236 
Cmnposition  of  Salvarsan. 
Am.  Jour.  Pharm- 
Aprii,  1920. 
Repeated  comparative  irritation  experiments,  when  made  upon 
the  shaven  abdomens  of  guinea  pigs,  led  to  the  conclusion,  that,  in 
general,  a  2  per  cent,  mustard  oil  application  made  with  tragacanth 
base,  ably  represented  in  irritation  efficiency,  a  3  per  cent,  mustard 
oil  application  made  with  a  base  composed  of  paraffin  and  yellow 
petrolatum. 
The  keeping  qualities  of  the  application  made  with  tragacanth 
base  are  excellent  provided  the  container  is  kept  hermetically  sealed; 
the  collapsible  tin  tube  being  the  logical  container  for  this  applica- 
tion. 
PharmaceuticaIv  Research  Laboratory, 
H.  K.  MuLFORD  Company, 
PniiyADELPHiA,  Pa. 
THE  COMPOSITION  OF  SALVARSAN. 
At  a  meeting  of  the  Chemical  Society  on  March  18,  a  communi- 
cation from  the  Wellcome  Chemical  Research  Laboratories  on  the 
composition  of  salvarsan  by  Professor  F.  L.  Pyman  and  Mr.  R.  G. 
Fargher  was  read  by  the  latter.  Commercial  salvarsan  prepared 
by  the  reduction  of  3-nitro-4-hydroxyphenylarsinic  acid  by  means 
of  sodium  hyposulphite,  solution  of  the  3  :  3^-diamino-4  :  4^-di- 
hydroxyarsenobenzene  so  obtained  in  methyl  alcohol  containing 
hydrogen  chloride,  and  precipitation  of  the  salt  by  means  of  ether, 
is  generally  regarded  as  3  :  3^-diamino-4  :  4^-dihydroxyarseno- 
benzene  dihydrochloride  containing  combined  solvent.  The  latter 
according  to  the  earlier  work  of  Bhrlich  and  Bertheim,  is  methyl 
alcohol,  and  it  has  been  suggested  recently  by  Kober  that  the  vari- 
able toxicity  of  salvarsan  can  be  accounted  for  on  this  assumption. 
On  the  other  hand  the  circulars  of  the  first  makers,  the  Farbwerk 
vorm.  Meister,  Lucius  u.  Briining,  suggest  that  the  combined  solvent 
is  water.  It  has  now  been  shown  that  the  retained  solvent  consists 
almost  entirely  of  water,  support  for  the  view  being  adduced  from 
the  elementary  analysis  of  salvarsan  and  direct  estimation  of  methyl 
alcohol,  the  amount  present  varying  from  nil  to  1.4  per  cent.  The 
replacement  of  ether  by  acetone  in  the  precipitation  leads  to  a  prod- 
uct, which,  in  addition  to  the  customary  solvent  which  can  be  re- 
moved in  a  vacuum,  contains  a  molecular  proportion  of  acetone. 
^  A  contribution  from  The  Wellcome  Chemical  Research  Laboratories, 
London,  Eng. 
