Am.  Jour.  Pharm. 
Aug.,  1892. 
Digit  alin. 
417 
(2)  The  digitalein  of  Schmiedeberg  is  certainly  also  a  mixture ; 
its  action  upon  the  heart  is  perhaps  due  to  the  presence  of  a  gluco- 
side  that  has  not  yet  been  separated  in  a  state  of  purity,  or  perhaps 
it  may  be  due  to  some  admixture  of  digitalin. 
(3)  On  the  contrary,  the  digitalin  of  Schmiedeberg  is  a  distinctly 
individual  substance  which  possesses,  in  a  marked  degree,  the 
characteristic  property  of  acting  upon  the  heart. 
This  substance  is  now  being  made  according  to  my  directions  by 
Messrs.  Boehringer,  and  it  is  to  be  obtained  as  a  medicinal  agent 
under  the  name  of  Digitalin  verum.  Unfortunately,  this  substance 
cannot  be  brought  into  an  actually  crystalline  condition.  For  that 
reason  it  appears  to  be  the  more  appropriate  that  its  characters 
should  be  minutely  defined,  and  that  satisfactory  evidence  of  its 
chemical  individuality  should  be  given. 
Digitalin  has  the  form  of  a  white  amorphous  powder,  the  particles 
of  which  swell  up  when  immersed  in  water.  It  is  soluble  in  about 
one  thousand  parts  of  water,  and  in  about  one  hundred  parts  of 
fifty  per  cent,  alcohol.  The  water  solution  froths  on  being  shaken, 
and  it  is  remarkably  prone  to  become  mouldy.  Digitalin  is  dissolved 
in  considerable  amount  by  hot  absolute  alcohol  or  spirit  of  80  or 
90  per  cent.,  and  when  a  minimum  of  solvent  is  used,  the  solution 
on  cooling  becomes  almost  solid  from  the  separation  of  a  thick 
magma  of  granules,  which,  as  observed  by  Schmiedeberg,  appears 
to  the  naked  eye  as  if  it  were  a  case  of  crystallization.  Exami- 
nation by  the  aid  of  the  microscope,  however,  shows  that  the  mass 
consists  of  granules  which,  though  of  very  uniform  size,  are  entirely 
destitute  of  structure. 
The  uniformity  of  this  deposit  is,  however,  in  itself  a  very 
characteristic  feature  of  the  substance  ;  it  is,  moreover,  an  excellent 
criterion  of  its  purity.  When  digitalin  contains  only  a  small  per- 
centage amount  of  the  glucosides  associated  with  it  in  digitalis,  it  is 
impossible  to  effect  its  separation  from  solution  in  the  form  above 
described.  When  it  also  contains  some  digitonin,  and  85  per  cent, 
alcohol  is  used  for  dissolving  it,  crystals  will  be  found  among  the 
granules  deposited  from  the  solution  after  cooling. 
These  impurities  of  digitalin  may .  be  detected  with  greater 
accuracy  by  means  of  the  following  tests  : 
(1)  A  few  granules  when  mixed  with  about  2  cc.  of  caustic  potash 
solution  (1  :  10)  should  retain  their  whiteness  for  at  least  one 
