646  United  States  Pharmacopoeial  Revision.  { ^Spimher!'^ 920! 
tion  of  Cannabis  conforms  to  the  requirements  of  the  U  S.  Pharma- 
copoeia. 
Aconite. — The  proposed  "time  Umit"  of  twelve  hours  is  very 
objectionable  as  this  means  twelve  hours  after  the  pigs  are  injected. 
When  you  add  to  this  the  time  of  weighing  animals,  preparing  solu- 
tions for  injections,  making  injections,  etc.,  the  test  consumes  thir- 
teen hours,  which  cannot  be  included  in  the  ordinary  working  day 
and  makes  a  rather  long  week  for  men  employed  in' laboratories 
which  run  these  assays  almost  daily.  We  would  suggest  a  twenty 
four  hour  "time-limit." 
Pittenger,  by  recording  the  results  obtained  by  using  twenty- 
three  and  twenty-four  hours  as  a  "time  limit,"  proved  that  the  most 
concordant  results  are  obtained  by  using  twenty-four  hours  as  the 
"time  limit."  We  do  not  doubt  that  a  twelve-hour  method  would 
be  just  as  accurate  as  the  twenty-four  hour  method,  but  it  is  very 
objectionable  for  the  reason  stated. 
We  recommend  that  Gelsemium  and  Veratrum  also  be  assayed 
by  the  Guinea  Pig  Method. 
We  cannot  too  strongly  recommend  that  the  biologic  assay  for 
Aconite  be  made  compulsory  instead  of  the  chemical  assay,  for  while 
we  agree  that  the  chemical  assay  is  a  very  accurate  determination 
of  the  alkaloidal  content  of  Aconite,  it  is  not  nearly  as  good  an  index 
of  the  therapeutic  value  of  the  drug  or  its  preparations,  as  the  phar- 
macodynamic test,  as  it  has  been  definitely  proven  by  many  workers 
that  the  results  of  the  present  chemical  assay  do  not  parallel  the 
therapeutic  activity  of  the  drug. 
In  other  words,  it  often  happens  that  a  preparation  of  Aconite 
will  run  high  in  the  chemical  test  and  low  in  the  physiologic  test, 
due  to  the  fact  that  a  chemical  assay  does  not  express  the  true  ac- 
tivity of  the  drug  because  it  also  estimates  other  alkaloids  of  lower 
activity  than  Aconitine. 
This  discrepancy  between  the  two  tests  is  easily  understood  when 
the  nature  of  Aconitine  is  considered  and  it  is  realized  how  the  acetyl 
and  benzyl  groups  are  split  off,  thus  reducing  the  physiologic  ac- 
tivity of  the  product  without  destroying  its  alkaloidal  nature,  and 
allowing  it  to  still  be  estimated  as  an  alkaloid  in  the  chemical  assay 
process. 
The  present  Pharmacopoeia  makes  the  chemical  test  compulsory 
and  at  the  same  time  recommends  that  the  drug  be  assayed  by  the 
pharmacodynamic  method.    For  the  reason  stated  above,  it  i& 
