Ajainmry,^9ia3rrn'}  Digitalis  Glucosides  and  Allied  Drugs.  31 
confirmed  by  Kiliani.  Digitalin  Schmiedeberg  forms  a  white  mass, 
readily  soluble  in  alcohol,  hot  dilute  acetic  acid  and  a  mixture  of 
alcohol  and  chloroform,  but  is  only  slightly  soluble  in  cold  water, 
chloroform  and  ether.  When  split  up  by  acids  it  forms  digitaliresin 
and  glucose.  On  preparing  his  digitalin,  Schmiedeberg  found 
another  glucoside  soluble  in  water,  digitalein  Schmiedeberg;  when 
treated  with  acids  it  is  decomposed  into  glucose  and  a  body  probably 
identical  with  digitaliresin. 
Digitalin  Schmiedeberg  and  digitalein  Schmiedeberg  were  ex- 
amined more  minutely  by  Kiliani.  He  was  able  to  prove  that 
pure  digitalin,  for  the  preparation  of  which  he  worked  out  an 
exact  formula, 10  forms  an  amorphous  white  powder,  which  swells 
up  in  water  at  ordinary  temperature  and  is  soluble  1  in  1000  of 
water.  Moreover,  it  is  said  to  dissolve  in  50  parts  of  alcohol 
(50  p.  c.)  and  more  readily  in  hot  alcohol.  On  heating  it  remains 
white  up  to  2000  C,  begins  to  sinter  at  2100  C.  and  melts  at  about 
2170  C.  Kiliani  gave  it  the  formula  (C3  H8  02) 7  =  C35  H56  014, 
but  also  mentions  that  it  may  have  the  formula  C36  H5S  014. 
According  to  Kiliani,  on  heating  with  dilute  alcoholic  hydrochloric 
acid  it  splits  up  into  digitaligenin,  glucose  and  digitalose.  (Archiv 
der  Pharmazie  1892,  p.  250.) 
Kiliani  at  first  doubted  the  chemical  individuality  of  the  digitalein 
of  Schmiedeberg.  Keller 11  and  Houdas  12  also  took  it  to  be  digi- 
tonin.  But  Kiliani  proved  later  that  the  seeds  and  leaves  of  digi- 
talis contain  a  cardiac  poison,  soluble  in  water,  which  contains 
no  digitalin,  the  physiological  activity  of  which,  therefore,  precludes 
its  identity  with  digitonin.  Kiliani  and  Windaus  13  suspected  the 
presence  of  a  lactone  in  digitalein,  because  its  neutral  aqueous 
solution  gives  an  acid  reaction  on  standing.  This  proves  digitalein 
to  be  a  distinct  substance,  of  uniform  composition.  Kraft,14  on 
the  other  hand,  accepts  the  nomenclature  of  digitalein  only  as  a 
generic  term  for  all  the  active  glucosides  which  are  soluble  in 
water  and  are  present  in  digitalis.  He  also  places  in  this  class 
gitalin,  an  amorphous  glucoside,  melting  at  1 50-1 55 0  C,  which  he 
10  Archiv  der  Pharmazie  1892,  Vol.  230,  p.  252  and  1895,  Vol.  233,  p.  299. 
11  Keller,  Berichte  der  chemischen  Gesellschaft  Berlin  1897,  P-  i2S- 
12  Houdas,  Comptes  rendus  1891,  p.  648. 
13  Kiliani-Windaus,  Archiv  der  Pharmazie  1899,  p.  458. 
14  Kraft,  Schweizer  Wochenschrift  fiir  Chemie  und  Pharmazie,  1911,  p.  162 
and  173- 
