THE  AMERICAN 
JOURNAL  OF  PHARMACY 
JANUARY,  1902. 
ON  THE  PHARMACOLOGICAL  ASSAY  OF  DRUGS. 
By  Arthur  R.  Cushny, 
Professor  of  Materia  Medica  in  the  University  of  Michigan. 
It  has  long  been  a  commonplace  observation  that  the  galenical 
preparations  of  drugs  vary  in  their  therapeutic  efficiency,  and 
increasing  familiarity  with  the  chemistry  of  plants  has  shown  this 
to  be  due  to  variations  in  the  amount  of  the  active  principles.  This 
variation  is  often  of  little  importance  from  the  point  of  view  of  the 
practitioner,  while  in  other  cases  its  gravity  can  scarcely  be  exag- 
gerated. The  pharmacopoeias  have  accordingly  attempted  in  recent 
years  to  exclude  preparations  which  depart  markedly  from  the 
standard  strength ;  for  example  the  last  edition  of  the  United  States 
Pharmacopoeia  gave  directions  for  the  assay  of  opium,  r  ux  vomica 
and  cinchona  and  of  some  of  their  preparations.  This  is  undoubt- 
edly a  step  in  the  right  direction,  for  no  one  can  fail  to  recognize 
the  necessity  of  standardizing  within  reasonable  limits  the  strength 
of  a  preparation  so  widely  used  as  laudanum.  The  necessity  for 
the  assay  of  cinchona  and  mix  vomica  is  not  quite  so  apparent,  it  is 
true,  for  the  galenical  preparations  of  these  drugs  are  comparatively 
seldom  used  except  to  elicit  their  local  "  bitter "  action,  the  pure 
alkaloids  being  usually  prescribed  when  the  effects  in  the  blood 
and  central  nervous  system  are  desired ;  that  is,  when  there  is  even 
a  remote  probability  of  poisonous  symptoms  being  induced.  Still, 
any  tendency  toward  a  uniformity  in  strength  is  to  be  greeted  as 
an  important  advance  from  the  estimation  of  the  strength  by  the 
amount  of  the  crude  drug  employed.  So  far  the  chemical  assays 
directed  by  the  pharmacopoeia  have  embraced  in  the  vegetable 
(1) 
