WASSERMANN TESTS 155 



thermostability of serum of inherited syphilis is the highest that of primary 

 syphilis the least of luetic sera. 



McDonagh states that in the primary stage the Wassermann is 

 positive in 40% of cases. In secondary cases 97% give positive results 

 when treatment has not been instituted. In tertiary syphilis about 

 70% are positive. 



In 268 cases at the medical clinic of Johns Hopkins Hospital, Clough 

 failed to obtain a positive reaction in ninety-nine cases which were 

 negative clinically. 



In forty-five cases of syphilis he obtained 73% of positive results. 

 Excluding cases which had received thorough treatment 82% were 

 positive. Tabes gave 40% and general paresis 100 %. In five cases 

 of primary syphilis four gave positive reactions. 



Based upon the observation of Bauer, that human serum contains haemolytic 

 amboceptors for sheep corpuscles, and of Hecht, that the complement normally 

 present in human serum would suffice without the addition of guinea-pig serum 

 complement, the following method of Fleming is easy of application. 



For the test we use: 



1. Alcoholic extract of rabbit's heart, made by washing the recently removed 

 heart with salt solution to remove all blood. Cut into small pieces and grind in a 

 mortar with sand and for every gram of heart add 5 c.c. of 95% alcohol. Keep the 

 mixture at a temperature of 60 C. for two hours and filter. This is the stock 

 solution. For use dilute it ten times with normal salt solution. 



2. A 5% emulsion of washed sheep red cells, prepared as for the Wassermann 

 test. 



3. Suspected and control sera. 



With a capillary bulb pipette take up one part of serum and four parts of the 

 heart antigen, mix on a glass slide, again draw up into the capillary pipette and, 

 leaving a separating air space, next draw up one part of 5% emulsion of sheep red 

 cells. Then seal off tip of pipette and incubate at 37 C. for one hour. Now file 

 off tip and mix the red cells with the serum and antigen and again draw up into the 

 capillary pipette and incubate a second time for two hours. Haemolysis or the 

 reverse is shown in the fluid overlying the cell sediment. Various controls should 

 be made using normal and known syphilitic sera; also with normal salt instead of 

 serum. 



The objections to methods using human serum for complement are 

 i. the great variation in the complement content of different human 

 sera; 2. human complement requires about ten times as much ambo- 

 ceptor as guinea-pig complement and is less sensitive to fixation, and 

 3, the statement is made by s>me workers that while homologous 

 complement and amboceptor may be efficient yet the complement of a 



