36 
GLEANINGS  FROM  GERMAN  JOURNALS. 
Test  for  gaseous  sulphurous  acid. — Hugo  SchiS"  employs  paper 
moistened  with  solution  of  protonitrate  of  mercury  which  in- 
stantly assumes  a  gray  color  from  reduced  mercury  ;  it  is  re- 
quisite to  test  with  lead  paper  for  sulphuretted  hydrogen. 
Both  gases  are  not  present  at  the  same  time,  as  they  decom- 
pose each  other. — (Dingler's  Journ.  1861,  May.) 
Paraguay  tea. — Dr.  Stahlschmidt  found  that  the  distillate 
from  Paraguay  tea  was  opalescent,  had  a  peculiar  slight  odor  of 
tea  and  a  taste  resembling  peppermint.  From  18  lbs.  he  ob- 
tained 88  grm.  caffeina  —  -44  per  cent,  or  more  than  three 
times  as  much  as  Stenhouse,  by  the  following  process : — The 
decoction  was  precipitated  by  basic  acetate  of  lead,  the  decanted 
liquid  freed  from  lead  by  sulphuretted  hydrogen,  evaporated  and 
the  syrupy  residue  treated  with  hot  benzole.  On  cooling, 
caffeina  crystallizes  in  white  needles,  nearly  chemically  pure, 
which  may  be  re-crystallized  from  water  or  alcohol. — (Poggen- 
dorf's  Annalen,  cxii.  441.) 
Extr  actum  gentiance. —  Considering  the  presence  of  pectin 
and  pectase  in  gentian  root,  and  the  conversion  of  the  former 
by  the  latter  under  the  aid  of  a  moderate  heat  into  nearly  in- 
soluble pectic  acid,  Feldhaus  urges  the  propriety  of  exhausting 
the  root  by  digesting  it  for  several  days  at  a  temperature  of 
45°  C.  (113°  F.)  On  expressing  the  aqueous  liquid,  floccules 
of  the  acid  remain  behind  intermixed  with  the  ligneous  portion 
of  the  root.  The  infusion  is  now  evaporated  to  about  f  the 
weight  of  the  root  employed  and  mixed  with  an  equal  bulk  of 
strong  alcohol,  and  may  now  be  easily  strained  ;  the  residue  is 
washed  with  45  per  cent,  alcohol,  strongly  expressed  and  is 
then  almost  inert  and  but  slightly  bitter.  The  alcohol  is  regained 
by  distillation  and  the  extract  left  on  evaporation  (4|  lbs.  from 
20  lbs.  root)  is  rapidly  and  completely  soluble  in  water,  separat- 
ing but  few  floccules  on  standing.  Thus  prepared  very  little 
pectin  remains  in  the  extract,  it  not  being  completely  insolu- 
ble in  diluted  alcohol ;  but  aside  from  the  rapid  solubility,  the 
extract  has  no  pasty  consistence  and  is  not  liable  to  mould. 
The  same  process  is  applicable  to  other  extracts. — (Archiv  d. 
Ph.  cviu  294-298.  . 
Castor,— Dr.  F.  G.  Geiss  reports  that  the  beaver  is  still  found 
