Am'ju°]y"'ifohsfrm'}     Notes  on  "Physiological  Testing."  331 
talis  preparations  does  not  correspond  to  the  toxicity  of  the  digitoxin 
present,  and  experiments  on  dogs  show  a  similar  disagreement.1 
Vanderkleed,  however,  claims  some  degree  of  parallelism  between 
the  digitoxin  content  and  the  toxicity  of  digitalis  on  guinea  pigs. 
The  weight  of  evidence,  however,  is  that  digitalis  leaves  do  not  owe 
their  activity  to  any  one  yet  discovered  principle. 
These  preparations  are  usually  standardized  by  merely  determining 
their  toxicity  on  frogs.  Houghton  has  reported  in  the  National  Stand- 
ard Dispensatory  the  method  of  performing  this  test.  He  used  the 
normal  lethal  dose  of  o-ooi  5  gramme  per  gramme  frog  for  the  fluidex- 
tract  digitalis  and  0*00015  gramme  for  the  fluidextract  strophanthus, 
o*oi  1  gramme  for  fluidextract  squills.  Haynes  used  as  his  standard 
that  2y2  minims  of  a  tincture  of  digitalis  should  kill  a  frog  of  20 
grammes  weight  in  three  hours,  while  minim  of  tincture  of  stro- 
phanthus should  kill  a  frog  weighing  17  grammes.  Others,  again,  re- 
cognizing that  the  characteristic  action  of  this  group  is  the  systolic 
stoppage  of  the  frog  heart,  have  demanded  that  the  preparation  be 
standardized  with  reference  to  the  quantity  which  shall  cause  sys- 
tolic stoppage  of  the  ventricle  within  a  certain  period,  some  say  twenty 
minutes,  some  an  hour  or  more.2  Famulener  and  Lyons,  in  the 
Proceedings  of  the  American  Pharmaceutical  Association  for  1902, 
have  described  this  method  in  full.  The  exact  period  at  which  sys- 
tolic stoppage  occurs  is  at  times  hard  to  decide.3  In  none  of 
the  work,  as  far  as  I  have  been  able  to  find,  is  there  any  accurate 
description  of  the  frogs  used.  In  fact,  the  old  classification  of  frogs 
is  very  unreliable,  and  frogs  vary  so  much  in  their  response  to  drugs 
1  Wood,  H.  C,  Jr.  Does  Digitoxin  Represent  the  Therapeutic  Virtues  of 
Digitalis?    Amer.  Jour.  Pharm.,  1908,  p.  107. 
2Ziegenbein,  H.  Werthbestimmung  der  Digitalisblatter.  Arch.  d.  Pharm., 
1902,  vol.  1,  p.  454. 
Biihrer,  C.  TJeber  d.  Grenzen  d.  Wirksamkeit  einiger  toxisch.  Fluidex- 
tracte.  Corresp.  d.  Schweizer  Aerzte,  1900,  Vol.  30,  p.  617.  Siebert.  Werth- 
bestimmung von  Digitalis  und  Strophanthus  durch  Priifung  an  Froschherz. 
Berl.klin.  Woch.,  Vol.  40,  p.  813.  1903.  Dixon,  W.  E.  Bio-Chemical  Stand- 
ardization of  Drugs.  Pharm,  Jour.,  Vol.  75,  p.  156.  1905.  Focke,  C.  Die 
physiol.  Werthbestimmung  d.  Digitalisblatter.  Arch.  d.  Pharm.,  Vol.  241,  p. 
128.  1903;  Ueber  den  gleichmassig.  Wirkungswert  von  gut  praparirtem  und  gut 
aufbewahrtem  Digitalisblatterpulver.  Ther.  d.  Gegenw.,  1904,  p.  250;  Zur 
physiol.  Wertheinstellung  d.  Digitalisblatter.    Ther.  d.  Gegenw.,  1904,  p.  527. 
3  Wang,  B.  Werthbestimmung  d.  Digitalisblatter.  Festschrift  Olof  Ham- 
marsten  gewidmet.    Upsala,  1906,  p.  7. 
