Recently Kahn1 proposed a precipitation reaction for syphilis for which he claims a high degree of sensitiveness and specificity, combined with simplicity and ease in manipulation. These claims led us to investigate this reaction, and this paper will present a preliminary report of our findings. The Wassermann test was carried out with a sheep-cell system and guinea-pig complement. Two antigens were used on each case. One an absolute alcohol extract of human heart muscle, reinforced with 0.4 per cent. cholesterin, and the other acetone insoluble lipoids with cholesterin, proposed by Kolmer.2 The fixation period was from sixteen to eighteen hours in the icebox.
The serums were obtained from unselected cases from this hospital, the University Hospital and various state asylums of Michigan. The serums were separated from the clots by centrifugation and were used, as a rule, within twenty-four hours after reaching the laboratory.
Altogether, 2,165 serums were