562 THE RELATION OF COLLOIDS AND LIPOIDS TO IMMUNITY 



inside of the pipet are removed by washing. These washings are later 

 added to the beakers to which they belong. In filling the pipets with 

 acid or alkali, the latter should first be drawn up into the pipet at least 

 once, and then emptied again before the pipet is finally filled for delivery 

 into the next test-beaker. Only by careful attention to these points 

 in the technic can reliable results be obtained. 



Redding the Results. If beakers 1 to 3 contained the antiserum to the 

 antigen used, a positive epiphanin reaction will be obtained, and if the 

 barium hydroxid and sulphuric acid were previously carefully adjusted 

 to each other, it will be found that beakers 1 to 3 will be lighter than the 

 antigen control, beaker 4. The presence of a specific antigen-antibody 

 combination has shifted the phenolphthalein end-point in the sense of 

 increased H-ion concentration. The exact differences in the alkalinity 

 between beakers 1 to 3 and beaker 4 can be quantitatively determined 

 by titration with JQQ suphuric acid, and the results expressed as a curve. 



If the antigen and antibody were not specific, the epiphanin reac- 

 tion will be negative. Beakers 1 to 3 will be more alkaline than the 

 antigen control, beaker 4, because, as previously pointed out, serums 

 alone or antigen with non-specific serums shift the phenolphthalein 

 end-point in the sense of increased OH-ion concentration. 



The results may be plotted as curves. The titration values in JQQ 

 sulphuric acid are placed on the ordinates, and the serum dilutions on 

 the abscissae. The positive values are plotted above the line and the 

 negative values below the line. No reaction is regarded as positive 

 unless it gives a titration value of at least 0.05 c.c. ^sulphuric acid. 

 Values below 0.05 c.c. are easily within the limits of error. 



The following method, employed by Seifert, is much simpler, but is 

 open to the error on account of using the antigen and serum in too con- 

 centrated a state. In a small test-tube place 0.1 c.c. of a 1 : 10 solution 

 of the serum in normal salt solution, and add 0.1 c.c. of an alcoholic 

 extract of syphilitic liver. To this slowly add 1 c.c. of decinormal 

 sulphuric acid and 1 c.c. of a solution of barium hydroxid of the exact 

 concentration needed to neutralize the sulphuric acid solution. On the 

 addition of the drop of the phenolphthalein solution the fluid turns red 

 when the serum is from a syphilitic, whereas no change in tint occurs 

 with non-syphilitic serum. 



Practical Value. The reaction appears to be of considerable value 

 jn the diagnosis of syphilis. With serums and antigen in proper dilu- 

 tions, the results closely parallel those secured by the Wassermann reac- 



