152 THE METHOD OF COMPLEMENT FIXATION. 



reaction, have infected others or have all of a sudden developed tertiary 

 or postluetic manifestations, tabes, paralysis, diseases of the aorta, etc. 



An objection has frequently been raised, that in spite of existing disease, the reaction 

 has been found negative. If the statistics covering the largest number of cases are 

 studied, it will be seen that such instances are rare. Few exceptions are discovered in 

 every biological reaction, especially one which is complicated and where five different 

 ingredients come into play; even in the immunization of animals differences will be found 

 in that some produce a highly agglutinating or precipitating, etc., serum, while others 

 will show few or even no antibodies. Individual differences are prevalent to such extent 

 that exceptions to the rule must be taken for granted. Fortunately, a negative reaction 

 in existing lues is so rare, that for practical purposes its possibility may be overlooked, 

 at least, with reservation. 



As a general rule, antibodies persist in an organism for a certain time past infection, 

 when the individual has become perfectly well. Exceptions, to the effect that it may 

 be possible for a positive Wassermann reaction to similarly signify a past infection or a 

 state of immunity, have been raised. But it must be said that immunity in syphilis is a 

 condition thus far unproven and almost unknown. All symptoms previously attributed to 

 such an immunity can more easily be explained in the light of a continuation of the 

 disease. As for the "lues reagine" remaining after the cure of the infection, undoubtedly 

 this phenomenon is possible. The analogy with other diseases seems lost, however, 

 when one considers that the syphilitic reaction is discovered thirty or forty years after an 

 infection, while antibodies in general persist for weeks, months or at the most for several 

 years, following an infection. Still it may be possible that the syphilis "reagine" is char- 

 acterized by the difficulty with which it is excreted and by the tendency of the cells when 

 once stimulated to produce antibodies to continue to do so. The influence of mercury, 

 however, demonstrates that this phenomenon is closely allied to similar actions exhibited 

 by the class of bacteria. If a patient whose serum gives a positive reaction is subjected 

 to mercurial treatment, the reaction becomes negative in several weeks. The mercury 

 has destroyed the stimulant or irritant which has led the cells to the production of anti- 

 bodies. If this stimulant is excluded, the "lues reagine" disappears from the blood just 

 as bacterial antibodies disappear after the bacteria have been eradicated. Thus there 

 is no basis for attributing to the luetic antibodies any exceptional properties. 



The fact that mercury leads to an alteration in the reaction, 



Citron's prompted the author to employ the Wassermann test as a 



"Biological guide to the biological mercurial treatment. The aim was not 



Mercurial only to cause a disappearance of all manifestations, but to obtain 



Treatment." a ne g a tiv e reaction. It soon appeared that a negative reaction 



once obtained did not necessarily remain such. As soon as a 



recurrence set in the reaction became positive again; in fact, the reaction 



also reappeared without a return of symptoms. In the latter case such a 



return alone was regarded as a fresh manifestation of a reactivation process 



and an indication for treatment. It became advisable therefore, to repeat 



the test at definite intervals and depend upon the return of the reaction for 



further treatment. This basis of therapy, which at first met with marked 



opposition, has recently won many followers. 



The experiments of Boas in Copenhagen are especially instructive 

 from this point of view. 



