other observers during the past year.
Just issued from the