171  Cortex  Juglandis  Cinerece.  {Axk^5SHm 
fected  by  that  acid.  It  is  completely  precipitated  from  either  strong 
or  diluted  solutions  by  hydrochloric  acid. 
It  seems  to  be  slightly  soluble  in  water,  is  sparingly  soluble  in  chlo- 
roform, and  insoluble  in  benzin.  Ether  dissolves  about  50  per  cent, 
of  it.  It  fuses  at  170°  F.  When  heated  on  platinum  foil  it  first 
fuses,  and  then  takes  fire,  burning  with  a  smoky,  luminous  flame. 
Volatile  Oil. — A  portion  of  the  bark  was  placed  in  a  retort,  mixed 
with  a  little  more  than  enough  water  to  cover  it  and  subjected  to  dis- 
tillation, whereby  a  yellowish  distillate  was  obtained,  which  had  a 
slight  acid  reaction,  and  a  strong,  peculiar,  aromatic  odor.  From 
this,  by  cohobation,  I  finally  obtained  a  colorless  liquid,  on  the  sur- 
face of  which  minute  globules  of  oil  could  be  seen  floating.  The 
odor  of  the  volatile  oil  is  peculiar,  and  not  very  pleasant.  The  yield 
was  so  very  small  that  I  could  not  determine  anything  in  regard  to  it. 
Volatile  Acid.  — About  one  troy  ounce  of  the  bark  was  treated  as 
in  the  former  experiment,  and  subjected  to  distillation.  Before  the 
contents  of  the  retort  had  begun  to  boil,  I  obtained  about  half  a  fluid 
ounce  of  a  bright  yellow  distillate,  which  was  odorless  ;  this  I  sepa- 
rated and  set  aside,  and  then  continued  the  distillation  till  about  six 
fluid  ounces  of  a  nearly  colorless  distillate  had  been  obtained.  The 
distillate  first  obtained  was  agitated  with  ether,  till  the  latter  ceased 
to  be  colored,  and  the  ethereal  solution  was  drawn  off.  This  had  a 
bright  yellow  color,  and,  on  evaporating  the  ether,  yielded  an  orange- 
yellow  residue  in  which  were  numerous  long  acicular  crystals,  which 
had  an  acid  reaction,  and  a  hot,  acrid  taste.  When  treated  with 
liquor  potassse,  the  crystals  acquired  a  deep-violet  color.  This  vola- 
tile acid  probably  constitutes  the  acrid  principle  of  the  bark,  therefore 
we  can  readily  understand  why  a  long-boiled  decoction  of  the  bark 
is  devoid  of  an  acrid  taste.  The  second  portion  of  the  distillate  was 
not  acid  in  reaction,  and  was  not  subjected  to  further  investigation. 
It  would  almost  seem  as  if  this  volatile  acid  was  decomposed  at  the 
boiling  point  of  the  decoction,  inasmuch  as  the  condensed  vapor  of 
the  liquid  in  the  retort  ceased  to  have  a  yellow  color  the  moment 
the  latter  began  to  boil,  and,  also,  ceased  to  have  an  acid  reaction. 
A  fresh  portion  of  bark,  when  treated  with  petroleum  benzin, 
yielded  an  oily  extract,  from  which  neither  alcohol  or  diluted  alcohol 
would  separate  any  crystalline  principle.  The  extract,  distilled  with 
water,  yielded  a  light  yellow  distillate,  from  which  ether  took  up  an, 
oily  matter  which  was  not  colored  purple  by  alkalies.    But  the  water 
