Am.  Jour.  Pharm.1 
Aug.,  1892.  J 
Digit  a  I  in. 
419 
ally  individual  substance.  However,  the  best  support  of  this  view 
is  furnished  by  the  behavior  of  digitalin  with  dilute  hydrochloric 
acid.  The  substance  is  thus  split  up  very  definitely  into  digitali- 
genin,  glucose  and  digitalose.  When  pure  digitalin  is  used  the  first 
named  product  separates  at  once  in  fine  crystals,  but  when  the 
material  operated  upon  contains  some  of  the  other  glucosides,  the 
digitaligenin  cannot  be  made  to  crystallize  at  all,  or  only  by  very 
tedious  operations. 
In  Schmiedeberg's  experiments  on  the  splitting  up  of  digitalin 
with  watery  hydrochloric  acid  he  obtained  besides  a  glucose  an 
insoluble  resinous  substance — digitaliresin — which  he  was  able  to 
decompose  again  into  sugar  and  a  second  resin.  On  repeating  this 
experiment  it  becomes  at  once  obvious  that  this  digitaliresin  cannot 
possibly  be  a  chemically  individual  substance,  for  it  begins  to  be 
deposited  from  the  first  moment  that  heat  is  applied,  and  it  may 
easily  be  seen  that  the  resin  carries  down  with  it  unaltered  granules 
of  digitalin.  When  the  application  of  heat  is  continued  for  the 
purpose  of  decomposing  the  digitalin  thus  mechanically  carried 
down,  the  acid  causes  a  further  decomposition  at  the  surface  of  the 
resin,  while  inside  the  mass  there  still  remains  unaltered  digitalin 
and  digitaliresin.  In  order,  therefore,  to  effect  a  definite  splitting 
up,  care  must  be  taken  that  nothing  is  deposited  while  heating  with 
the  acid,  and  this  may  be  done  in  the  following  way : 
The  digitalin  is  first  mixed  with  8  parts  of  50  per  cent,  alcohol, 
2  parts  concentrated  hydrochloric  acid  (1-19)  added,  shaken  together, 
and  heated  for  half-an-hour  in  a  boiling  water-bath  under  a  reflux 
condenser.  The  liquid,  clear  at  first  rapidly  becomes  dark-colored, 
but  does  not  during  the  heating  deposit  more  than  mere  traces  ol 
resinous  substance.  Upon  cooling,  after  removal  from  the  water- 
bath,  there  is  an  abundant  formation  of  brilliant  acicular  crystals  of 
digitaligenin  aggregated  in  warty  masses.  The  crystallization  takes 
place  more  readily  on  rubbing  the  sides  of  the  glass,  or  on  dropping 
in  a  crystal  of  the  substance.  On  separating  the  crystals,  washing 
with  50  per  cent,  alcohol,  and  drying,  the  quantity  thus  obtained 
amounts  regularly  to  30  per  cent,  of  the  digitalin  operated  upon. 
When  the  filtrate  is  mixed  with  an  equal  volume  of  water,  repeatedly 
shaken  with  ether,  and  the  ether  shaken  with  very  dilute  soda  solu- 
tion to  remove  hydrochloric  acid,  a  further  quantity  of  the  same 
substance  is  to  be  obtained.    By  repeated  crystallization  from  the 
