300 IMMUNOLOGICAL METHODS OF DIAGNOSIS 



the Germans put it, of which, very fortunately, but few modern 

 physicians are apt to be guilty. 



Considered from the diagnostic standpoint a well-pronounced 

 positive reaction may probably always be regarded as indicating the 

 existence of syphilis, if we can rule out such diseases as frambesia, 

 leprosy, sleeping sickness, and scarlatina. In malignant disease a 

 certain degree of complement fixation may also be obtained, in a 

 considerable number of cases, but I have not been able to convince 

 myself that a triple plus (+ ++) reaction can ever be ascribed to 

 the malignant process in itself. Partial reactions (+ or ), on the 

 other hand, are here not infrequently met with and may even be 

 seen in persons who neither show any present signs nor give any 

 history of syphilis in the past. What these feeble reactions mean 

 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 standpoint 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 standpoint 

 of diagnosis as well as of treatment. As pointed out in a pre- 

 vious 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 (provocatory stimulation). This possibility 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 274). 



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, 



