322 APPLIED IMMUNOLOGY 



or localized, with expressions as epilepsy, monoplegia, etc., 

 remarkable results are observed. In tabes dorsalis, partic- 

 ularly if the intravenous administration of the drug be sup- 

 plemented with intraspinal injection of autosalvarsanized or 

 artificially salvarsanized serum, there is reasonable hope of 

 arresting the disease if attacked in its infancy. In paresis 

 and encephalitis the authors have never observed noteworthy 

 benefit, the diseases exhibiting continuous retrogression. The 

 drug is of great value in hereditary lues and in pregnant 

 syphilitics. 



The provocative employment of salvarsan and neosalvar- 

 san is a matter of considerable importance. The arsenical 

 preparations similar to mercury may be utilized to provoke 

 a positive Wassermann reaction in a syphilitic patient other- 

 wise exhibiting a negative serological reaction. Thus in 

 patients who have previously received antisyphilitic treat- 

 ment, or in whom the clinical evidence for syphilis is strong 

 and the ordinary Wassermann reaction has resulted nega- 

 tively, the so-called provocative dose of salvarsan, neosalvar- 

 san or mercury should be employed, and the blood-serum 

 again tested at the end of twenty-four to forty-eight hours. 

 It has been our practice to use 0.1 gramme of salvarsan or 

 0.15 gramme of neosalvarsan, administered intravenously, 

 for this purpose. The explanations offered for the employ- 

 ment of arsenical and mercurial preparations in this role are 

 that the positive serological reaction is due to the liberation 

 of endotoxins from the killed spiroch^etse or to the stimula- 

 tion of the latent spirochastse by a dose of the drug in- 

 sufficient to effect a complete destruction. The phenomenon 

 or biochemical reaction is doubtless closely related to the 

 Herxheimer reaction. 



In non- syphilitic diseases, salvarsan enjoys an extensive 

 employment. Indeed in relapsing fever, tertian malaria, 



