Am"jJnoiy^i903a'm'}        Epinephrin  and  its  Compounds.  313 
trichloracetic  acid  in  penetrating  the  tissue,  dissolving  out  the  active 
principle  and  producing  so  light-colored  a  product. 
METHOD  OF  PURIFYING  THE  ABOVE  PRODUCT. 
Twenty-three  grammes  of  the  crystalline  material  obtained  from 
first  extractions  was  stirred  up  in  80  c.c.  of  water  containing  6 
grammes  of  oxalic  acid,  and  then  800  c.c.  of  absolute  alcohol  was 
added  in  small  quantities,  accompanied  by  vigorous  stirring.  Ether 
was  then  added  until  the  total  volume  was  nearly  1  litre.  The 
flask  is  then  set  aside  for  a  day  or  more,  when  the  alcohol-ether 
fluid  can  be  poured  off  from  the  abundant  sticky  precipitate.  Rela- 
tively little  of  the  substance  is  found  in  this  alcohol-ether  fluid  in 
the  form  of  an  oxalate,  and  may  easily  be  recovered  from  it 
only  slightly  contaminated  with  ash  by  simple  precipitation  with 
ammonia. 
The  gummy  precipitate,  which  contains  almost  all  of  our  sub- 
stance, is  dissolved  as  far  as  possible  in  about  50  c.c.  of  water  con- 
taining 12  or  more  grammes  of  trichloracetic  acid.  It  is  then 
precipitated  with  absolute  alcohol,  added  in  small  quantities  at  a 
time  until  800  c.c.  has  been  added.  Approximately  150  c.c. 
of  ether  is  then  added  and  the  whole  set  aside  until  the  supernatant 
liquid  is  clear.  The  mineral  constituents  (alkaline  earths)  will  then 
be  found  to  have  been  thrown  down  in  the  form  of  a  white  precipi- 
tate, while  the  active  principle,  together  with  some  water-soluble 
mineral  constituents,  is  contained  in  the  alcohol-ether  fluid.  From 
this  fluid  it  is  now  obtained  by  precipitation  by  ammonia.  After 
being  very  thoroughly  washed  with  water,  alcohol  and  ether  it  is 
found  to  be  entirely  ash-free. 
For  purposes  of  analysis  it  is  only  necessary  to  recrystallize  it  by 
precipitation  with  ammonia  from  a  solution  in  aqueous  hydrochloric  or 
trichloracetic  acid.  For  example,  a  portion  of  the  white  amorphous 
precipitate  obtained  by  ammonia  from  the  alcohol-ether  mixture 
just  referred  to  was  dissolved  in  dilute  oxalic  acid,  precipitated  by 
ammonia  ;  again  dissolved  in  dilute  trichloracetic  acid  and  thoroughly 
washed  with  water  that  has  been  freed  of  carbonic  acid,  then  with 
alcohol  and  ether  and  dried  in  vacuo  over  sulphuric  acid.  As  thus 
prepared,  especially  when  the  precipitation  with  ammonia  is  not 
effected  too  rapidly,  the  substance  forms  nodular  aggregates  of  well- 
formed  microscopic  prisms  terminated  sharply  by  pyramidal  planes. 
