522  British  Pharmaceutical  Conference.  {A%Jc°t%?Safm- 
expressed  at  the  last  meeting  of  the  Conference  that  glycerin  might  be  freed 
from  arsenical  contamination  by  distillation,  and  stated  that  he  had  now  found 
this  not  to  be  the  case.  But  he  had  found  that  by  treating  glycerin,  previously 
diluted,  with  recently  precipitated  ferric  hydrate  the  arsenic  can  be  completely 
removed,  and  at  the  same  time  the  glycerin  is  freed  from  all  sulphur  compounds. 
The  same  object  can  be  obtained  by  suitable  treatment  with  potassium  per- 
manganate, but  in  that  case  redistillation  of  the  glycerin  is  necessary.  Mr. 
Lewkowitsch  also  referred  to  the  same  statement  as  to  the  removal  of  arsenic 
from  glycerin  by  distillation  and  said  it  was  impracticable,  as  the  arsenious 
ether  of  glycerin  is  decomposed  by  heating  to  250°C,  arseniuretted  hydrogen 
and  other  volatile  arsenious  compounds  distilling  over.  So  far  as  he  is  aware 
there  is  no  process  for  completely  freeing  glycerin  from  arsenic  on  a  practical 
scale  after  it  has  once  been  introduced  by  the  use  of  arsenial  materials  in  the 
manufacture.  He  pointed  out  that  glycerin  free  from  arsenic  is  obtained  in 
those  processes  where  the  hydrolysis  of  fats  is  effected  by  means  of  water  or 
by  lime  saponification,  and  also  when  sulphuric  acid  is  used  free  from  arsenic, 
as  it  may  be  prepared  from  the  sulphur  obtained  by  Chance's  process.  Out  of  ten 
samples  of  glycerin  coming  from  as  many  different  works  examined  for  arsenic 
three  would, have  had  to  be  rejected,  four  contained  small  traces  that  might  be 
disregarded,  and  only  three  were  free.  Concerning  soap-lye  glycerin  a  very 
unnecessary. caution,  Mr.  Lewkowitsch  said,  had  been  given,  because  up  to  the 
present  no  chemically  pure  glycerin  had  been  prepared  from  soap-lyes  in  conse- 
quence of  the  difficulties  incident  to  the  purification  of  it.  But  a  sample 
specially  prepared  by  himself  from  this  material  compared  well  with  samples 
from  other  sources.  In  the  discussion  that  followed  the  reading  of  the  paper 
the  question  was  raised  as  to  the  source  of  the  minute  quantities  of  iron  that 
are  sometimes  observed  in  glycerin,  and  whether  they  might  be  due  to  a  treat- 
ment like  that  suggested  by  Mr.  Siebold. 
Antidotes  to  Strychnine. — Mr.  Siebold  next  read  a  short  note  on  some  experi- 
ences in  reference  to  strychnine  antidotes.  The  conclusions  arrived  at  were 
that  tannic  acid  is  without  effect,  that  animal  charcoal  might  be  of  some  use 
if  administered  very  soon  after  the  ingestion  of  poison,  but  that  physiological 
remedies  are  most  likely  to  be  of  service. 
Caffeine  and  Mercuric  Chloride. — Mr.  R.  H.  Davies  then  read  a  note  on  a 
compound  of  caffeine  and  mercuric  chloride  which  is  formed  as  a  crystalline 
precipitate  when  a  solution  of  corrosive  sublimate  is  added  to  a  solution  of 
caffeine  in  water.  The  reaction  is  a  very  delicate  one,  and  the  compound 
formed  has  a  composition  corresponding  to  that  of  a  chloromercurate  of 
caffeine. 
Tests  for  Methylated  Spirit,  by  Messrs.  Campbell  and  Stark.— A  comparative 
examination  of  the  tests  for  methylated  spirit  was  undertaken  with  a  view  to 
deciding  their  relative  reliability  and  suitability  for  pharmaceutical  testing. 
Emerson  Reynold's  test,  depending  upon  the  presence  of  acetone  and  the 
formation  with  it  of  aceto-mercuric  compounds,  was  found  not  to  be  effective 
when  less  than  2  per  cent,  of  wood  spirit  was  added  to  a  distillate  consisting  of 
the  first  50  cc.  passing  over  from  200  cc.  of  spirit.  With  Cazeneuve's  test, 
depending  on  the  reducing  action  of  acetone  and  other  bodies  on  potassium 
permanganate,  the  limits  of  the  test  were  reached  with  the  presence  of  o'5  per 
