THE TECHNIQUE OF SERUM REACTIONS 317 



growths of about ten agar slant cultures in 10 c.c. of sterile, distilled 

 water. This is shaken for twenty-four hours in a shaking apparatus. 

 At the end of this time 0.5 per cent of carbolic acid is added and the 

 fluid cleared by centrifugalization. 



The Wassermann Test for the Diagnosis of Syphilis. 14 The sub- 

 stances for the test are the following : 



I. The Antigen. In their original experiments, Wassermann and 

 his collaborators made use of salt-solution extracts of the organs 

 (chiefly of the spleen) of a syphilitic fetus. The tissue was cut into 

 small pieces and to one part by weight of this substance, four parts of 

 normal salt solution and 0.5 per cent of carbolic acid were added. This 

 was shaken in a shaking apparatus for twenty-four hours, and after 

 this the coarser particles removed by centrifugalization. The reddish 

 supernatant fluid was used as the antigen and could be preserved for 

 a long time in dark bottles in the ice chest. 



Alcoholic extracts of syphilitic organs were subsequently used by 

 a number of authors, syphilitic liver being extracted for twenty-four 

 hours with five times the volume of absolute alcohol. This was filtered 

 through paper and the alcohol evaporated in vacuo at a temperature 

 not above 40 C. About 1 gram of this material was then emulsified 

 in 100 c.c. of salt solution to which 0.5 per cent of carbolic acid has 

 been added. 



It was soon found that the Wassermann antigen was a purely non- 

 specific substance, and since this discovery was made, there are few 

 laboratories in which syphilitic organs are still used. It appears 

 that lipoidal extracts from almost any tissue can be employed, and 

 that fairly useful antigens can even be obtained with solutions of 

 commercial lecithin and mixtures of commercial lecithin and sodium 

 oleate. It is apparent, therefore, that in the Wassermann reaction an 

 even suspension of lipoidal substances constitutes the antigen, and 

 that the complement-fixing complex is made by these antigens in com- 

 bination with some substance spoken of by Noguchi as * * lipotrophic ' ' in 

 the syphilitic serum, which has probably no relation to true antibody. 

 Our own work with treponema pallidum antigen would tend to con- 

 firm this, as well as the experience of Noguchi, Craig and Nichols, 

 Kolmer, and others, who have found that a pure treponema pallidum 

 extract gives reactions in only a few late tertiary cases, running not 



14 Wassermann, Neisser und Bruck, Deut. med. Woch., xix, 1906; Wassermann, 

 Neisser, Bruck und Schucht, Zeit. f. Hyg., lv. 1906. 





