FIXATION OF COMPLEMENT 133 



On the other hand, we may obtain a negative Was- 

 sermann reaction in the presence of sypliilitic infection 

 under certain conditions to be mentioned below in 

 detail. 



Primary Stage of Syphilis, — The Wassermann re- 

 action as a rule does not become positive until at least 

 two weeks after the appearance of the chancre, the 

 average time being from three to four weeks, though 

 cases have been known in which it was positive before 

 the chancre appeared. In our records the earliest 

 positive Wassermann reaction was obtained four 

 days after the appearance of the primary lesion. Oc- 

 casionally it does not become positive until after the 

 secondary symptoms have manifested themselves. 

 The Wassermann reaction has proved that many in- 

 stances of so-called " soft sores " are in reality due to 

 syphilitic infection, or at least a mixed infection exists. 

 The earliest means of making an absolute diagnosis of 

 the primary lesion of syphilis is by finding the Tre- 

 ponema pallidum in the secretion from the sore by 

 dark field illumination or by stained smears. This 

 method fails, however, in a certain percentage of cases, 

 especially when local treatment has been applied; so 

 that, while a negative Wassermann reaction in the sus- 

 pected primary stage of syphilis does not exclude the 

 disease, a positive reaction will frequently serve to 

 establish the diagnosis. 



