320 APPLIED IMMUNOLOGY 



the universal, omnipotent, all-sufficient panacea for lues 

 originally claimed by its advocates, although the authors 

 have repeatedly observed, in the primary stage of the disease 

 before the advent of a positive Wassermann, a single inten- 

 sive dose of salvarsan suffice to effect a cure, thereby ful- 

 filling the dictum of Ehrlich. Possibly the cure not attained 

 by a single dose may be accomplished by repeated injections 

 or a combination with mercury and iodine. This much only 

 is assured at present, that in the great majority of patients 

 the immediate effect of salvarsan properly administered is 

 a symptomatic cure; concerning the remote results, addi- 

 tional time must elapse before definite conclusions can be 

 drawn. 



Chemico-physical Properties. — The Ehrlich-Bertheim- 

 Hata arsenical preparation No. 606, synthetically known as 

 dioxy-diamido-arseno-benzene-dihydrochloride, may be repre- 

 sented by the following structural formula : 



HO. ,0H 



^CeHa — As = As - Ceiiz<^ 

 HCINh/ ^NHaHCI 



It is commercially known in the market at present as " sal- 

 varsan," and appears as a light yellowish powder, markedly 

 acid in reaction and very unstable on exposure to the atmos- 

 phere. For these reasons the drug must be neutralized and 

 prepared in solution strictly fresh each time before its ad- 

 ministration. 



Ehrlich observed that formaldehyde-sulphoxylates of so- 

 dium possess the property of restraining for a time the auto- 

 oxidation of solutions of dioxy-diamido-arseno-benzene, and 

 by the interaction of the two evolved dioxy-diamido-arseno- 

 benzene-monomethane-sulphinate of sodium or No. 914, com- 



