I9I4] 



/. Bronfenbrenner and J. Rockman 



379 



ing uniform procedure : 25 mg. of pure metallic iodin were emulsi- 

 lied in paraffin oil; 2.5 cc. of this liquid were mixed with 0.2 cc. of 

 the fresh (6 hr.) serum to be tested. The mixture was shaken in 

 a small test tube closed with a cork stopper, then placed in the dark 

 for 16 hr., when 2 drops of starch sol. were added to the contents 

 of each tube. The normal sera gave a dark blue coloration, whereas 

 the syphilitic sera remained colorless or were colored slightly blue.^ 



Data pertaining to the Wassermann and Landau tests 



As may be seen f rom the accompanying summary, we succeeded 

 in bringing the total number of positive Landau reactions in the 

 cases of known Syphilis up to 65 percent, which equals the percent- 

 age of positive Wassermann reactions in the same cases, but in 

 doing so we obtained also 30 percent of positive Landau reactions 

 among the normal controls. 



Without attempting to discuss the results, it is clear that the 

 Landau reaction is not more specific than the Wassermann reaction. 

 Although in 20 cases of syphilis, where the Wassermann reaction 

 was negative, the Landau was positive (which at first would sug- 

 gest a greater sensitiveness of the Landau reaction over the Was- 

 sermann) ; in 21 other cases the results were the opposite, as can be 

 Seen from the table. On the other hand, out of 70 cases in which 

 no Syphilis was diagnosed (where there was no indication of this 

 disease in the patient's history and where Wassermann reaction was 

 invariably negative), 21 cases gave a positive Landau reaction, — a 

 fact that definitely speaks against its specificity, 



3 In 100 cases out of the 220 we also used the modified technic of Landau,, 

 namely, the iodin was completely dissolved in carbon tetrachlorid in the Propor- 

 tion of 50 mg. of iodin to 5 cc. of carbon tetrachloride. For each 0.2 cc. of 

 serum o.i cc. of this iodin Solution was added. Syphilitic sera, after 4 hr. at 

 room temperature, remain transparent and show a yellow reddish color, whereas 

 normal sera become grayish white and opaque. In general we failed to find this 

 technic any better than the first described. 



