The Use of "Antigens" in Diagnosis by the Wassermann Reaction: The Necessity for Further Investigation.

While appreciating the value of adopting a " standard " antigen in making the Wassermann reaction, the authors point out the limitations of those in common use, which should preclude their adoption as " standard ".The property of a syphilitic antigen is that when mixed with syphilitic serum (heated to 56° C) in suitable proportion and added to fresh guinea-pig serum, it deprives the serum of its hemolytic power.Attention is called to the evolution of knowledge as to the syphi litic antigen.It is desirable that the quantitive difference between a negative and a positive serum should be as great as possible, as measured by the excess of the amount of complement which the serum-antigen will inactivate, because this is the only index of positiveness which exists.Examination shows that alcoholic heart extracts possess this [quality to an outstanding degree, therefore