Am.  Jour  .  Pharm.  ) 
August ,  1910.  J 
Standardisation  of  Drugs. 
361 
express  the  belief  that  many  hundreds  of  patients  die  annually 
from  digitalis  and  allies  not  possessing  the  virtues  required  of 
them."  To  the  foregoing  we  would  add  that  we  are  equally  con- 
vinced that  the  want  of  precise  methods  of  dosage  is  responsible  for 
many  cases  of  poisoning  with  digitalis,  and  it  is  with  this  group  of 
drugs  that  we  have  been  engaged  for  the  most  part. 
We  are  aware  that  many  will  raise  the  objection  that  the  details 
of  biologic  assays  are  of  little  more  than  theoretical  importance  to  the 
retail  pharmacist  because  he  is  unable  to  conduct  these  operations. 
We  believe  that  the  progressive  pharmacist  must  be  prepared  to 
make  the  simple  biologic  tests  at  least,  if  he  is  to  pretend  to  keep 
pace  with  the  progress  of  his  profession,  and  it  is  our  purpose  to  out- 
line the  technic  of  our  method,  which  is  so  simple  that  it  may 
be  mastered  by  the  retail  pharmacist,  and  conducted  with  the  appara- 
tus which  he  has  at  hand. 
H.  C.  Wood,  Jr.,  has  recently  sought  to  convey  the  impression 
that  it  is  hopeless  to  expect  any  degree  of  precision  by  means  of  the 
test  on  animals  even  when  it  is  conducted  by  the  trained  pharmacolo- 
gist. Wood  says :  "  And  first  I  shall  speak  of  its  limitations.  We 
sometimes  read  of  the  physiological  test  being  used  as  a  control  of 
the  chemical  assay.  To  attempt  to  corroborate  the  findings  of  the 
chemist  by  a  test  on  the  living  animal  is  about  as  sensible  as  it  would 
be  for  a  navigator  to  regulate  his  chronometer  by  an  Ingersoll  watch  ; 
the  relative  accuracy  of  the  chemical  and  physiological  assay  is  about 
the  same  as  that  of  the  $200  chronometer  and  the  dollar  watch." 
To  this  statement  we  wish  to  enter  certain  exceptions. 
Method. — The  method  of  standardization  which  we  have  chosen 
for  the  digitalis  group  and  some  other  drugs,  consists  in  determining 
the  minimal  fatal  dose  per  kg.  of  cat  when  the  drug  is  injected  slowly 
into  the  femoral  vein,  the  standard  chosen  for  the  digitalis  group 
being  the  cat  unit. 
The  cat  unit  may  be  defined  most  accurately  perhaps,  as  the 
amount  of  crystalline  ouabain  1  which  is  fatal  within  about  ninety 
minutes  to  a  kilogramme  of  cat  when  the  drug  is  injected  slowly 
and  almost  continuously  into  the  femoral  vein.  A  cat  unit  is  equal 
to  almost  precisely  0.1  mg.  of  crystalline  ouabain,  or  one  ten- 
millionth  of  the  weight  of  the  animal. 
1  The  older  term  ouabain  is  to  be  preferred  to  that,  of  crystalline  strophan- 
thin  which  has  lead  to  much  confusion. 
