224 
Digitalis.  Foxglove. 
J  Am.  Jour.  Pharm. 
\       May,  1913. 
Digitoxin,  C^H^O^,19  easily  crystallizable,  is  insoluble  in  water 
(when  free  of  other  digitalis  glucosids  or  extractive  matters)  ;  it 
dissolves  freely  in  alcohol  and  chloroform,  slightly  in  ether,  and  is 
insoluble  in  petroleum  ether  (Keller,  1897).  Schmiedeberg  could 
not  establish  the  presence  of  sugar  as  a  constituent  of  digitoxin; 
he  obtained  only  the  amorphous  toxiresin  by  the  action  of  acids.  I 
resolved  digitoxin  into  crystallized  digit oxigenin,  C22H3204,  and 
two  molecules  of  easily  crystallizable  sugar,  C0H12O4,  digitoxose.20 
Nativelles  digitalin  and  Arnaud's  digitaline  cristallisee  are  probably 
identical  with  digitoxin. 
Digitalin  (characteristic  granules,  very  little  soluble  in  water, 
insoluble  in  ether,  chloroform,  freely  dissolving  in  alcohol). 
Schmiedeberg  proved  this  to  be  a  glucosid,  but  he  obtained  as 
product  of  hydrolysis  only  a  resinous  substance  (digitali-resin) .  I 
established  the  digitalin  to  be  a  uniform  substance,  C35H56014,  not- 
withstanding its  refusal  to  crystallize,  and  I  resolved  the  pure  "  digi- 
talinum verum"  into  well  crystallized  digitaligenin,  C22H3203,  or 
C22H30O3,  dextrose  and  digitalose,  C7H1405. 
Digitalein. — At  first  I  had  questioned  the  existence  of  this  sub- 
stance as  an  individual  body,  but  later  researches  proved  without 
doubt  that  the  seeds  and  the  leaves  contain  a  considerable  quantity 
of  an  easily  water-soluble  substance,  vigorously  acting  upon  the 
heart;  yet  all  endeavors  to  isolate  that  very  decomposable  matter 
in  pure  condition  have  thus  far  proved  fruitless. 
Cloetta's  digalen  (like  many  another  similar  digitalis-product) 
contains  certainly  a  high  percentage  of  digitalein,  but  it  is  not 
proved  to  be  a  uniform  substance,  and  Cloetta's  claim  of  having 
transformed  it  into  digitoxin  and  vice  versa,  is  surely  erroneous. 
Tests  for  Digitoxin,  Digitalinum  verum  and  Digit cmin. — Keller's 
test  for  digitoxin :  Dissolve  the  substance  in  glacial  acetic  acid 
containing  a  little  ferric  chloride;  float  this  solution  upon  strong 
sulphuric  acid ;  at  the  line  of  contact  appears  a  dark  zone,  and  after 
a  few  minutes  the  acetic  acid  liquor  becomes  dark  blue  (indicating 
in  this  way  1/10  of  a  milligramme  of  digitoxin  in  1  Cc.  of  acetic 
acid).  This  test  is  more  sure  and  can  also  serve  for  digitalinum 
verum,  and  (negatively)  for  digit onin;  when  used  in  the  form 
uBer.  d.  d.  chem.  Ges.,  Vol.  31,  p.  2457  (1898). 
20  For  constitution  see:  Ibid.  Vol.  38,  p.  4040  (1905). 
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