204  Keeping  Properties  of  Digitalis.  {^S^iS™- 
specialties,  which,  of  course,  are  said  not  to  be  subject  to  such  de-  • 
terioration.  In  addition,  however,  to  these  obviously  interested 
claims  we  find  reports  of  great  loss  in  activity  of  the  leaf  coming 
from  men  of  such  reputation  as  Focke,1  who  found  deterioration 
amounting  to  76  per  cent,  of  the  original  value  in  two  and  three- 
fourths  months  in  a  leaf  containing  about  12  per  cent,  of  moisture. 
He  found  a  similar  loss  in  one  year  in  a  leaf  having  6  to  8  per 
cent,  of  moisture ;  leaves  with  6.5  per  cent,  of  moisture  lost  from  14 
to  53  per  cent,  in  strength  in  a  year;  those  having  3  per  cent,  of 
moisture  lost  15  per  cent,  in  activity  in  the  same  period;  and  there 
was  5  per  cent,  loss  in  a  year  when  the  moisture  had  been  reduced  to 
1.5  per  cent.,  the  low  point  recommended  by  Focke  to-  ensure  the 
keeping  properties  of  the  leaf. 
Houghton  and  Hamilton  2  report  their  results  in  a  series  of 
observations  upon  the  loss  of  potency  of  different  digitalis  prepa- 
rations. An  extract  of  digitalis  made  by  percolation  with  fairly 
strong  alcohol  showed,  on  tests  of  eleven  samples,  an  average  loss 
of  activity  of  about  40  per  cent,  in  a  period  of  five  years — an 
annual  loss  of  about  8  per  cent.  Eight  samples  of  a  fluid  extract 
of  digitalis,  made  according  to  the  U.  S.  P.  VII,  with  a  menstruum 
of  62.5  per  cent,  alcohol,  showed  an  average  loss  of  25  per  cent,  in 
six  years — an  annual  loss  of  about  4  per  cent.  Eleven  samples  of 
fluid  extract  of  digitalis  made  according  -to  the  U.  S.  P.  VIII, 
using  48  per  cent,  alcohol  as  the  menstruum,  showed  an  average  loss 
of  10  per  cent,  per  year,  or  a  total  loss  in  activity  of  35  per  cent, 
in  three  and  one-half  years.  Lastly,  six  samples  of  tincture  of  digi- 
talis made  according  to, the  U.  S.  P.  VIII  showed  a  loss  in  potency 
of  27  per  cent,  in  three  years — an  annual  loss  of  9  per  cent.  These 
results  would  seem  to  show  that  the  official  alcoholic  fluid  prepa- 
rations of  digitalis  undergo  deterioration  at  a  rate  ranging  from 
4  to  10  per  cent,  per  year,  varying  somewhat  in  relation  to  their 
alcoholic  content. 
England  3  says  of  the  commercial  fluid  extract  of  digitalis,  "  It 
is,  largely, 'a  concentrated  hydro- alcoholic  solution  of  certain  proxi- 
mate principles,  or  their  decomposition  products  arising  from  the 
use  of  heat."  He  cites  an  observation  of  Roger,  giving  no  refer- 
ence, however,  to  the  effect  that  a  5  per  cent,  maceration  of 
1  Arch.  d.  Pharm.,  1903,  cxli,  128. 
2  Am.  Jour.  Pharm.,  Oct.,  1909. 
3  Phil.  Polyclinic,  Jan.,  1897. 
