Am.  Jour.  Pharm.  ) 
Oct.,  1879.  f 
Chemical  Notes. 
493 
glucoside.  The  second  not  only  possesses  the  composition  of  helicin,  an 
oxydation  product  of  salicin,  but  examination  shows  it  to  be  absolutely 
identical  with  the  naturally  derived  product.  The  helicin,  acted  upon 
with  nascent  hydrogen,  yields  salicin,  the  glucoside  of  the  willow.  The 
author  proposes  to  extend  this  method  to  the  study  of  a  number  of  the 
more  important  glucosides,  mentioning  among  others  suberythric  acid, 
the  glucoside  of  the  madder  root. — Comptes  Rendus,  No.  89,  p.  355. 
Test  for  Alcohol. — Jaquemart  proposes  to  test  a  liquid  for  alcohol  by 
means  of  a  solution  of  mercuric  nitrate.  This  reagent  acts  at  once 
upon  alcohol,  and  while  different  products  are  formed  a  partial  reduc- 
tion to  mercurous  salt  takes  place.  If,  after  the  action  is  complete 
ammonia  is  added,  a  black  precipitate  is  formed  which  is  more  copious 
and  deeper  in  color,  as  more  alcohol  is  present.  Methyl  alcohol,  under 
like  circumstances,  effects  no  reduction  of  the  mercuric  salt;  5  to  6  cc. 
of  the  solution  to  be  tested,  decolorized  by  animal  charcoal  if  necessary, 
will  suffice  for  the  reaction. — Fres.  7jt its.  fur  Anal.  Chem.^o.  18,  p.  291. 
On  the  preparation  of  crystallised  Albumenoid  Compounds. — E.  Drechsel 
has  taken  a  method  suggested  by  Schmiedeberg  for  extracting  the 
vitellin  from  Para  nuts  in  a  crystalline  state,  and  has  improved  and 
extended  it,  so  that  it  is  now  a  general  method  for  obtaining  albumenoid 
compounds  in  a  crystallized  state.  The  aqueous  solution  of  the  impure 
vitellin  is  precipitated  by  carbonic  acid  gas,  the  well-washed  precipitate 
digested  at  35°C.  with  magnesia  and  water;  the  filtered  solution  is  then 
placed  in  a  dialyser  and  this  placed  in  absolute  alcohol.  The  water 
diffuses  very  rapidly  into  the  alcohol,  and  small  crystalline  grains  sepa- 
rate out  of  the  solution.  These  are  perfectly  granular  and  easily 
washed.  They  are  thrown  upon  a  filter  (best  a  sand-filter  in  a  wide 
tube),  washed  first  with  5  per  cent,  alcohol,  then  with  absolute 
alcohol,  and  finally  with  pure  ether.  They  are  then  dried  in  a  stream 
of  dry  air  at  ordinary  temperatures.  These  crystals  are  the  magnesia 
compound  of  vitellin.  Drechsel  proposes  to  apply  this  method  of 
alcohol  dialysis  to  the  extraction  and  determination  of  the  urea  in  the 
blood  as  well  as  to  the  preparation  of  crystallized  albumenoids. — your., 
fiirpr.  Ch.,  1879,  p.  19,  331. 
