Aside from the academic questions involved, there is an important practical problem which concerns the specificity of the desensitized state in anaphylaxis. If the occasional hypersensitiveness of man to serums which contain specific immune substances could be reduced or eliminated, the safety of employment of such serums would be much enhanced. The danger of specific desensitization lies largely in the possibility of severe or even fatal shock during desensitization. Nonspecific

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... might eliminate this danger. Although there are certain hypersensitive states to pure or relatively pure proteins, as for example, those of the vegetable pollens, the fatalities in man have so far resulted from injections of serum. \Ve have therefore confined this study to serum anaphylaxis in the hope that ultimately a practical method may be devised for employment in man. It does not necessarily follow that results in animals, which have been artificially sensitized, are entirely applicable to natural hypersensitiveness in man, but there are instances of the acquired state in man which seem to be identical with that of animals and it has yet to be proved that natural hypersusceptibility differs materially. If, therefore, nonspecific desensitization in the acquired serum hypersusceptibility of animals can be demonstrated satisfactorily it is worthy of further trial in human experiments. Most studies of anaphylaxis have dealt with serum anaphylaxis and the same is true of the desensitized state. The specificity of the desensitized state has been supported by the work of Otto/ Rosenau and Anderson," Szyrnanowsky," Kumagai and Odaira.' and in particular by Besredka." Nonspecific, usually transitory, reduction of shock has been produced by the injection of various substances, but the final issue as regards specificity of this phenomenon is still a matter of considerable dispute. Biedl and Kraus 6 assert