316 IMMUNOLOGICAL METHODS OF DIAGNOSIS 



we do not know, but we are inclined to think that they may possibly 

 be the expression of some inherited syphilitic taint, though we have 

 but few data to support this belief. As the result of a fairly wide 

 experience with the reaction we have come to the conclusion that 

 from the diagnostic stand-point triple-plus reactions only should be 

 considered as positive evidence of syphilis, while the feebler grades, 

 in individuals with an admitted history of the disease, may be 

 regarded as indicating that the infection is probably limited to 

 relatively small areas, from which an insignificant absorption of 

 spirochetal substance is taking place, with a correspondingly limited 

 formation of the lipoidophilic antibody. If the actual focus of 

 infection should be sufficiently restricted it is, of course, conceivable 

 that a negative reaction even might be obtained, and it is for this 

 reason that a single negative reaction has a limited value only from 

 the stand-point of diagnosis as well as of treatment. As pointed out 

 in a previous chapter, however (see section on Salvarsan), it is 

 frequently possible by the administration of a few large doses of 

 mercury to evoke a positive reaction in individuals in whom the 

 disease has almost been eradicated, whereby a larger number of 

 spirochetes is destroyed at one time and a more intense stimulus 

 given to antibody formation (prowcatory stimulation). This possi- 

 bility has not yet received the recognition which it deserves, but 

 should be utilized in all doubtful cases, as well as in determining 

 whether a continuance of treatment is desirable or not (see page 

 286). 



In very early cases of syphilis, in which a sufficient length of time 

 for the formation of antibodies has not yet elapsed, the result will, 

 of course, also be negative, but in these the diagnosis can usually 

 be made by direct demonstration of the spirochete with the micro- 

 scope. 



With the limitations just set forth a diagnosis of syphilis can be 

 reached by means of the Wassermann reaction in over 90 per cent, 

 of the cases taken at random, the different types giving different 

 values, as shown in the accompanying table, which is taken from 

 Noguchi. The values given were obtained with the Noguchi system, 

 i. e., with an antihuman hemolytic system, but represent practically 

 what the method furnishes which we have described above. 



