Amirf vci'  S™' }    Standardization  of  Digitalis  Bodies.  115 
active  specimen  to  be  2.75  times  weaker  than  crystalline  digitoxin, 
while  Weis  also  found  the  drug  very  much  weaker  than  it  is  claimed 
to  be.  In  contrast  with  these  findings  we  were  unable  to  fix  the  dose 
of  the  liquid  preparation  on  frogs  by  the  one  hour  method,  but  by 
extracting  the  amorphous  digitoxin,  so-called,  from  the  tablets  and 
using  it  in  solution  in  saline  we  found  that  the  fatal  dose  per  gram 
of  frog  was  0.0085  mS->  or  that  the  drug  is  of  equal  activity  to 
crystalline  digitoxin.  This  finding  compares  well  with  the  result  of 
tests  of  the  liquid  preparation  by  the  cat  method,  from  which  we 
found  the  most  potent  sample  to  be  almost  identical  in  activity  with 
crystalline  digitoxin. 
It  is  evident  from  these  illustrations,  and  from  others  which 
could  be  cited,  that  the  frog  method  does  not  give  results  which  can 
be  transferred  to  man,  in  the  matter  of  showing  the  relative  activity 
of  different  preparations.  This  fact  was  early  observed  by  Focke, 
the  first  to  suggest  the  use  of  the  frog  and  the  strongest  advocate 
of  the  frog  methods.  He  says,  ''But  the  relative  values  for  the 
different  preparations,  for  example,  Folia  Digitalis  Titrata  and  a 
so-called  digitalis  pure  principle,  found  on  frogs  can  never  be 
transferred  to  man." 
As  to  the  possibilities  offered  by  the  guineapig  method  for  the 
transference  of  the  results  to  man,  they  are  about  the  same  as  with 
the  frog  methods. 
The  cat  method  does,  however,  give  results  with  practically 
all  of  the  members  of  the  series,  which  are  strictly  conformable  to 
the  relative  activities  of  the  several  members  for  man.  Thus,  ouabain 
is  nearly  twice  as  active  on  man  as  is  the  average  specimen  of 
amorphous  strophanthin,  and  is  1.75  times  as  active  on  the  cat.  Of 
course  it  is  to  be  understood  that  this  comparison  is  between  the 
intravenous  doses  in  both  instances,  though  in  both  man  and  cat 
these  two  drugs  show  a  similar  tendency  to  great  irregularities  in 
rate  and  degree  of  absorption  from  the  gastro-intestinal  tract. 
It  has  been  suggested  that,  to  make  allowances  for  the  varia- 
bilities found  in  frogs  from  one  cause  or  another,  each  batch  be 
standardized  against  some  uniform  and  constant  preparation.  Im- 
purities, variation  in  strength  of  different  samples  of  many  of  the 
isolated  glucosides,  and  the  uncertain  keeping  qualities  of  the  crude 
drugs  and  galenical  preparations  have  limited  the  choice  of  the 
drugs  for  this  purpose  to  either  ouabain  or  crystalline  digitoxin. 
In  view  of  the  profound  influence  of  rate  of  absorption  on  the 
results  obtained  by  the  frog  tests,  the  establishment  of  the  reaction 
