206  Keeping  Properties  of  Digitalis.  {Am'^t'l^rm' 
meroial  samples  of  the  leaf.  This  is  also  borne  out  by  the  recom- 
mendation of  Foeke  to  prepare  the  leaf  for  keeping  by  drying  it 
rapidly  with  the  aid  of  moderate  heat. 
Two  tinctures  of  digitalis,  made  with  70  per  cent,  alcohol,  in 
Hale's  hands  showed  a  frog  titre  after  eight  years  which  was  equal 
to  that  of  the  average  fresh  tincture  prepared  from  a  high  grade  new 
specimen  of  English  leaf.  On  the  other  hand,  assays  of  a  number 
of  digitalis  preparations  obtained  in  the  open  market  showed  a 
little  deterioration  in  twenty-two  months.  Three  samples  of  official 
fluid  extract  lost  4.3,  6.9,  and  8.7  per  cent,  respectively  in  this  time. 
Four  non-official  preparations,  obtained  at  the  same  time  and  under 
like  conditions,  showed  deterioration  from  14.3  to  33.3  per  cent,  in 
the  same  interval  of  time. 
Moran  5  records  a  number  of  observations,  which  include  some 
contradictory  results,  made  upon  different  samples  of  tinctures  of 
the  same  age ;  thus,  one  showed  no  deterioration  in  four  years,  while 
another  is  stated  to  have  appeared  "  to  have  deteriorated  consid- 
erably," in  the  same  time.  He  also  tested  a  tincture  which  was 
twenty-four  years  old  and  one  made  from  an  extract  which  was 
nineteen  years  old.  In  the  case  of  both  of  these  he  says  that  the 
activity  was  probably  due  to  the  saponin  present,  inferring  that  they 
retained  no  digitalis  action  at  all.  In  the  meagre  details  that  he 
gives,  however,  he  states  that  the  perfusion  of  20.0  c.c.  of  the  twenty- 
four  year  old  specimen  through  the  heart  of  a  frog  caused,  "  No 
tonic  effect,  acceleration  of  beat;  systolic  arrest."  Of  the  tincture 
from  the  nineteen  year  old  extract  only  11.0  c.c.  were  required  to 
give  "  No  tonic  effect;  no  slowing;  systolic  arrest."  When  the 
tincture  which  had  not  deteriorated  was  used  slowing  and  tonic 
effect  were  observed  and  systolic  arrest  was  caused  by  12.0  c.c.  It 
is  true  that  the  typical  digitalis  action  on  the  frog's  heart  is  early 
slowing  with  the  so-called  1  tonic  effect,'  and  systolic  arrest  is  the 
typical  end  reaction.  However  it  is  not  infrequent  to  see  a  heart 
poisoned  with  digitalis  react  atypically  with  no  slowing,  or  even 
with  acceleration,  and  in  any  case  the  stage  of  slowing  is  usually 
soon  followed  by  one  of  acceleration.  It  is  quite  possible  that 
Moran's  frogs  happened  to  react  atypically,  or  that  the  stage  of 
slowing  was  brief  and  overlooked,  the  heart  passing  into  that  of 
acceleration.    Clark 6  perfused   frog's  hearts   with  digitonin,  the 
8  Medical  Chronicle,  No.  55,  1911-1912,  p.  1. 
*  Brit.  Med.  Jour.,  1912,  II,  p.  687. 
