488 THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 



positively, then it is almost certain that syphilitic infection of the 

 central nervous system is present. 



In untreated and active cases of tabes dorsalis the blood-serum reacts 

 positively in from 96 to 100 per cent, of cases. In treated cases the 

 number of positive reactions drops to about 40 to 50 per cent; in general, 

 therefore, a positive reaction with the serums of tabetics may be ex- 

 pected in 73 per cent, of cases. With the cerebrospinal fluid the per- 

 centage of positive reactions is somewhat lower, being about 60 per 

 cent. The positive Wassermann reaction is less constant in locomotor 

 ataxia than in general paralysis, due probably to the fact that the former 

 is more chronic and that intercurrent periods of arrest are more prone 

 to occur. 



In cerebral syphilis the blood-serum, and particularly the cerebro- 

 spinal fluid, will react positively less frequently than in general paralysis. 

 In some instances a positive reaction is found with the cerebrospinal 

 fluid and not with the serum, a matter difficult to explain and believed 

 to be due to the confining of the reacting substances in the subarachnoid 

 space. On the other hand, the lesions are probably not brought in 

 direct contact with the spinal fluid. 



There is much evidence to indicate that localization of syphilis in the 

 nervous system is dependent upon a particular strain of Treponema 

 pallidum; other strains appear to possess a special affinity for the 

 visceral organs, bones, etc. 



(e) In tertiary syphilis not accompanied by lesions of the central 

 nervous system the Wassermann reaction with cerebrospinal fluid may 

 be positive in a relatively large percentage of cases. 



4. In Latent Syphilis. In cases of latent syphilis the Wassermann 

 reaction may constitute the only evidence of the existence of the disease, 

 and prompt institution of treatment may prevent the development of 

 tertiary lesions, which are so likely to follow. When the spirochetes 

 are few in number and are dormant, there is little tissue destruction or 

 alteration, and, as a result, so little reagin is frequently present in the 

 body-fluids that the Wassermann reaction will fail to detect the disease. 



(a) In 363 cases of early latent syphilis, or those included within a 

 period of three years after infection, Boas found positive reactions in 

 about 40 per cent. ; in latent cases of long standing, or in those following 

 manifest tertiary lesions, the same investigator found 22 per cent, of 

 ppsitive reactions among those who had received proper treatment; of 

 those receiving indifferent treatment, 74 per cent, reacted positively, 

 giving a general average of about 48 per cent. Craig has found 67 per 

 cent, positive reactions in latent syphilis. 



