530 
Methods  for  Digitalis  Assay. 
Am.  Jour.  Pharm. 
August,  1920. 
to  test  but  really  to  establish  uniformity  in  preparations  of  this  drug. 
Prevost,^  in  1893,  used  frogs  and  chose  as  end-point  the  systolic 
stoppage  of  the  heart. 
Fraenkel,^^  in  1902,  was  the  first  to  apply  this  method,  now  offi- 
cial in  the  U.  S.  P.,^^  as  an  exact  method  for  quantitative  assay,  se- 
lecting one  hour  as  the  time  for  systolic  stoppage. 
Focke,^  in  1902,  and  frequently  at  later  dates,  wrote  on  the  use 
of  frogfs  for  standardizing  digitalis.  He  selected  the  systolic  stop- 
page in  7  to  10  minutes  as  the  end-point  and  suggested  a  formula  by 
which  to  deduce  the  value  from  the  data,  including  the  weight  of 
the  frog,  the  dose  and  the  time  of  systolic  stoppage.  He  has  written 
voluminously  on  the  subject. 
From  this  time  on  no  absolutely  new  method  has  been  devised, 
the  research  being  confined  to  modifications  and  adaptations  of  the 
methods  proposed  by  earlier  workers. 
Such  is  the  Hatcher  Cat  Method,^  the  Reed  and  Vanderkleed 
Guinea  Pig  Method,!^  the  M.  S.  D.  Frog  Heart  Method,ii  and  the 
Pittenger  Gold  Fish  Method,  although  the  latter  is  the  only  pub- 
lished one  using  this  test  object. 
Laying  aside  for  the  moment  the  question  as  to  the  validity 
of  any  of  these  methods,  we  should  attempt  to  consider,  in  a  broad 
way,  the  more  or  less  derisive  question,  "Is  the  sample  of  drug 
that  has  been  found  to  possess  the  greatest  power  to  kill  a  cat,  the 
one  that  will  prove  most  efficient  in  curing  a  man?"  Rusby^^  is 
skeptical  of  such  methods  because  as  a  botanist  he  is  not  fully  in- 
formed as  to  their  applicability. 
Lloyd, perhaps  for  the  same  reason,  says  in  reference  to  a 
toxicity  experiment  recorded  by  Withering:  "In  those  days  of 
heroic  medication  it  was  naturally  concluded  that  a  drug  that  could 
thus  kill  a  turkey  must  be  good  medicine  to  cure  a  human  being, 
a  process  of  reasoning  not  yet  altogether  obsolete." 
Beal,^^  with  no  circumlocution  but  directly  to  the  point,  says: 
"If  we  would  know  the  physiologic  action  of  a  drug  upon  the  human 
we  must  observe  its  action  on  the  human,  this  cannot  be  deduced 
with  any  degree  of  certainty  by  its  action  on  one  of  the  lower  animals." 
All  these  comments  are  based  on  a  wrong  conception  of  phar- 
macology. While  there  are  occasional  instances  where  the  action 
of  a  drug  on  one  animal  differs  fundamentally  from  that  on  another 
or  on  a  human,  such  anomalies  are  usually  traceable  to  fundamental 
differences  in  the  two  species.    To  illustrate,  the  cat  and  dog  vomit 
