APPENDIX 319 



ing the toxic, by the introduction of the halogen group into 

 the benzine ring, conceived the idea that arsenic in certain 

 combinations could be so compounded that its administra- 

 tion in a sufficiently large dose would not be injurious or 

 toxic to the organism and would at the same time destroy 

 all spirochsetse, sterilizing the system. Repeated trials en- 

 abled Ehrlich and his collaborators to produce a synthetic 

 drug, No. 606 in the experimental series, later styled " sal- 

 varsan," the use of which was claimed to be a " therapia 

 sterilisans magna " for the cure of syphilis. Subsequently, 

 further refinement led to the production of neosalvarsan or 

 No. 914, apparently less toxic but likewise less efficient. 



Be it understood that the treatment of syphilis by arsen- 

 ical preparations is not by any means a new idea. Syph- 

 ilologists for decades have recognized the benefit to patients 

 when arsenic supplemented or alternated mercury and iodine, 

 but owing to the toxicity of the trioxide of arsenic, it has been 

 necessary to administer it in minimal dosage. Consequently, 

 during recent years other forms of arsenic, less toxic and of 

 higher drug content, have been synthesized, recommended and 

 utilized. Among these arsenical preparations may be men- 

 tioned the arylarsonates (soamin and orsudan), atoxyl, 

 arsacetin, arsenophenylglycin paramidophenylarsenoxide and 

 sodium cacodylate. Some of these have fallen into almost 

 complete disrepute owing to gastro-intestinal disturbances, 

 nephritis and neurological manifestations, including blind- 

 ness, occasioned by their administration, and all have failed 

 to measure up to the virtue of salvarsan and neosalvarsan. 



Valuable and important as Ehrlich's discovery has 

 already proved itself to be in the treatment of syphilis, ad- 

 mittedly the sheet-anchor in the pharmacology of that dis- 

 ease, it is extremely doubtful if salvarsan will prove to be 



