Am'ju°y,r'i^9.rm'  }       Chemical  Assay  of  Foxglove.  471 
so  depart,  yet  is  commercially  acceptable  and  medicinally  satisfac- 
tory, he  is  hardly  likely  to  modify  his  output.  One  has,  therefore, 
to  be  prepared  to  meet  variation  in  commercial  samples,  hence  the 
suggestion  earlier  in  this  article.  Users  of  aspirin  must,  however, 
exercise  care  in  regard  to  the  development  of  odor.  Sellers  will 
not  always  recognize  the  complaint  of  buyers  in  this  respect,  but  it 
is  very  important.  Odor  sometimes  develops  to  a  remarkable  and 
inexplicable  extent  in- use,  and  on  keeping,  which  no  amount  of  ref- 
erence to  figures  will  negative.  It  is  wise  to  put  aside  all  samples 
that  are  the  least  suspicious  in  this  regard. 
It  is  hoped  that  the  subject  of  aspirin  standards  may  be  of  inter- 
est to  others,  and  that  some  further  expression  of  experience  and 
views  may  be  forthcoming. 
This  note  is  the  result  of  work  carried  out  in  the  analytical  labo- 
ratories of  Evans  Sons  Lescher  &  Webb,  Ltd.,  at  Liverpool. 
THE  CHEMICAL  ASSAY  OF  FOXGLOVE.1 
By  Tschirch  and  Wolter. 
Up  to  the  present  no  reliable  chemical  assay  of  foxglove  leaves 
has  been  devised,  and  the  biochemical  method  has  been  more  and 
more  generally  adopted.  The  chief  constituents  of  the  leaves  are 
digitoxin,  digitonin  and  digitaleins.  Digitoxin,  the  separation  of 
which  has  hitherto  been  made  the  basis  of  a  chemical  method  of 
assay,  is  not  a  definite  substance,  but  a  mixture  to  which  the  name 
of  pseudodigitoxin  may  be  applied.  Digitalin  is  a  cardiac  poison. 
Digitonin  belongs  to  the  saponin  group.  Digitalein  is  a  group  desig- 
nation for  the  water-soluble  glucosides,  one  of  which  (gitalin)  pro- 
duces the  specific  action  of  foxglove.  The  authors  tested  all  the 
chemical  methods  of  assay  that  have  been  proposed  by  determining 
the  physiological  activity  of  the  substance  isolated  and  weighed,  and 
comparing  it  with  the  physiological  activity  of  the  leaves.  They 
found  in  agreement  with  Ziegenbein  and  with  Jermstadt,  that  the 
digitoxin  content  was  not  in  proportion  to  the  physiological  activity 
of  the  leaves.  Keller's  process  for  the  determination  of  digitoxin 
was  carried  through  and  the  solutions  tested  at  each  step  to  ascer- 
tain where  any  loss  might  occur;  it  was  found  that  five  shakings 
1Schweis.  Apoth.  Zeit.,  Vol.  56,  p.  469.  Reprinted  from  The  Pharm. 
Jour,  and  Pharm.,  April  12,  1919. 
