Amaphi  i,  iP872RM  }   Gleanings  from  the  European  Journals.  165 
After  the  reaction  with  the  stannous  chloride  the  crude  acid  contains 
bichloride  of  tin,  which  readily  distils  over  when  the  acid  is  rectified. 
The  author  recommends  Duflos'  process  for  the  removal  of  arsenic 
from  crude  muriatic  acid  as  the  best ;  it  consists  in  diluting  the  acid 
to  a  specific  gravity  of  1*13,  removing  any  sulphurous  acid  present 
by  powdered  peroxide  of  manganese,  and  digesting  the  liquid  with 
bright  strips  of  metallic  copper,  which  appears  also  to  remove  thal- 
lium, that  is  occasionally  present.  The  formation  of  perchloride  from 
the  protochloride  of  iron  is  then  prevented  by  adding  to  the  acid  in 
the  retort  some  copper  clippings. — Pharm.  Cent.  Halle  1872,  N.  6., 
p.  52. 
Pure  Carbolic  Acid  is  now  prepared  by  Schering,  of  Berlin. 
Hager  has  compared  it  with  Calvert's  pure  acid  and  found  both  not 
to  be  affected  in  color  by  the  light.  Calvert's  carbolic  acid  fused  at 
41°  C,  Schering's  at  43-5°  C.  ;  the  former  congealed  at  33,  the  latter 
at  36° ;  the  former  dissolved  at  a  medium  temperature  in  19-20 
parts,  Schering's  in  17*5  parts  of  water;  100  parts  of  Schering's 
carbolic  acid  dissolve,  at  a  medium  temperature,  20  parts  of  water, 
Calvert's  only  18  parts.  The  author  ascribes  these  small  differences 
to  the  presence  of  a  little  water  in  Calvert's,  while  Schering's  acid 
appears  to  be  anhydrous.* — Ibid.,  N.  8,  p.  68. 
Preparation  of  Collodium. — The  process  which  has  been  for  years 
successfully  used  in  the  laboratory  of  the  university  of  Munich  is  as 
follows :  30  grm.  finely  powdered  saltpetre  and  30  grm.  sulphuric 
acid  are  mixed  in  a  glass  cylinder  by  means  of  a  glass  rod  until  the 
former  is  dissolved,  2  grm.  cotton  are  then  added  and  the  whole  well 
stirred  for  five  minutes.  After  washing  with  much  water,  then  with 
alcohol  and  drying,  the  cotton  dissolves  readily  in  a  mixture  of  equal 
parts  of  alcohol  and  ether,  and  the  solution  leaves  on  evaporation  a 
perfectly  transparent  film.  The  presence  of  much  nitric  acid  in  the 
oil  of  vitriol  seems  to  render  the  collodium  film  opaque.  The  prepa- 
tion,  at  one  operation,  of  a  larger  quantity  of  collodium  cotton  than 
30  grammes  appears  to  alter  somewhat  the  optical  behavior  of  the 
collodium  ;  and  the  same  result  is  obtained  if  the  last  traces  of  acid 
are  removed  by  ammonia. — N.  Repert.  f  Pharm.,  1872,  N.  1,  p.  6. 
Ampelopsis  hederacea. — Wittstein  analyzed  the  leaves  of  this  plant 
*  Why  should  the  latter  then  require  for  solution  less  water  than  the  former? 
Ed.  Am.  Jour.  Pharm. 
