AlocSer,Fimm'}  Pharmacy  and  Chemistry.  469 
preparateur  of  Chevreul,  Collinet,  preparateur  of  Dumas,  and 
Ubaldini,  conceived  the  idea  of  meeting  to  discuss  work  accom- 
plished by  the  chemists  in  the  great  scientific  center — Paris.  Friedel, 
Perrot,  Wurtz,  Barreswill  and  other  noted  chemists  of  the  time 
soon  endorsed  the  idea  of  their  assistants,  and  the  Societe  Chimique 
de  Paris  was  an  established  fact.  To-day  this  is  one  of  the  most 
important  scientific  bodies  in  the  world,  and  publishes  a  bulletin  of 
over  3,000  pages  annually.  Since  1900  its  members  have  discovered 
over  2,000  new  compounds,  which  form  one  of  the  most  remarkable 
scientific  exhibits  of  the  World's  Fair.  Though  each  sample  is 
shown  in  a  small  glass  only,  still  they  require  a  large  6  by  12-foot 
case  to  house  them  all. 
One  of  the  most  striking  exhibits  in  the  case  are  the  delicate  tests 
of  Armand  Gautier,  proving  that  arsenic  is  found  in  all  articles  of 
food,  and  in  all  parts  of  the  animal  organism.  Of  course,  the  per 
cent,  is  very  small.  Only  his  most  refined  method  of  analysis  could 
reveal  the  minute  traces  of  arsenic  present.  The  small  apparatus 
actually  used  by  Gautier  is  also  shown.  This  consists  essentially  of 
three  parts :  an  evolution  flask,  a  decomposing  tube  and  the  mirror 
deposition  tube.  The  first  is  essentially  a  small  three-tubulatured 
Wolff"  bottle,  holding  not  over  200  c.c.  The  central  tubulature  has 
a  ground-in-glass  separatory  funnel ;  this  is  to  hold  the  acid  liquid 
to  be  tested.  The  second  is  a  safety  tube,  that,  by  simply  pressing 
a  Mohr's  pinch-cock,  allows,  when  too  rapid  an  evolution  of  hydro- 
gen takes  place,  this  gas  to  bubble  through  a  silver  solution.  The 
third  is  the  exit  tube ;  this  has  a  small  bulb  to  catch  acid  mechani- 
cally thrown  upwards ;  from  this  a  wide  tube  admits  of  the  introduc- 
tion of  caustic  potash  to  retain  antimony,  to  dry  the  gas  and  remove 
all  traces  of  acid. 
The  now  thoroughly  purified  gas  passes  to  the  reduction  tube ; 
this  is  a  thin,  hard  glass  tube  encased  in  close- woven  copper  netting, 
and  heated  to  redness  for  fully  6  inches  of  its  length  in  a  minute 
combustion  furnace.  At  the  end  of  the  furnace  an  asbestos  shield 
prevents  direct  heat  radiation  warming  this  portion  ;  a  linen  cloth 
wrapped  about  the  tube,  continually  wetted  with  water,  causes  a 
prompt  cooling  of  the  gases,  and  a  sharply  defined  mirror  deposits 
in  the  thin  tube  extension.  Any  undecomposed  gases  pass  into  the 
silver  solution,  where  the  arseniuretted  hydrogen  precipitates  the  sil- 
ver.  No  such  blackening  is  noted  when  reasonable  care  is  exercised. 
