AlMarchr"moarm'}        Physiological  Standardization.  103 
From  external  conditions  which  affect  the  result  it  is  easier  to 
protect  ourselves  if  we  but  know  those  which  are  likely  to  influence 
the  effect  of  the  drug  under  study.  The  difference  in  the  suscepti- 
bility of  frogs  to  many  poisons  in  summer  and  winter  is  well  known. 
Edmunds  and  Hale  have  conclusively  shown  the  importance  of  this 
in  the  assay  of  digitalis,  and  my  own  experience  has  convinced  me 
of  the  futility  of  hoping  for  accuracy  in  the  assay  of  ergot  on  a  hot 
summer  day.  There  are  many  other  circumstances  whose  impor- 
tance may  be  great  but  of  which  we  know  but  little,  as  age,  sex, 
breed,  nourishment,  etc.  The  difficulties  arising  from  imperfect 
absorption,  from  the  presence  of  antagonistic  principles  in  crude 
drugs,  of  the  perversities  of  inanimate  objects,  and  similar  technical 
obstacles  I  shall  not  occupy  your  time  in  discussing.  I  wish  to 
emphasize,  however,  that  even  with  the  utmost  care  and  with  fre- 
quently repeated  experiments  we  must  be  prepared  for  an  error  of 
from  10  to  15  per  cent,  or  even  more. 
Believing  as  I  do  that  the  biological  assay  is  less  accurate,  more 
difficult,  and  often  more  costly,  I  cannot  see  how  it  can  hope  to 
compete  with  the  chemical  as  a  routine  means  of  standardization. 
But  when  we  recall  that  there  are  over  a  hundred  crude  vegetable 
drugs,  including  some  of  our  most  potent  poisons,  recognized  by 
the  Pharmacopoeia,  for  which  we  have  no  official  process  of  assay, 
it  is  evident  that  there  is  need  for  a  subsidiary  method  of  determin- 
ing the  comparative  activity  of  our  materia  medica.  It  is  probable 
that  for  some  of  these  a  chemical  test  will  be  provided  in  the  next 
edition  of  that  magnificent  work  which  stands  as  incontrovertable 
evidence  that  in  certain  lines,  at  least,  the  sister  professions  of 
America  are  second  to  none  in  the  world,  but  for  many  of  these 
substances  there  is  little  hope  that  any  reliable  chemical  test  will  be 
devised  in  the  near  future.  Some  of  them  are  as  unsuited  for  the 
pharmacologist  as  they  are  for  the  chemist,  but  many  of  them,  and 
especially  the  more  powerful  ones,  should  lend  themselves  compara- 
tively readily  to  the  physiological  assay.  Among  those  which  seem 
pre-eminently  suitable  for  biological  standardization  I  may  mention 
such  important  remedies  as  digitalis,  squill,  apocynum,  aspidium, 
cannabis  indica,  ergot,  gelsemium,  lobelia,  and  veratrum,  etc.  If  I 
can  show  you  that  the  pharmacologist  is  able  to  solve  many  of  the 
vexatious  pharmaceutical  problems  that  cling  to  these  drugs,  will 
you  not  grant  me  that  he  is  worthy  your  most  earnest  encourage- 
ment in  his  work? 
